Telemetry captures stroke patients' cardiac problems

To detect "silent" or new cardiac abnormalities, all patients hospitalized for stroke should receive continuous cardiac rhythm monitoring (telemetry) for at least the first 24 hours after the stroke is detected, according to a Loyola University Health System study presented at the American Stroke Association's International Stroke Conference 2006.

Currently, only some stroke patients are put on telemetry, which electronically sends patients' heart rhythm and other cardiac data captured by machines in the patients' room to a central location in the hospital. There it is displayed on computer screens for staff to monitor for abnormalities on an ongoing basis.

"Many patients have paroxysmal or otherwise 'silent' arrythmias, which may not show up until after a stroke occurs," said study co-author Dr. Michael J. Schneck, associate professor, department of neurology, Loyola University Chicago Stritch School of Medicine, Maywood, Ill.

"Continuous cardiac rhythm monitoring allows for the discovery of unsuspected paroxysmal abnormalities, such as atrial fibrillation, which may be important in determination of antithrombotic therapy post stroke," said Schneck, who is certified in the subspecialty of vascular neurology by the American Board of Psychiatry and Neurology, Inc. "Also, atrial fibrillation is a predictive factor for severe stroke as well as early death with acute ischemic stroke."

For the study, Schneck and colleagues reviewed records of 337 stroke patients. A total of 289 patients had been placed on telemetry. Among the telemetry patients, 80 percent had normal rhythms but the remainder had abnormal rhythms. Results of the study shows 17 percent of patients placed on telemetry developed new cardiac rhythms while monitored.

"This finding is significant in that the new rhythm may have both immediate and long-term neurologic and cardiac implications," said Schneck, director of Loyola University Health System's neuro-intensive care program and associate director of the stroke program.

Many stroke patients have significant abnormal--but potentially treatable--cardiac rhythms following stroke.

"Approximately 30 percent of patients with atrial fibrillation and flutter do not know they have an irregular heartbeat," he said. "Therefore, patients without a known arrythmia, who are not placed on telemetry units, may have an underlying rhythm that predisposes them to stroke or future cardiac dysfunction.

"It is also possible that cardiac dysrhythmias may result from the effects on the body after a stroke," said Schneck.

Cardiovascular risk factors were discovered more frequently in the patients placed on telemetry as compared to those who were not monitored. In addition, patients whose cardiac rhythms changed following admission had a higher percentage of coronary artery disease than those whose rhythms remained static.

New-onset atrial fibrillation was detected in 22 patients representing 7.6 percent of all patients monitored on telemetry. Nine patients were subsequently placed on blood thinners upon discharge from the hospital. The other 13 patients had major exclusionary factors for the medicine, including a high fall risk or intracranial hemorrhage.

"Monitoring rhythms is of prognostic significance for patients in the years of life that follow and may help to determine appropriate secondary preventive interventions," said Schneck.

All patients found to have a new rhythm following telemetry monitoring had no previous history of arrhythmia. Therefore, this data would suggest that, upon admission to the hospital, it is necessary to monitor all patients regardless of these factors.

Schneck said that any arrhythmia may be alarming for reasons pertaining to each abnormality. "However when evaluating stroke patients, atrial fibrillation is of particular consideration," he said. "It is well-known that it there is a strong association between this rhythm and ischemic cardioembolic stroke. It also is important to identify these dysrhythmias as early as possible in order to prevent the progression of infarct size with subsequent worsening neurologic deficits."

Co-authors of the study with Schneck are Matthew E. Harinstein, Dr. Preeya Patel and Dr. John T. Barron.