Ventricular Tachyarrhythmias and Ventricular Storm in Acute Coronary Syndrome

Ventricular arrhythmias are common complications of acute coronary syndrome (ACS). They occur in almost all patients and are related to the formation of re-entrant circuits at the confluence of the necrotic and viable myocardium, as well as to irritable ischemic myocardium. Premature ventricular contractions occur in approximately 90% of patients with ACS. At the other end of the spectrum, the incidence of ventricular fibrillation (VF) is reported as approximately 2% to 4%. The incidence of VF in patients with ACS seen in CCUs over the past three decades appears to have declined.One should always look for treatable causes including active Ischemia, electrolyte disturbances, decompensated heart failure and proarrhythmic effect of drugs. The most effective drugs in this setting are beta blockers, Amiodarone, Sotalol, Mexiletine and in rare situations Procainamide or Quinidine. Other adjunctive measures are sedation or general anesthesia and left stellate ganglion denervation.During the last decade, radiofrequency ablation has proved to be an effective therapy for patients in electrical storm who are refractory to drug therapies. Patients with monomorphic VT will mostly have scar related reentry and the underlying substrate is amenable to ablation. Polymorphic VT or VF is usually secondary to ischemia, hemodynamic instability or metabolic derangements but early coupled or Purkinje related PVCs are increasingly reported as the initiating triggers and are an appropriate target for ablation.