Heart attack patients who develop serious arrhythmia in connection with procedures to open blocked arteries face a significantly higher risk of death for several months after the procedure, when compared with similar patients who do not develop such complications, according to research published in the May 6 issue of the Journal of the American Medical Association.
"The findings suggest that we should take another look at how we've been assessing the importance and the impact of these episodes," said the study's senior author Christopher Granger, MD, a cardiologist at the Duke Heart Center in Durham, N.C.
Granger said that until recently, the medical community generally felt that an episode of arrhythmia--while worrisome--did not complicate outcomes much for patients with blocked arteries because fast and effective treatments usually get blood flowing properly again.
"But this study tells us that we were wrong. Now we know that an episode of ventricular fibrillation at any point significantly affects a patient's chance of a successful outcome," he noted.
The researchers examined the records of 5,745 MI patients enrolled in a multicenter, international study of MI patients scheduled to undergo PCI procedures between 2004 and 2006. They tracked which patients experienced arrhythmia, when it occurred, and what happened to patients afterwards.
They found that almost 6 percent of the patients experienced at least one episode of sustained ventricular arrhythmia either before or after the procedure.
Granger and colleagues found that ventricular fibrillation occurred in 329 of the patients in the group. They found 25 of them experienced fibrillation before catheterization, 180 experienced it during the procedure and 117 afterwards. Investigators found that those who experienced fibrillation at any point were three-fold more likely to die within the first three months after the procedure, when compared with those who did not have any arrhythmia.
Patients with larger heart attacks and who had less blood flow to the heart muscle were more likely than others to experience arrhythmias, according to the authors. A majority of the episodes occurred within two days of the PCI procedure.
"The study is important because it has helped us identify a subset of patients who may need extra time in the hospital under more intense monitoring in order to get them safely through that two-day period post-procedure when the vast majority of these arrhythmic episodes occur," said the study's lead author Rajendra Mehta, MD, a cardiologist at the Duke Heart Center.
Researchers say the chances of a serious episode of arrhythmia fall significantly after the initial 48 hours following catheterization.