Post-infarct ventricular tachycardia masquerading as supraventricular tachycardia: Using 3-dimensional mapping to delineate the circuit between scar and His-Purkinje system

Figures

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  Figure 1. The 12-lead surface electrocardiograms (ECG) for cases 1, 2, and 3. A, C, E: Sinus rhythm. B, D, F: Ventricular tachycardia. See case text for detailed description of each ECG.

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  Figure 2. Case 1. Left: Left ventricular CARTO (Biosense Webster, Wokingham, Berkshire) bipolar voltage (0.5–1.5 mV) map collected in atrial paced rhythm. His patch highlighted by ripple map encircled in yellow design line. Right: local activation time (LAT) map in ventricular tachycardia (VT) suggesting focal activation (red) adjacent to the His patch. Extended early meets late set to 25% with white wavefront discontinuity lines (WADLs) highlighting adjacent areas with LAT difference >25% the mapped tachycardia cycle length, with WADL noted between exit site and His. Patch of mid-diastolic electrograms (EGMs) highlighted by ripple map encircled in white design line. The His, diastolic patch, and VT exit are all adjacent. White design overlaid on the left substrate map. Top right: Example of diastolic EGM. Bottom right: Ablation catheter at mid-diastolic site with VT termination in 11 seconds.

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  Figure 3. Case 2. Left: Left ventricular CARTO (Biosense Webster, Wokingham, Berkshire) bipolar voltage (0.5–1.5 mV) map collected in ventricular tachycardia (VT). Patch of diastolic electrograms (EGMs) highlighted by ripple map encircled in white design line. Left bundle branch (LBB) EGM mapped in intrinsic rhythm encircled in yellow design line. Right: Local activation time map in VT suggesting focal activation (red) adjacent to diastolic patch and LBB. Wavefront discontinuity line (WADL) noted between exit site and LBB. The LBB, diastolic patch, and VT exit are all adjacent. Top right: Example of diastolic EGM from diastolic patch and Purkinje-type EGM from focal exit.

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  Figure 4. Case 3. Far left: Sinus QRS template. Left: Left ventricular CARTO (Biosense Webster, Wokingham, Berkshire) bipolar voltage (0.5–1.5 mV) map collected in atrial paced rhythm. His patch highlighted by ripple map encircled in yellow design line. Post QRS, a distinct patch of late ripple activation, encircled in white design line, seen beneath His patch. Middle: Electrogram examples of 3 distinct potentials (His, myocardial, and late activation). Right: Pacing captures the late potential and reveals a narrow QRS, similar to the clinical ventricular tachycardia.

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  Figure 5. An illustration of the putative mechanism of narrower complex ventricular tachycardia: ripple bars traverse through a septal diastolic isthmus between areas of scar, before exiting adjacent to the His/left bundle branch/Purkinje system. LV, left ventricle.