Patient: 42-year-old male with familial dilated cardiomyopathy and diabetes, left ventricular ejection fraction 19%, NYHA functional class II, with frequent ventricular premature beats.
Index arrhythmia: ventricular fibrillation.
Problem: admission after out-of-hospital cardiac arrest with external defibrillation by the emergency squad.
ICD pulse generator: Ventak 1625 with an Endotak 072 lead (Guidant/CPI, USA).
Detection: VT = 180/min. Duration: 2, 5 s. COMMITTED.
VVI 40 bpm.
Electrogram (See Figure 6.1a) Electrogram interpretation
Wide band ventricular electrogram, obtained via standard electrocardiog-rapher, coupled to the programming wand. The sequence shows six consecutive arrhythmias (recognized as VT when upward spikes are displayed). Only the first five are shocked (downward spikes, numbered from 1 to 5). The first event is polymorphic VT degenerating to VF. The initial rhythm is faster than 180 bpm. The complexes are illegible after the shocks because of a polarization effect.
Fortunately, the rescue squad arrived after this sequence.
Diagnosis: For the first event: polymorphic VT, degenerating to VF.
Action: defibrillation; metoprolol IV; the patient was put on the emergency list for heart transplantation.
From top to bottom: surface electrocardiogram obtained by coupling a standard ECG machine to the programming wand and a bipolar (near-field) intracardiac ventricular electrogram. The latter was obtained at the time of ICD removal, during heart transplantation.
Diagnosis: sinus rhythm, with intraventricular conduction delay (the QRS width is at least 240 ms). The intracardiac amplitude is very small (less than 0.5 mV). The morphology of the available wide band electrogram in sinus rhythm suggests that arrhythmias 2, 3, and 4 might have been fast conducted supraventricular rhythm.
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