C63-09 Stiff Left Atrium Syndrome Following Catheter Ablation

Abstract Stiff left atrial (LA) syndrome, characterized by decreased LA compliance, is a rare complication following catheter ablation. Repeat LA ablations can lead to progressive atrial scarring, LA diastolic dysfunction, elevated LA pressures, and subsequently, pulmonary hypertension (PH). Diagnosis is made in the right clinical setting with right heart catheterization (RHC) showing PH and characteristic large V waves on pulmonary capillary wedge pressure tracings (PCWP). The role of cardiac magnetic resonance imaging (CMR) in assessing atrial scarring is not established. The case presented highlights a diagnostic strategy for stiff LA syndrome that integrates clinical history, RHC findings, and characteristic hemodynamic features with CMR to noninvasively evaluate the presence of LA scarring. Case Description A 75-year-old woman presents with progressive dyspnea on exertion. Her past medical history is notable for atrial fibrillation with repeat left atrial catheter ablation via trans-septal approach, complicated with iatrogenic atrial septal defect (ASD) evident on post ablation trans-esophageal echocardiography. She reports exertional dyspnea, near-syncopal events, and leg swelling. Abnormal echocardiography findings: mild concentric LV hypertrophy. Dilated LA and mildly elevated LV filling pressures. Mild mitral regurgitation. On stress echocardiography, there was an increased RVSP from 46 to 70 mmHg, which prompted a RHC: image below Given the suspicion of stiff LA syndrome, CMR was performed and demonstrated depressed RV function (RVEF 51%). No RV delayed myocardial enhancement. Small ASD with small shunt. Mildly enlarged LA and RA and late gadolinium enhancement (LGE) noted in the LA wall. The constellation of her clinical presentation, CMR finding of LA scarring, and characteristic PAWP tracing in the absence of left sided heart and valvular disease supported our diagnosis of stiff LA syndrome. Discussion Abnormal LA diastolic function manifests as large V waves on RHC and are defined as V waves exceeding the mean PCWP by ≥ 10 mmHg or being more than twice the mean PCWP. Given the elevated LA pressures, transseptal puncture used for diagnosis or interventions can lead to iatrogenic ASD owing to the sustained pressure gradient perpetuating left to right. CMR with LGE offers a modality to assess and quantify LA fibrosis and correlates with invasive electroanatomic mapping used to evaluate LA scarring. The case presented highlights a diagnostic strategy for stiff LA syndrome that obviates the need for direct LA pressure measurements through transseptal approach thereby reducing the risk of iatrogenic ASD and integrates CMR to noninvasively evaluate LA scarring. This abstract is funded by: None