title: Paced QRS duration and myocardial scar amount: predictors of long-term outcome of right ventricular apical pacing.
abstract: Long-term right ventricular apical pacing (RVAP) is reportedly associated with heart failure (HF) development. However, the predictors of pacing-induced HF (PHF) remained unclear. We retrospectively enrolled 234 patients without structural heart disease who underwent a permanent pacemaker implantation with RVAP between 1982 and 2004. RVAP-induced HF was defined as left ventricular ejection fraction decrease >5 % with HF symptom without other HF development etiology. The QRS duration of a paced beat (pQRSd) and myocardial scar score were analyzed from each patient's 12-lead ECG. During a mean 15.6 years (range 3.3-30.0 years), 48 patients (20.5 %) patients developed RVAP-induced HF. The PHF group patients had a longer pQRSd (192.4 ± 13.5 vs. 175.7 ± 14.7 ms in non-PHF patients, p < 0.001) and a higher myocardial scar score (5.2 ± 1.9 vs. 2.7 ± 1.9, respectively p < 0.001). In multivariate Cox regression analysis, old age at implantation [Hazard ratio (HR) 1.62, 95 % confidential interval (CI) 1.22-2.16, p = 0.001], a longer pQRSd (HR 1.54, 95 % CI 1.15-2.05, p = 0.003), a higher myocardial scar score (HR 1.23, 95 % CI 1.03-1.49, p = 0.037), and a higher percentage of ventricular pacing (HR 1.31, 95 % CI 1.01-1.49, p = 0.010) were independent predictors of PHF. Based on the results of the receiver-operating characteristic (ROC) curve, the pQRSd cutoff was 185 ms (AUC 0.79, sensitivity 66.7 %, specificity 76.3 %) and myocardial scar score cutoff value was 4 (AUC 0.81, sensitivity 81.3 %, specificity 66.1 %). The pQRSd was positively correlated with scar score (r = 0.70, p < 0.001). pQRSd ≥185 ms and/or myocardial scar score ≥4 might be independent long-term prognostic markers of PHF.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi, Korea.
authors.forename: Seung-Ah
authors.initials: SA
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Korea.
authors.forename: Myung-Jin
authors.initials: MJ
authors.lastname: Cha
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi, Korea.
authors.forename: Youngjin
authors.initials: Y
authors.lastname: Cho
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi, Korea.
authors.forename: Il-Young
authors.initials: IY
authors.lastname: Oh
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Korea.
authors.forename: Eue-Keun
authors.initials: EK
authors.lastname: Choi
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Korea. seil@snu.ac.kr.
authors.forename: Seil
authors.initials: S
authors.lastname: Oh
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects* / Q000379:methods; D016009:Chi-Square Distribution; D002921:Cicatrix / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012372:ROC Curve; D056910:Republic of Korea; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right
keywords: Myocardial scar; Paced QRS duration; Pacing-induced heart failure; Right ventricular apical pacing