Impact of Sleep-Disordered Breathing Treatment on Ventricular Tachycardia in Patients with Heart Failure

Sleep apnea in patients undergoing coronary artery bypass grafting: Impact on perioperative outcomes

Sleep-disordered breathing is common in patients with coronary artery disease undergoing coronary artery bypass grafting. Sleep-disordered breathing is associated with increased perioperative morbidity, arrhythmias (e.g. atrial fibrillation) and mortality. This study investigated the impact of sleep-disordered breathing on the postoperative course after coronary artery bypass grafting, including development of atrial fibrillation. This prospective single-centre cohort study included adults undergoing coronary artery bypass grafting. All were screened for sleep-disordered breathing (polygraphy) and atrial fibrillation (electrocardiogram) preoperatively; those with known sleep-disordered breathing or atrial fibrillation were excluded. Endpoints included new-onset atrial fibrillation, duration of mechanical ventilation, time in the intensive care unit, and postoperative infection. Regression analysis was performed to identify associations between sleep-disordered breathing and these outcomes. A total of 508 participants were included (80% male, median age 68 years). The prevalence of any (apnea-hypopnea index ≥ 5 per hr), moderate (apnea-hypopnea index = 15-30 per hr) and severe (apnea-hypopnea index > 30 per hr) sleep-disordered breathing was 52.9%, 9.3% and 10.2%, respectively. All-cause 30-day mortality was 0.98%. After adjustment for age and sex, severe sleep-disordered breathing was associated with longer respiratory ventilation support (crude odds ratio [95% confidence interval] 5.28 [2.18-12.77]; p < 0.001) and higher postoperative infection rates (crude odds ratio 3.32 [1.45-7.58]; p < 0.005), but not new-onset atrial fibrillation or mortality. New-onset atrial fibrillation was significantly associated with postoperative infection and prolonged hospital stay. The significant associations between sleep-disordered breathing and several adverse outcomes after coronary artery bypass grafting support the need for preoperative sleep-disordered breathing screening in individuals undergoing cardiac surgery.

Ventricular assist devices and sleep-disordered breathing-A mechanical heart stimulating a sleepy brain

Sleep-disordered breathing, including obstructive sleep apnea (OSA) and central sleep apnea (CSA), is common in severe heart failure (HF) patients. There is limited data on the effect of left ventricular assist devices (LVAD) on sleep apnea. We performed a retrospective review of 350 durable LVAD patients and found 5 with a history of pre- and post-LVAD sleep studies. All five patients had OSA, and three had concomitant CSA. We observed reduced apnea-hypopnea index following LVAD placement. This was due to a near abolishment of CSA in three mixed sleep apnea patients-as seen by a central apnea index improvement from an average of 25.9 ± 13.1 to 1.4 ± 2.5 events per hour (p = 0.063). LVAD placement was associated with an increase in thermodilution cardiac output from 2.7 ± 0.6 to 4.1 ± 1.1 L/min (p = 0.014). These findings support chemoreception physiology seen in patients with poor circulation and the effect of restoring this circulation with LVAD support.

Early identification of heart failure deterioration through respiratory monitoring with adaptive servo-ventilation

Cardiac decompensation is associated with worse prognosis in patients with heart failure. Reliable methods to predict cardiac decompensation events are not yet available. Sleep-disordered breathing (SDB) is a frequent comorbidity in heart failure, and it has been shown to correlate with heart failure severity. This prospective observational trial investigated SDB characteristics in patients with heart failure with the aim to identify patterns that may predict early cardiac decompensation. Patients with heart failure with diagnosed SDB and hospitalised for cardiac decompensation were prospectively enrolled and treated with adaptive servo-ventilation (ASV). SDB characteristics, daily body weight and clinical cardiac decompensation events were collected over a 1-year follow-up. Clinical events were categorised by an independent clinical event committee. A total of 43 patients were enrolled (81% male, mean [SD] age 71 [11] years, body mass index 30 kg/m² , 95% New York Heart Association function class III or IV, mean [SD] left ventricular ejection fraction 37% [11%], median apnea-hypopnoea index [AHI] of 37 events/h). A total of 48 cardiac decompensation events were recorded during the 1-year study period. Respiratory rate was found to be significantly lower in patients with cardiac decompensation. The AHI and applied inspiratory pressure ASV-device support were significantly increased 10 days before a clinical cardiac decompensation event. Device usage was also found to be significantly decreased 2 nights before cardiac decompensation. Device-derived respiratory data in ASV therapy devices for SDB may therefore serve as a monitoring tool to predict early clinical cardiac decompensation events. Prediction and avoidance of cardiac decompensation, in turn, may attenuate serious health consequences in patients with heart failure.