Heart rate and cardiac allograft vasculopathy in heart transplant recipients

Abstract BACKGROUND: Elevated heart rate (HR) has been indicated as risk factor for cardiovascular disease. Experimental data support a role of HR in the progression and severity of atherosclerotic lesions. Sinus tachycardia is common in heart transplant patients due to the lack of autonomic control. This study assessed the role of HR in the development of cardiac allograft vasculopathy (CAV) in heart transplant recipients. METHODS: Data from 244 allograft recipients were analyzed. Known factors affecting CAV and mean HR obtained from 24-hour recordings at 1 year (dichotomized at ≥90 beats/min) were tested in univariate and multivariable Cox analysis. RESULTS: During a median of 96 months, 60 patients (25%) experienced CAV. Surprisingly, HR < 90 but not ≥90 beats/min was significantly associated with an increased CAV development. Univariate analysis showed several predictors were associated with the end point; however, at multivariable analysis, only donor's age, chronic renal failure, and left ventricular end-diastolic wall thickness were significant predictors of CAV, with hazard ratios of 1.02 (95% confidence interval, 1.00-1.04), 1.90 (1.13-3.21), and 1.11 (1.00-1.22), respectively. A highly statistically significant difference in donor's age was found among patients with mean heart rate ≥90 or <90 beats/min (30 ± 13 vs 40 ± 14 years, p < 0.0001). CONCLUSIONS: In the denervated heart, sinus tachycardia is not a risk factor for coronary atherosclerosis. HR in heart transplant recipients reflects "intrinsic heart rate" and is a simple epiphenomenon of the donor's age.