Background: Chronotropic incompetence (CI) is an independent predictor of cardiovascular events and overall mortality. The prevalence and significance of CI in renal transplant patient has not been examined.
Methods: 38 non-heart failure renal transplant recipients were recruited for a transthoracic echocardiogram and treadmill stress test using the modified Bruce protocol.
Results: 15 patients (39.5%) had CI (defined as failure to reach 85% of the maximum age-predicted heart rate, or <8 0% of predicted heart rate reserve). CI patients had higher left ventricular (LV) mass (216.5 ± 56.1 vs. 183.1 ± 40.0 g, p = 0.04), increased septal wall thickness (11.7 ± 1.4 vs. 10.7 ± 1.1 mm, p = 0.03) and posterior wall thickness (10.9 ± 1.9 vs. 9.5 ± 1.7 mm, p = 0.02). At multivariate analysis, CI was associated with elevated serum creatinine [odds ratio (OR) 1.04, p = 0.03] and increased LV mass (OR 1.03, p = 0.03). CI was associated with shorter exercise duration (3.53 ± 2.20 vs. 8.08 ± 2.34 min, p < 0.01) and lower metabolic equivalents (5.40 ± 2.05 vs. 9.82 ± 2.39, p < 0.01). At multivariate analysis, exercise duration was negatively associated with CI (β = -0.54, p < 0.01).
Conclusions: CI is present in approximately 40% of asymptomatic renal transplant recipients and is associated with reduced exercise tolerance, left ventricular hypertrophy, and worse allograft function .