Excerpt

A 54-year-old diabetic, hypertensive male presented to the emergency room with acute onset shortness of breath. He did not have any recent surgery or prolonged immobilization. Clinical examination revealed tachycardia, respiratory rate of 34/min, and systemic saturation (SaO₂) of 92%, at room air. Electrocardiogram showed normal sinus rhythm and non-specific ST-T changes in chest leads. Transthoracic and transesophageal echocardiogram revealed enlarged right atrium (RA) and right ventricle (RV) with a high estimated pulmonary artery (PA) systolic pressure (90 mmHg). There was a large thrombus (37 × 18 mm) in the RA (Fig. 1a, arrow), which was extending into the left atrium (LA) (Fig. 1b, arrow) through a patent foramen ovale (PFO) (Supplementary Material Video 1). There was no thrombus in the left atrial appendage. A computed tomography (CT) angiogram confirmed the presence of thrombus in the main and branch pulmonary arteries (Fig. 1c, arrows). Ultrasound Doppler did not reveal any deep vein thrombosis of lower limbs. The workup for the hypercoagulable states was negative. He was administered an intravenous infusion of 100 mg Alteplase in 2 h. There was a gradual and progressive improvement in respiratory distress following thrombolysis. A repeat echocardiogram after 48 h showed no thrombus across the PFO (Fig. 1d). He was discharged on an oral anticoagulant (Warfarin) with advice to maintain an International Normalized Ratio (INR) of 2–3. He had marked improvement in exertional dyspnea and his PA systolic pressure dropped to 30 mmHg at 3 months of follow-up.

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