High prevalence of left ventricular systolic and diastolic asynchrony in patients with congestive heart failure and normal QRS duration

Objective: To study the possible occurrence of left ventricular (LV) systolic and diastolic asynchrony in patients with systolic heart failure (HF) and narrow QRS complexes. Design: Prospective study. Setting: University teaching hospital. Patients: 200 subjects were studied by echocardiography. 67 patients had HF and narrow QRS complexes (less than or equal to 120 ms), 45 patients had HF and wide QRS complexes (> 120 ms), and 88 served as normal controls. Interventions: Echocardiography with tissue Doppler imaging was performed using a six basal, six mid-segmental model. Main outcome measures: Severity and prevalence of systolic and diastolic asynchrony, as assessed by the maximal difference in time to peak myocardial systolic contraction (T-s) and early diastolic relaxation (T-epsilon), and the standard deviation of T-s (T-s-SD) and of T-p (T-p-SD) of the 12 LV segments. Results: The mean (SD maximal difference in T, (controls 53 (23) ms v narrow QRS 107 (54) ms v wide QRS 130 (51) ms, both p < 0.001 controls) and in T -SD (controls 17.0 (7,8) ms v narrow QRS 318 (16.9) ms v wide QRS 42.0 (16.5) ms, both p < 0.001 v controls) was prolonged in the narrow QRS group compared with normal controls. Similarly, the maximal difference in T, (controls 59 (19) ms v narrow QRS 104 (71) ms v wide QRS 148 (87) ms, both p < 0.001 v controls) and in T-epsilon-SD (controls 18.5 (5.8) ms v narrow QRS 33.3 (277) ms v wide QRS 48.6 (30.2) ms, both p < 0.001 v controls) was prolonged in the narrow QRS group, The prevalence of systolic and diastolic asynchrony was 5 1 % and 46%, respectively, in the narrow QRS group, and 73% and 69%, respectively, in the wide QRS group. Stepwise multiple regression analysis showed that a low mean myocardial systolic velocity from the six basal LV segments and a large LV end systolic diameter were independent predictors of systolic asynchrony, while a low mean myocardial early diastolic velocity and QRS complex duration were independent predictors of diastolic asynchrony. Conclusions: LV systolic and diastolic mechanical asynchrony is common in patients with HF with narrow QRS complexes. As QRS complex duration is not a determinant of systolic asynchrony, it implies that assessment of intraventricular synchronicity is probably more important than QRS duration in considering cardiac resynchronisation treatment.