Baseline Echocardiographic Parameters Associated With Post-Pacing Cardiomyopathy in Patients With Normal Left Ventricular Ejection Fraction Undergoing Pacemaker Implantation for Atrioventricular Block.

UNLABELLED: In patients with atrioventricular (AV) block and left ventricular ejection fraction (LVEF) of > 50%, dual-chamber pacemaker (DCPM) implantation remains the standard of care. However, in this population the relationship between other baseline echocardiographic parameters and the development of post-pacing cardiomyopathy (PPCMP) remains poorly defined.

OBJECTIVE

To identify preimplant echocardiographic parameters associated with the development of PPCMP in patients with normal LVEF undergoing DCPM implantation for AV block.

METHODS

Among 140 consecutive patients who underwent DCPM implant for AV block between January 1st 2016 and December 31st, 2019, data from 111 patients with available follow-up through December 31, 2024, was retrospectively analyzed. PPCMP was defined as a 10% reduction in LVEF and/or absolute LVEF < 50% with an average ventricular pacing burden of ≥ 20%.

RESULTS

Of 140 patients, 111 with complete data were included (mean age: 76 ± 10 years; 55% male and 88% white). Preimplant LVEF was 61 ± 4% with echocardiogram performed 2(0-26) days before DCPM implant. Over a mean follow-up of 4 ± 2.3 years, 46 patients (41%) developed PPCMP (LVEF%: 45[35-50] vs 62[58-64]; p < 0.001). Preimplant left atrial (LA) dimension (cm; 4.3[3.8-4.5] vs 3.8[3.5-4.3]; p = 0.03) and LA dimension index (mL/m2; 38 ± 12 vs 32 ± 11; p = 0.008) were larger in patients who developed PPCMP. Among PPCMP patients, LVEF reduction correlated inversely with mitral annular septal and lateral E/e' ratios (r = -0.33, p = 0.03 and r = -0.34, p = 0.04, respectively), early diastolic mitral inflow velocity (r = -0.34, p = 0.02) and LA size (r = -0.35, p = 0.01). Larger LA size also correlated with higher E/e' ratios (r = 0.4, p < 0.02) but not with history of AF, HTN, obesity and mitral valve disease. In multivariable regression analyses, each 1-cm increase in LA size was associated with a 5.54-fold higher hazard of first heart failure (HF) admission (Cox, p = 0.0008) and a ~125% increase in total HF admissions (Poisson, p = 0.006) during the study period.

CONCLUSION

Among patients with normal LV systolic function undergoing DCPM for AV block, pre-existing LV diastolic dysfunction, reflected by larger LA size, elevated E/e' ratios, and higher early diastolic mitral inflow velocity, is strongly associated with development of PPCMP. Preimplant recognition of these parameters may help identify patients who would benefit from upfront biventricular or conduction system pacing to mitigate the risk of PPCMP.