STIFF LEFT ATRIAL SYNDROME: THE MYSTERY BEHIND A PRESUMPTIC DIAGNOSIS OF PULMONARY ARTERY HYPERTENSION

Abstract

SESSION TITLE: Global Case Report Posters SESSION TYPE: Global Case Reports PRESENTED ON: October 18-21, 2020 INTRODUCTION: Atrial Fibrillation (AF) is one of the most prevalent arrhythmia. Radio frequency catheter ablation (RFCA) is an effective treatment for AF and is superior to medical therapy. here we report a case of he stiff left atrium syndrome (SLAS) is a newly recognized post-procedure complication of RFCA due to left atrial (LA) scarring and fibrosis. CASE PRESENTATION: A 66 y/o female with a history of AF status post four RFCAs, suspected heart failure with preserved ejection fraction (HFpEF) with associated PH presented to the emergency room with shortness of breath. An echo cardiogram showed normal left ventricular (LV) systolic function and dilation of the Left atrium. Right heart catheterization (RHC) showed a pulmonary capillary wedge pressure (PCWP) of 32mmHg, a mean pulmonary artery pressure (PAP) of 62mmHg, and near normal peripheral vascular resistance indicating PVH. Due to refractory symptoms a follow up left and RHC showed similar MPAP and PCWP but left ventricular end diastolic pressure (LVEDP) was surprisingly normal at 12mmHg. A CT scan showed normal pulmonary veins without stenosis. Given the discrepancy of elevated LA pressure with a normal LVEDP, a diagnosis of SLAS was confirmed. Treatment with diuretics and control of risk factors were initiated. DISCUSSION: The differential diagnosis for a patient presenting with dyspnea and pulmonary hypertension with a history of prior RFCA includes HfpEF, pulmonary vein stenosis, valvular pathology, and SLAS, with HFpEF begin the most common . The estimated incidence of SLAS after RFCA is 1.4% - 8%. Key distinguishing features of SLAS include prominent V-waves on LA pressure tracings (via PCWP) disproportionate to the LVEDP. The diagnosis of SLAS is challenging and can be easily missed. For example, isolated post-capillary PH with a normal LV ejection fraction would suggest a diagnosis of HFpEF. However, a LHC in a patient with a stiff left atrium that demonstrated a significantly elevated LA V-wave and a surprisingly normal LVEDP would indicate no LVDD. Thus, in addition to imaging with echocardiography, invasive hemodynamic testing with simultaneous LHC to measure the LVEDP in addition to RHC for the PAP and PCWP is essential to make the difficult diagnosis of SLAS. Diuretics are currently considered mainstay treatment for SLAS. Recent studies have evaluated the novel use of an interatrial septal device to create an atrial septostomy which relieves LA pressure by creating a left-to-right shunt. In a trial for patients with HFpEF, an atrial septostomy led to a significant decrease in PCWP (28%), symptomatic improvement, a longer 6-minute walk distance, and better quality of life after 30 days. CONCLUSIONS: This case demonstrates the diagnostic challenge of SLAS and the importance of invasive hemodynamic testing with simultaneous RHC and LHC in addition to imaging to identify the true underlying cause of pulmonary hypertension. Reference #1: Gibson, D.N., et al., Stiff left atrial syndrome after catheter ablation for atrial fibrillation: clinical characterization, prevalence, and predictors. Heart Rhythm, 2011. 8(9): p. 1364-71. Reference #2: Maeder, M.T., et al., Pulmonary hypertension in stiff left atrial syndrome: pathogenesis and treatment in one. ESC heart failure, 2018. 5(1): p. 189-192. Reference #3: Chandrashekar, P., et al., Atrial Septostomy to Treat Stiff Left Atrium Syndrome. Circulation. Heart failure, 2017. 10(7): p. e004160. DISCLOSURES: No relevant relationships by Mark Cromer, source=Web Response No relevant relationships by Abhijit Raval, source=Web Response