PMC8645586_01
(A) Episode of VT detected by ICD. Sinus rhythm is restored following one attempt of ATP burst stimulation with subsequent shock application according to the ICD programming protocol shown on the upper left corner. (B) ECG of the patient in sinus rhythm after shock therapy, with a QRS duration of 112 ms. Abbreviations: VT, ventricular tachycardia; ICD, implantable cardioverter defibrillator; VF, ventricular fibrillation; ATP, antitachycardia pacing; vent, ventricular.
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F1
A 65-year-old man with ischemic cardiomyopathy was referred to the electrophysiology laboratory for radiofrequency (RF) ablation of VT following repetitive ICD shocks, even after appropriate antiarrhythmic therapy (Figure 1A). A baseline ECG showed sinus rhythm with a QRS duration of 112 ms (Figure 1B).
Scar distribution in endocardium. Bipolar voltage map of the left ventricular endocardium. Scar cutoff is set at <0.5 mV (red area); border zone is set at 0.5-1.5 mV. Note predilection of scar distribution to basal septal endocardium of left ventricular.
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F2
Arrhythmia substrates were identified in the basal septal endocardium of the left ventricular (Figure 2).
(A) A 12-lead ECG after ablation. The underlying rhythm is sinus rhythm with QRS duration of 360 ms. Note the initial QRS complex mimicking atrial electrical activity in standard (highlighted in blue). The real P wave is indicated by the arrow. Another QRS complex in this sequence is highlighted in purple. The wave highlighted in orange is the T wave. (B) The right ventricular-left ventricular interval is 200 ms in the absence of ventricular pacing. (C) Following ECG optimization by CRT-P programming, the QRS complex is significantly narrowed.
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F3
TTE demonstrated an LVEF of 34%, with paradoxical motion of the left and right ventricle during both the diastole and systole. The postprocedural ECG is shown in Figure 3A. The first QRS complex in this sequence, highlighted in Figure 3A in a blue color, mimicked atrial depolarization in the limb leads. The second QRS complex in this sequence, highlighted in Figure 3A in a purple color, resembled a left bundle branch block (LBBB) pattern and the wave highlighted in Figure 3A in orange was a T wave. The intracardiac recordings from the right and left ventricle showed marked intraventricular conduction delay (200 ms) (Figure 3B). Following postimplant ECG optimization, the interventricular interval was narrowed from 200 ms in intrinsic intraventricular conduction to 20 ms in biventricular pacing (Figures 3B,C).
Radiologic images of the cardiac resynchronization therapy system showing lead positioning. LV, left ventricular; RV, right ventricular.
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F4
The procedure was successfully performed with extracorporeal membrane oxygenation support (Figure 4).
The response of echocardiography when the CRT-D is turned on and off. CRT-D, cardiac resynchronization therapy with defibrillation.
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F5
After turning on CRT-D, the fused E/A waves were separated in TTE, which suggested that the heart responded well to the CRT-D therapy (Figure 5).