Title: " Patterns of ventricular dyssynchrony in heart failure - Implications for Cardiac Resynchronisation therapy "

Abstract:

Cardiac Resynchronization Therapy (CRT) has proven to be beneficial for patients with heart failure with wide QRS. The basis for CRT is correction of ventricular dyssynergy, but about a third of them fail to show adequate clinical response. Tissue Doppler Imaging (TDI) is a new echocardiographic modality, which reliably demonstrates LV dyssynchrony.

This prospective study was undertaken to assess the patterns of LV dyssynchrony in unselected heart failure population with narrow and wide QRS electrocardiograms using TDI.

50 consecutive symptomatic patients (37 males and 13 females) with systolic heart failure (LVEF£40%) underwent TDI for assessment of ventricular dyssynchrony. Their mean age was 55 .11 yrs and mean LVEF was 32 . 6%. 33(66%) patients had wide QRS (> 120 msec, mean159 26 msec) while 17 (34%) patients had narrow QRS. (< 120 msec, mean 92 .4 msec). Intraventricular dyssynchrony was demonstrated in 30 patients (60%). The distribution of regional dyssynchrony was lateral wall (40%), Septal (20%), Inferior wall (12%), and posterior wall (8%). Dyssynchrony was demonstrated in 1 region in 38%,2 regions in 12% and > 2 regions in 6% of the patients. The prevalence of dyssynchrony in patients with wide and narrow QRS, (61% vs. 59% p=ns) with and without regional wal. 1 motion abnormality (RWMA) (50% vs. 66-6%) was similar. (P=ns). 38% of patients with LBBB did not have dyssynchrony.

Intraventricular dyssynchrony is present in about two thirds of heart failure population and is present in a significant proportion of patients with and without wide QRS.About a third of patients with LBBB do not demonstrate dyssynchrony. These may have implications for selection of patients for resynchronization therapy and selection of site for LV pacing.