室内传导阻滞中以左束支传导阻滞最危险

洛杉矶——在美国心脏协会(AHA)科学年会上，一项针对新泽西州1994~2009年25,000余例心肌梗死(MI)幸存者的资料分析结果表明，MI后最常见的室内传导阻滞为右束支传导阻滞(RBBB)，但其致死和致病风险最小，而左束支传导阻滞(LBBB)患者死亡率和心血管疾病发病率风险最大。此外，左前分支传导阻滞(LAHB)对于MI后患者的危险程度几乎与LBBB相当。

新泽西医科和牙科大学心血管研究所的John S. Pantazopoulos博士及其同事分析了新泽西心血管研究所心梗数据采集系统(MIDAS)25,026例患者16年的随访资料。研究者排除了先天性心脏病、二尖瓣回流、房颤、心衰史患者，以及首次发生室内传导阻滞前接受起搏器、冠脉旁路手术或经皮冠脉介入治疗患者。

结果显示，最常见传导异常为RBBB，所占比例为54%(13,454例)，LBBB、LAHB和LAHB+RBBB患者分别占27%、15%和4%。

校正人口统计学和临床混淆因素(包括高血压、糖尿病和肾衰)后的多变量分析结果显示，与RBBB患者相比，LBBB、LAHB和LAHB+RBBB患者心血管死亡风险分别增加2.7、2.6和2.6倍，全因死亡率分别增加48%、59%和62%。

与RBBB患者相比，LBBB患者随访期间心衰、二尖瓣回流和房颤发生率分别增加3.8倍、68%和34%；LAHB患者新发心衰发生率增加2.6倍，房颤发生率增加15%；LAHB+RBBB患者心衰发生率增加2.4倍。以上结果均有统计学显著意义。

Pantazopoulos博士声称无利益冲突。资深研究者John B. Kostis博士担任默克公司代言人，并接受赛诺菲公司酬金和诺华公司研究经费。

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By: MITCHEL L. ZOLER, Cardiology News Digital Network

LOS ANGELES – The most common intraventricular conduction block following a myocardial infarction is a right bundle branch block, but it is also the least deadly and pathogenic. Left bundle branch blocks produced the most morbidity and mortality in a review of more than 25,000 myocardial infarction survivors from throughout New Jersey during 1994-2009.

The findings also showed that left anterior hemiblocks (LAHB) put post-MI patients in nearly as much jeopardy as did left bundle branch blocks (LBBB), Dr. John S. Pantazopoulos and his associates reported in a poster at the annual scientific sessions of the American Heart Association.

The researchers reviewed 16-year follow-up data from 25,026 patients enrolled in the Myocardial Infarction Data Acquisition System (MIDAS) run by the Cardiovascular Institute of New Jersey in New Brunswick. They excluded post-MI patients with congenital heart disease, a history of mitral regurgitation, atrial fibrillation, heart failure, a pacemaker, coronary bypass surgery, or a percutaneous coronary intervention prior to the first appearance of their intraventricular conduction block.

The most common conduction abnormality was a right bundle branch block (RBBB), in 13,454 patients (54%). LBBB occurred in 27%, 15% had LAHB, and 4% had LAHB plus RBBB. Dr. Pantazopoulos and his associates performed multivariate analyses to determine the morbidity and mortality risk faced by LBBB, LAHB, and LAHB plus RBBB patients compared with patients who only had RBBB. Their analysis controlled for several demographic and clinical confounders, including hypertension, diabetes, and renal failure.

The analysis showed that compared with patients with RBBB, those with LBBB had a 2.7-fold increased risk of cardiovascular death and a 48% increased rate of all-cause death, reported Dr. Pantazopoulos, a cardiologist at the Cardiovascular Institute of the University of Medicine and Dentistry of New Jersey in New Brunswick. Patients with LAHB had a 2.6-fold increased risk of cardiovascular death and 59% increased rate of all-cause death compared with RBBB patients, and those with LAHB plus RBBB had a 2.6-fold higher cardiovascular death rate and a 62% increased all-cause death rate. All these increases were statistically significant.

Patients with LBBB also had a 3.8-fold increased rate of developing heart failure during follow-up, a 68% increased rate of incident mitral regurgitation, and a 34% increased rate of atrial fibrillation compared with patients with RBBB. Patients with LAHB had a 2.6-fold increased rate of new-onset heart failure and a 15% higher rate of atrial fibrillation, and patients with both LAHB and RBBB had a 2.4-fold increased rate of heart failure. All of these increased rates were statistically significant.

Dr. Pantazopoulos said that he had no disclosures. The senior researcher on the study, Dr. John B. Kostis, has been a speaker for Merck, has received honoraria from Sanofi, and has received a research grant from Novartis.