Beneficial effects of upgrading to His bundle pacing in chronically paced patients with left ventricular ejection fraction50

Heart failure is common in patients with permanent pacemakers. Right ventricular (RV) pacing may worsen cardiac function, while the nonresponder rate of cardiac resynchronization therapy (CRT) for heart failure treatment remains 25%-30%.The purpose of this study was to assess clinical outcomes of upgrading to permanent His bundle pacing (pHBP) in patients with heart failure who underwent device upgrade from right ventricular pacing or CRT nonresponse.Eighteen patients with pacing-dependent heart failure and left ventricular ejection fraction (LVEF)50% underwent pHBP attempts at device replacement. Of those 18 patients, 16 (88.9%) received pHBP successfully and followed for a mean of 36.2 months. All these patients underwent clinical evaluation, echocardiography, brain natriuretic peptide assay, and chest radiography immediately before replacement and during follow-up visits.Of the 16 patients (mean age 70.6 ± 12.9 years; 9 [56.3%] men), 11 (68.8%) patients had pacing-induced cardiomyopathy (PICM) while the remaining 5 (31.2%) patients were CRT nonresponders. After upgrading to pHBP, QRS duration was significantly shortened (from 156.9 ± 21.7 to 107.1 ± 16.5 ms; P.01). At 1-year follow-up after HBP, left ventricular end-diastolic dimensions decreased from baseline 62.3 ± 6.9 to 55.5 ± 7.7 mm (P.01) and LVEF increased from baseline 35.7% ± 7.9% to 52.8% ± 9.6% (P.01). Other improvements after HBP upgrade included mitral valve regurgitation, serum brain natriuretic peptide concentrations, cardiothoracic ratios, and New York Heart Association functional class (P.01 for all).In paced patients with clinically symptomatic heart failure and LVEF50%, pHBP upgrade was feasible in 88.9%, with improved left ventricular function and remodeling. Hence, pHBP can be an alternative for patients with pacing-induced cardiomyopathy and CRT nonresponders.