Morphologies and prognostic significance of left ventricular volume/time curves with cardiac magnetic resonance in patients with non-ischaemic heart failure and left bundle branch block

Alberto Aimo,Alessandro Valleggi,Giovanni Donato Aquaro,Andrea Barison,Michele Emdin,Sara Salerni

doi:10.1007/s10554-021-02194-3

Abstract

Patients with non-ischaemic systolic heart failure (HF) and left bundle branch block (LBBB) can display a wide or narrow pattern (WP/NP) of the systolic phase of the left ventricular (LV) volume/time (V/t) curve in cardiac magnetic resonance (CMR). The clinical and prognostic significance of these patterns is unknown. Consecutive patients with non-ischaemic HF, LV ejection fraction < 50% and LBBB underwent 1.5 T CMR. Maximal dyssynchrony time (time between the earliest and latest end-systolic peaks), systolic dyssynchrony index (standard deviation of times to peak volume change), and contractility index (maximum rate of change of pressure-normalized stress) were calculated. The endpoint was a composite of cardiovascular death, HF hospitalization, and appropriate defibrillator shock. NP was found in 29 and WP in 72 patients. WP patients had higher volumes and NT-proBNP, and lower LVEF. WP patients had a longer maximal dyssynchrony time (absolute duration: 192 ± 80 vs. 143 ± 65 ms, p < 0.001; % of RR interval: 25 ± 11% vs. 8 ± 4%, p < 0.001), a higher systolic dyssynchrony index (13 ± 4 vs. 7 ± 3%, p < 0.001), and a lower contractility index (2.6 ± 1.2 vs 3.2 ± 1.7, p < 0.05). WP patients had a shorter survival free from the composite endpoint regardless of age, NT-proBNP or LVEF. Nonetheless, WP patients responded more often to cardiac resynchronization therapy (CRT) than those with NP (24/28 [86%] vs. 1/11 [9%] responders, respectively; p < 0.001). In patients with non-ischaemic systolic HF and LBBB, the WP of V/t curves identifies a subgroup of patients with greater LV dyssynchrony and worse outcome, but better response to CRT.

Highlights

Cardiac magnetic resonance (CMR) provides morphologic and functional information relevant to a broad array of cardiovascular disorders
Consecutive patients with non-ischaemic systolic heart failure (HF) (LVEF < 50%) and left bundle branch block (LBBB) evaluated in the outpatient clinic of a tertiary referral centre for HF (Fondazione Toscana Gabriele Monasterio, Pisa, Italy) were referred to CMR examination at the same Institution
The wide pattern (WP) was associated with more severe dyssynchrony and lower left ventricular (LV) contractility

Summary

Introduction

Cardiac magnetic resonance (CMR) provides morphologic and functional information relevant to a broad array of cardiovascular disorders. Several techniques for the evaluation of LV dyssynchrony by CMR have been proposed [3]. Conventional analysis of the short-axis, balanced steady-state free precession (bSSFP) acquisition allows to calculate LV volume/time curves and their first derivative dV/dt across all cardiac phases; cardiac dyssynchrony can be assessed by visualizing how steep the ventricular emptying is and how it is distributed throughout systole. Sohal et al introduced the systolic dyssynchrony index, defined as the standard deviation of the regional times to peak volume change from segmental volume/time (V/t) curves [4]. Further analyses may be performed by tracking myocardial deformation during the cardiac cycle and calculating systolic strain and strain rate.

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