A Shocking Case of Far-Field Atrial Oversensing in Giant-Cell Myocarditis

Figures

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  Figure 1. Telemetry and Electrocardiography of Atypical Atrial Flutter (A) Telemetry showing 2:1 atrial tachycardia. Visible atrial deflections are marked with arrows; atrial rate is about 210 to 220 beats/min. (B) 12-Lead electrocardiogram showing atypical atrial flutter with 2:1 atrioventricular conduction; atrial rate is approximately 216 beats/min, and ventricular rate is about 108 beats/min. Electrocardiogram is displayed at twice gain with 20-Hz filter applied.

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  Figure 2. Device Interrogation Report Showing Ventricular Episodes

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  Figure 3. Progressively Diminishing R-Wave Amplitude Prior to Hospitalization

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  Figure 4. Implantable Cardioverter-Defibrillator Lead With Insufficient Slack and Proximal End of Shocking Coil Positioned in the Right Atrium Arrow denotes proximal end of shocking coil positioned in the right atrium.

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  Figure 5. Intracardiac Signals From Device Interrogation Intracardiac far-field signals (top trace) and near-field electrograms from the integrated right ventricular lead (bottom trace). No right ventricular signals are visually evident on the near-field electrograms; a small far-field R-wave is intermittently visible (arrows).