Biventricular pacing during cardiac magnetic resonance imaging

Abstract

Aims We aimed to assess the effect of cardiac resynchronization on left ventricular (LV) function, volumes, geometry, and mechanics in order to demonstrate reverse remodelling using cardiac magnetic resonance (CMR) with resynchronization on. Methods and results New York Heart Association (NYHA) Class II–III patients on optimal medical therapy with LV ejection fraction (LVEF) ≤35%, and complete LBBB with broad QRS (>150 ms) were prospectively recruited. Cardiac magnetic resonance examination was performed at baseline and at 6-month follow-up, applying both biventricular and AOO pacing. The following data were measured: conventional CMR parameters, remodelling indices, global longitudinal, circumferential, radial strain, global dyssynchrony [mechanical dispersion (MD) defined as the standard deviation of time to peak longitudinal/circumferential strain in 16 LV segments], and regional dyssynchrony (maximum differences in time between peak septal and lateral transversal displacement). Thirteen patients (64 ± 7 years, 38% male) were enrolled. Comparing the baseline and follow-up CMR parameters measured during biventricular pacing, significant increase in LVEF, and decrease in LV end-diastolic volume index (LVEDVi) and LV end-systolic volume index (LVESVi) were found. Left ventricular remodelling indices, global longitudinal, circumferential, and radial strain values showed significant improvement. Circumferential MD decreased (20.5 ± 5.5 vs. 13.4 ± 3.4, P < 0.001), while longitudinal MD did not change. Regional dyssynchrony drastically improved (362 ± 96 vs. 104 ± 66 ms, P < 0.001). Applying AOO pacing resulted in an immediate deterioration in LVEF, LVESVi, circumferential strain, global and regional dyssynchrony. Conclusion Cardiac magnetic resonance imaging during biventricular pacing is feasible and enables a more precise quantification of LV function, morphology, and mechanics. As a result, it may contribute to a better understanding of the effects of resynchronization therapy and might improve responder rate in the future.

Cardiovascular Imaging Applications in Clinical Management of Patients Treated with Cardiac Resynchronization Therapy

“…Beyond conventional CMR parameters, remodelling indices, global strain, global dyssynchrony (i.e., mechanical dispersion, defined as the standard deviation of time to peak longitudinal/circumferential strain in 16 LV segments), and regional dyssynchrony (maximum differences in time between peak septal and lateral transversal displacement), were analysed. The authors found a significant improvement in LV functional and dyssynchrony parameters during biventricular pacing at follow-up [45]. By switching from biventricular to right atrial pacing, an immediate deterioration of LV function and mechanics was observed [45].…”

“…The authors found a significant improvement in LV functional and dyssynchrony parameters during biventricular pacing at follow-up [45]. By switching from biventricular to right atrial pacing, an immediate deterioration of LV function and mechanics was observed [45].…”

“…Long-term changes in LV dyssynchrony have been also analysed by using nuclear imaging [44] and MRI [45]. In the study by Domenichini et al [44], LVEF and RV ejection fraction (RVEF) were measured by radionuclide angiography at baseline and mid-term follow-up.…”

“…The authors found that baseline left bundle branch block morphology was a marker of positive response to CRT in terms of improvement not only in LVEF but also in RVEF [44]. In a recent study by Vago et al [45], CMR was performed in CRT patients at baseline and at a 6-month follow-up, with acquisitions both during biventricular pacing and right atrial pacing. Beyond conventional CMR parameters, remodelling indices, global strain, global dyssynchrony (i.e., mechanical dispersion, defined as the standard deviation of time to peak longitudinal/circumferential strain in 16 LV segments), and regional dyssynchrony (maximum differences in time between peak septal and lateral transversal displacement), were analysed.…”

Safety of magnetic resonance imaging scanning in patients with cardiac resynchronization therapy–defibrillators incorporating quadripolar left ventricular leads

“…Some recent publications included a limited number of CRT patients within a larger study, 4,5 but most studies to date have included only bipolar LV leads with limited thoracic or chest MRI locations. Exception are the studies of Sheldon et al, 6 who included 1 patient with a quadripolar lead, and Vago et al, 7 who performed cardiac MRI on 13 patients implanted with MRI-conditional CRTs during biventricular pacing (DOO) and right atrial pacing (AOO) with no reported device complications. The use of quadripolar LV leads has become standard of care.…”