Similar incidence of PICM in patients with preserved and moderate range ejection fraction
S Howell, T Hamakarim, J Yu, S Mangal, V Edem, N Vijesuriya, F De Vere, A Liew, S Niederer, A RinaldiAbstract
Background
PICM is correlated with a high morbidity with an increase in hospitalisations and mortality. There is limited evidence to guide risk prediction of PICM, particularly in patients who had moderate LVEF 35-49% prior to implant. There is an unmet clinical need to understand of the prevalence and incidence of PICM in individuals with pacing devices and the contributory factors.
Methods
Retrospective review of patients with right ventricular pacing leads for symptomatic bradycardia, who developed PICM versus patients who did not. PICM was defined as >10% reduction in left ventricular ejection fraction reduction since pre-pacemaker implantation echocardiogram. Continuous variables in both groups were compared with multivariate logistic regression test and categorical variables were compared using the Chi-square test. A p-value of less than 0.05 was considered as statistically significant. Data was analysed with Stata 18.
Results
245 patients who received treatment at between June 2021 and May 2024 were screened and 145 patients fulfilled inclusion criteria. The mean age was ±72 years & 63.34% were male. 72% (n = 104) received a dual chamber and 28% (n=40) a single RV chamber pacemaker between 1987 to 2024. The prevalence of PICM in this cohort was 27.27% and further 20.8% developed a LVEF reduction of 5%, whilst 52% had no change in LVEF. There was no statistical difference in PICM incidence between patients who had moderate LVEF 35-49% prior to implant (n= 16) and were either not eligible or had a failed CRT implant, in comparison to patients with LVEF >50% at baseline (31.25% (n= 30) vs 28% (n=5), p 0.786). The incidence of PICM according to RV pacing site was RV apex 62.16%, RV septal 37.84%, p 0.354 in all patients and RV apex 41,67 % and RV septal 58.33%, p 0.49 with moderate LVEF prior to implant. Pre implant QRS duration was significantly different between both groups (94ms vs 134 ms, p 0.0006, Table 1) and was associated with a higher risk of PICM (OR 1.11, p 0.02) as was smoking, diabetes and AF. For every 1% increase in pacing burden the odds of PICM rose by 1.6% (p 0.0001). A longer paced QRS was significantly correlated with PICM.
Conclusion
PICM was common in this patient cohort occurring in 28% of patients with a pre implant LVEF >50%. Predictors of PICM included longer pre implant QRS duration, higher pacing percentage. New predictors were the presence of diabetes, atrial fibrillation and prior smoking. No difference in PICM was found in preserved and moderately reduced LVEF independent of RV pacing site. Future studies will show if prevention or treatment of these risk factors can reduce the incidence of PICM, especially in the case of physiological pacing which is associated with QRS reduction.Table 1&2Figure 1