Use of a high-density mapping catheter for Purkinje-related ventricular tachycardia in a patient with a previous history of anterior myocardial infarction

Figure 1. A: Findings of the 12-lead electrocardiogram during normal sinus rhythm. QRS complexes during sinus rhythm revealed the presence of a left anterior fascicular block. B: Results of the 12-lead electrocardiogram during ventricular tachycardia: fast heart rate (200 beats per minute), narrow QRS interval (121 ms), right bundle branch block, and left axis deviation. C: Magnetic resonance imaging revealed a broad transmural scar in the septum and anterior wall of the left ventricle owing to a previous myocardial infarction. D: Endocardial left ventricle voltage mapping during sinus rhythm showed a wide area with low voltages around the infarct scars. Low-voltage area (red) and dense scar area (gray) were defined as a peak-to-peak bipolar voltage of 0.1–0.6 and <0.1 mV, respectively.

Figure 2. A: A duodecapolar electrode catheter (Inquiry Livewire; Abbott, St. Paul, MN) located at the apical-inferior septum of the left ventricle could record left posterior fascicular potentials during sinus rhythm. Moreover, it revealed a presystolic potential (P2) during ventricular tachycardia. The P2 potentials exhibited retrograde conduction via the left posterior Purkinje fiber (blue arrow). B: The Advisor HD Grid Mapping Catheter (Abbott, St. Paul, MN) located on the anterior wall of the left ventricle exhibited late potentials during the ventricular tachycardia (red circle). C: The Advisor HD Grid Catheter located on the left ventricular apical-anterior wall exhibited the mid-diastolic potentials during ventricular tachycardia (red circle). Some potentials were small and had dull signals representing the far-field signals of the epicardium. D: The Advisor HD Grid Mapping Catheter located at the apical-inferior septum of the left ventricle exhibited at the mid-to-late diastolic potentials, which could not be recorded with a duodecapolar electrode catheter.

Figure 3. Activation pattern of ventricular tachycardia (VT). A–G: The activation map revealed that the impulse propagated retrogradely from the VT exit site to the left posterior Purkinje fibers and another propagated from the VT exit site to the apical-anterior wall site via the endocardium. The impulse that propagated retrogradely via the Purkinje fiber entered from the endocardial side of the apical-anterior wall region surrounded by the scar regions, then propagated on the epicardium to the septum, and finally exited from a distal site of the left posterior fascicule area. H: Successful ablation site of the VT. The radiofrequency energy (30 W) was applied to the VT isthmus site using an 8F, 4-mm flexible irrigated-tip catheter with 1-4-1-mm interelectrode spacing (FlexAbility Ablation Catheter, Abbott, St. Paul, MN). The VT terminated and could no longer be induced by an isoproterenol infusion or programmed stimulation.