Effects of frequent right ventricular apical pacing on heart failure in a population with single-chamber pacemaker implantation

Objective:To evaluate the risk of new-onset heart failure and the changes of serum concentration of N-terminal fragment of the prohormone brain-type natriuretic peptide (NT-proBNP) in a population with right ventricular apical pacing as different cumulative percent of right venticular pacing (CUM%VP).Methods:A cohort study was conducted among 74 patients with sick sinus syndrome (SSS) or atrioventricular block (AVB) after single-chamber ventricular pacemaker implantation. According to the cut-point of 75% of CUM%VP, patients were divided into group A (CUM%VP≥75%, n=29) and group B (CUM%VP75%, n=45). The primary composite endpoint was defined as new-onset heart failure (NYHA class ≥Ⅲ or hospitalization for heart failure)and death from all causes. The left ventricular ejection fraction (LVEF) and left ventricular end-diastolic volumes (LVEDV) were measured echocardiographically and the serum concentration of NT-proBNP by ECLIA, and their absolute alterations(△LVEF, △LVEDV, △NT-proBNP) as compared with the baseline measurements were also calculated. Additionally, the data of NT-proBNP were expressed as median and interval of quartiles rank [25%, 75% percentiles]. Results:Before pacemaker implantation, there were no differences in age, sex, basic diseases, cardiac function, and constituent ratio in type of pacemakers between group A and B. The mean duration of follow-up was (31.0±11.4) months. There were no death, dropout, and loss to follow-up. By comparing the outcomes of group A with those of group B at end of the study, it showed that: ①LVEF in group A was significantly lower[(56.4±7.4)% vs (60.9±6.8)%, P=0.01], with a more absolute decrease in LVEF[△LVEF: (-4.1±8.67)% vs (2.0±5.7)%, P=0.001] than those in group B; LVEDV in group A was significantly larger (150.2 ml±11.5 ml vs 145.0 ml±10.0 ml, P=0.043), with a more absolute increase in LVEDV (△LVEDV: 7.75 ml±12.62 ml vs 2.80 ml±7.53 ml, P=0.04) than those in group B; NYHA class in group A was significantly higher than that in group B(1.93±0.99 vs 1.51±0.69, P=0.036); ②serum concentration of NT-proBNP and absolute changes of NT-proBNP in group A were all higher than those in group B (NT-proBNP: 2 245[446, 3 312] pg/ml vs 376 [214, 950] pg/ml, P=0.001; △NT-proBNP: 1 443[115, 2 931]pg/ml vs 187[80, 489]pg/ml, P=0.003), and serum concentration of NT-proBNP was increased with cardiac function exacerbation; ③the primary endpoint presented no death but new-onset heart failure in 24.1% (7 of 29)cases of group A and 6.7% (3 of 45) of group B, respectively (RR=3.6, 95% CI 1.017-12.885, P=0.032); The accumulative events-free survival rates (or survival time) were 75.9% (or 42.6±13.9 months) in group A and 93.3% (or 50.8±11.4 months) in group B, respectively (P=0.015). Conclusions:Frequent right ventricular apical pacing increases the risk of new-onset of heart failure in a population with single-chamber pacemaker implantation,and the serum concentration of NT-proBNP, and CUM%VP combined with NT-proBNP may be used as a prospectively predictive indicator of heart failure for these people.