Abstract
Background: Patent foramen ovale (PFO) is a common finding linked to cryptogenic stroke. Transesophageal echocardiography identifies high-risk anatomical features, but it remains unknown whether electrocardiography (ECG) may distinguish between high-risk and low-risk PFO anatomies. Methods: This retrospective single-center study included 207 consecutive patients (median age 45 years; 46.9% male) who underwent percutaneous PFO closure between January 2021 and June 2025. Patients were stratified into low-risk (score 0-1, n = 46), and high-risk (score 2-5, n = 161) groups using the Nakayama risk score. Baseline 12-lead ECGs were analyzed for crochetage R wave, right bundle branch block, RSR' pattern, and T-wave abnormalities. Clinical, laboratory, and echocardiographic data were systematically evaluated. Results: High-risk patients more frequently exhibited crochetage R waves (40.4% vs. 17.4%, p = 0.004) and spontaneous Doppler shunting (53.3% vs. 31.0%, p = 0.010). Crochetage R wave strongly correlated with the presence of a large right-to-left shunt (≥20 bubbles: 97.2% vs. 82.0%, p = 0.002), reinforcing its pathophysiological significance. The presence of a crochetage R wave was independently associated with high-risk PFO anatomy (OR: 32.4; 95% CI: 2.64-397.7; p = 0.007). In addition, spontaneous Doppler shunting (OR: 5.4; 95% CI: 1.1-26.4; p = 0.039) and absence of lipomatous hypertrophy (OR: 0.10; 95% CI: 0.01-0.71; p = 0.022) were independent predictors of high-risk PFO anatomy. Conclusions: In patients with PFO, ECG changes such as the crochetage R wave are driven by anatomical risk features and shunt magnitude and may aid noninvasive risk stratification in cryptogenic stroke.