Simple Measures to Prevent Vasovagal Syncope
Abstract & Commentary
By Michael H. Crawford, MD, Professor of Medicine, and Chief of Clinical Cardiology, at the University of California, San Francisco. Dr. Crawford is on the speaker's bureau for Pfizer.
Synopsis: Physical counterpressure maneuvers are a risk-free, effective, and low-cost treatment method in patients with vasovagal syncope and recognizable prodromal symptoms, and should be advised as first-line treatment in patients presenting with vasovagal syncope with prodromal symptoms.
Source: van Dijk N, et al. Effectiveness of physical counterpressure maneuvers in preventing vasovagal syncope. J Am Coll Cardiol. 2006;48:1652-1657.
Vasovagal syncope is a common and often disabling disorder that lacks solid evidence-based treatment options. Thus, the Physical Counterpressure Maneuvers trial was conducted in 15 centers worldwide that treat syncope patients. Patients with recurrent typical vasovagal syncope with prodromal symptoms were recruited. Patients with overt heart disease, orthostatic hypotension and other causes of syncope were excluded. Patients with negative head-up tilt-table tests were included if their symptoms were classic. Patients were randomized to standardized optimal conventional therapy with or without training in physical counterpressure maneuvers. Conventional therapy included the admonition to increase salt and water intake, but not drug therapy. The physical maneuvers included leg crossing, handgrip and arm tensing without doing the Valsalva maneuver. The primary endpoint was the risk of recurrent syncope. Conventional therapy was applied to 117 patients and counterpressure to 106. Mean follow-up of the 208 patients (mean age, 38 years) not lost to follow-up was 14 months. Syncope recurred 142 times in the conventional group and 76 in the counterpressure group for a recurrence rate of 51% and 32%, respectively (RR .36, CI = .11–.53, P = .005). Presyncopal events were similar in both groups, 74% vs 83% (P = NS). Women had more recurrences then men, but the effectiveness of counterpressure was not different. Patients preferred arm tensing to handgrip and leg tensing. There were no injuries during follow-up. The authors concluded that physical counterpressure maneuvers are an effective risk-free, low-cost method to prevent vasovagal syncope in patients with prodromal symptoms and should be the therapy tried first.
Recurrent vasovagal syncope is often treated by drugs such as fludrocortisone to increase salt and water retention, but this therapy has not been subjected to a randomized controlled trial. Vasoactive drugs have not been superior to placebo in trials and pacemaker studies have had mixed results. Thus, this is the first randomized controlled trial that has shown benefit from any treatment for vasovagal syncope. Unfortunately, although simple, it cannot be applied to everyone with vasovagal syncope. Some patients may have no prodromal symptoms or symptoms that are too brief to act quickly to prevent syncope. The authors believe this may explain some of the treatment failures, since not every syncopal event is the same in a patient. They may have prodromal symptoms, but not always.
There are some limitations to the study. Not everyone got carotid sinus massage, so some with this condition could have been in the trial and explained some of the treatment failures. Also, some may have inadvertently performed a Valsalva maneuver which would thwart the benefit of muscle tensing. Only the patients were blinded, so physician interpretation of recurrences could have been biased in some cases. In addition, head-up tilt-table testing was not positive in everyone, so some could have had other causes of syncope that would not respond to muscle tensing. There may have been some patients in the trial that could have responded to drug therapy.
Despite these limitations, this was an impressive study with a number needed to treat of 5 to prevent one recurrent syncopal event. It makes sense to try this simple approach first in appropriate patients before embarking on drug therapy or devices.