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 (LAP) 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 LAP, examined its potential association with diuretic regimen, presence of atrial fibrillation and acute decompensated heart failure (ADHF) events.Across >15,500 measurement days with an average follow up time of 25.5±18.6 months 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 =0.98, p=0.50).Patients who suffered ADHF events demonstrated higher left atrial pressures (14.3 [9.5, 19.9] vs 10.4 [5.4, 17.3] mmHg, p < 0.01). Higher LAP was also independently associated with increased risk of ADHF events (OR 1.40, 95% CI 1.10-1.78; p < 0.01). Diurnal variation was present irrespective of acute decompensated heart failure status (p = 0.79). 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 association with ADHF events.