Circadian Rhythm Of Pulmonary Artery Pressures In HFpEF Assessed With Cardiomem: Preliminary Results

Purpose : Systemic blood pressure is known to display a circadian rhythm in most healthy individuals, characterized by a nocturnal fall and a diurnal rise. Dysregulation of this pattern is associated with higher risk of cardiovascular disease. However, the circadian rhythm in the pulmonary arterial circulation and its impact on cardiovascular disease is less established. The aim of this study is to perform a preliminary investigation of any circadian variations of pulmonary artery (PA) pressures in patients with implanted cardiomem devices. Methods : Among 15 subjects with heart failure with preserved ejection fraction (HFpEF) and an implanted cardiomem device who were offered participation in this study, four subjects enrolled. Study participants recorded PA pressure signals three times a day: AM (7-9AM), mid-day (Noon-2PM), and PM (7-9PM). We excluded the readings that were preceded by changes in the diuretic regimen (change in dose and/or prn use of metolazone) within 3 days prior to the reading. Results : In the first two subjects (#1 and #2), we identified a “steady trend or slight rise” in PA pressures from morning-to-evening. These subjects had clinical stability (defined as no hospitalizations within the last year or medication changes within last 3-months), and relatively well controlled risk factors (diabetes, hypertension, sleep apnea). In the other two subjects (#3 and #4), we identified a “drop” in PA pressures from morning-to-evening. Subjects #3 and #4 have poorly controlled sleep-disordered breathing and DM, respectively. Both of these disease processes have been implicated in circadian misalignment of systemic BP. Conclusion : Based on these preliminary findings, a diurnal rise or steady PA pressures may reflect well-controlled risk factors in HFpEF. However, a nocturnal rise may indicate poorly controlled risk factors like sleep apnea or metabolic syndrome. Future studies are needed to confirm the circadian misalignment and its impact on cardiovascular outcomes. : Systemic blood pressure is known to display a circadian rhythm in most healthy individuals, characterized by a nocturnal fall and a diurnal rise. Dysregulation of this pattern is associated with higher risk of cardiovascular disease. However, the circadian rhythm in the pulmonary arterial circulation and its impact on cardiovascular disease is less established. The aim of this study is to perform a preliminary investigation of any circadian variations of pulmonary artery (PA) pressures in patients with implanted cardiomem devices. : Among 15 subjects with heart failure with preserved ejection fraction (HFpEF) and an implanted cardiomem device who were offered participation in this study, four subjects enrolled. Study participants recorded PA pressure signals three times a day: AM (7-9AM), mid-day (Noon-2PM), and PM (7-9PM). We excluded the readings that were preceded by changes in the diuretic regimen (change in dose and/or prn use of metolazone) within 3 days prior to the reading. : In the first two subjects (#1 and #2), we identified a “steady trend or slight rise” in PA pressures from morning-to-evening. These subjects had clinical stability (defined as no hospitalizations within the last year or medication changes within last 3-months), and relatively well controlled risk factors (diabetes, hypertension, sleep apnea). In the other two subjects (#3 and #4), we identified a “drop” in PA pressures from morning-to-evening. Subjects #3 and #4 have poorly controlled sleep-disordered breathing and DM, respectively. Both of these disease processes have been implicated in circadian misalignment of systemic BP. : Based on these preliminary findings, a diurnal rise or steady PA pressures may reflect well-controlled risk factors in HFpEF. However, a nocturnal rise may indicate poorly controlled risk factors like sleep apnea or metabolic syndrome. Future studies are needed to confirm the circadian misalignment and its impact on cardiovascular outcomes.