1. ¹Department of Medicine, Weill Medical College of Cornell University, New York, NY, USA
2. ²Department of Medicine, Glostrup University Hospital, Glostrup, Denmark
3. ³Haukeland University Hospital, Bergen, Norway
4. ⁴Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland
5. ⁵Sahlgrenska University Hospital/Östra, Gothenburg, Sweden

Correspondence: Dr RB Devereux, Weill Medical College of Cornell University, Division of Cardiology, Box 222, 525 East 68th Street, New York, NY 10021, USA. E-mail: rbdevere@med.cornell.edu

Abstract

Electrocardiographic (ECG) left bundle branch block (LBBB) is associated with left ventricular hypertrophy (LVH), but its relation to left ventricular (LV) geometry and function in hypertensive patients with ECG LVH is unknown. Echocardiograms were performed in 933 patients (548 women, mean age 667 years) with essential hypertension and LVH by baseline ECG in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study. LBBB, defined by Minnesota code 7.1, was present in 47 patients and absent in 886 patients. Patients with and without LBBB were similar in age, gender, body mass index, blood pressure, prevalence of diabetes, and history of myocardial infarction. Despite similarly elevated mean LV mass (12625 vs 12426 g/m²) and relative wall thickness (0.410.07 vs 0.410.07, P=NS), patients with LBBB had lower LV fractional shortening (306 vs 346%), ejection fraction (5610 vs 618%), midwall shortening (142 vs 162%), stress-corrected midwall shortening (9013 vs 9713%) (all P<0.001), and lower LV stroke index (387 vs 429 ml/m²) (P<0.05). Patients with LBBB also had reduced LV inferior wall and lower mitral E/A ratio (0.750.18 vs 0.870.38) (all P<0.05). The above univariate results were confirmed by multivariate analyses adjusted for gender, age, blood pressures, height, weight, body mass index, heart rate, and LV mass index. Among hypertensive patients at high risk because of ECG LVH, the presence of LBBB identifies individuals with worse global and regional LV systolic function and impaired LV relaxation without more severe LVH by echocardiography.