Diurnal variation in left atrial pressure in ambulatory patients with chronic heart failure

Aims Circadian patterns influence cardiovascular physiology, yet have not been characterized in intracardiac pressures of ambulatory chronic heart failure patients. We aimed to assess diurnal variation via a novel remote intracardiac left atrial pressure sensor. Methods and Results Daily ambulatory left atrial pressure measurements were obtained with an implantable intracardiac sensor. Patients performed morning and evening measurements during longitudinal follow-up. We compared diurnal variability in morning and evening left atrial pressure, examined its potential changes by diuretic regimen, presence of atrial fibrillation and subsequent acute decompensated heart failure events. Across >15,500 measurement days with an average follow up time of 25.5±18.6months in 73 heart failure patients, median left atrial pressure was higher in the evening than in the morning (12.4 [6.8, 18.3] vs.10.7 [5.5, 17.3] mmHg; p < 0.01). Neither higher diuretic dose, twice-daily dosing, nor atrial fibrillation modified this diurnal variation (p =0.34, p=0.06). Patients who suffered acute decompensated heart failure events demonstrated higher left atrial pressures (14.3 [9.47, 19.86] vs 10.4 [5.44, 17.26] mmHg, p < 0.01) associated with increased risk of further acute events (OR 1.35, 95% CI 1.08–1.69; p < 0.01). Diurnal variation was present irrespective of acute decompensated heart failure status (p = 0.16). Conclusions Using direct ambulatory intracardiac LAP monitoring, we observed consistent diurnal variation with higher evening pressures, largely unchanged by diuretic dose or dosing schedule, atrial fibrillation, or subsequent ADHF events.