Antiarrhythmic drugs case study

Drug commonly induces an otherwise common illness this effect will not be discovered by informal clinical observation. If very common, it may be discovered in formal therapeutic trials and in case-control studies, but if only moderately common it may require observational cohort studies, e.g. proarrhythmic effects of antiarrhythmic drugs. 

Underdetection Ventricular tachycardia will not be detected in some cases, even in the presence of adequate sensing. One troublesome cause of underdetection is slow ventricular tachycardia with rates that are lower than the programmed tachycardia detection rate. Patients who receive concomitant antiarrhythmic drugs may be predisposed to this problem owing to slowing of ventricular tachycardia. In one study, 8% of patients who received ICDs developed ventricular tachycardia with rates that had significant overlap with spontaneous sinus rates (89). Similarly, irregularity of the tachycardia, which causes sensed rates to straddle two zones (between sinus rhythm and ventricular tachycardia or between ventricular tachycardia and ventricular fibrillation). 

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