Early and late changes in right heart echocardiographic parameters in hypertrophic cardiomyopathy patients after transvenous cardiac device implantation.

Abstract Background Transvenous dual-chamber pacemakers (PPM) or implantable cardioverter defibrillators (ICD) are routinely implanted in patients with hypertrophic cardiomyopathy (HCM) to manage bradycardia, treat symptomatic obstruction, and mitigate risk of sudden cardiac death. The short- and long-term effects of different types of right ventricular (RV) lead crossing the tricuspid valve (TV) on HCM patients’ right heart structure and function are unknown. Differences between pacing and defibrillator leads may be clinically important in device selection because of potential deleterious effects on TV and right heart function. Purpose To assess early and late changes in right heart transthoracic echocardiographic (TTE) parameters following dual chamber PPM/ICD implant in HCM patients. Methods Retrospective assessment of HCM patients with dual chamber PPM/ICD device and available pre, early (1 year) and late (1 year) post implant TTE. Clinically reported measurements assessed were right atrial area (RAa), right ventricular basal diameter (RVd), pulmonary artery systolic pressure (PASP) and tricuspid regurgitation (TR) category. Changes in parameters were assessed between the three time points, with comparison between ICD / PPM subgroups made. Results Between July 2017 and April 2024, 213 consecutive HCM patients underwent device implantation (64% male, 60.4±14.5 years, 67% ICD) with available TTE imaging. Median duration was 0.5 (IQR 0.2 to 1) years between pre-implant TTE and device implant; 0.7 (IQR 0.4 to 1.1) years between device implant and early post-implant TTE, and 3 (IQR 1.8 to 4.7) years between device implant and late TTE. Of the 161 patients with paired data, mean pre, early and late RAa was 17.7±6.1, 19.6±6.5 and 21.1±7.3cm2 respectively (p0.0001), (Figure 1 panel A). Of the 160 patients with paired data, mean pre, early and late RVd was 36.2±5.5, 38.1±5.5 and 40±5.8mm respectively (p0.0001). Of the 60 patients with paired data, mean pre, early and late PASP was 32.2±12.1, 32.2±10.8 and 37.3±12.6mmHg, p=0.053 (Figure 1, panel C). Of the 160 patients with paired TR severity data there were significant increases in category across the three time points (p0.0001), (Figure 1, panel D further work will determine the extent to which observed changes are secondary to the disease progression rather than iatrogenic.