Continuous Autonomic Assessment in Patients With Symptomatic Heart Failure

Abstract

Background-Heart rate variability (HRV) as an indirect autonomic assessment provides prognostic information when measured over short time periods in patients with heart failure. Long-term continuous HRV can be measured from an implantable device, but the clinical value of these measurements is unknown. Methods and Results-A total of 397 patients with New York Heart Association class III or IV heart failure were studied.Of these, 370 patients had information from their implanted cardiac resynchronization device for mortality risk stratification, and 288 patients had information for measured parameters (ie, HRV, night heart rate, and patient activity) and clinical event analyses. Continuous HRV was measured as the standard deviation of 5-minute median atrial-atrial intervals (SDAAM) sensed by the device. SDAAM Ͻ50 ms when averaged over 4 weeks was associated with increased mortality risk (hazard ratio 3.20, Pϭ0.02) and SDAAM were persistently lower over the entire follow-up period in patients who required hospitalization or died. SDAAM decreased a median of 16 days before hospitalization and returned to baseline after treatment. Automated detection of decreases in SDAAM was 70% sensitive in detecting cardiovascular hospitalization, with 2.4 false-positives per patient-year of follow-up. Conclusions-This study demonstrates that SDAAM continuously measured from an implanted cardiac resynchronization device is lower in patients at high mortality and hospitalization risk. SDAAM declines as patient status decompensates.Continuous long-term SDAAM may be a useful tool in the clinical management of patients with chronic heart failure.

Use of heart rate variability analysis to determine the risk of cardiac ischaemia in high‐risk patients undergoing general anaesthesia

“…These results were confirmed prospectively. The predictive value of HRV for cardiac mortality has been demonstrated in a number of prospective cohort studies [8,25,26]. In 842 patients followed for 1 year after cardioversion the HRV footprint (a graphical display of R-R intervals from 24 h analysis) and the standard deviation of R-R intervals were predictors of cardiac death, with lower HRV values in the 66 patients who died during study follow up [8].…”

“…In 842 patients followed for 1 year after cardioversion the HRV footprint (a graphical display of R-R intervals from 24 h analysis) and the standard deviation of R-R intervals were predictors of cardiac death, with lower HRV values in the 66 patients who died during study follow up [8]. Another trial investigated 397 patients with New York Heart Association class III or IV heart failure and an implanted defibrillator [25]. A standard deviation of R-R intervals below 50 ms measured from the implanted device was associated with increased cardiac mortality.…”

Cardiac resynchronization therapy: a breakthrough in heart failure management

“…Given the high incidence and prognostic implication of atrial and ventricular tachycardia in HF, monitoring of arrhythmias via the device provides important information for the optimization of treatment with antiarrhythmic and anticoagulant drugs. Furthermore, parameters such as heart rate, heart rate variability and physical activity may indicate changes in autonomic balance and functional status over time [90,91]. Recently, device-based sensors that may improve optimal fluid management in HF have received increasing attention.…”

Reducing Events in Patients with Chronic Heart Failure (REDUCEhf ) Study Design: Continuous Hemodynamic Monitoring with an Implantable Defibrillator

“…16 As measured from an implanted electrical device, HRV declined significantly in association with the development of volume overload and congestion, suggesting vagal withdrawal and sympathetic activation as patients decompensated to the point of hospital admission. 17 Significant physiologic alterations in cardiac autonomic control were noted several weeks before patients actually sought medical attention, suggesting that the progression to congestive decompensation begins long before patients present with overt signs or symptoms of worsening heart failure. In addition to potentially serving as an early warning mechanism, device-enabled physiologic monitoring offers the distinct advantages of continuous data acquisition in the patient's own environment with the opportunity for remote data access using secure Internet-based information systems.…”