Effect of cardiac resynchronization therapy on the risk of ventricular tachyarrhythmias in patients with chronic kidney disease

Background: The effect of chronic kidney disease (CKD) on benefit from cardiac resynchronization therapy with defibrillator (CRT-D) in reducing ventricular tachyarrhythmia (VTA) risk among mild heart failure (HF) patients is not well understood. Methods: We evaluated the impact of baseline renal function on VTAs in 1274 left bundle branch block (LBBB) patients enrolled in MADIT-CRT. Two prespecified subgroups were created based on estimated glomerular filtration rate (GFR): GFR <60 (n = 413) and GFR ≥60 ml/min/1.73 m² (n = 861). Primary end point was ventricular tachycardia/ventricular fibrillation/death (VT/VF/death). Secondary end points were any VT/VF and ventricular tachycardia ≥ 200 bpm or VF (fast VT/VF). Results: There were 413 (32%) LBBB patients presenting with CKD, primarily of moderate severity (GFR mean 48.1 ± 8.3). For patients with and without CKD, CRT-D was associated with lower risk of the primary end point (GFR<60: HR = 0.61, 95% CI: 0.41–0.89, p =.010; GFR≥60: HR = 0.58, 95% CI: 0.52–0.89, p =.005), relative to ICD-only treatment. For patients in both renal function categories, CRT-D in comparison to ICD alone was associated with lower risk of VT/VF (GFR<60: HR = 0.68, 95% CI: 0.42–1.10, p =.113; GFR≥60: HR = 0.65, 95% CI: 0.48–0.88, p =.005) and fast VT/VF (GFR<60: HR = 0.49, 95% CI: 0.25–0.96, p =.038; GFR≥60: HR = 0.55, 95% CI: 0.39–0.80, p =.001), when accounting for competing mortality risk. This effect was independent of CRT-induced reverse remodeling. Conclusion: Among mild HF patients with LBBB, those with and without CKD both derived benefit from CRT-D in risk reduction in VTAs, independent of cardiac reverse remodeling.