Heart Rate Variability In Patients With Left Ventricular Assist Device

Left ventricular assist devices (LVADs) are essential for patients with advanced heart failure, but their continuous blood flow may impair autonomic nervous system baroreflex control, altering heart rate variability (HRV). Previous studies show decreased HRV correlates with lower functional capacity and higher all-cause mortality in various groups, including stroke and myocardial infarction. Yet, HRV's relationship with functional capacity in LVAD patients remains unexamined. PURPOSE: To exam the HRV and functional capacity patterns in patients with LVADs during hospitalization. METHODS: This study examined medical charts of three patients with LVADs and complex medical histories at New York-Presbyterian Hospital. The Activity Measure for Post Acute Care (AM-PAC) scores and Johns Hopkins Highest Level of Mobility (JH-HLM) scores were measures of functional capacity. EKG data and functional capacity scores were collected at 10 standardized intervals between October and November 2022, along with post-discharge events. HRV was measured using the Root mean square of successive normal-to-normal interval differences (RMSSD). RESULTS: All three patients were on beta blockers. Patient #1, with osteomyelitis and stroke history, showed RMSSD increase from 68 to 107 ms, with AM-PAC and JH-HLM scores rising from 6 to 19 and 3 to 7. Patient #2, with an ostomy and mood disorder, displayed RMSSD improvement from 77 to 106 ms, with AM-PAC and JH-HLM scores increasing from 13 to 22 and 4 to 8. In patients #1 and #2, functional scores and HRV improved resembling HRV responses in other populations. Patient #3, with a history of stroke, respiratory failure, and altered mental status, demonstrated minor changes in RMSSD, fluctuating between 65 and 73 ms, with a slight increase in AM-PAC and JH-HLM scores from 10 to 17 and 3 to 7 respectively. Patient #3 was readmitted 1 week post discharge due to fall and cognitive decline, while here were no adverse events recorded for patients #1 and #2. CONCLUSIONS: This study provides a snapshot of HRV and functional capacity in 3 patients with LVADs. While patients #1 and #2 demonstrated HRV improvements similar to other populations, #3's complex case highlighted the individual variability in HRV among LVAD recipients. Further research on HRV's role in this group is needed.