Left ventricular volumes and systolic function after long-term right ventricular pacing may be predicted by paced QRS duration, but not pacing site

Do the predictors of right ventricular pacing-induced cardiomyopathy add up?

Objective

Knowledge of factors causing pacing-induced cardiomyopathy (PICM) is incomplete. We sought to estimate the incidence and predisposing factors for PICM and evaluate if the risk they portend adds up.

Methods

Single centre retrospective study where consecutive patients with preserved LVEF undergoing pacemaker (PM) implantation between 2012 and 2018 were analysed.

Results

A total of 749 patients (68.4 % male; mean age 59.2 ± 14.08 years) were included in the analysis. PICM developed in 74 (9.9%) patients over a median follow up of 2.2 years (IQR 1.1–3.2). Pre-implant LVEF, paced QRS duration and RV pacing burden were independent predictors of PICM. Using 90 % specificity cut-off values for LVEF and paced QRS, and the value separating lowest tertile of RV pacing from the higher tertiles, three risk factors were identified: (i) baseline LVEF < 55 %, (ii) paced QRS duration > 160 msec, and (iii) RV pacing burden > 33 %. Patients with two or more risk factors were at the highest risk (OR 11.62, 95 % CI 4.62–29.21, p-value < 0.001) for developing PICM while those with one risk factor had an intermediate risk (OR 3.89, 95 % CI 1.62–9.34, p-value 0.002) when compared to those without any risk factors.

Conclusion

Low-normal baseline LVEF, wider paced QRS and higher RV pacing burden independently predicted the development of PICM. The presence of ≥2 factors increased the odds of PICM, twelve-fold. A narrower paced QRS, the only modifiable risk factor may help mitigate development of PICM.

Incidence and predictors of pacemaker-induced cardiomyopathy with comparison between apical and non-apical right ventricular pacing sites

BACKGROUND

Asynchronous activation of left ventricle (LV) due to chronic right ventricular (RV) pacing has been known to predispose to LV dysfunction. The predictors of LV dysfunction remain to be prospectively studied. This study was designed to follow up patients with RV pacing to look for development of pacing-induced cardiomyopathy (PiCMP), identify its predictors and draw comparison between apical vs non-apical RV pacing sites.

METHODS

Three hundred sixty-three patients undergoing dual-chamber and single-chamber ventricular implants were enrolled and followed up. Baseline clinical parameters; paced QRS duration and axis; RV lead position by fluoroscopy; LV ejection fraction (LVEF) by Simpson's method on transthoracic echocardiography (TTE); intraventricular dyssynchrony (septal-posterior wall contraction delay) and interventricular dyssynchrony (aortopulmonary ejection delay) on TTE were recorded. The patients were followed up at 6-12 monthly interval with estimation of LVEF and pacemaker interrogation at each visit. Pacemaker-induced cardiomyopathy (PiCMP) was defined as a fall in ejection fraction of 10% as compared to the baseline LVEF. Patients developing PiCMP were compared to other patients to identify predictors.

RESULTS

The mean age of study population was 59.8 years, 68.3% being males. Fifty-one percent and 49% patients underwent VVIR and DDDR pacemaker implantation, respectively. After attrition, 254 patients were analysed. PiCMP developed in 35 patients (13.8%) over a mean follow-up of 14.5 months. After multivariate analysis, burden of ventricular pacing > 60% [HR 4.26, p = 0.004] and interventricular dyssynchrony (aortopulmonary ejection delay > 40 msec) [HR 3.15, p = 0.002] were identified as predictors for PiCMP in patients undergoing chronic RV pacing. There was no effect of RV pacing site (apical vs non-apical) on incidence of PiCMP [HR 1.44, p = 0.353).

CONCLUSIONS

Incidence of PiCMP with RV pacing was found to be 13.8% over a mean follow-up of 14.5 months. Burden of right ventricular pacing and interventricular dyssynchrony were identified as the most important predictors for the development of PiCMP. Non-apical RV pacing site did not offer any benefit in terms of incidence of PiCMP over apical lead position.

Paced QRS morphology predicts incident left ventricular systolic dysfunction and atrial fibrillation

BACKGROUND

The prognostic significance of paced QRS complex morphology on surface ECG remains unclear. This study aimed to assess long-term outcomes associated with variations in the paced QRS complex.

METHODS

Adult patients who underwent dual-chamber pacemaker implantation with 20% or more ventricular pacing and a 12-lead ECG showing a paced complex were included. The paced QRS was analyzed in leads I and aVL. Long-term clinical and echocardiographic outcomes were compared at 5 years.

RESULTS

The study included 844 patients (43.1% female; age 75.0 ± 12.1). Patients with a longer paced QRS (pQRS) duration in lead I had a lower rate of atrial fibrillation (HR 0.80; p = 0.03) and higher rate of systolic dysfunction (HR 1.17; p < 0.001). Total pacing complex (TPC) duration was linked to higher rates of ICD implantation (HR 1.18; p = 0.04) and systolic dysfunction (HR 1.22, p < 0.001). Longer paced intrinsicoid deflection (pID) was associated with less atrial fibrillation (HR 0.75; p = 0.01), more systolic dysfunction (HR 1.17; p < 0.001), ICD implantation (HR 1.23; p = 0.04), and CRT upgrade (HR 1.23; p = 0.03). Exceeding thresholds for TPC, pQRS, and pID of 170, 146, and 112 ms in lead I, respectively, was associated with a substantial increase in systolic dysfunction over 5 years (p < 0.001).

CONCLUSIONS

Longer durations of all tested parameters in lead I were associated with increased rates of left ventricular systolic dysfunction. ICD implantation and CRT upgrade were also linked to increased TPC and pID durations. Paradoxically, patients with longer pID and pQRS had less incident atrial fibrillation.

Major determinant of the occurrence of pacing-induced cardiomyopathy in complete atrioventricular block: a multicentre, retrospective analysis over a 15-year period in South Korea

OBJECTIVES

The predictors of pacing-induced cardiomyopathy (PICM) for complete atrioventricular block (CAVB) have not yet been defined. The aim of this study was to investigate the major determinant of the occurrence of PICM.

SETTING

This is a multicentre, retrospective analysis of CAVB from tertiary referral centres in Daejeon, South Korea.

PARTICIPANTS

A cohort of 900 consecutive patients with an implanted pacemaker was collected from December 2001 to August 2015. Of these, a total of 130 patients with CAVB with pacing-dependent rhythm who underwent ECG and echocardiogram before and after implantation were analysed for the occurrence of PICM.

OUTCOME MEASURES

Cox proportional hazards models evaluated the determinant of PICM by ECG, device parameters and echocardiogram over a mean of 4.5 years.

RESULTS

PICM was observed in 16.1% (n=21) of all patients with CAVB (age, 64±11 years; male, 36.2%). The preimplant left ventricular (LV) ejection fraction (66%±9% vs 66%±8%) and non-apical pacing (40.4% vs 33.3%) were similar; however, the native QRS duration (124±34 ms vs 149±32 ms) and the paced QRS duration (pQRSd) (139±29 ms vs 167±28 ms) were significantly different between the two groups. The postimplant LV ejection fraction (61%±7% vs 31%±8%) was also significantly different at the end of follow-up. A pQRSd significantly correlated with PICM (HR 1.05, 95% CI 1.02 to 1.09, P=0.001). A pQRSd with a cut-off value of above 140 ms had a sensitivity of 95% while a pQRSd with a cut-off value of above 167 ms had a specificity of 90% for PICM.

CONCLUSION

In patients with CAVB with pacing-dependent rhythm, regardless of the pacing site, the pQRSd is a major determinant of the occurrence of PICM.