Calcium channel blockers are used in all, except-

Ans. is 'c' i.e., Sick sinus syndrome The electrophysiological properties of Verapamil enables it be used as an antiarrhythmic.Electrophysiological effects of verapamilo The basic action of verapamil is to depress Ca2+ mediated depolarization. This result in following actions -Decrease S.A. node automaticityDecrease ventricular automaticityIncrease A. V nodal ERP (This is the most consistent action of Verapamil and due to this A-V conduction is markedly slowed however intraventricular conduction is not slowed).Use of Verapamil as an antiarrhythmic -1.PSVT-It is effective in 80% casesIt should not be used if PSVT is accompanied with hypotension or CHF.2.To control ventricular rate in Atrial flutter or Atrial fibrillation (May be used as an alternative to or in addition to Digitalis).Verapamil is contraindicated in following arrhythmias-1 Ventricular arrhythmias - Injection of verapamil has precipitated ventricular fibrillation, therefore contraindicated.2 Digitalis toxicity - Verapamil is contraindicated in Digitalis toxicity because additive A-V block may occur.3.Heart block and sick sinus.Other uses of verapamil:Angina pectoris- All CCB's are effective in reducing frequency and severity of classical as well as variant angina.It is beneficial in angina in the following wayClassical angina - Reduces cardiac work, mainly as a result of reduced afterload.Variant angina - Prevent arterial spasm.HypertensionHypertrophic cardiomyopathySuppress nocturnal leg crampsMigraine