Successful Substrate Ablation for Ventricular Fibrillation in a Patient With Nonischemic Cardiomyopathy

Figures

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  Figure 1. Preprocedural Electrocardiogram and Echocardiogram (A) 12-lead electrocardiogram showed a normal QRS interval (120 ms) without any ischemic change. (B) Echocardiography showed dilation of the left ventricle (end-diastolic dimension 67 mm and end-systolic dimension 62 mm) and reduced ejection fraction (17%). Thickness of the interventricular septum (9 mm) and the posterior wall (10 mm) was relatively preserved.

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  Figure 2. Voltage Maps and Intracardiac Electrograms During the Initial Procedure Both bipolar and unipolar voltage mapping generally demonstrated a low-voltage area in the basal to apical septum (A), but a relatively preserved area at the mid-septum according to the unipolar voltage map (B). (C) The intracardiac electrogram of VF initiation showing the Purkinje potential preceding QRS onset with latency at the mid-septum, where a good pacemap was obtained (D). ABL = ablation; CS = coronary sinus; dis = distal; prox = proximal; PVC = premature ventricular contraction; RAO = right anterior oblique; RV = right ventricle; VF = ventricular fibrillation.

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  Figure 3. 12-Lead and Intracardiac Electrograms in SR and Local Pacing (A) In the basal septum, low-voltage fractionated signals were recorded during SR. Pacing at this site resulted in a stimulus QRS latency and narrow QRS. (B) 12-lead electrocardiograms of pacing and local electrograms during SR in the septum. Local pacing demonstrates multiple narrow QRS morphologies with a stimulus QRS latency. EGM = electrogram; SR = sinus rhythm; other abbreviations as in Figure 2.

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  Figure 4. Schematic Representation During Sinus Rhythm and Local Pacing Local abnormal fractionated signals (probably damaged Purkinje-related electrograms) during sinus rhythm and narrow QRS with a stimulus QRS latency by means of locally pacing this signal may be explained by the following mechanism: (A) Antegrade activation to this site (B) through the proximal Purkinje fibers may be blocked (red line) and this site is retrogradely activated (blue dotted arrow) over the distal Purkinje fibers. (B) During local pacing (red circle), the ventricle is retrogradely activated (i) through the distal Purkinje system (blue dotted arrows), or (ii) through both the proximal and the distal Purkinje system. LAF = left anterior fascicule; LPF = left posterior fascicule; RBB = right bundle branch.