His Bundle Pacing Improves LV Diastolic Function in Patients with Heart
Failure with Preserved Systolic Function
Abstract
Cardiac resynchronization therapy (CRT) is highly effective for patients
with left bundle branch block (LBBB), heart failure and left ventricular
(LV) systolic dysfunction. Chronic right ventricular (RV) apical pacing
is associated with pacing-induced cardiomyopathy and can be associated
with exertional intolerance. The goal of this study was to assess the
acute hemodynamic effects of His-bundle Pacing (HBP) compared to RV
apical pacing in absence of LV systolic dysfunction in patients with
exertional intolerance. Our patient population consisted of 5 patients
with preserved LV systolic function and complete AV block. All five
patients suffered from exertional intolerance in spite of preserved LV
systolic function. At the time of generator change, all patients
underwent implantation of a HBP lead. The QRS duration decreased from
179±13 ms with RVP to 113±6 with HBP (p < 0.001). Compared to
RVP, HBP was associated with significantly longer diastolic filling time
and improved septal early diastolic myocardial relaxation velocity (E’).
Four of five patients noted acutely improved exertional dyspnea. In
patients with AV block, exertional intolerance and preserved LV systolic
function who are treated with chronic RV apical pacing, HBP may improve
acute diastolic function and symptoms of exertional intolerance when
compared to RV apical pacing. Randomized controlled trials are warranted
to explore the effects of conduction system pacing in this unique
patient population.