Ischaemic aetiology predicts exercise dyssynchrony in patients with heart failure with reduced ejection fraction

Left ventricular (LV) dyssynchrony is common in patients with heart failure with reduced ejection fraction (HFREF). However, various conditions including exercise may alter its presence. LV dyssynchrony at exercise (ExDYS) has been associated with lower cardiac performance and exercise capacity but with higher cardiac resynchronization therapy (CRT) response. Therefore, understanding mechanisms underlying ExDYS may improve patient selection for CRT.

To investigate for predictors of ExDYS among patients with HFREF and prolonged QRS duration.

Consecutive patients with stable, chronic HF, LVEF<35%, sinus rhythm and QRS≥120ms were eligible. 2D echocardiography and tissue-Doppler were performed at rest and peak cyclo-ergometer exercise to assess LV systolic (LVEF) and diastolic function [mitral E-to-e'-wave velocities (E/e')] and dyssynchrony. Dyssynchrony was defined as a maximal difference between time-to-peak systolic velocities of≥65ms from opposing basal segments.

We included 48 patients (aged 63.7±12.2, 81.3% male). Ischaemic aetiology (ICM) was present in 23 (47.9%). Dyssynchrony at rest (rDYS) was present in 32 (66.6%) patients, while ExDYS in 23 (47.9%). ExDYS correlated with ICM, lower LVEF and higher E/e' ratio. ICM remained significant predictor of ExDYS in multiple regression model (OR:4.3, 95%CI:1.2-15.7, p=003). On exercise, 19 (39.5%) patients changed the rDYS status. While, exercise-induced dyssynchronization was observed only in ICM patients, exercise-induced resynchronization was more likely in patients with lower rest E/e' ratio (OR:0.85, 95%CI:0.75-0.97, p=0.02).

Ischaemic aetiology of HFREF is an important predictor of ExDYS. Restoration of LV synchronicity during exercise is more likely in patients with less advanced LV diastolic dysfunction.