ROCHESTER, Minn. -- The more possible physical causes of fainting that exist in a patient are likely to increase the risk of an earlier death, medical researchers report in the April issue of Mayo Clinic Proceedings.
The researchers studied 987 patients who were referred to Mayo Clinic for syncope (fainting) evaluation from Jan. 1, 1996, through Dec. 31, 1998. Syncope, which is the loss of consciousness resulting from insufficient blood flow to the brain, is a common phenomenon, especially in the elderly, researchers report.
Of the patients studied, 18.4 percent were found to have multiple potential causes of syncope and, on average, died earlier than those with a single potential cause of syncope.
By identifying the multiple causes and frequency of fainting in patients, researchers hope to direct future research on therapeutic interventions to reduce recurrent symptoms and improve survival in patients. The researchers identified some of the predictors of multiple potential causes of fainting were older age, atrial fibrillation and use of cardiac medications.
"Our findings emphasize the importance of identifying patients who may have potential multiple causes of syncope and the need for implementing the appropriate therapeutic interventions," says Win-Kuang Shen, M.D, a Mayo Clinic cardiologist and lead author of study.
The study grouped the causes of fainting in patients into 10 categories. The Mayo Clinic study used a new method of categorizing the causes of syncope. Previous studies have assigned either a single cause or an unknown cause. Past studies have had lower findings of patients with heart rates either too slow or too fast than the ones in this study. In the Proceedings study researchers reported 13.6 percent of patients had bradycardia (slow heart rate), 12.1 percent had ventricular tachycardia (heart beating too fast) and 47.7 percent had vasovagal syncope (common fainting).
All of the patients were evaluated by electrophysiologic testing, table tilt testing or both. Electrophysiologic testing involves the attachment of electrodes to a long, thin tube (catheter) threaded through a vein in the patient's arm or leg to the patient's heart. Once in place these electrodes can map the spread of electrical impulses through the heart. These electrodes can also give off electrical impulses of their own to pace the heart and see how it reacts. A tilt-table exam is a way to test for causes of fainting. Heart rate and blood pressure are monitored as the patient lies flat on a table. The table is then tilted. Doctors can see how the heart responds to the change in angle -- similar to the change in angle someone undergoes from lying down to standing up.
Along with Dr. Shen, researchers involved with this study include: Bernard Gersh, M.D., Lin Chen, M.D., Stephen Hammill, M.D, and David Hodge from Mayo Clinic and Wouter Wieling, M.D., from the University of Amsterdam's Academic Medical Center in the Netherlands.
Mayo Clinic Proceedings is a peer-reviewed and indexed general internal medicine journal, published for more than 75 years by Mayo Foundation, with a circulation of 130,000 nationally and internationally.
Materials provided by Mayo Clinic. Note: Content may be edited for style and length.
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