Refractory ventricular tachycardia storm associated with severe hypokalemia in Fanconi syndrome

ECMO for drug-refractory electrical storm without a reversible trigger: a retrospective multicentric observational study

AIMS

Drug-refractory electrical storm (ES) is a life-threatening medical emergency. We describe the use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) in drug-refractory ES without a reversible trigger, for which specific guideline recommendations are still lacking.

METHODS AND RESULTS

Retrospective observational study in four Iberian centres on the indications, treatment, complications, and outcome of drug-refractory ES not associated with acute coronary syndromes, decompensated heart failure, drug toxicity, electrolyte disturbances, endocrine emergencies, concomitant acute illness with fever, or poor compliance with anti-arrhythmic drugs, requiring VA-ECMO for circulatory support. Thirty-four (6%) out of 552 patients with VA-ECMO for cardiogenic shock were included [71% men; 57 (44-62) years], 65% underwent cardiopulmonary resuscitation before VA-ECMO implantation, and 26% during cannulation. Left ventricular unloading during VA-ECMO was used in 8 (24%) patients: 3 (9%) with intraaortic balloon pump, 3 (9%) with LV vent, and 2 (6%) with Impella. Thirty (88%) had structural heart disease and 8 (24%) had an implantable cardioverter-defibrillator. The drug-refractory ES was mostly due to monomorphic ventricular tachycardia (VT) and ventricular fibrillation (VF) (59%), isolated monomorphic VT (26%), polymorphic VT (9%), or VF (6%). Thirty-one (91%) required deep sedation, 44% overdrive pacing, 36% catheter ablation, and 26% acute autonomic modulation. The main complications were nosocomial infection (47%), bleeding (24%), and limb ischaemia (21%). Eighteen (53%) were weaned from VA-ECMO, and 29% had heart transplantation. Twenty-seven (79%) survived to hospital discharge (48 (33-82) days). Non-survivors were older [62 (58-67) vs. 54 (43-58); P < 0.01] and had a higher first rhythm disorder-to-ECMO interval [0 (0-2) vs. 2 (1-11) days; P = 0.02]. Seven (20%) had rehospitalization during follow-up [29 (12-48) months], with ES recurrence in 6%.

CONCLUSIONS

VA-ECMO bridged drug-refractory ES without a reversible trigger with a high success rate. This required prolonged hospital stays and coordination between the ECMO centre, the electrophysiology laboratory, and the heart transplant programme.

Refractory Electrical Storm in the Absence of Structural Ischemic Heart Disease

Ventricular tachycardia (VT) is characterized as a ventricular rhythm with a QRS >120 milliseconds (ms) and >100 beats-per-minute (BPM) in the absence of an aberrant conduction. It is classified as sustained when lasting >30 seconds. Risk factors associated with the development of VT include increasing age and coronary artery disease with concurrent left ventricular dysfunction, other forms of structural heart disease and acquired or congenital abnormalities in the cardiac sodium, potassium or calcium channels. Diagnosing VT is challenging based on history and physical exam alone. Combination of electrocardiogram (EKG), electrolytes and cardiac enzymes, echocardiogram, cardiac catheterization, and electrophysiology testing are required to appropriately diagnose and characterize the etiology. The case below describes an 84-year-old female with a known history of symptomatic bradycardia status post pacemaker who presented to the emergency department (ED) after a routine device check which revealed VT with associated dyspnea. The patient did not do well with medical therapy and required ablative therapy to resolve VT.