Researchers at the University of Pittsburgh led by Dr. Norman Wang, assistant professor of medicine in Pitt’s Division of Cardiology, conducted a study where they observed a population of patients who were newly diagnosed with the two conditions at the same time – abnormal heart rhythms with a high heart rate, also known as tachycardia, and heart failure with reduced pumping capacity. The first author, Dr. Yasser Rodriguez, is a senior fellow in Pitt’s Cardiovascular Fellowship Training Program.
Treatment of patients with these co-existing cardiovascular diseases was the subject of the landmark Atrial Fibrillation and Congestive Heart Failure (AF-CHF) trial, published in 2007 in The New England Journal of Medicine. Subjects in the present study, where there was a high suspicion of the fast abnormal heart rhythm as the cause reduced heart pumping capacity, known as tachycardia-induced cardiomyopathy, were excluded from the AF-CHF trial.
The researchers chose the study population from patients who were referred for treatments to restore normal heart rhythm (rhythm control strategy), and were also diagnosed with heart failure with impaired pumping capacity. Rhythm control strategies consisted of electrical shocks using pads placed on the chest (cardioversion), medications, and/or catheter-based ablation procedures. Their goal was to determine any characteristics unique to this population that could inform treatment strategies specific to this group of patients.
In the group of 25 patients who participated in the study, their major findings were:
- Successful control of the abnormal heart rhythms resulted in normalization of heart pumping function in nearly all patients.
- In 28 percent of the patients, a blood clot was found in the left atrial appendage, a small pouch in the upper left chamber of the heart. In these cases, proceeding with rhythm control treatment is not advisable at least until the clot has been dissolved, said Dr. Wang, as the treatment could dislodge the clot potentially leading to a stroke. This finding also supports the use of testing to diagnose for a clot before treatment is started.
- One in five patients (20 percent) had heavy or binge alcohol use. Alcohol use not only increases the risk of atrial fibrillation, it could also directly reduce the pumping capacity of the heart. This group of patients must be screened for alcohol use, said Dr. Wang.
- Almost all the patients were males (96 percent), and all of them were Caucasian. Though it cannot be affirmed that this finding is representative of the incidence in the general population, further study is required to determine if Caucasian males are at higher risk for this condition, according to the study authors.
- Over 75 percent of patients who presented with rapid atrial fibrillation and received cardioversion as the initial therapy had recurrence of atrial fibrillation within 90 days. More aggressive treatment with additional stronger medications and/or catheter-based ablation procedures may decrease the risk of recurrence.
- Three of four patients were prematurely implanted with a battery-powered implantable cardioverter-defibrillator designed to treat other potentially life-threatening abnormal heart rhythms before confirming that their rhythm was under satisfactory control. “We really need to understand how well atrial fibrillation is controlled before implanting a device,” said Dr. Wang.
- Their findings supported the existing evidence for a treatment strategy that focused on restoring normal rhythm. More research is needed to determine if leaving patients in the abnormal heart rhythm but slowing the heart rate (rate control strategy) has similar efficacy.
Researchers stressed that the study was conducted in a very small group of people and needs to be verified in a larger study population. Nevertheless, this is the first study to look at this distinct population and highlights the need for better understanding of this group and more refined treatment recommendations, the authors concluded. The long-term goals will focus on improving patient outcomes and optimizing health care utilization.
To read the study, which was recently published in the journal Pacing and Clinical Electrophysiology, click here.