Indicators of Cardiac Autonomic Dysfunction Associated with Chronic Hyperglycemia: Implications on Vascular Surrogates and Heart Failure

Abstract

<p><strong>Background:</strong> Limited data exist on the role of chronic hyperglycemia-related cardiac autonomic dysfunction in incident heart failure (HF). We investigated the relations of resting heart rate (HR) and PR interval with chronic hyperglycemia, and effects on new-onset HF.</p><p><strong>Methods:</strong> We prospectively studied 550 patients with prior coronary disease, ischemic stroke and/ or type 2 diabetes. Incident HF was ascertained. Heart rate-PR interval dissociation was defined as counter-physiological co-occurrence of increased PR interval (>mean; 173.3ms) and increased resting HR (>mean; 64.4 beats/min).</p><p><strong>Results:</strong> Over 63 ±11 months, 6.7% patients developed new-onset HF. Resting HR³75bpm was independently predictive of new-onset HF (HR=3.35 [95%CI: 1.24 - 9.04], <em>P=0.017</em>). Furthermore, baseline HR was associated with HbA1c (R=0.11, <em>P=0.012</em>). At univariable and multivariable analyses, HbA1c remained independently associated with resting HR³75 bpm (OR=1.18, 95%CI [1.00-1.40], <em>P=0.046</em>). Moreover, the normal inverse relation between PR interval and resting HR is lost in this group of high-risk cardiac patients (R=-0.03, P=0.46). Heart rate-PR interval dissociation was significantly associated with HbA1c>7 (28% versus 17%, <em>P=0.006</em>).</p><p><strong>Conclusion:</strong> Chronic hyperglycemia is associated with elevated resting HR and counter-physiological dissociation of HR and PR interval, and that such elevated resting HR is a predictor of new-onset HF in cardiovascular patients with prevailing diabetes.</p>