Chronotropic incompetence, echocardiographic abnormalities and exercise intolerance in renal transplant recipients

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.

38 non-heart failure renal transplant recipients were recruited for a transthoracic echocardiogram and treadmill stress test using the modified Bruce protocol.

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).

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 .