Studies of RFA for treatment of atrial fibrillation report higher efficacy rates than do studies of AAD therapy and a lower rate of complications
BACKGROUND Although radiofrequency catheter ablation ( RFA ) has evolved from an experimental procedure to an important treatment option for atrial fibrillation , the relative safety and efficacy of catheter ablation relative to that of antiarrhythmic drug ( AAD ) therapy has not been established .
Propranolol Decreases Tachycardia and Improves Symptoms in the Postural Tachycardia Syndrome: Less Is More
Background — Postural tachycardia syndrome ( POTS ) induces disabling chronic orthostatic intolerance with an excessive increase in heart rate on st and ing . β-Blockade is an appealing treatment approach , but conflicting preliminary reports are conflicting . We tested the hypothesis that propranolol will attenuate the tachycardia and improve symptom burden in patients with POTS . In protocol 1 , a low dose ( 20 mg ) was compared with placebo , and the dose response was assessed in protocol 2 . Methods and Results — In protocol 1 , patients with POTS ( n=54 ) underwent acute drug trials of propranolol 20 mg orally and placebo , on separate mornings , in a r and omized crossover design . Blood pressure , heart rate , and symptoms were assessed while the patients were seated and after st and ing for up to 10 minutes before and hourly after the study drug . Supine ( P<0.001 ) and st and ing ( P<0.001 ) heart rates were significantly lower after propranolol compared with placebo . The symptom burden improvement from baseline to 2 hours was greater with propranolol than placebo ( median , −4.5 versus 0 arbitrary units ; P=0.044 ) . In protocol 2 , 18 patients with POTS underwent similar trials of high-dose ( 80 mg ) versus low-dose ( 20 mg ) propranolol . Although the high dose elicited a greater decrease than the low dose in st and ing heart rate ( P<0.001 ) and orthostatic tachycardia ( P<0.001 ) , the improvement in symptoms at 2 hours was greater with low-dose propranolol ( −6 versus −2 arbitrary units ; P=0.041 ) . Conclusions — Low-dose oral propranolol significantly attenuated tachycardia and improved symptoms in POTS . Higher-dose propranolol did not further improve , and may worsen , symptoms
Studies of RFA for treatment of atrial fibrillation report higher efficacy rates than do studies of AAD therapy and a lower rate of complications
BACKGROUND Although radiofrequency catheter ablation ( RFA ) has evolved from an experimental procedure to an important treatment option for atrial fibrillation , the relative safety and efficacy of catheter ablation relative to that of antiarrhythmic drug ( AAD ) therapy has not been established .