Management of hemodynamically stable wide QRS complex tachycardia in patients with implantable cardioverter defibrillators

Figures

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  FIGURE 1. Chest X-ray in anterior-posterior and lateral projections are important for the identification of the type of implantable cardioverter defibrillator (ICD) and for the application of the magnet which should be fixed on top of the ICD can for disabling therapies. (A) Panel shows the typical position of a transvenous ICD immediately below the left clavicula. (B) Panel shows the radiologic antero-posterior and lateral projections in an 8 year-old girl with an epicardial ICD and the can located in the epigastric area. In panel (C), the typical position of the S-ICD system is appreciated.

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  FIGURE 2. Proposed systematic and structured diagnostic tree for the ECG diagnosis of wide QRS complex tachycardia (WCT). AV, atrio-ventricular; V-A II grade block: retrograde “P” wave is present after the end of the QRS complex with a 2:1 sequence; VT, ventricular tachycardia.

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  FIGURE 3. In this 49 year old patient (Patient 1) with a previous antero-septal infarct several years before, WCT at 190 bpm, QRS axis is deviated to the right; atypical RBBB morphology and the presence of a monophasic R wave in aVR indicate VT. The ECG at rest in sinus rhythm, shows the absence of an R wave from V1-V6 indicative of antero-septal transmural necrosis. Patient 2 presents with a WCT at 180 bpm, with a normal QRS axis and typical LBBB pattern in the precordial leads (QS in V1, monophasic R-wave in V6). QRS morphology in sinus rhythm is the same as the one during tachycardia. Intravenous adenosine, allowed to diagnose atrial tachycardia conducting with LBBB.

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  FIGURE 4. The different steps of the first phase are summarized.

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  FIGURE 5. (A) Panel shows the print-out of the S-ICD electrogram of a 46 year old patient with dilatative cardiomyopathy. The ventricular tachycardia at 160 bpm with shock therapies set at 200 bpm. The device electrogram (EGM) shows how there is double-counting of the QRS due to T-wave oversensing and a 80 Joules shock is delivered with successful interruption of the arrhythmia. (B) Panel shows the ECG of the VT. The patient experienced repeated shocks following gastroenteritis with hypokalemia without loss of consciousness. The arrhythmia was successfully controlled by hydration, intravenous KCl, and intravenous 150 mg of amiodarone (the patient was already under chronic treatment with amiodarone).

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  FIGURE 6. The figure proposes a device-based management algorithm for the treatment of wide QRS complex tachycardia (WCT) in ICD patients, based on the type of ICD, specific ICD features according manufacturer, and stimulation therapies delivery from the atrium (in case of supraventricular tachycardia) or from the ventricle (in case of ventricular tachycardia). AF, atrial fibrillation; CL, cycle length; CPR, cardio-pulmonary resuscitation; CRT-D: cardiac resynchronization ICD; DC ICD, dual-chamber ICD; FVT, fast ventricular tachycardia; MCS, mechanical cardio-circulatory support; PLSGB, percutaneous left stellate ganglion block; PoliVT, polymorphic ventricular tachycardia; S-ICD, subcutaneous ICD; SC ICD, single-chamber ICD; SVT, supraventricular tachycardia; TCA, transcatheter ablation; VT, ventricular tachycardia.

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  FIGURE 7. Telemetry of a 77 year-old CRT-D male patient with a dilated post-infarct heart disease, severely depressed left ventricular ejection fraction, chronic obstructive lung disease, and renal impairment who presents with electrical storm (“high-risk” profile). On the recording, the initial rhythm is a normal pacing rhythm in VDD modality with some single monomorphic premature ventricular beats (PVBs). A fast ventricular tachycardia (FVT) is triggered by the PVB. The first ATP burst of 14 pulses causes degeneration of the VT into a low-amplitude polymorphic FVT refractory to two ATP burst attempts. A 3rd ramp ATP causes degeneration into ventricular flutter which is terminated after a single ICD shock. This patient was stabilized with endovenous amiodarone and underwent transcatheter ablation on the next day.