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 m(2) (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.