ABSTRACT
The purpose of this review is to update the reader on the relevance of autonomic nervous system imbalance in clinical cardiology. Increased sympathetic tone associates with the metabolic syndrome, hypertension and cardiac arrhythmias. With the kidneys playing a pivotal role in increased peripheral resistance, sodium and water retention and other mechanisms, renal denervation (RD) may theoretically restore autonomic imbalance and improve cardiovascular outcomes. Landmark RD trials and novel uses for RD in cardiac arrhythmia management are discussed.
Subject(s)
Atrial Fibrillation/surgery , Autonomic Denervation/trends , Autonomic Nervous System/surgery , Hypertension/surgery , Kidney/innervation , Animals , Atrial Fibrillation/diagnosis , Atrial Fibrillation/mortality , Atrial Fibrillation/physiopathology , Autonomic Denervation/adverse effects , Autonomic Nervous System/physiopathology , Diffusion of Innovation , Evidence-Based Medicine , Forecasting , Humans , Hypertension/diagnosis , Hypertension/mortality , Hypertension/physiopathology , Randomized Controlled Trials as Topic , Risk Factors , Treatment OutcomeABSTRACT
PURPOSE: To determine the association between device-determined diagnostic indices, including intrathoracic impedance, and heart failure (HF) hospitalization. METHODS: Clinical and device diagnostic data of 558 HF patients indicated for CRT-D therapy (In Sync Sentry, Medtronic Inc.) were prospectively collected from 34 centers. Device-recorded intrathoracic impedance fluid index threshold crossing event (TCE), mean activity counts, tachyarrhythmia events, night heart rate (NHR) and heart rate variability (HRV) were compared within patients with vs. without documented HF hospitalization. RESULTS: Mean follow-up was 326 +/- 216 days. Patients hospitalized for HF had significantly higher rates of TCE, a higher percentage of days with the thoracic impedance fluid index above the programmed threshold, a higher percentage of days with low activity, with low HRV or with high NHR. Multivariate analysis showed that TCE resulted in a 36% increased probability of HF hospitalization. Both TCE duration and patient activity were also significantly associated with hospitalization. Kaplan Meier analysis indicated that patients with more TCE events were significantly more likely to be hospitalized (log rank test, p = 0.005). CONCLUSIONS: Decreased intrathoracic impedance, low patient activity and low HRV were all independently associated with increased risk for HF hospitalization in HF patients treated with resynchronization therapy. Device-derived diagnostic data may provide valuable and reliable indices for the prognostic stratification of HF patients.
