Abstract
The aim of this study is to observe the differences between mechanical and electrical dyssynchrony in patients with impaired systolic ventricular function and symptomatic heart failure and to highlight the importance of mechanical dyssynchrony besides electrical dyssynchrony in clinical guidelines and clinical practice. Fifty-eight patients with heart failure, who are with the New York Heart Association (NYHA) functional class II-IV and left ventricular ejection fraction (LVEF) under 35%, were enrolled. Patients were divided into two groups, according to the duration of QRS complex (> 120 ms and ≤ 120 ms respectively). Echocardiographic parameters of interventricular (interventricular mechanical delay - IMD) and intraventricular (septal-to-posterior wall motion delay - SPWMD) dyssynchrony were measured in both groups. Results indicate that the duration of the QRS complex (i.e. electrical dyssynchrony) is not a fully reliable indicator of ventricular dyssynchrony; therefore ecocardiographic evaluation of mechanical dyssynchrony should also be recommended for better selection of candidates for cardiac resynchronization therapy (CRT).