Relativity Study Of Clinical Characteristics For Complete Left Bundle Branch Block With Cardiac Insufficiency:Report Of 400 Cases

Objective: Complete left bundle branch blocks(CLBBB) is generally associated with a poorer prognosis in comparison to normal intraventricular conduction. Early studies reported a mean survival of less than 5 years after documentation of LBBB. However, a few patients with LBBB appear to have a good prognosis which does not differ from that of patients with right bundle branch block[3-6], thus to assess etiology of LBBB and cardiac function is of great value. However, at current,few clinical studies on cardiac dysfunction for CLBBB. We aimed to investigate the clinical characteristics of CLBBB patients complicated by myocardial dysfunction and assess the heart function effected by QRS duration. These studies can provide reference value for clinical diagnosis and treatment.Methods The data of 400 hospitalized patients in the First Affiliated Hospital of Dalian Medical University(from September 1st,2010 to November 1st,2014) with CLBBB were retrospectively analyzed.These patients were also divided into two groups according to the difference in clinical characteristics( sex, age, coronary disease, hypertension, valvulopathy, dilated cardiomyopathy, atrial fibrillation, ventricular arrhythmias, hyperlipemia and other atrio-ventricular block),the difference in clinical characteristics between CLBBB patients complicated with and without myocardial dysfunction were compared.The independent predictors for myocardial dysfunction in CLBBB patients were determined by Logistic regression analysis。Analysised in patients with CLBBB that QRS interval is correlated with left ventricular systolic function. These patients were also divided into two groups according to QRS duration :QRS duration=120ms-160ms( n=225),QRS duration≥160ms(n=117),Left ventricular end diameter(LVEDD),left ventricular ejection fraction(LVEF) were measured by Dopper echocardiography. We propose that the QRS duration identify significant left ventricular systolic dysfunction in patients with LBBB.Results The 400 CLBBB patients complicated by Coronary heart disease 、hypertension、dilated cardiomyopathy 、hyperlipemia 、atrial fibrillation、ventricular arrhythmia、atrio-ventricular block Without organic heart disease and diabetes mellitus accounted for62.7%,59.5%,21.7%,36.2%,15.2%,18.5%,21.2%,24.5%and8%,respectively.About70.2% of CLBBB patients were complicated with cardiac myocardial dysfunction.the difference in clinical characteristics between CLBBB patients complicated with and without myocardial dysfunction were compared which have indicated that age≥65years,hypertension、coronary disease、atrial fibrillation、dilated cardiomyopathy and hyperlipemia were related to complete left bundle branch block(CLBBB)The results of logistic analysis showed that age≥ 65 years(P<0.01,B=3.123),Dilated cardiomyopathy(P< 0.05,B=2.209),hypertension(P<0.01,B=6.514), Coronary heart disease(P<0.01,B=2.688) were positively related to myocardial dysfunction The QRS duration also had a significant(P <0.001) inverse correlation with EF and LVEDD, The mean EF( 33.3±0.824) of the patients with a QRS duration of ≥160milliseconds(n = 175) was significantly lower than the mean EF(52.11±0.625) of the patients with a QRS duration of <160 milliseconds(n = 225, P <0.01),meanwhile The mean LVEDD(62.14±0.77) of the patients with a QRS duration of ≥160 milliseconds(n= 175) was significantly more than the mean LVEDD(49.71±0.544) of the patients with a QRS duration of <160 milliseconds(n = 225, P <0.01)Conclusion The most common combination is CLBBB with vascular hypertension,coronary heart disease, hyperlipemia, dilated cardiomyopathy. More than half of the CLBBB merged myocardial dysfunction。CLBBB patients, ≥ 65 years, with hypertension, coronary heart disease 、 dilated cardiomyopathy and hyperlipemia, are more susceptibly to suffer from myocardial dysfunction.The QRS duration has a more significant inverse relationship with EF and prolongation of QRS duration(≥160 milliseconds) in the presence of LBBB is a marker of significant left ventricular systolic dysfunction. The prolongation of QRS duration( ≥ 160milliseconds) was rather worse.