Association of cardiovascular magnetic resonance-derived circumferential strain parameters with the risk of ventricular arrhythmia and all-cause mortality in patients with prior myocardial infarction and primary prevention implantable cardioverter defibrillator

Abstract

Background: Impaired left ventricular (LV) contraction and relaxation may further promote adverse remodeling and may increase the risk of ventricular arrhythmia (VA) in ischemic cardiomyopathy. We aimed to examine the association of cardiovascular magnetic resonance (CMR)-derived circumferential strain parameters for LV regional systolic function, LV diastolic function and mechanical dispersion with the risk of VA in patients with prior myocardial infarction and primary prevention implantable cardioverter defibrillator (ICD).

Methods: Patients with an ischemic cardiomyopathy who underwent CMR prior to primary prevention ICD implantation, were retrospectively identified. LV segmental circumferential strain curves were extracted from short-axis cine CMR. For LV regional strain analysis, the extent of moderately and severely impaired strain (percentage of LV segments with strain between - 10% and - 5% and > - 5%, respectively) were calculated. LV diastolic function was quantified by the early and late diastolic strain rate. Mechanical dispersion was defined as the standard deviation in delay time between each strain curve and the patient-specific reference curve. Cox proportional hazard ratios (HR) (95%CI) were calculated to assess the association between LV strain parameters and appropriate ICD therapy.

Results: A total of 121 patients (63 ± 11 years, 84% men, LV ejection fraction (LVEF) 27 ± 9%) were included. During a median (interquartile range) follow-up of 47 (27;69) months, 30 (25%) patients received appropriate ICD therapy. The late diastolic strain rate (HR 1.1 (1.0;1.2) per - 0.25 1/s, P = 0.043) and the extent of moderately impaired strain (HR 1.5 (1.0;2.2) per + 10%, P = 0.048) but not the extent of severely impaired strain (HR 0.9 (0.6;1.4) per + 10%, P = 0.685) were associated with appropriate ICD therapy, independent of LVEF, late gadolinium enhancement (LGE) scar border size and acute revascularization. Mechanical dispersion was not related to appropriate ICD therapy (HR 1.1 (0.8;1.6) per + 25 ms, P = 0.464).

Conclusions: In an ischemic cardiomyopathy population referred for primary prevention ICD implantation, the extent of moderately impaired strain and late diastolic strain rate were associated with the risk of appropriate ICD therapy, independent of LVEF, scar border size and acute revascularization. These findings suggest that disturbed LV contraction and relaxation may contribute to an increased risk of VA after myocardial infarction.

Keywords: Circumferential strain; Ischemic cardiomyopathy; Magnetic resonance; Ventricular arrhythmia.

Fig. 1

Kaplan-Meier curves for the cumulative incidence of appropriate implantable cardioverter defibrillator (ICD) therapy, with the observed median as the cut-off. P values for the log-rank test are shown

Fig. 2

Example of left ventricular (LV) circumferential strain in a patient without and with appropriate ICD therapy. LV bullseye representation of peak systolic strain, late diastolic strain rate and mechanical dispersion and LV segmental strain curves per slice with LV segmental peak systolic strain (orange dots), early diastolic strain rate (red dots), late diastolic strain rate (blue dots) and normalized curves with the patient-specific reference curve (black dotted lines). In the LV bullseye for mechanical dispersion, LV segments with early and late contraction patterns are shown in red and blue, respectively. (Upper panel) 71-year-old woman without appropriate ICD therapy (LV ejection fraction (LVEF) 30%). (Lower panel) 71-year-old man with appropriate ICD therapy at 40 months after ICD implantation (LVEF 26%). In the presented patient with appropriate ICD therapy, the extent of moderately impaired strain (percentage of LV segments with peak systolic strain between − 5% and − 10%) is relatively large, the early and late diastolic strain rate are low, whereas mechanical dispersion is comparable in the presented cases