People who suffer an ischemic stroke and have an abnormality in the heart's electrical cycle at the time of emergency treatment have a higher risk of death within 90 days than people without abnormal electrical activity, according to research published online March 20 in the Journal of Stroke and Cerebrovascular Diseases.
The study also provides a threshold at which the threat of death is highest: QTc intervals greater than 440 milliseconds in women and 438 milliseconds in men have the worst prognosis, according to the researchers.
"From a clinical perspective, our study offers additional parameters to consider while treating stroke patients in the emergency department setting," said corresponding author Latha G. Stead, MD, professor and chair of the department of emergency medicine at the University of Rochester Medical Center in Rochester, N.Y. "It appears that reviewing the medications a patient is taking and looking specifically for those that might prolong the QTc interval would be a useful practice."
The investigators studied the medical records of 345 ischemic stroke patients at the Mayo Clinic, treated between 2001 and 2004, and followed for 90 days. Further analysis was done to see if the researchers could identify a QTc cutoff that would accurately predict death within 90 days.
Stead and colleagues reported that approximately 35 percent of the patients had a prolonged QTc interval at the time of the emergency department visit. An estimated 81 percent of all patients were expected to survive the next three months. However, results showed that only 70.5 percent of the patients with a prolonged QTc interval survived compared with 87.1 percent of the patients without a prolonged QTc interval.
In addition, researchers found that although the causes of death ranged from stroke to cardiac illnesses, to cancer and respiratory failure, most patients died of stroke or cardiac causes. In those cases, about half of the patients had prolonged QTc intervals. Among the stroke survivors, patients with prolonged QT intervals had poorer functional outcomes.
The Mayo Foundation Emergency Medicine Career Research Career Development Award supported the study.