Debate: Best Beta-Blockers for Long QT?

Is one beta blocker better than another for patients born with long QT syndrome?

In a report published Sept 23 in The Journal of the American College of Cardiology, Abeer Abu-Zeitone, PhD, and colleagues found that in their study group, nadolol worked best at preventing a recurrent serious cardiac event and that propranolol, the oldest beta-blocker available, did the worst. The researchers also evaluated how patients had fared with atenolol and metoprolol.

But in an editorial commenting on the findings, Arthur Wilde, MD, PhD, and Michael Ackerman MD, PhD, questioned the study’s methodology and predicted that many heart centers will continue to use propranolol.

Abu-Zeitone and his team at the University of Rochester, Rochester, NY, wrote the report based on a retrospective study of the records of 1,530 Rochester patients with Long QT syndrome (LQTS), all of whom were prescribed one of these four commonly prescribed beta-blockers.The heart rhythm problem is associated with serious cardiac events, including syncopal episodes, aborted cardiac arrest, and sudden cardiac death.Although current American College of Cardiology and American Heart Association guidelines call for using beta-blockers in all patients with LQTS, those guidelines do not recommend one over another.

The patients in the Rochester study were all under age 40 when first prescribed beta-blockers, and none had implantable cardioverter-defibrillators.The team noted which drugs patients got, and if they later had a serious cardiac event. The team then looked at recurrences to see if there were higher rates in any of the four groups.

There were, they said.

“Our findings highlight the somewhat augmented therapeutic benefit of nadolol, and we believe it is the preferred beta blocker in the general management of patients with LQTS,” while “propranolol is the least effective agent in preventing recurrent cardiac events in these high-risk patients.”

In an accompanying editorial in The Journal of the American College of Cardiology, Wilde (a cardiology and researcher at the Academic Medical Centre, Amsterdam, NL) and Ackerman (a consultant for Boston Scientific, Gilead Sciences, and Medtronic) found some problems with the study’s methodology. They questioned whether the patients who got propranolol might have included some whose subtype of LQTC put them at higher risk. They also noted that nadolol is not available in all countries, posing a problem for cardiologists there who might want to prescribe it based on the new study results.

The editorial co-authors stopped far short of recommending that physicians use nadolol instead of the other beta-blockers or that they discontinue propranolol.

“Great caution must be exercised before rendering such a conclusion,” they wrote in the editorial, since retrospective studies in general have limitations as to lack of randomization, data reliability, and that there is no way to know whether patients actually took their prescribed medications.”

Only a large, randomized prospective study would yield definitive evidence of which drugs were better, they wrote.