Termination of Sustained Ventricular Fibrillation During Radiofrequency Catheter Ablation

Figures

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  Figure 1. 12-Lead Electrocardiogram of Spontaneous Ventricular Fibrillation Initiation 12-lead electrocardiogram shows sinus rhythm with a right bundle branch block. The QRS axis is normal. There are persistent ST-segment elevations in leads III and aVF with Q waves consistent with incomplete reperfusion. Midway through the tracing, ventricular fibrillation is initiated by a stereotypic premature ventricular complex (asterisk) with indeterminate V1 morphology with superior axis and dominant S waves, consistent with localization to the moderator band, septum, or distal left posterior fascicle toward the apex.

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  Figure 2. 12-Lead Electrocardiogram of Sustained Polymorphic/Ventricular Fibrillation Preceding the Initial Application of Radiofrequency Energy

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  Figure 3. Local Electrogram Recorded at Successful Moderator Band Site Intracardiac electrocardiogram recorded from the tip of the ablation catheter (Abl d) during sustained ventricular fibrillation at 100 mm/s sweep speed. Before radiofrequency delivery, intermittent high-frequency electrogram components, which may be consistent with Purkinje potentials, were recorded (red asterisks).

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  Figure 4. Anatomic Location of Ablation That Resulted in Termination of Ventricular Fibrillation From Moderator Band Electroanatomic map shows ablation catheter (Abl) within the right ventricle (RV). Intracardiac echocardiography confirmed contact with lesion formation (Abl) on the moderator band, which is an intracavitary structure within the RV. During radiofrequency energy delivery, sustained ventricular fibrillation (85 seconds) directly terminated to monomorphic ventricular tachycardia during the delivery of RF ablation in 3.8 seconds of ablation.

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  Figure 5. Mapping of Exit Region of Monomorphic Ventricular Tachycardia Within Extensive Inferior Scar Substrate (A) The resulting monomorphic ventricular tachycardia was mapped to an exit site lateral to the posteromedial papillary muscle with multielectrode catheter. The activation map and local signals (−65 ms) on the duodecapolar catheter suggest a focal breakout at the site of electrode pair 12 to 13. (B) Extensive low-voltage zone involving inferior wall from septum to lateral wall was detected with substrate mapping. (C) Termination of the exit region returned the patient to sinus rhythm. The sinus rhythm electrogram is low voltage without Purkinje or late potentials.