Sinus Venosus Atrial Septal Defect as a Cause of Palpitations and Dyspnea in an Adult: A Diagnostic Imaging Challenge

Figure 1

Electrocardiogram obtained during exercise stress test demonstrating sinus tachycardia at approximately 155 beats per minute (bpm). There is an abrupt onset of supraventricular tachycardia with intermittent aberrant conduction and a ventricular rate of 290 bpm. Standard paper speed is 25 millimeters per second, and amplitude is 10 millimeters per millivolt.