Echocardiographic mechanical dyssynchrony predicts long-term mortality in patients with cardiac resynchronisation therapy

Abstract

Cardiac resynchronisation therapy (CRT) is an established treatment for patients with symptomatic heart failure with reduced left ventricular ejection fraction (LVEF ≤ 35%; HFrEF) and conduction disturbances (QRS duration ≥ 130 ms). The presence of mechanical dyssynchrony (MD) on echocardiography has been hypothesised to be of predictive value in determining indication for CRT. This study investigated the impact of MD (apical rocking [AR] and septal flash [SF]) on long-term survival in CRT recipients. HFrEF patients (n = 425; mean age 63.0 ± 10.6 years, 72.3% male, 60.7% non-ischaemic aetiology) with a guideline-derived indication for CRT underwent device implantation. MD markers were determined at baseline and after a mean follow-up of 11.5 ± 8.0 months; long-term survival was also determined. AR and/or SF were present in 307 (72.2%) participants at baseline. During post-CRT follow-up, AR and/or SF disappeared in 256 (83.4%) patients. Overall mean survival was 95.9 ± 52.9 months, longer in women than in men (109.1 ± 52.4 vs. 90.9 ± 52.4 months; p < 0.001) and in younger (< 60 years) versus older patients (110.6 ± 53.7 vs. 88.6 ± 51.1 months; p < 0.001). Patients with versus without MD markers at baseline generally survived for longer (106.2 ± 52.0 vs. 68.9 ± 45.4 months; p < 0.001), and survival was best in patients with resolved versus persisting MD (111.6 ± 51.2 vs. 79.7 ± 47.6 months p < 0.001). Age and MD at baseline were strong predictors of long-term survival in HFrEF patients undergoing CRT on multivariate analysis. Novel echocardiography MD parameters in HFrEF CRT recipients predicted long-term mediated better outcome, and survival improved further when AR and/or SF disappear after CRT implantation.

Keywords: Apical rocking; Cardiac resynchronisation therapy; Long-term survival; Mechanical dyssynchrony; Septal flash.

Fig. 1

Structure and course of the study. AR apical rocking, CRT cardiac resynchronisation therapy, SF septal flash

Fig. 2

Kaplan–Meier survival curves for patients with versus without mechanical dyssynchrony on baseline echocardiography

Fig. 3

Kaplan–Meier survival curves for patients with versus without resolution of mechanical dyssynchrony after cardiac resynchronisation therapy

Fig. 4

Example of Septal flash (SF) simply identified on 2D echocardiography using M-Mode, SF represented as a short inward early systolic motion of the septum due to the early septal excitation and contraction

Fig. 5

Example of Apical rocking in 2D images, apical rocking occurs due to early activation and contraction of the septum pulling the apex towards right ventricle (marked below in yellow and red) followed by delayed activation and contraction of the lateral wall pulling the apex back to the left (marked below in blue and turquoise) and stretching the relaxed septum