Isolated Atrial Myocarditis With Atrial Standstill

Figures

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  Figure 1. Initial ECG Initial ECG with an absence of P waves and narrow QRS complex with an escape rhythm at a bradycardic rate of 42 beats/min. ECG = electrocardiogram.

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  Figure 2. Transthoracic Echocardiography Performed at Admission Transthoracic echocardiography performed at admission (A) with no visible A-wave in the mitral inflow Doppler image. (B) Right ventricle is dilated and shows severe systolic dysfunction with massive tricuspid regurgitation. (C) Estimated systolic pulmonary artery pressure is 58 mm Hg.

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  Figure 3. Right Heart Catheterization Right heart catheterization displaying markedly elevated V waves in the PAWP. The tracing also demonstrates upstream pressure transmission to the PA. PA = pulmonary artery; PAWP = pulmonary arterial wedge pressure waveform.

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  Figure 4. Cardiac Magnetic Resonance Cardiac magnetic resonance showing late gadolinium enhancement in the left atrium (red arrow, consistent with fibrotic changes.

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  Figure 5. Electrograms During Electrophysiological Examination (A) Electrograms demonstrating septal pacing attempts via a pentaspline multipolar mapping catheter. Despite successful capture of the local septal atrial myocardium, as seen on Penta 9-10, pacing consistently resulted in complete atrioventricular block. (B) A Decapolar mapping catheter (CS) (Abbott) was inserted in the coronary sinus with the proximal bipole (CS 9-10) positioned at the coronary sinus ostium. The underlying rhythm is a junctional escape rhythm with narrow QRS complexes on the surface electrocardiogram. The CS shows only far-field ventricular signals without evidence of atrial activity. Additionally, pacing from the proximal CS bipole (CS 9-10) does not result in atrial capture.

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  Figure 6. Follow-Up Transthoracic Echocardiography Performed 6 Weeks Postdischarge (A) Right ventricle is mildly dilated but shows normal systolic function. Tricuspid regurgitation is reduced, and (B) estimated systolic pulmonary artery pressure has improved to 29 mm Hg. (C) Left atrial activity remains absent.