*6.5.2.1 Ventricular extrasystole or premature ventricular contractions (PVCs)*

PVCs are commonly seen during anesthesia and can be caused by multiple factors such as electrolyte and acid-base disorders, hypoxia, hypercarbia, hypothermia, anesthetic agents, sympathomimetic drugs, and very commonly direct laryngoscopy and tracheal intubation. They are also frequently observed during cardiac and thoracic surgical procedures. PVCs are ectopic beats arising from below the AV node and give rise to a wide and bizarre QRS complex. PVCs can be unifocal, multifocal, or they can alternate with sinus beats in every second (bigeminy) or every third (trigeminy) beat pattern. The management of PVCs should focus on the correction of underlying problems. Asymptomatic or healthy patients generally do not require any treatment. Frequent PVCs, multifocal PVCs, and PVCs occurring on the T wave should be considered a potentially serious event as they can precede runs of life-threatening ventricular tachycardia or fibrillation and require prompt treatment. The immediate availability of a defibrillator is paramount in the event of a deterioration in the rhythm. Lidocaine is the drug of choice. Amiodarone is also helpful. Propanolol, procainamide, and quinidine are other drugs that can be given to abolish PVCs. However, these anti-arrhythmic drugs (classes I and III) may have proarrhythmic effects, particularly in patients with underlying heart disease [23]. Early and continuous vigilance is necessary throughout therapy. It is important to ensure that serum electrolytes (especially potassium) are kept well within the normal range. Cardiac function should be optimized and cardiac ischemia should be managed aggressively. The drugs should be prescribed only if the overall effect is clearly beneficial. Furthermore, the Cardiac Arrhythmia Suppression Trial (CAST) shows that proarrhythmic death can occur even when PVCs are apparently eliminated. Occasionally, PVCs are induced when there is severe bradycardia. Atropine, isoproterenol, or pacing may be effective to abolish the PVCs by speeding up the SA node.
