Upgrading Pacemaker to Cardiac Resynchronization Therapy: An Option for Patients with Chronic Right Ventricular Pacing and Heart Failure

Introduction: Long-term pacing from the right ventricle (RV) has been shown to induce a deleterious effect on left ventricular function. Cardiac resynchronization therapy (CRT) is an established treatment for heart failure (HF) patients. The purpose of this study was to assess the benefit from upgrading to CRT in chronically RV-paced patients with a low left ventricular ejection fraction (LVEF<35%). Methods: Thirty-seven HF patients (age 71.4 ± 7.7, 26 male), who fulfilled CRT indications, were included. Study subjects had undergone VVI or DDD pacemaker implantation 6.1 ± 5.7 years earlier and were referred to our centre because of worsened clinical condition or a depleted battery. Patients were assessed at baseline and six months after CRT. Evaluation included NYHA classification, functional capacity assessed by sixminute walk test (6MWT), hospitalization rate and echocardiographic assessment. Results: Biventricular pacing was possible in 34 of the 37 cases (91.7%) who had their device upgraded to CRT-P (n=8) or to CRT-D (n=26). After the implementation of CRT the patients showed a noteworthy clinical improvement. Average NYHA class changed from 3.3 ± 0.6 to 2.5 ± 0.9 (p<0.001), 6MWT performance increased from 246 ± 105 m to 321 ± 101 m (p<0.001), while six-month hospitalization rate dropped from 1.4 ± 1 to 0.7 ± 0.8 admissions (p<0.001). LVEF increased from 26.3 ± 5.4% to 31.4 ± 6.7% (p<0.001) and left ventricular end-systolic volume changed from 134.3 ± 46 mL to 111.9 ± 41.1 mL (p<0.001). A reduction in QRS duration by 28 ms (p<0.001) was also noted. Conclusions: RV-paced patients should be closely monitored, and upgrade to CRT should be considered promptly if they develop moderate or severe HF.