<prompt> Propronolol is useful in all except -Atrial flutterParkinsonian tremorThyrotoxicosisHOCM  <response>: Ans. is b i.e., Parkinsonian tremor o Propranolol inhibits the tremors which are due to overactivity of adrenergic system b 2-receptor, e.g. in thyrotoxicosis. o But, parkinsonian tremor and intention tremor are not due to sympathetic overactivity -- b -blocker has no role. b -blockers are DOC for HOCM and for controling the ventricular rate in atrial fibrillation. 