Steve Meek, Francis Morris
ABC of clinical electrocardiography.Introduction. I-Leads, rate, rhythm, and cardiac axis.
BMJ. 2002 Feb 16;324(7334):415-8.
Abstract/Text
Frank Bogun, Daejoon Anh, Gautham Kalahasty, Erik Wissner, Chadi Bou Serhal, Rabih Bazzi, W Douglas Weaver, Claudio Schuger
Misdiagnosis of atrial fibrillation and its clinical consequences.
Am J Med. 2004 Nov 1;117(9):636-42. doi: 10.1016/j.amjmed.2004.06.024.
Abstract/Text
PURPOSE: Computer algorithms are often used for cardiac rhythm interpretation and are subsequently corrected by an overreading physician. The purpose of this study was to assess the incidence and clinical consequences of misdiagnosis of atrial fibrillation based on a 12-lead electrocardiogram (ECG).
METHODS: We retrieved 2298 ECGs with the computerized interpretation of atrial fibrillation from 1085 patients. The ECGs were reinterpreted to determine the accuracy of the interpretation. In patients in whom the interpretation was incorrect, we reviewed the medical records to assess the clinical consequences resulting from misdiagnosis.
RESULTS: We found that 442 ECGs (19%) from 382 (35%) of the 1085 patients had been incorrectly interpreted as atrial fibrillation by the computer algorithm. In 92 patients (24%), the physician ordering the ECG had failed to correct the inaccurate interpretation, resulting in change in management and initiation of inappropriate treatment, including antiarrhythmic medications and anticoagulation in 39 patients (10%), as well as unnecessary additional diagnostic testing in 90 patients (24%). A final diagnosis of paroxysmal atrial fibrillation based on the initial incorrect interpretation of the ECGs was generated in 43 patients (11%).
CONCLUSION: Incorrect computerized interpretation of atrial fibrillation, combined with the failure of the ordering physician to correct the erroneous interpretation, can result in the initiation of unnecessary, potentially harmful medical treatment as well as inappropriate use of medical resources. Greater efforts should be directed toward educating physicians about the electrocardiographic appearance of atrial dysrhythmias and in the recognition of confounding artifacts.
J C Roos, A J Dunning
Right bundle-branch block and left axis deviation in acute myocardial infarction.
Br Heart J. 1970 Nov;32(6):847-51.
Abstract/Text
Of 114 patients with acute myocardial infarction admitted consecutively to a coronary care unit, 10 had recent antero-septal myocardial infarction associated with right bundle-branch block and obvious left axis deviation, and I had recent antero-septal myocardial infarction with right bundle-branch block and right axis deviation. Attention is drawn to the high mortality (7 out of 11 patients), due mainly to cardiogenic shock. Frequent complications were sudden complete heart block (5 patients) and ventricular asystole (4 patients) without previous lengthening of the atrioventricular conduction time. An external on-demand pacemaker was inserted in 10 patients, and no patient died of complete heart block or ventricular asystole.
R Childers, S Lupovich, M Sochanski, H Konarzewska
Left bundle branch block and right axis deviation: a report of 36 cases.
J Electrocardiol. 2000;33 Suppl:93-102.
Abstract/Text
Right axis deviation (RAD) with left bundle branch block (LBBB) is a rare combination. From a database of 636,000 electrocardiograms we report a series of 36 patients with this disorder. The majority of subjects had dilated cardiomyopathy with biventricular enlargement. LBBB was fixed in 21 of 36 cases. It was freshly acquired, episodic, intermittent, or physiologic in 15 of 36. The RAD was episodic in 30 of 36; it was fixed and concurrent with LBBB in only 2 cases, and never episodically concurrent. Reported for the first time here were 4 of 36 cases in which the combination of LBBB and RAD was elicited with atrial premature impulses as a rare form of QRS aberration. In one case where the combination was intermittent, a clear relationship with freshly acquired intermittent posterior fascicular block was demonstrated. The possible relationship of the deviation with variable degrees of right ventricular overload is discussed.
Steve Meek, Francis Morris
Introduction. II--basic terminology.
BMJ. 2002 Feb 23;324(7335):470-3.
Abstract/Text
Yasuyuki Nakamura, Tomonori Okamura, Aya Higashiyama, Makoto Watanabe, Aya Kadota, Takayoshi Ohkubo, Katsuyuki Miura, Fumiyoshi Kasagi, Kazunori Kodama, Akira Okayama, Hirotsugu Ueshima, NIPPON DATA80 Research Group
Prognostic values of clockwise and counterclockwise rotation for cardiovascular mortality in Japanese subjects: a 24-year follow-up of the National Integrated Project for Prospective Observation of Noncommunicable Disease and Its Trends in the Aged, 1980-2004 (NIPPON DATA80).
Circulation. 2012 Mar 13;125(10):1226-33. doi: 10.1161/CIRCULATIONAHA.111.070045. Epub 2012 Feb 3.
Abstract/Text
BACKGROUND: Although clockwise rotation and counterclockwise rotation are distinct findings of the ECG, their prognostic significance is rarely studied.
METHODS AND RESULTS: We studied prognostic values of clockwise and counterclockwise rotation on total, cardiovascular disease (CVD), and subtype mortality using the National Integrated Project for Prospective Observation of Noncommunicable Disease and Its Trends in the Aged, 1980-2004 (NIPPON DATA80) database with a 24-year follow-up. At baseline in 1980, data were collected on study participants aged ≥30 years from randomly selected areas in Japan. We followed 9067 participants (44% men; mean age, 51 years). During the 24-year follow-up, mortality was as follows: 2581 total, 887 CVD, 179 coronary heart disease, 173 heart failure, and 411 stroke. The multivariate-adjusted hazard ratio (HR) with the use of the Cox model including biochemical and other ECG variables revealed that clockwise rotation was significantly positively associated with heart failure in men and women combined (HR=1.79; 95% confidence interval [CI], 1.13-2.83; P=0.013), CVD in men and in men and women combined (HR=1.49; 95% CI, 1.12-1.98; P=0.007 in men; HR=1.28; 95% CI, 1.02-1.59; P=0.030 in combined), and total mortality in men and in men and women combined (HR=1.19; 95% CI, 1.00-1.49; P=0.0496 in men; HR=1.15; 95% CI, 1.00-1.32; P=0.045 in combined). Counterclockwise rotation was significantly inversely associated stroke in men and women combined (HR=0.77; 95% CI, 0.62-0.96; P=0.017), CVD in men and in men and women combined (HR=0.74; 95% CI, 0.59-0.94; P=0.011 in men; HR=0.81; 95% CI, 0.70-0.94; P=0.006 in combined), and total mortality in women (HR=0.87; 95% CI, 0.77-0.98; P=0.023).
CONCLUSIONS: We found a significant positive association of clockwise rotation and a significant inverse association of counterclockwise rotation with CVD mortality in men and in men and women combined, independent of confounding factors including other ECG changes.
Galen S Wagner, Peter Macfarlane, Hein Wellens, Mark Josephson, Anton Gorgels, David M Mirvis, Olle Pahlm, Borys Surawicz, Paul Kligfield, Rory Childers, Leonard S Gettes, James J Bailey, Barbara J Deal, Anton Gorgels, E William Hancock, Jan A Kors, Jay W Mason, Peter Okin, Pentti M Rautaharju, Gerard van Herpen, American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology, American College of Cardiology Foundation, Heart Rhythm Society
AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part VI: acute ischemia/infarction: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology.
J Am Coll Cardiol. 2009 Mar 17;53(11):1003-11. doi: 10.1016/j.jacc.2008.12.016.
Abstract/Text
Jani T Tikkanen, M Juhani Junttila, Olli Anttonen, Aapo L Aro, Samuli Luttinen, Tuomas Kerola, Solomon J Sager, Harri A Rissanen, Robert J Myerburg, Antti Reunanen, Heikki V Huikuri
Early repolarization: electrocardiographic phenotypes associated with favorable long-term outcome.
Circulation. 2011 Jun 14;123(23):2666-73. doi: 10.1161/CIRCULATIONAHA.110.014068. Epub 2011 May 31.
Abstract/Text
BACKGROUND: Early repolarization (ER) in inferior/lateral leads of standard ECGs increases the risk of arrhythmic death. We tested the hypothesis that variations in the ST-segment characteristics after the ER waveforms may have prognostic importance.
METHODS AND RESULTS: ST segments after ER were classified as horizontal/descending or rapidly ascending/upsloping on the basis of observations from 2 independent samples of young healthy athletes from Finland (n=62) and the United States (n=503), where ascending type was the dominant and common form of ER. Early repolarization was present in 27/62 (44%) of the Finnish athletes and 151/503 (30%) of the US athletes, and all but 1 of the Finnish (96%) and 91/107 (85%) of US athletes had an ascending/upsloping ST variant after ER. Subsequently, ECGs from a general population of 10 864 middle-aged subjects were analyzed to assess the prognostic modulation of ER-associated risk by ST-segment variations. Subjects with ER ≥0.1 mV and horizontal/descending ST variant (n=412) had an increased hazard ratio of arrhythmic death (relative risk 1.43; 95% confidence interval 1.05 to 1.94). When modeled for higher amplitude ER (>0.2 mV) in inferior leads and horizontal/descending ST-segment variant, the hazard ratio of arrhythmic death increased to 3.14 (95% confidence interval 1.56 to 6.30). However, in subjects with ascending ST variant, the relative risk for arrhythmic death was not increased (0.89; 95% confidence interval 0.52 to 1.55).
CONCLUSIONS: ST-segment morphology variants associated with ER separates subjects with and without an increased risk of arrhythmic death in middle-aged subjects. Rapidly ascending ST segments after the J-point, the dominant ST pattern in healthy athletes, seems to be a benign variant of ER.
Michel Haïssaguerre, Nicolas Derval, Frederic Sacher, Laurence Jesel, Isabel Deisenhofer, Luc de Roy, Jean-Luc Pasquié, Akihiko Nogami, Dominique Babuty, Sinikka Yli-Mayry, Christian De Chillou, Patrice Scanu, Philippe Mabo, Seiichiro Matsuo, Vincent Probst, Solena Le Scouarnec, Pascal Defaye, Juerg Schlaepfer, Thomas Rostock, Dominique Lacroix, Dominique Lamaison, Thomas Lavergne, Yoshifusa Aizawa, Anders Englund, Frederic Anselme, Mark O'Neill, Meleze Hocini, Kang Teng Lim, Sebastien Knecht, George D Veenhuyzen, Pierre Bordachar, Michel Chauvin, Pierre Jais, Gaelle Coureau, Genevieve Chene, George J Klein, Jacques Clémenty
Sudden cardiac arrest associated with early repolarization.
N Engl J Med. 2008 May 8;358(19):2016-23. doi: 10.1056/NEJMoa071968.
Abstract/Text
BACKGROUND: Early repolarization is a common electrocardiographic finding that is generally considered to be benign. Its potential to cause cardiac arrhythmias has been hypothesized from experimental studies, but it is not known whether there is a clinical association with sudden cardiac arrest.
METHODS: We reviewed data from 206 case subjects at 22 centers who were resuscitated after cardiac arrest due to idiopathic ventricular fibrillation and assessed the prevalence of electrocardiographic early repolarization. The latter was defined as an elevation of the QRS-ST junction of at least 0.1 mV from baseline in the inferior or lateral lead, manifested as QRS slurring or notching. The control group comprised 412 subjects without heart disease who were matched for age, sex, race, and level of physical activity. Follow-up data that included the results of monitoring with an implantable defibrillator were obtained for all case subjects.
RESULTS: Early repolarization was more frequent in case subjects with idiopathic ventricular fibrillation than in control subjects (31% vs. 5%, P<0.001). Among case subjects, those with early repolarization were more likely to be male and to have a history of syncope or sudden cardiac arrest during sleep than those without early repolarization. In eight subjects, the origin of ectopy that initiated ventricular arrhythmias was mapped to sites concordant with the localization of repolarization abnormalities. During a mean (+/-SD) follow-up of 61+/-50 months, defibrillator monitoring showed a higher incidence of recurrent ventricular fibrillation in case subjects with a repolarization abnormality than in those without such an abnormality (hazard ratio, 2.1; 95% confidence interval, 1.2 to 3.5; P=0.008).
CONCLUSIONS: Among patients with a history of idiopathic ventricular fibrillation, there is an increased prevalence of early repolarization.
Copyright 2008 Massachusetts Medical Society.
Aapo L Aro, Olli Anttonen, Jani T Tikkanen, M Juhani Junttila, Tuomas Kerola, Harri A Rissanen, Antti Reunanen, Heikki V Huikuri
Prevalence and prognostic significance of T-wave inversions in right precordial leads of a 12-lead electrocardiogram in the middle-aged subjects.
Circulation. 2012 May 29;125(21):2572-7. doi: 10.1161/CIRCULATIONAHA.112.098681. Epub 2012 May 10.
Abstract/Text
BACKGROUND: T-wave inversion in right precordial leads V(1) to V(3) is a relatively common finding in a 12-lead ECG of children and adolescents and is infrequently found also in healthy adults. However, this ECG pattern can also be the first presentation of arrhythmogenic right ventricular cardiomyopathy. The prevalence and prognostic significance of T-wave inversions in the middle-aged general population are not well known.
METHODS AND RESULTS: We evaluated 12-lead ECGs of 10 899 Finnish middle-aged subjects (52% men, mean age 44 ± 8.5 years) recorded between 1966 and 1972 for the presence of inverted T waves and followed the subjects for 30 ± 11 years. Primary end points were all-cause mortality, cardiac mortality, and arrhythmic death. T-wave inversions in right precordial leads V(1) to V(3) were present in 54 (0.5%) of the subjects. In addition, 76 (0.7%) of the subjects had inverted T waves present only in leads other than V(1) to V(3). Right precordial T-wave inversions did not predict increased mortality (not significant for all end points). However, inverted T waves in leads other than V(1) to V(3) were associated with an increased risk of cardiac and arrhythmic death (P<0.001 for both).
CONCLUSIONS: T-wave inversions in right precordial leads are relatively rare in the general population, and are not associated with adverse outcome. Increased mortality risk associated with inverted T waves in other leads may reflect the presence of an underlying structural heart disease.
M Malik, P Färbom, V Batchvarov, K Hnatkova, A J Camm
Relation between QT and RR intervals is highly individual among healthy subjects: implications for heart rate correction of the QT interval.
Heart. 2002 Mar;87(3):220-8.
Abstract/Text
OBJECTIVE: To compare the QT/RR relation in healthy subjects in order to investigate the differences in optimum heart rate correction of the QT interval.
METHODS: 50 healthy volunteers (25 women, mean age 33.6 (9.5) years, range 19-59 years) took part. Each subject underwent serial 12 lead electrocardiographic monitoring over 24 hours with a 10 second ECG obtained every two minutes. QT intervals and heart rates were measured automatically. In each subject, the QT/RR relation was modelled using six generic regressions, including a linear model (QT = beta + alpha x RR), a hyperbolic model (QT = beta + alpha/RR), and a parabolic model (QT = beta x RR(alpha)). For each model, the parallelism and identity of the regression lines in separate subjects were statistically tested.
RESULTS: The patterns of the QT/RR relation were very different among subjects. Regardless of the generic form of the regression model, highly significant differences were found not only between the regression lines but also between their slopes. For instance, with the linear model, the individual slope (parameter alpha) of any subject differed highly significantly (p < 0.000001) from the linear slope of no fewer than 21 (median 32) other subjects. The linear regression line of 20 subjects differed significantly (p < 0.000001) from the linear regression lines of each other subject. Conversion of the QT/RR regressions to QTc heart rate correction also showed substantial intersubject differences. Optimisation of the formula QTc = QT/RR(alpha) led to individual values of alpha ranging from 0.234 to 0.486.
CONCLUSION: The QT/RR relation exhibits a very substantial intersubject variability in healthy volunteers. The hypothesis underlying each prospective heart rate correction formula that a "physiological" QT/RR relation exists that can be mathematically described and applied to all people is incorrect. Any general heart rate correction formula can be used only for very approximate clinical assessment of the QTc interval over a narrow window of resting heart rates. For detailed precise studies of the QTc interval (for example, drug induced QT interval prolongation), the individual QT/RR relation has to be taken into account.
J M Kwok, T D Miller, T F Christian, D O Hodge, R J Gibbons
Prognostic value of a treadmill exercise score in symptomatic patients with nonspecific ST-T abnormalities on resting ECG.
JAMA. 1999 Sep 15;282(11):1047-53.
Abstract/Text
CONTEXT: Exercise testing of patients with ST-T abnormalities on the resting electrocardiogram (ECG) is problematic because in the presence of pre-existing ST-T abnormalities, the exercise test is less specific for the diagnosis of coronary artery disease. The prognostic capability of the Duke treadmill score in patients with ST-T abnormalities vs those with normal findings on resting ECG has, to our knowledge, not been evaluated.
OBJECTIVE: To compare the prognostic accuracy of the Duke treadmill score in patients with nonspecific ST-T abnormalities vs those with normal results on resting ECG.
DESIGN: Inception cohort study with 7 years of follow-up.
SETTING: Nuclear cardiology laboratory of a US referral center.
PATIENTS: All symptomatic patients who underwent exercise thallium testing between 1989 and 1991,939 of whom had nonspecific ST-T abnormalities and 1466 of whom had normal findings on resting ECG. Exclusion criteria included congenital, valvular, or cardiomyopathic heart disease; prior coronary artery revascularization; resting ECG with secondary ST-T abnormalities; or missing data.
MAIN OUTCOME MEASURES: Rates of overall mortality and cardiac death for subjects classified by Duke treadmill score risk group.
RESULTS: For the end point cardiac death, 7-year survival in the study population in the low-, intermediate-, and high-risk groups was 97%, 92%, and 76%, respectively (P<.001). Compared with the control group, the study group had lower 7-year survival (94% vs 98%; P<.001), fewer low-risk patients (426 [45%] vs 811 [55%]; P<.001) with worse 7-year survival (97% vs 99%; P= .008), and more high-risk patients (49 [5%] vs 34 [2%];P<.001) with a nonsignificant trend toward worse 7-year survival (76% vs 93%; P= .36).
CONCLUSIONS: The Duke treadmill score can effectively risk-stratify patients with ST-T abnormalities on the resting ECG. In classified risk categories, patients with ST-T abnormalities have a worse prognosis than those with normal results on resting ECG.
循環器病の診断と治療に関するガイドライン（2007−2008年度合同研究班報告）冠動脈病変の非侵襲的診断法に関するガイドライン.
Guidelines for noninvasive diagnosis of coronary artery lesions (JCS 2009). Circ J 2009;73:1019-1089.
R J Gibbons, G J Balady, J W Beasley, J T Bricker, W F Duvernoy, V F Froelicher, D B Mark, T H Marwick, B D McCallister, P D Thompson, W L Winters, F G Yanowitz, J L Ritchie, R J Gibbons, M D Cheitlin, K A Eagle, T J Gardner, A Garson, R P Lewis, R A O'Rourke, T J Ryan
ACC/AHA Guidelines for Exercise Testing. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Exercise Testing).
J Am Coll Cardiol. 1997 Jul;30(1):260-311.
Abstract/Text
Jonathan Myers, Ross Arena, Barry Franklin, Ileana Pina, William E Kraus, Kyle McInnis, Gary J Balady, American Heart Association Committee on Exercise, Cardiac Rehabilitation, and Prevention of the Council on Clinical Cardiology, the Council on Nutrition, Physical Activity, and Metabolism, and the Council on Cardiovascular Nursing
Recommendations for clinical exercise laboratories: a scientific statement from the american heart association.
Circulation. 2009 Jun 23;119(24):3144-61. doi: 10.1161/CIRCULATIONAHA.109.192520. Epub 2009 Jun 1.
Abstract/Text
S M Zeldis, B J Levine, E L Michelson, J Morganroth
Cardiovascular complaints. Correlation with cardiac arrhythmias on 24-hour electrocardiographic monitoring.
Chest. 1980 Sep;78(3):456-61.
Abstract/Text
Long-term ambulatory electrocardiographic (Holter) monitoring is frequently used to evaluate patients with various cardiovascular complaints, including palpitations, dyspnea, discomfort in the chest, dizziness, and syncope. In the present study, 518 consecutive 24-hour electrocardiographic recordings were reviewed to determine correlations between cardiac diagnoses, presenting complaints, and specific electrocardiographic abnormalities. Two hundred seventy-four patients (53 percent) had significant arrhythmias; 212 (41 percent) had significant ventricular arrhythmias, and 106 (20 percent) significant atrial arrhythmias, including 44 patients (8 percent) with both. No presenting complaint or cardiovascular diagnosis correlated closely with any specific cardiac arrhythmia. Major arrhythmias, including supraventricular and ventricular tachycardias, often occurred asymptomatically (in 44/54 and 37/40 patients, respectively); however, among 371 patients with accurate historic logs, only 176 (47 percent) had long-term electrocardiographic studies in which their typical symptoms occurred during the monitoring period. Fifty (13 percent) of the 371 patients had concurrence of their presenting complaints with an arrhythmia, and 126 patients (34 percent) had their typical symptoms associated with a normal electrocardiogram, which was helpful in excluding an abnormality of rhythm or conduction as the primary cause for their complaints.
E B Bass, E I Curtiss, V C Arena, B H Hanusa, A Cecchetti, M Karpf, W N Kapoor
The duration of Holter monitoring in patients with syncope. Is 24 hours enough?
Arch Intern Med. 1990 May;150(5):1073-8.
Abstract/Text
To determine the incremental yield of ambulatory monitoring in the evaluation of syncope, three serial 24-hour Holter recordings were obtained in a consecutive series of 95 patients with syncope, the cause of which was not explained by history, physical examination, or 12-lead electrocardiogram. The mean age of patients was 61 years and 41% were men. Major electrocardiographic abnormalities were found in 26 patients (27%), including unsustained ventricular tachycardia (19 patients), pauses of at least 2 seconds (8 patients), profound bradycardia (1 patient), and complete heart block (1 patient). The first 24-hour Holter recording had at least one major abnormality in 14 patients (15%) (95% confidence interval, 8.3% to 23.4%). Of the 81 patients without a major abnormality on the first Holter recording, the second Holter recording had major abnormalities in 9 (11%) (95% confidence interval, 5.1% to 20.0%). Of the 72 patients without a major abnormality on the first two Holter recordings, only 3 patients (4.2%) had a major abnormality on the third Holter recording (95% confidence interval, 0.8% to 11.7%). Four factors were significantly associated with an increased likelihood of a major abnormality on 72 hours of monitoring: age above 65 years (relative risk, 2.2), male gender (relative risk, 2.0), history of heart disease (relative risk, 2.2), and an initial nonsinus rhythm (relative risk, 3.5). These results suggest that 24 hours of Holter monitoring is not enough to identify all potentially important arrhythmias in patients with syncope. Monitoring may need to be extended to 48 hours if the first 24-hour Holter recording is normal.
Sally J Aldous, Mark Richards, Louise Cullen, Richard Troughton, Martin Than
Diagnostic and prognostic utility of early measurement with high-sensitivity troponin T assay in patients presenting with chest pain.
CMAJ. 2012 Mar 20;184(5):E260-8. doi: 10.1503/cmaj.110773. Epub 2012 Jan 30.
Abstract/Text
BACKGROUND: High-sensitivity troponin assays are now available for clinical use. We investigated whether early measurement with such an assay is superior to a conventional assay in the evaluation of acute coronary syndromes.
METHODS: Patients presenting to an emergency department with chest pain who did not have ST-segment elevation were prospectively recruited from November 2007 to December 2010. Patients underwent serial testing with a conventional cardiac troponin I assay. Samples were also obtained at presentation and two hours later for measurement of troponin T levels using a high-sensitivity assay. The primary outcome was diagnosis of myocardial infarction on admission; secondary outcomes were death, myocardial infarction and heart failure at one year.
RESULTS: Of the 939 patients enrolled in the study, 205 (21.8%) had myocardial infarction. By two hours after presentation, the high-sensitivity troponin T assay at the cut-off point of the 99th percentile of the general population (14 ng/L) had a sensitivity of 92.2% (95% confidence interval [CI] 88.1%-95.0%) and a specificity of 79.7% (95% CI 78.6%-80.5%) for the diagnosis of non-ST-segment myocardial infarction. The sensitivity of the assay at presentation was 100% among patients who presented four to six hours after symptom onset. By one year, the high-sensitivity troponin T assay was found to be superior than the conventional assay in predicting death (hazard ratio [HR] 5.4, 95% CI 2.7-10.7) and heart failure (HR 27.8, 95% CI 6.6-116.4), whereas the conventional assay was superior in predicting nonfatal myocardial infarction (HR 4.0, 95% CI 2.4-6.7).
INTERPRETATION: The high-sensitivity troponin T assay at the cut-off point of the 99th percentile was highly sensitive for the diagnosis of myocardial infarction by two hours after presentation and had prognostic utility beyond that of the conventional assay. To rule out myocardial infarction, the optimal time to test a second sample using the high-sensitivity troponin T level may be four to six hours after symptom onset, but this finding needs verification in future studies before it can become routine practice.
Martin Than, Sally Aldous, Sarah Jane Lord, Stephen Goodacre, Christopher M A Frampton, Richard Troughton, Peter George, Christopher Michael Florkowski, Michael Ardagh, David Smyth, David Lewis Jardine, William Frank Peacock, Joanna Young, Gregory Hamilton, Joanne M Deely, Louise Cullen, A Mark Richards
A 2-hour diagnostic protocol for possible cardiac chest pain in the emergency department: a randomized clinical trial.
JAMA Intern Med. 2014 Jan;174(1):51-8. doi: 10.1001/jamainternmed.2013.11362.
Abstract/Text
IMPORTANCE: Patients with chest pain represent a high health care burden, but it may be possible to identify a patient group with a low short-term risk of adverse cardiac events who are suitable for early discharge.
OBJECTIVE: To compare the effectiveness of a rapid diagnostic pathway with a standard-care diagnostic pathway for the assessment of patients with possible cardiac chest pain in a usual clinical practice setting.
DESIGN, SETTING, AND PARTICIPANTS: A single-center, randomized parallel-group trial with blinded outcome assessments was conducted in an academic general and tertiary hospital. Participants included adults with acute chest pain consistent with acute coronary syndrome for whom the attending physician planned further observation and troponin testing. Patient recruitment occurred from October 11, 2010, to July 4, 2012, with a 30-day follow-up.
INTERVENTIONS: An experimental pathway using an accelerated diagnostic protocol (Thrombolysis in Myocardial Infarction score, 0; electrocardiography; and 0- and 2-hour troponin tests) or a standard-care pathway (troponin test on arrival at hospital, prolonged observation, and a second troponin test 6-12 hours after onset of pain) serving as the control.
MAIN OUTCOMES AND MEASURES: Discharge from the hospital within 6 hours without a major adverse cardiac event occurring within 30 days.
RESULTS: Fifty-two of 270 patients in the experimental group were successfully discharged within 6 hours compared with 30 of 272 patients in the control group (19.3% vs 11.0%; odds ratio, 1.92; 95% CI, 1.18-3.13; P = .008). It required 20 hours to discharge the same proportion of patients from the control group as achieved in the experimental group within 6 hours. In the experimental group, 35 additional patients (12.9%) were classified as low risk but admitted to an inpatient ward for cardiac investigation. None of the 35 patients received a diagnosis of acute coronary syndrome after inpatient evaluation.
CONCLUSIONS AND RELEVANCE: Using the accelerated diagnostic protocol in the experimental pathway almost doubled the proportion of patients with chest pain discharged early. Clinicians could discharge approximately 1 of 5 patients with chest pain to outpatient follow-up monitoring in less than 6 hours. This diagnostic strategy could be easily replicated in other centers because no extra resources are required.
TRIAL REGISTRATION: anzctr.org.au Identifier: ACTRN12610000766011.
W J Brady, S A Syverud, C Beagle, A D Perron, E A Ullman, C Holstege, R J Riviello, A Ripley, C A Ghaemmaghami
Electrocardiographic ST-segment elevation: the diagnosis of acute myocardial infarction by morphologic analysis of the ST segment.
Acad Emerg Med. 2001 Oct;8(10):961-7.
Abstract/Text
UNLABELLED: Acute myocardial infarction (AMI) is one of many causes of ST-segment elevation (STE) in emergency department (ED) chest pain (CP) patients. The morphology of STE may assist in the correct determination of its cause, with concave patterns in non-AMI syndromes and non-concave waveforms in AMI.
OBJECTIVES: To determine the impact of STE morphologic analysis on AMI diagnosis and the ability of this technique to separate AMI from non-infarction causes of STE.
METHODS: The electrocardiograms (ECGs) of consecutive ED adult CP patients (with three serial troponin I determinations) were interpreted in two-step fashion by six attending emergency physicians (EPs): 1) the determination of STE by three EPs followed by 2) STE morphologic analysis (either concave or non-concave) in those patients with STE. The impact of STE morphology analysis was investigated in the identification of AMI and non-AMI causes of STE. Acute myocardial infarction was diagnosed by abnormal serum troponin I values (>0.1 mg/dL) followed by a rise and fall of the serum marker; STE diagnoses of non-AMI causes were determined by medical record review. Interobserver reliability concerning STE morphology was determined. Study inclusion criteria included at least three troponin values performed in serial fashion no more frequently than every three hours, initial ED ECG, ED diagnosis, and final hospital diagnosis.
RESULTS: Five hundred ninety-nine CP patients were entered in the study, with 171 (29%) individuals having STE on their ECGs. Of the 171 patients who had STE, 56 had AMI, 50 had unstable angina pectoris (USAP), and 65 had non-coronary final diagnoses. Forty-nine patients had non-concave STE, 46 with AMI and three with USAP; no patient with a non-coronary diagnosis had a non-concave STE morphology. The sensitivity and specificity of the non-concave STE morphology for AMI diagnoses were 77% and 97%, respectively; the positive and negative predictive values for non-concave morphology in AMI diagnoses were 94% and 88%, respectively. Interobserver reliability in the STE morphology determination revealed a kappa coefficient of 0.87.
CONCLUSIONS: A non-concave STE morphology is frequently encountered in AMI patients. While the sensitivity of this pattern for AMI diagnosis is not particularly helpful, the presence of this finding in adult ED chest pain patients with STE strongly suggests AMI. This technique produces consistent results among these EPs.
W J Brady, A D Perron, M L Martin, C Beagle, T P Aufderheide
Cause of ST segment abnormality in ED chest pain patients.
Am J Emerg Med. 2001 Jan;19(1):25-8. doi: 10.1053/ajem.2001.18029.
Abstract/Text
The objective of this study was to determine the electrocardiographic diagnoses of chest pain patients with ST segment elevation (STE) on the 12-lead electrocardiogram (ECG). This study was a retrospective ECG review of adult chest pain patients in a university hospital emergency department (ED) over a 3-month period (January 1, 1996 to March 31, 1996). STE was determined if the ST segment was elevated >/=1 mm in the limb leads and >/=2 mm in the precordial leads in at least two anatomically contiguous leads. Results showed 902 patients who met entry criteria and of whom 202 (22.4%) had STE. Thirty-one (15%) patients had STE acute myocardial infarction (AMI) as the final hospital diagnosis which caused the STE; 171 (85%) patients with STE had non-AMI diagnosis responsible for the ST segment elevation, including left ventricular hypertrophy (LVH) 51 (25%), left bundle branch block (LBBB) 31 (15%), benign early repolarization (BER) 25 (12%), right bundle branch block 10 (5%), nonspecific bundle branch block 10 (5%), left ventricular aneurysm 5 (3%), acute pericarditis 2 (1%), ventricular paced rhythm 2 (1%), and undefined ST segment elevation 35 (17%). Forty-four patients had AMI as the final diagnosis of whom 31 showed STE on presentation to the ED. In 2 of 31 (6%) cases of STE AMI, the ST segment waveform was atypical for acute infarction. We concluded that AMI is not the most common cause of STE in ED chest pain patients. LVH is most often responsible for electrocardiographic STE followed by AMI and LBBB which occur at equal frequencies.
L A Otto, T P Aufderheide
Evaluation of ST segment elevation criteria for the prehospital electrocardiographic diagnosis fo acute myocardial infarction.
Ann Emerg Med. 1994 Jan;23(1):17-24.
Abstract/Text
STUDY OBJECTIVE: To determine retrospectively the diagnostic accuracy of various ECG ST segment elevation criteria for the prehospital ECG diagnosis of acute myocardial infarction.
DESIGN AND SETTING: During a six-month period, paramedics acquired prehospital 12-lead ECGs on adult chest pain patients. Investigators interpreted ECGs independently, retrospectively, and blinded to patient outcome. ECGs were classified as meeting or not meeting the six ST segment elevation criteria regardless of ECG morphology if the criteria were present in two or more anatomically contiguous leads: 1 mm or more ST segment elevation; 2 mm or more ST segment elevation; 1 mm or more ST segment elevation in the limb leads or 2 mm or more ST segment elevation in the precordial leads; and the first three criteria with the simultaneous presence of reciprocal changes. ECGs that did not meet any ST segment elevation criteria were classified as normal, nonspecific ST/T wave changes, abnormal but not ischemic, and ischemic. Hospital charts were reviewed for final cardiac diagnosis.
TYPE OF PARTICIPANT: Four hundred twenty-eight stable adult prehospital chest pain patients in whom paramedics acquired prehospital 12-lead ECGs.
INTERVENTIONS: None.
MEASUREMENTS AND MAIN RESULTS: Of the 428 cases, 123 (29%) met 1 mm or more ST segment elevation criteria. Sixty-three (51%) of these 123 patients did not have myocardial infarctions. ECG characteristics most frequently associated with these non-myocardial infarction ECGs were left bundle branch block (21%) and left ventricular hypertrophy (33%). The three criteria that required the presence of reciprocal changes had the highest positive predictive values (93% to 95%), with sensitivities ranging from 20% to 33%. The criteria of 1 mm or more ST segment elevation with the simultaneous presence of reciprocal changes had a positive predictive value of 94% and included 18 of the 21 (86%) myocardial infarction patients who had ST segment elevation and received thrombolytic therapy within five hours after hospital arrival. Of the 428 cases, 305 (71%) did not meet any ST segment elevation criteria and had a sensitivity of 81% and a negative predictive value of 49% for the absence of acute myocardial infarction.
CONCLUSION: Fifty-one percent of patients whose prehospital 12-lead ECG met 1 mm or more ST segment elevation criteria had non-myocardial infarction diagnoses. ST segment elevation alone lacks the positive predictive value necessary for reliable prehospital myocardial infarction diagnosis. Inclusion of reciprocal changes in prehospital ECG myocardial infarction criteria improved the positive predictive value to more than 90% and included a significant majority (62% to 86%) of acute myocardial infarction patients with ST segment elevation who received thrombolytic therapy within five hours after hospital arrival. ST segment elevation criteria that include reciprocal changes identify patients who stand to benefit most from early interventional strategies.
William J Brady, Andrew D Perron, Scott A Syverud, Charlotte Beagle, Ralph J Riviello, Chris A Ghaemmaghami, Edward A Ullman, Brian Erling, Anne Ripley, Christopher Holstege
Reciprocal ST segment depression: impact on the electrocardiographic diagnosis of ST segment elevation acute myocardial infarction.
Am J Emerg Med. 2002 Jan;20(1):35-8.
Abstract/Text
Acute myocardial infarction (AMI) is one of many causes of electrocardiographic ST segment elevation (STE) in ED chest pain (CP) patients; at times, the electrocardiographic diagnosis may be difficult. Coexistent ST segment depression has been reported to assist in the differentiation of non-infarction causes of STE from AMI-related ST segment elevation. The objective was to determine the effect of AMI diagnosis on the presence of STD among ED CP patients with electrocardiographic STE. Adult CP patients with electrocardiographic STE in at least 2 anatomically distributed leads were reviewed for the presence or absence of ST segment depression in at least 1 lead and separated into 2 groups, both with and without ST segment depression. A comparison of the 2 groups was performed in 2 approaches: all STE patients and then only with STE patients who lacked confounding electrocardiographic pattern (bundle branch block [BBB], left ventricular hypertrophy [LVH], or right ventricular paced rhythm [VPR]). All patients in the study underwent prolonged observation in the ED (at least 8 hours) with 3 serial troponin T determinations and 3 electrocardiograms (ECG). AMI was diagnosed by abnormal serum troponin T values (>0.1 mg/dL); electrocardiographic STE diagnoses of non-AMI causes were determined by medical record review. There were 171 CP patients with STE were entered in the study with 112 (65.5%) individuals show ST segment depression. When considering all study patients, ST segment depression was present at statistically equal rates in AMI and non-AMI situations (P = NS). The sensitivity, specificity, positive predictive value, and negative predictive value for the electrocardiographic diagnosis of AMI were 63%, 34%, 30%, and 67%, respectively. Patients with confounding patterns (LVH 46, BBB 19, and VPR 6) were removed from the analysis group, leaving 100 patients for analysis; 38 of these patients had ST segment depression. When considering this group of study patients, ST segment depression was present significantly more often in AMI patients (P <.0001). The sensitivity, specificity, positive predictive value, and negative predictive value for the electrocardiographic diagnosis of AMI were 69%, 93%, 93%, and 71%, respectively. Clinical diagnoses were as follows: 56 AMI, 50 USAP, and 65 noncoronary syndrome. When all CP patients with electrocardiographic STE are considered, the presence of ST segment depression is not helpful in distinguishing AMI from non-AMI. If one considers only patterns which lack electrocardiographic ST segment depression caused by altered intraventricular conduction, the presence of ST segment depression strongly suggests the diagnosis of AMI. In these cases, reciprocal ST segment depression is of considerable value in establishing the electrocardiographic diagnosis of STE AMI.
Joseph Rhinehardt, William J Brady, Andrew D Perron, Amal Mattu
Electrocardiographic manifestations of Wellens' syndrome.
Am J Emerg Med. 2002 Nov;20(7):638-43. doi: 10.1053/ajem.2002.34800.
Abstract/Text
Wellens' syndrome is a pattern of electrocardiographic T-wave changes associated with critical, proximal left anterior descending (LAD) artery stenosis. The syndrome is also referred to as LAD coronary T-wave syndrome. Syndrome criteria include T-wave changes plus a history of anginal chest pain without serum marker abnormalities; patients lack Q waves and significant ST-segment elevation; such patients show normal precordial R-wave progression. The natural history of Wellens' syndrome is anterior wall acute myocardial infarction. The T-wave abnormalities are persistent and may remain in place for hours to weeks; the clinician likely will encounter these changes in the sensation-free patient. With definitive management of the stenosis, the changes resolve with normalization of the electrocardiogram. It is vital that the physician recognize these changes and the association with critical LAD obstruction and significant risk for anterior wall myocardial infarction.
Copyright 2002, Elsevier Science (USA). All rights reserved.)
Jeffrey A Tabas, Robert M Rodriguez, Hilary K Seligman, Nora F Goldschlager
Electrocardiographic criteria for detecting acute myocardial infarction in patients with left bundle branch block: a meta-analysis.
Ann Emerg Med. 2008 Oct;52(4):329-336.e1. doi: 10.1016/j.annemergmed.2007.12.006. Epub 2008 Mar 17.
Abstract/Text
STUDY OBJECTIVE: Numerous investigators have evaluated the ECG algorithm described by Sgarbossa et al to predict acute myocardial infarction in the presence of left bundle branch block and have arrived at divergent conclusions. To clarify the utility of the Sgarbossa ECG algorithm, we perform a systematic review and meta-analysis of these trials.
METHODS: A structured search was applied to MEDLINE and Scopus databases, beginning with the year that the algorithm was derived (1996). Two reviewers independently screened citations, assessed for method quality, and extracted data (individual study characteristics, screening performance, and interobserver agreement) with a standardized extraction tool. We assessed qualifying studies for heterogeneity and generated summary estimates for the sensitivity, specificity, and positive and negative likelihood ratios with fixed-effect models.
RESULTS: We identified 11 studies with 2,100 patients that met criteria for at least 1 component of the analysis. Ten studies with 1,614 patients reported a Sgarbossa ECG algorithm score of greater than or equal to 3. These yielded a summary sensitivity of 20% (95% confidence interval [CI] 18% to 23%), specificity of 98% (95% CI 97% to 99%), a positive likelihood ratio of 7.9 (95% CI 4.5 to 13.8), and a negative likelihood ratio of 0.8 (95% CI 0.8 to 0.9). The summary diagnostic odds ratio revealed homogeneity. Seven studies with 1,213 patients reported a Sgarbossa ECG algorithm score of greater than or equal to 2. These yielded sensitivities ranging from 20% to 79% and specificities ranging from 61% to 100%. Positive likelihood ratios ranged from 0.7 to 6.6 and negative likelihood ratios ranged from 0.2 to 1.1. The summary diagnostic odds ratio revealed heterogeneity. Intra- and interobserver agreement was substantial. Sensitivity analysis using the highest-quality studies yielded similar results.
CONCLUSION: A Sgarbossa ECG algorithm score of greater than or equal to 3, representing greater than or equal to 1 mm of concordant ST elevation or greater than or equal to 1 mm ST depression in leads V1 to V3, is useful for diagnosing acute myocardial infarction in patients who present with left bundle branch block on ECG. The scoring system demonstrates good to excellent overall interobserver variability. A score of 2, representing 5 mm or more of discordant ST deviation, demonstrated ineffective positive likelihood ratios. A Sgarbossa ECG algorithm score of 0 is not useful in excluding acute myocardial infarction.
M Kosuge, K Kimura, T Ishikawa, T Shimizu, K Hibi, N Nozawa, S Umemura
Clinical implications of persistent ST segment depression after admission in patients with non-ST segment elevation acute coronary syndrome.
Heart. 2005 Jan;91(1):95-6. doi: 10.1136/hrt.2003.030973.
Abstract/Text
