"The findings suggest that we should take another look at how we've been assessing the importance and the impact of these episodes," says Christopher Granger, M.D., a cardiologist at the Duke Heart Center and the senior author of the study.

Granger says that until recently, the medical community generally felt that an episode of arrhythmia (also known as fibrillation or tachycardia) – while worrisome – didn't 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."

Researchers examined the records of 5745 heart attack patients enrolled in an international study of heart attack patients scheduled to undergo catheterization and stenting 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.

They found that ventricular fibrillation occurred in 329 of the patients in the study group. Twenty-five 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 3-fold more likely to die within the first three months after the procedure, when compared to 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. 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," says Rajendra Mehta, M.D., a cardiologist at the Duke Heart Center and the lead author of the study. Researchers say the chances of a serious episode of arrhythmia fall significantly after the initial 48 hours following catheterization.

Colleagues from Duke who contributed to the study include Renato Lopes, Paul Armstrong, Aijing Starr and Karen Pieper. Additional co-authors include Judith Hochman, from New York University School of Medicine; Petr Widimsky, from Kralovske Vinohrady University Hospital, Prague, Czech Republic; and Paul Armstrong, from the University of Alberta, Canada.

Note: If no author is given, the source is cited instead.

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