Polysomnographic and clinical characteristics of patients with left atrial enlargement and central sleep apnea with and without atrial fibrillation during polysomnography

SESSION TITLE: Sleep, Breathing, and the Heart SESSION TYPE: Original Investigations PRESENTED ON: 10/11/2023 07:15 am - 08:15 am PURPOSE: Central Sleep Apnea (CSA) is prevalent in patients with heart failure (HF) and Atrial Fibrillation (AF) and could be associated with adverse outcomes. Left atrial enlargement (LAE) has been shown to correlate with increased CO2 chemosensitivity and high loop gain, which could promote CSA. This study aims to describe the clinical and polysomnographic characteristics of patients diagnosed with CSA and LAE with preserved ejection fraction. We compared these characteristics in patients with and without atrial fibrillation during polysomnography (PSG). METHODS: 30 patients with LAE were part of a cohort of 62 successive patients with PSG-confirmed CSA or PAP-emergent CSA. 3 patients with heart failure with reduced ejection fraction were excluded. 27 patients were divided into 2 groups based on the occurrence of AF at the time of PSG. Left atrial enlargement was estimated by measuring left atrial anteroposterior diameter in the parasternal long-axis view using 2DE. Normal AP dimension is 2.7 to 3.8 cm in females and 3.0 to 4.0 cm in males. We used non-paired Wilcoxon Signed-Rank Test for continuous variables and the Chi-square test for categorical variables. P-value of < 0.05 was statistically significant. RESULTS: 18 patients with CSA and LAE had no AF during PSG (group 1); 9 patients had AF during PSG (group 2). The two groups had similar demographics and comorbidities. Mean age was 76±9 vs. 78±11, males 94% vs. 67%. History of AF 44% vs. 89% (p=0.07), obesity 72% vs. 56%, mean BMI 32±6 vs. 31±8, hypertension 89% vs. 78%, diabetes 28% vs. 0%, coronary artery disease 67% vs. 33% (p=0.22), COPD 11% in both groups and history of stroke 6% vs. 22%, respectively. Echocardiography data showed diastolic dysfunction in 67% vs. 44% (p=0.49), EF>50% in all patients and left ventricular hypertrophy 61% vs. 67%. Mean left atrial area 4.45 ± 0.4 cm vs. 4.99 ± 0.8 cm (p= 0.036) and left atrial volume index (LAVI) 36 ± 9.4 vs. 43.4 ± 13.6 (p=0.14). Mean values for apnea-hypopnea index (AHI) were 59±24 vs. 51±20, and central apnea index (CAI) 16±17 vs. 26±22 (p=0.23). Hunter-Cheyne-Stokes breathing (HCSB) was observed more in group 2 (5.9 vs. 55.6, p=0.018). Both groups had similar baseline oxygen saturation (SPO2) on room air (95±2 vs. 94±2) and lowest SPO2 76±8 vs. 79±7. Median sleep efficiency was 76% [IQR 69, 89] in group 1 vs. 81% in group 2 [IQR 65, 82]. All 27 patients underwent CPAP-titration study, obstructive apnea/hour 1.3±2.2 vs. 1.3±2.1, CAI 21±17 vs. 23±8 (p=0.78) with PAP-emerging/persistent central apnea in 50% vs. 22 % (p=0.33). No correlation was found between LAVI and CAI (p=0.97). CONCLUSIONS: We conclude that left atrial enlargement with or without AF is a risk factor for CSA or CPAP-emergent CSA. Based on animal and human studies, enlarged left atrium and associated increased left atrial pressure increases the loop gain promoting CSA and CPAP-emergent CSA. CLINICAL IMPLICATIONS: Clinicians should be aware of the LAE relationship to CSA. DISCLOSURES: No relevant relationships by Amr Aboelnasr No relevant relationships by Mohammad Amin Eshghabadi No relevant relationships by Fatima Hussain Consultant relationship with Respicardia Please note: upto present by Shahrokh Javaheri, value=Consulting fee No disclosure on file for Joseph Richter