Bilateral Renal Denervation Restores Autonomic Imbalance in Rats With Heart Failure

Background: Long-term renal denervation (RD) has been shown to reduce overall sympathetic outflow in chronic heart failure (HF). Recently, in an animal HF model, unilateral RD reduced sympathetic tone and increased parasympathetic tone, suggesting that unilateral RD, as an alternative to bilateral RD, could restore autonomic balance in HF. We studied the effects of unilateral and bilateral RD on autonomic function and balance in myocardial infarcted rats. Methods: Rats underwent bilateral or unilateral RD and surgically induced myocardial infarction (MI). After acclimatization to a 12 h light-dark cycle, aortic pressure, heart rate and locomotor activity were continuously recorded for 48 hours by using instrumented radiotelemetry pressure transducer. Sympathetic nerve activity was assessed by low-frequency components (0.15–0.79 Hz) of diastolic blood pressure variability (LFdp). Results: Urinary sodium excretion was increased in MI rats with bilateral RD than in those with unilateral RD (P < .05). A transient increase in LFdp was observed during the awaking period, which was increased by 27% in MI rats without RD (n = 8) when compared to sham-operated controls (n = 9). In rats with MI and bilateral RD (n = 7), LFdp during the awaking period was decreased when compared with MI rats with unilateral RD (n = 6) (1162 ± 195 vs 1427 ± 273 (SE) mmHg², P < .05). Conclusions: These data suggested that bilateral RD, but not unilateral RD, could modify circadian autonomic function in MI rats.