Wednesday, July 30, 2008

Atrial fibrillation is associated with greater risk of death for acute coronary patients
by Kelly Winget

In a recent study, researchers found that patients who develop irregular heartbeats following a heart attack are at greater risk for poor outcomes and have a higher risk of mortality within a year.

The results of the study, led by DCRI researchers, were published in the July issue of Heart.

Atrial fibrillation (AF), which is the most common type of cardiac arrhythmia, is a fairly frequent complication after a patient has had a heart attack. For the study, researchers wanted to assess how this type of irregular heartbeat affects the outcomes in patients who have acute coronary syndromes.

Researchers also wanted to determine if ST-segment elevation further impacted the complications. One type of heart attack, non-ST segment elevation (NSTE), doesn't change a patient's ECG readings and physicians have to rely on chemical markers in the blood to know that the heart has been damaged. Another kind, ST-segment elevation myocardial infarction (STEMI), affects a large area of the heart and causes visible changes to an ECG reading.

The researchers reviewed data on more than 120,500 patients who had either STEMI or NSTE acute coronary syndromes. Data came from patients enrolled in 10 clinical trials.

According to the study, 7.5 percent of patients developed AF while hospitalized, and those who developed it had a greater risk of dying in the first seven days. Developing AF also increased a patient's risk of mortality within a year. Patients who had STEMI were somewhat more likely to develop AF than patients with NSTE.

The patients who were most likely to develop AF were also older, had heart rates that were greater than 85 beats per minute and systolic blood pressure that was greater than 110 mm Hg. Smoking status, prior heart attacks and a history of high blood pressure also increased a patient's risk of developing AF.

Despite the slightly increased risk for STEMI patients to develop AF, both patient groups had similar results of worse outcomes than patients who did not develop AF. Researchers hope the findings can help improve the care of patients who develop this type of irregular heartbeat.

DCRI researchers involved in the study include Renato Lopes, MD, Karen Pieper, John Horton, Sana Al-Khatib, MD, Kristin Newby, Rajendra Mehta, MD, Kenneth Mahaffey, MD, Bob Harrington, MD, Magnus Ohman, M.B, CH.B, and Chris Granger, MD.