List of Authors:
Cheuk-Man Yu, MD, FRCP; Fang Fang, PhD, Jeffrey Wing-Hong Fung, MD, FRCP Qing Zhang, MM, PhD; Omar Razali, MD; Gabriel Wai-Kwok Yip, MD, FACC; Hussin Azlan, MD; Hamish Chi-Kin Chan, FRCP; Joseph Yat-Sun Chan, FHKAM(Medicine)
Abstract:
Objectives: Pacing to Avoid Cardiac Enlargement (PACE) trial is a prospective, double-blinded, randomized, multicenter study that reported the superiority of biventricular (BiV) pacing to right ventricular apical (RVA) pacing in prevention of left ventricular (LV) adverse remodeling and deterioration of systolic function at 1-year. In the current analysis, we reported the results at extended 2-year follow-up and the potential baseline predictors of deterioration of LV systolic function.
Methods: Patients (N=177) with bradycardia and preserved LV ejection fraction (EF) were randomized to receive RVA or BiV pacing. Co-primary end-points were LV end-systolic volume (LVESV) and LVEF measured mostly be 3D echocardiography. Primary analysis was based on intention-to-treat, and drop outs were analyzed according to last-observation-carried-forward principle.
Results: Eighty-one (92%) out of 88 patients in RVA pacing group and 82 (92%) out of 89 patients in BiV pacing group completed 2-year follow-up. In the RVA pacing group, LVEF further decreased from 1st to 2nd year, but remain unchanged in the BiV pacing group, leading to a significant difference of 9.9 points at 2nd year (p<0.001) (Table). Similarly, LVESV continue to enlarge from 1st to 2nd year in the RVA pacing group, leading to a difference of 13.0ml (p<0.001). There were 4 deaths in the RVA group and 3 in BiV group (log-rank χ2=0.15, p=0.62); and 6 hospitalization in RVA pacing group 5 in BiV pacing group for heart failure (Log rank χ2=0.17, p=0.68). Eighteen patients in BiV pacing group (20.2%) and 55 in RVA pacing group (63.0%) had significant reduction of LVEF, ie.≥5% (2=32.6, p<0.001).
Conclusion: LV adverse remodeling and deterioration of systolic function continues at the 2nd year after RVA pacing, which was prevented effectively by the use of BiV pacing.
| |
RVA pacing (n=81)
|
BiV pacing (n=82)
|
| |
Baseline
|
1 Year |
2 Year |
Baseline |
1 Year |
2 Year |
| LV end-diastolic volume, ml |
73.3±19.8 |
76.7±22.5 |
75.5±30.5 |
74.3±17.5 |
71.5±17.8 |
70.6±17.5 |
| LV end-systolic volume, ml |
28.4±10.7 |
35.7±16.2† |
38.3±20.3†‡ |
28.2±9.4 |
27.6±10.2* |
25.3±10.2* |
| LV ejection fraction, % |
61.5±6.6 |
54.8±9.2† |
53.0±10.1†‡ |
61.8±6.7 |
62.2±7.0* |
62.9±8.8* |
*p<0.001 vs. corresponding column of the RVA pacing group;
†p<0.05 vs. baseline in the same pacing group;
‡p<0.05 vs.1 year in the same pacing group.
Report:
Chronic right ventricular pacing, adverse remodelling, and CRT: an ounce of prevention?
(European Heart Journal, ESC Clinical trial update complimentary, doi:10.1093/eurheartj/ehr337)
This editorial refers to ‘Biventricular pacing is superior to right ventricular pacing in bradycardia patients with preserved systolic function: 2-year results of the PACE trial,’ by J.Y.-S Chan et al., doi:10.1093/eurheartj/ehr336
In medicine, it is encouraging when research yields results consistent with our understanding of the operative mechanisms, especially when there is a direct potential impact on clinical practice. Chan et al. have provided us with such a result and a clear message.1 The 2-year follow-up in the Pacing to Avoid Cardiac Enlargement (PACE) trial confirms that chronic right ventricular (RV) pacing in patients with bradycardia and preserved left ventricular (LV) function leads to sustained and progressive deterioration of LV ejection fraction (EF) and increases in LV volumes. This adverse remodelling process was prevented by pacing with cardiac resynchronization therapy (CRT).
Adverse LV remodelling is a complex maladaptive process involving... [more in EHJ: doi:10.1093/eurheartj/ehr337].