PMC5412623_01
Presenting electrocardiogram. The electrocardiogram shows a narrow complex tachycardia at 180 beats/min with RP interval < PR interval.
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Her 12-lead electrocardiogram at presentation, shown in Figure 1, depicts a rapid and regular supraventricular tachycardia at a rate of 180 beats/min, with a short RP interval (ie, RP interval < PR interval).
Ventricular thrombi and pulmonary emboli. A: A cardiac magnetic resonance view in a 4-chamber orientation. Early gadolinium enhancement imaging reveals the presence of avascular masses in the right ventricle (RV) and left ventricle (LV), suggestive of thrombi. B and C: Computed tomographic images. In panels B and C, multiplanar reconstruction images of the left inferior lobe pulmonary artery (LPA) and interlobar right pulmonary artery (RPA) show sharply defined filling defects (asterisk), consistent with bilateral pulmonary emboli. D: A triangular opacity in the right upper lobe along the anterior chest wall (arrow), consistent with a pulmonary infarction.
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On cardiac magnetic resonance imaging, shown in Figure 2A, biventricular thrombi were identified, with a left ventricular ejection fraction of 27% and a right ventricular ejection fraction of 29%. Computed tomography pulmonary angiography, displayed in Figures 2B-2D, revealed bilateral pulmonary emboli with associated pulmonary infarction.
Electrophysiology study. Shown are the recordings from surface electrocardiographic leads I, II, aVF, V1, and V6 and intracardiac tracings from the high right atrium (HRA), His bundle proximal (His p) and distal (His d), coronary sinus (CS) proximal (9-10) to distal (1-2), and right ventricular apex (RVA). A stimulation (STIM) channel is also shown. A: Two atrial extrastimuli (S2 and S3) delivered from the HRA at coupling intervals of 270 and 250 ms result in prolongation of the A3-H3 interval, followed by sustained supraventricular tachycardia with a septal VA interval of 18 ms. B: The tachycardia (cycle length 299 ms) is entrained by ventricular pacing at 280 ms, with 1:1 ventriculoatrial conduction. Upon cessation of ventricular pacing, a V-A-H response is observed, consistent with atrioventricular nodal reentrant tachycardia.
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During isoproterenol infusion (1 microg/min), typical slow-fast AVNRT was reproducibly inducible with 2 atrial extrastimuli (Figure 3).