Diagnosis of paradoxical embolism with contrast echocardiography

Abstract

Contrast echocardiography is useful in detecting rightto-left intracardiac shunting. Clinical events that cause reversal of the normal interatrial pressure gradient can lead to transient right-to-left shunting across a patent foramen ovale, creating conditions conducive to paradoxical embolism. We present a patient with pulmonary embolism and associated systemic embolization. During the acute stage, contrast echocardiography demonstrated right-to-left shunting at the atria1 level throughout the respiratory cycle. After the patient’s clinical recovery, contrast echocardiography demonstrated atrial right-toleft shunting only upon release of Valsalva’s maneuver. A 60-year-old woman was transferred to Moffitt Hospital, University of California, San Francisco, because of left arm pain, a pulseless left upper extremity, and increasing dyspnea. The day before her admission, the patient had been admitted to another hospital with a complaint of weakness over a 3-week period and acute right arm pain. Physical examination revealed a pulseless right upper extremity and angiography revealed an occlusion of the right axillary artery. A Fogarty embolectomy was successful in removing a pathologically confirmed thrombus. The morning of the transfer, the patient complained of acute shortness of breath and left arm pain. Arterial blood gases on 2 L of nasal oxygen revealed a PO, of 30 mm Hg, PcoZ of 29 mm Hg, and pH of 7.54. The patient was transferred to Moffitt Hospital. There was no history of pleuritic chest pain, hemoptysis, calf tenderness, immobilization, fever, chills, or sweats. The patient did not smoke. She had undergone varicose vein stripping and a hysterectomy several years previously, but was otherwise healthy and active. Physical examination in the emergency department revealed an alert, anxious woman in moderate respiratory distress. Her temperature was 38°C and pulse 110 bpm and regular. Respirations were 3O/min; blood pressure was 110/70 mm Hg in the right arm and unobtainable in the left arm, and paradoxical pulse was 3 mm Hg. The lungs were clear without rubs or assymetrlc breath sounds. Jugular venous pressure was 12 cm H,O with A wave accentuation. The carotid pulse was of normal upstroke and contour. There was a l+ left parasternal precordial lift, and the point of maximal impulse was in the midclavicular line. S, was normal; S, was