今日の臨床サポート

1度・2度房室ブロック

著者: 安喰恒輔 川口工業総合病院

監修: 今井靖 自治医科大学 薬理学講座臨床薬理学部門・内科学講座循環器内科学部門

著者校正済:2021/09/01
現在監修レビュー中
参考ガイドライン:
  1. 日本循環器学会/日本不整脈心電学会:不整脈非薬物治療ガイドライン(2018年改訂版)(2018 JCS/JHRS Guideline on Non-Pharmacotherapy of Cardiac Arrhythmias)
  1. 日本循環器学会/日本不整脈心電学会:不整脈薬物治療ガイドライン(2020 年改訂版)(JCS/JHRS 2020 Guideline on Pharmacotherapy of Cardiac Arrhythmias)
  1. 日本循環器学会/日本不整脈心電学会:2021 年 JCS / JHRS ガイドライン 不整脈非薬物治療 フォーカスアップデート版(JCS / JHRS 2021 Guideline Focused Update on Non-Pharmacotherapy of Cardiac Arrhythmias)
  1. American College of Cardiology (ACC)/American Heart Association (AHA)/[https://www.hrsonline.org Heart Rhythm Society (HRS): 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients with Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society
  1. European Society of Cardiology (ESC): 2013 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy.
患者向け説明資料

概要・推奨   

  1. 基礎心疾患を伴わない健常成人の第1度房室ブロックの予後は良好であり、症状がなければ治療は推奨されない(推奨度1)。
  1. 高齢者あるいは基礎心疾患を有する患者では、第1度房室ブロックは予後不良の予測因子となるが、無症候性の第1度房室ブロックに対するペースメーカ植込みは推奨されない(推奨度4)。
  1. 症状の強い第1度房室ブロックは、ペースメーカ植込みの適応となることがある(推奨度2)。
  1. 閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります
  1. 閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となりま
  1. 閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります
  1. 閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必
  1. 閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご契約が必要となります。閲覧にはご
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薬剤監修について:
オーダー内の薬剤用量は日本医科大学付属病院 薬剤部 部長 伊勢雄也 以下、林太祐、渡邉裕次、井ノ口岳洋、梅田将光による疑義照会のプロセスを実施、疑義照会の対象については著者の方による再確認を実施しております。
※薬剤中分類、用法、同効薬、診療報酬は、エルゼビアが独自に作成した薬剤情報であり、
著者により作成された情報ではありません。
尚、用法は添付文書より、同効薬は、薬剤師監修のもとで作成しております。
※薬剤情報の(適外/適内/⽤量内/⽤量外/㊜)等の表記は、エルゼビアジャパン編集部によって記載日時にレセプトチェックソフトなどで確認し作成しております。ただし、これらの記載は、実際の保険適用の査定において保険適用及び保険適用外と判断されることを保証するものではありません。また、検査薬、輸液、血液製剤、全身麻酔薬、抗癌剤等の薬剤は保険適用の記載の一部を割愛させていただいています。
(詳細はこちらを参照)
著者のCOI(Conflicts of Interest)開示:
安喰恒輔 : 特に申告事項無し[2021年]
監修:今井靖 : 講演料(第一三共株式会社)[2021年]

改訂のポイント:
  1. 参照ガイドラインを最新のものに改めた。
  1. 房室ブロックの原因となりうる薬剤を追加した。

病態・疫学・診察

疾患情報(疫学・病態)  
  1. 第1度房室ブロックとは、生理的な心房レートにおいて、PR間隔が0.21秒以上に延長している状態である。第2度房室ブロックとは、房室伝導が間欠的な状態である。
 
第1度房室ブロック

PR間隔が延長している。

出典

img1:  Figure 77-14 in Rosen's Emergency Medicine, 7th ed.
 
 
 
  1. 第2度房室ブロックのうち、2個以上のPに対してQRSが1個のみ伝導するもの(房室伝導比が2:1未満のもの)を特に高度房室ブロックと呼ぶ。定義上は第2度房室ブロックに分類されるが、治療は完全(3度)房室ブロックに準じるため、別稿「 高度・完全房室ブロック 」で解説する。
  1. 第2度房室ブロックは、PR間隔が徐々に延長しつつQRS波が脱落するⅠ型(ウェンケバッハ[Wenckebach]型あるいはモービッツ[Mobitz]Ⅰ型ともいう)と、PR間隔が不変のままQRS波が脱落するⅡ型(モービッツ[Mobitz]Ⅱ型ともいう)に分類されるが、房室伝導比が2:1以下の場合は分類できない。
 
Ⅰ型第2度房室ブロック

2拍目から3拍目にかけてPR間隔が延長し、次いでQRS波が脱落する。4拍目と5拍目についても同様である。

出典

img1:  Figure 77-15 in Rosen's Emergency Medicine, 7th ed.
 
 
 
Ⅱ型第2度房室ブロック

PR間隔は一定のまま、突然QRS波が脱落する(矢印)。脚ブロックを伴うため、QRS幅は広い。本例は幼児であるため、基本レートが速い。

 
2:1 房室ブロック

2:1 房室ブロックは第2度房室ブロックであるが、心房から心室への興奮が連続しないため、Ⅰ型かⅡ型かは判断できない。

出典

 
  1. 12誘導心電図における第1度房室ブロックの頻度は、健常な若年成人で0.5~2%とされ[1][2][3]、加齢とともに増加する[4][5]。健常小児では成人より高頻度(約10%)にみられる[6][7][8]
  1. 12誘導心電図における第2度房室ブロックの頻度は、健常な若年成人で0.004~0.005%とまれだが[1][2]、24時間心電図では6%に観察される[9]
  1. 治療方針や予後が異なるため、基礎疾患および誘因を同定することがきわめて重要である。
評価・治療のポイント  
  1. アダムス・ストークス発作と心不全症状・徴候の有無・重症度を評価する。

これより先の閲覧には個人契約のトライアルまたはお申込みが必要です。

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文献 

著者: R L JOHNSON, K H AVERILL, L E LAMB
雑誌名: Am J Cardiol. 1960 Jul;6:153-77.
Abstract/Text
PMID 14407510  Am J Cardiol. 1960 Jul;6:153-77.
著者: G W MANNING, G A SEARS
雑誌名: Am J Cardiol. 1962 Apr;9:558-63.
Abstract/Text
PMID 14469378  Am J Cardiol. 1962 Apr;9:558-63.
著者: L V Perlman, L D Ostrander, J B Keller, B N Chiang
雑誌名: Chest. 1971 Jan;59(1):40-6.
Abstract/Text
PMID 5099809  Chest. 1971 Jan;59(1):40-6.
著者: J Erikssen, J E Otterstad
雑誌名: Clin Cardiol. 1984 Jan;7(1):6-13.
Abstract/Text During a baseline cardiovascular survey PR was measured in a strictly standardized way in 1832 men aged 40-59 years, free from coronary heart disease (CHD). Of 1758 men still alive, 1585 underwent an identical follow-up study 7 years later. A total of 1570 were in sinus rhythm. The following findings were made: (1) Baseline and follow-up prevalence of a prolonged PR (greater than or equal to 0.22 s) was identical (5.3 vs. 5.4%). (2) Only 60% of restudied men with a prolonged PR also had prolonged PR at follow-up. (3) Only 1 of 98 with a prolonged baseline PR had a more advanced AV block at follow-up, whereas an additional 4 had conditions which might influence the AV node (1 Bechterew's disease and 3 mild aortic valve stenosis). (4) The incidence of all CHD events found during the follow-up study (CHD deaths, myocardial infarction, angina pectoris, and pathologic exercise ECGs) was moderately but significantly lower in men with a prolonged PR than among men with a PR less than or equal to 0.21 s. Thus a prolonged PR is rarely an indicator of impending, more severe conduction disturbances; it is mostly a benign, functional finding in middle-aged men free from overt heart disease and is not positively associated with CHD. Rather PR may be moderately and inversely associated with latent CHD.

PMID 6705291  Clin Cardiol. 1984 Jan;7(1):6-13.
著者: S Rajala, K Kaltiala, M Haavisto, K Mattila
雑誌名: Eur Heart J. 1984 Feb;5(2):168-74.
Abstract/Text The electrocardiograms of 559 persons, 83% of the total population 85 years of age or over in the city of Tampere, were evaluated according to the classification of the modified Minnesota code. Electrocardiograms showed no codable item in only 3.6% of the subjects. The prevalence of the most frequent electrocardiographic findings was: T wave inversion 53.3%, counter-clockwise rotation 42.9%, ST junction depression 42.8%, premature beats 33.8%, Q-QS pattern 21.3% and atrial fibrillation 17.4%. The prevalence of left axis deviation, left anterior hemiblock and right bundle branch block was statistically significantly higher in men than in women. Electrocardiographic abnormalities suggestive of ischaemic heart disease were present in 45.3% with no statistically significant relation to sex or age. The results are discussed and compared with those of electrocardiographic studies concerning age groups over 80 and 90 years.

PMID 6723687  Eur Heart J. 1984 Feb;5(2):168-74.
著者: O Scott, G J Williams, G I Fiddler
雑誌名: Br Heart J. 1980 Sep;44(3):304-8.
Abstract/Text Ambulatory monitoring of the electrocardiogram was performed in 131 healthy boys aged between 10 and 13 years for two consecutive periods of 24 hours. When awake the maximal heart rates ranged from 100 to 200 and the minimal from 45 to 80 beats per minute. During sleep maximal rates were 60 to 110 beats and minimal rates 30 to 70 beats per minute. Sinus arrhythmia was seen in every boy and in 36 (27.5%) no other changes were found. Sinuatrial block, Mobitz type I, was not seen. Sinuatrial block, Mobitz type II, occurred twice only. Complete sinuatrial block occurred in 8.4 per cent, never lasted more than one cycle, and was always followed by a junctional beat. First degree atrioventricular block occurred in 8.4 per cent and Mobitz type I atrioventricular block in 10.7 per cent. Premature beats were always single, atrial in 13 per cent, ventricular in 26 per cent, and except in two boys were never more than four in 24 hours. There were no episodes of ventricular or supraventricular tachycardia. Changes in P wave morphology were common and slow junctional rhythm occurred in 13 per cent during sleep.

PMID 7426187  Br Heart J. 1980 Sep;44(3):304-8.
著者: D P Southall, F Johnston, E A Shinebourne, P G Johnston
雑誌名: Br Heart J. 1981 Mar;45(3):281-91.
Abstract/Text Twenty-four hour electrocardiographic recordings were made on 104 randomly selected, healthy 7 to 11-year-old children. Ninety-two were technically adequate and suitable for analysis. The mean highest heart rate measured by direct electrocardiographic analysis over nine beats was 164 +/- 17. The mean lowest heart rates were 49 +/- 6 over three beats', and 56 +/- 6 over nine beats' duration. The maximum duration of heart rates less than 55/minute was 40 minutes. At their lowest heart rates 41 children (45 per cent) had junctional escape rhythms, the maximum duration of which was 25 minutes. Nine children showed PR intervals greater than or equal to 0.20 s and included three with Mobitz type I second degree atrioventricular block. Nineteen (21%) had isolated supraventricular or ventricular premature beats (less than 1/hour). Sixty subjects (65%) had sinus pauses that could not be distinguished on the surface electrocardiogram from those previously described as sinuatrial exit block or sinus arrest. The maximum duration of sinus pause measured over 24 hours on each child was 1.36 +/- 0.23 seconds. Thus apparently healthy children show variations in heart rate and rhythm over 24 hours hitherto considered to be abnormal.

PMID 7470341  Br Heart J. 1981 Mar;45(3):281-91.
著者: D F Dickinson, O Scott
雑誌名: Br Heart J. 1984 Feb;51(2):179-83.
Abstract/Text Ambulatory monitoring of the electrocardiogram in 100 healthy 14 to 16 year old boys showed heart rates ranging from 45 to 200 beats/minute during the day and from 23 to 95 beats/minute during sleep. Sinus arrhythmia was present in all cases and was the only variation noted in 17%. Sudden variations in the PP interval occurred in 41%, but a precise diagnosis of the mechanism was usually impossible; 15% had changes compatible with sinus arrest or temporary complete sinoatrial block, and one boy had a pattern compatible with type II second degree sinoatrial block. Escape rhythms were noted in 26%, first degree atrioventricular block in 12%, and second degree atrioventricular block (Mobitz type I) in 11%. Mobitz type II second degree atrioventricular block was seen on one occasion in one boy. Ventricular extrasystoles seen in 41% were of uniform morphology in 75% and multiform in 25%. Short episodes of ventricular tachycardia were recorded in 3%.

PMID 6197983  Br Heart J. 1984 Feb;51(2):179-83.
著者: M Brodsky, D Wu, P Denes, C Kanakis, K M Rosen
雑誌名: Am J Cardiol. 1977 Mar;39(3):390-5.
Abstract/Text Results are reported of portable 24 hour dynamic electrocardiographic monitoring in 50 male medical students without cardiovascular disease, as defined by normal clinical and noninvasive cardiovascular examination. During waking periods, maximal sinus rates ranged from 107 to 180 beats/min (mean +/- 5). Twenty-five subjects (50 percent) had episodes of marked sinus arrhythmia as defined by spontaneous changes in adjacent cycle lengths of 100 percent or more. Fourteen subjects (28 percent) had sinus pauses of more than 1.75 seconds, usually during sinus arrhythmia. Transient nocturnal type I second degree atrioventricular (A-V) block was noted in three subjects (6 percent). Of 28 patients (56 percent) having atrial premature beats, only 1 (2 percent) had more than 100 such beats (141) in 24 hours. Of 25 patients (50 percent) having premature ventricular contractions, only 1 (2 percent) had more than 50 such contractions (86) in 24 hours. In conclusion, frequent atrial and ventricular premature beats are unusual in a young adult male population. In contrast, bradyarrhythmias (including marked sinus arrhythmia with sinus pauses, sinus bradycardia and nocturnal A-V block) are common. These findings are useful in evaluating the clinical significance of arrhythmias detected with portable monitoring.

PMID 65912  Am J Cardiol. 1977 Mar;39(3):390-5.
著者: D Mymin, F A Mathewson, R B Tate, J Manfreda
雑誌名: N Engl J Med. 1986 Nov 6;315(19):1183-7. doi: 10.1056/NEJM198611063151902.
Abstract/Text The long-term prognosis of first-degree heart block in the absence of organic heart disease has not been clearly defined. We addressed this question in a 30-year longitudinal study of 3983 healthy men. We identified 52 cases that were present on entry into the study and 124 incident cases during follow-up. The incidence rose steadily after age 40 and was 1.13 per 1000 person-years over the entire period. Two thirds of the cases had only moderate prolongation of the PR interval (0.22 to 0.23 second). We compared four age-matched controls with each case for histories of scarlet fever, rheumatic fever, diphtheria, smoking, blood pressure, and body-mass index. No significant differences (P greater than 0.05) were found. Likewise, mortality from all causes did not differ between cases and controls. Although somewhat higher rates of morbidity and mortality from ischemic heart disease were observed in the cases than in the controls, the differences were not significant. Progression to higher grades of heart block occurred in only two cases. In view of the prognostic findings and the rare occurrence of advanced degrees of heart block, we conclude that primary first-degree heart block with moderate PR prolongation is a benign condition. This conclusion may not apply, however, to persons with more marked prolongation of the PR interval, a very rare condition.

PMID 3762641  N Engl J Med. 1986 Nov 6;315(19):1183-7. doi: 10.1056/N・・・
著者: J M PACKARD, J S GRAETTINGER, A GRAYBIEL
雑誌名: Circulation. 1954 Sep;10(3):384-400.
Abstract/Text
PMID 13190611  Circulation. 1954 Sep;10(3):384-400.
著者: G Rose, P J Baxter, D D Reid, P McCartney
雑誌名: Br Heart J. 1978 Jun;40(6):636-43.
Abstract/Text A screening examination including an electrocardiogram (limb leads only) coded by the Minnesota Code, using rigorous quality control was done on 18 403 male civil servants aged 40 to 64. The association of the findings with coronary heart disease has been tested in relation to age trends, symptomatic history, and coronary heart disease mortality rates in the ensuing five years. The results were positive for Q waves, left axis deviation, ST depression, and T wave changes (including minor T wave items as an isolated finding), ventricular conduction defects, and atrial fibrillation; but they were generally unimpressive for increased R amplitude and for lengthening or shortening of the PR interval, QT interval duration, premature beats, and extremes of heart rate. The prognosis of specific electrocardiographic findings discovered at screening is quite different from when they arise in clinical practice. Among the 6 per cent of men in this study with patterns suggesting ischaemia, the subsequent coronary heart disease mortality was little more than 1 per cent per year; and among those who were symptom free it was even less.

PMID 656238  Br Heart J. 1978 Jun;40(6):636-43.
著者: Writing Committee Members, Fred M Kusumoto, Mark H Schoenfeld, Coletta Barrett, James R Edgerton, Kenneth A Ellenbogen, Michael R Gold, Nora F Goldschlager, Robert M Hamilton, José A Joglar, Robert J Kim, Richard Lee, Joseph E Marine, Christopher J McLeod, Keith R Oken, Kristen K Patton, Cara N Pellegrini, Kimberly A Selzman, Annemarie Thompson, Paul D Varosy
雑誌名: Heart Rhythm. 2019 Sep;16(9):e227-e279. doi: 10.1016/j.hrthm.2018.10.036. Epub 2018 Nov 6.
Abstract/Text
PMID 30412777  Heart Rhythm. 2019 Sep;16(9):e227-e279. doi: 10.1016/j.・・・
著者: Michele Brignole, Angelo Auricchio, Gonzalo Baron-Esquivias, Pierre Bordachar, Giuseppe Boriani, Ole-A Breithardt, John Cleland, Jean-Claude Deharo, Victoria Delgado, Perry M Elliott, Bulent Gorenek, Carsten W Israel, Christophe Leclercq, Cecilia Linde, Lluís Mont, Luigi Padeletti, Richard Sutton, Panos E Vardas, ESC Committee for Practice Guidelines (CPG), Jose Luis Zamorano, Stephan Achenbach, Helmut Baumgartner, Jeroen J Bax, Héctor Bueno, Veronica Dean, Christi Deaton, Cetin Erol, Robert Fagard, Roberto Ferrari, David Hasdai, Arno W Hoes, Paulus Kirchhof, Juhani Knuuti, Philippe Kolh, Patrizio Lancellotti, Ales Linhart, Petros Nihoyannopoulos, Massimo F Piepoli, Piotr Ponikowski, Per Anton Sirnes, Juan Luis Tamargo, Michal Tendera, Adam Torbicki, William Wijns, Stephan Windecker, Document Reviewers, Paulus Kirchhof, Carina Blomstrom-Lundqvist, Luigi P Badano, Farid Aliyev, Dietmar Bänsch, Helmut Baumgartner, Walid Bsata, Peter Buser, Philippe Charron, Jean-Claude Daubert, Dan Dobreanu, Svein Faerestrand, David Hasdai, Arno W Hoes, Jean-Yves Le Heuzey, Hercules Mavrakis, Theresa McDonagh, Jose Luis Merino, Mostapha M Nawar, Jens Cosedis Nielsen, Burkert Pieske, Lidija Poposka, Frank Ruschitzka, Michal Tendera, Isabelle C Van Gelder, Carol M Wilson
雑誌名: Eur Heart J. 2013 Aug;34(29):2281-329. doi: 10.1093/eurheartj/eht150. Epub 2013 Jun 24.
Abstract/Text
PMID 23801822  Eur Heart J. 2013 Aug;34(29):2281-329. doi: 10.1093/eur・・・
著者: Susan Cheng, Michelle J Keyes, Martin G Larson, Elizabeth L McCabe, Christopher Newton-Cheh, Daniel Levy, Emelia J Benjamin, Ramachandran S Vasan, Thomas J Wang
雑誌名: JAMA. 2009 Jun 24;301(24):2571-7. doi: 10.1001/jama.2009.888.
Abstract/Text CONTEXT: Prolongation of the electrocardiographic PR interval, known as first-degree atrioventricular block when the PR interval exceeds 200 milliseconds, is frequently encountered in clinical practice.
OBJECTIVE: To determine the clinical significance of PR prolongation in ambulatory individuals.
DESIGN, SETTING, AND PARTICIPANTS: Prospective, community-based cohort including 7575 individuals from the Framingham Heart Study (mean age, 47 years; 54% women) who underwent routine 12-lead electrocardiography. The study cohort underwent prospective follow-up through 2007 from baseline examinations in 1968-1974. Multivariable-adjusted Cox proportional hazards models were used to examine the associations of PR interval with the incidence of arrhythmic events and death.
MAIN OUTCOME MEASURES: Incident atrial fibrillation (AF), pacemaker implantation, and all-cause mortality.
RESULTS: During follow-up, 481 participants developed AF, 124 required pacemaker implantation, and 1739 died. At the baseline examination, 124 individuals had PR intervals longer than 200 milliseconds. For those with PR intervals longer than 200 milliseconds compared with those with PR intervals of 200 milliseconds or shorter, incidence rates per 10 000 person-years were 140 (95% confidence interval [CI], 95-208) vs 36 (95% CI, 32-39) for AF, 59 (95% CI, 40-87) vs 6 (95% CI, 5-7) for pacemaker implantation, and 334 (95% CI, 260-428) vs 129 (95% CI, 123-135) for all-cause mortality. Corresponding absolute risk increases were 1.04% (AF), 0.53% (pacemaker implantation), and 2.05% (all-cause mortality) per year. In multivariable analyses, each 20-millisecond increment in PR was associated with an adjusted hazard ratio (HR) of 1.11 (95% CI, 1.02-1.22; P = .02) for AF, 1.22 (95% CI, 1.14-1.30; P < .001) for pacemaker implantation, and 1.08 (95% CI, 1.02-1.13; P = .005) for all-cause mortality. Individuals with first-degree atrioventricular block had a 2-fold adjusted risk of AF (HR, 2.06; 95% CI, 1.36-3.12; P < .001), 3-fold adjusted risk of pacemaker implantation (HR, 2.89; 95% CI, 1.83-4.57; P < .001), and 1.4-fold adjusted risk of all-cause mortality (HR, 1.44, 95% CI, 1.09-1.91; P = .01).
CONCLUSION: Prolongation of the PR interval is associated with increased risks of AF, pacemaker implantation, and all-cause mortality.

PMID 19549974  JAMA. 2009 Jun 24;301(24):2571-7. doi: 10.1001/jama.200・・・
著者: Ryan K Crisel, Ramin Farzaneh-Far, Beeya Na, Mary A Whooley
雑誌名: Eur Heart J. 2011 Aug;32(15):1875-80. doi: 10.1093/eurheartj/ehr139. Epub 2011 May 23.
Abstract/Text AIMS: First-degree atrioventricular block (AVB) has traditionally been considered a benign electrocardiographic finding in healthy individuals. However, the clinical significance of first-degree AVB has not been evaluated in patients with stable coronary heart disease. We investigated whether first-degree AVB is associated with heart failure (HF) and mortality in a prospective cohort study of outpatients with stable coronary artery disease (CAD).
METHODS AND RESULTS: We measured the P-R interval in 938 patients with stable CAD and classified them into those with (P-R interval ≥ 220 ms) and without (P-R interval <220 ms) first-degree AVB. Hazard ratios (HRs) and 95% confidence intervals were calculated for HF hospitalization and all-cause mortality. During 5 years of follow-up, there were 123 hospitalizations for HF and 285 deaths. Compared with patients who had normal atrioventricular conduction, those with first-degree AVB were at increased risk for HF hospitalization (age-adjusted HR 2.33: 95% CI 1.49-3.65; P= 0.0002), mortality [age-adjusted HR 1.58; 95% CI (1.13-2.20); P = 0.008], cardiovascular (CV) mortality [age-adjusted HR 2.33; 95% CI (1.28-4.22); P= 0.005], and the combined endpoint of HF hospitalization or CV mortality (age-adjusted HR 2.43: 95% CI 1.64-3.61; P ≤ 0.0001). These associations persisted after multivariable adjustment for heart rate, medication use, ischaemic burden, and QRS duration. Adjustment for left ventricular systolic and diastolic function partially attenuated the effect, but first-degree AVB remained associated with the combined endpoint of HF or CV death (HR 1.61, CI 1.02-2.54; P= 0.04).
CONCLUSION: In a large cohort of patients with stable coronary artery disease, first-degree AVB is associated with HF and death.

PMID 21606074  Eur Heart J. 2011 Aug;32(15):1875-80. doi: 10.1093/eurh・・・
著者: S Serge Barold, Arzu Ilercil, Fabio Leonelli, Bengt Herweg
雑誌名: J Interv Card Electrophysiol. 2006 Nov;17(2):139-52. doi: 10.1007/s10840-006-9065-x. Epub 2007 Mar 2.
Abstract/Text Marked first-degree AV block (PR> or =0.30 s) can produce a clinical condition similar to that of the pacemaker syndrome. Clinical evaluation often requires a treadmill stress test because patients are more likely to become symptomatic with mild or moderate exercise when the PR interval cannot adapt appropriately. Uncontrolled studies have shown that many such symptomatic patients with normal left ventricular (LV) function improve with conventional dual chamber pacing (Class IIa indication). In contrast, marked first-degree AV block with LV systolic dysfunction and heart failure is still a Class IIb indication, a recommendation that is now questionable because a conventional DDD(R) pacemaker would be committed to right ventricular pacing (and its attendant risks) virtually 100% of the time. It would seem prudent at this juncture to consider a biventricular DDD device in this situation. Patients with suboptimally programmed pacemakers may develop functional atrial undersensing because the P wave tends to migrate easily into the postventricular atrial refractory period (PVARP). Retrograde vetriculoatrial conduction block is uncommon in marked first-degree AV block so a relatively short PVARP can often be used at rest with little risk of endless loop tachycardia. The usefulness of a short PVARP may be negated by special PVARP functions in some pulse generators designed to time out a long PVARP at rest and a gradually shorter one with activity. First-degree AV block during cardiac resynchronization therapy (CRT) predisposes to loss of ventricular resynchronization during biventricular pacing because it favors the initiation of electrical "desynchronization" especially in association with a relatively fast atrial rate and a relatively slow programmed upper rate. Patients with first-degree AV block have a poorer outcome with CRT than patients with a normal PR interval, a response that may involve several mechanisms. (1) The long PR interval may be a marker of more advanced heart disease. (2) Patients with first-degree AV block may experience more episodes of undetected "electrical desynchronization". (3) "Concealed resynchronization" whereupon ventricular activation in patients with a normal PR interval may result from fusion of electrical wavefronts coming from the right bundle branch and the impulse from the LV electrode. The resultant hemodynamic response may be superior because the detrimental effects of right ventricular stimulation (required in the setting of a longer PR interval) are avoided.

PMID 17334913  J Interv Card Electrophysiol. 2006 Nov;17(2):139-52. do・・・
著者: D B Shaw, J I Gowers, C A Kekwick, K H J New, A W T Whistance
雑誌名: Heart. 2004 Feb;90(2):169-74.
Abstract/Text OBJECTIVE: To assess the need for pacing in adults with chronic Mobitz type I second degree atrioventricular block (Mobitz I).
DESIGN: Prospective study.
SETTING: District general hospital.
PATIENTS: 147 subjects aged > or = 20 years (age cohorts 20-44, 45-64, 65-79, and > or = 80) with chronic Mobitz I without second degree Mobitz II or third degree (higher degree) block on entry, seen from 1968 to 1993 and followed up to 30 June 1997. Sixty four had organic heart disease. The presence of symptomatic bradycardia was defined as highly likely in 47 patients (class 1); probable in 14 (class 2); and absent in 86 (class 3).
INTERVENTIONS: Pacemakers were implanted in 90 patients for the following indications: symptoms in 74 and prophylaxis in 16.
MAIN OUTCOME MEASURES: The main outcome measure was death, with conduction deterioration to higher degree block or symptomatic bradycardia the alternative measure.
RESULTS: Five year survival to death was reduced in unpaced patients relative to that expected for the normal population (overall mean (SD) 53.5 (6.7)% v 68.6%, p < 0.001; class 3, 54.4 (7.3)% v 70.1%, p < 0.001). Paced patients fared better than unpaced (overall (mean (SD) five year survival 76.3 (4.5)% v 53.5 (6.7)%, p = 0.0014; class 3, 87.2 (5.4)% v 54.4 (7.3)%, p = 0.020; and organic heart disease, 68.2 (7.6)% v 44.0 (9.9)%, p < or = 0.0014). There were no deaths in the < 45 cohort. Survival to first outcome (main or alternative) was further reduced to 31.7 (5.0)% in 102 patients unpaced initially and 34.2 (5.7)% in class 3. Only the 20-44 cohort and patients with sinus arrhythmia had > 50% survival.
CONCLUSION: Mobitz I block is not usually benign in patients > or = 45 years of age. Pacemaker implantation should be considered, even in the absence of symptomatic bradycardia or organic heart disease.

PMID 14729789  Heart. 2004 Feb;90(2):169-74.
著者: Elliott M Antman, Daniel T Anbe, Paul Wayne Armstrong, Eric R Bates, Lee A Green, Mary Hand, Judith S Hochman, Harlan M Krumholz, Frederick G Kushner, Gervasio A Lamas, Charles J Mullany, Joseph P Ornato, David L Pearle, Michael A Sloan, Sidney C Smith, Joseph S Alpert, Jeffrey L Anderson, David P Faxon, Valentin Fuster, Raymond J Gibbons, Gabriel Gregoratos, Jonathan L Halperin, Loren F Hiratzka, Sharon Ann Hunt, Alice K Jacobs, American College of Cardiology, American Heart Association Task Force on Practice Guidelines, Canadian Cardiovascular Society
雑誌名: Circulation. 2004 Aug 31;110(9):e82-292.
Abstract/Text
PMID 15339869  Circulation. 2004 Aug 31;110(9):e82-292.
著者: Arnaud Lazarus, Jean Varin, Dominique Babuty, Frédéric Anselme, Joel Coste, Denis Duboc
雑誌名: J Am Coll Cardiol. 2002 Nov 6;40(9):1645-52.
Abstract/Text OBJECTIVES: We hypothesized that pacemaker (PM) implantation in patients with myotonic dystrophy (MD) with a prolonged HV interval, even asymptomatic, may protect them against sudden death related to atrioventricular (AV) block. We sought to prospectively document the true incidence of AV block episodes in this high-risk population and accurately trace, in the long term, by the PM, the occurrence of arrhythmias that may remain undetected during conventional follow-up.
BACKGROUND: Myotonic dystrophy is associated with a high risk of sudden death, commonly attributed to AV block or ventricular arrhythmias, but cardiac pacing is only recommended as a secondary prevention.
METHODS: Patients with MD with an HV interval > or =70 ms, even in the absence of related symptoms, prospectively received a cardiac PM, including an algorithm capable of diagnosing episodes of bradycardia and tachyarrhythmias.
RESULTS: The population consisted of 49 patients (45.5 +/- 8.9 years old) followed for 53.5 +/- 27.2 months. Paroxysmal arrhythmias were recorded in 41 patients (83.7%), consisting of complete AV block (n = 21), sino-atrial block (n = 4), or atrial (n = 25) or ventricular (n = 13) tachyarrhythmias. No patient died of AV block during follow-up, but 10 deaths occurred, 4 of them sudden. An arrhythmic cause could be excluded by postmortem PM interrogation in two cases of typical sudden death.
CONCLUSIONS: Arrhythmias are common in patients with MD with infrahisian conduction abnormalities. The prophylactic implantation of a pacing system when the HV interval is > or =70 ms seems appropriate. The PM protects the patient against the clinical consequences of paroxysmal profound bradycardia and facilitates the diagnosis and management of frequent paroxysmal tachyarrhythmias.

PMID 12427418  J Am Coll Cardiol. 2002 Nov 6;40(9):1645-52.

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