A small group of students and research fellows from URMC’s Heart Research Follow-up Program flexed a lot of academic muscle at the American College of Cardiology’s 62nd Annual Scientific Session last weekend in San Francisco.
The group, which presented eight new studies, focused on two of the Medical Center’s greatest strengths – the use of implantable defibrillators in heart failure patients and the treatment of Long QT syndrome, an inherited heart rhythm disorder that puts patients at greater risk of sudden cardiac death.
“These studies help us better identify risk and benefit and improve the effectiveness of medical care in heart failure and Long QT patients,” said Arthur J. Moss, M.D., professor and founding director of the Heart Research Follow-up Program at URMC. “It is very unusual and quite an accomplishment for a group to present so many abstracts at one major meeting.”
“We are very lucky to have such talented trainees devoted to the mission of cardiovascular research. Their work is very clinically oriented and will trigger changes in clinical practice,” added Wojciech Zareba, M.D., Ph.D., professor and current director of the Heart Research Follow-up Program.
The studies presented include:
Weight Loss in Defibrillator Patients
A new analysis found that weight loss ups the risk of heart failure or death in patients with cardiac resynchronization therapy plus defibrillator (CRT-D), a device designed to prevent sudden cardiac death and strengthen the pumping action of the heart. The findings add fuel to the so-called “obesity paradox,” a phenomenon long recognized by cardiologists that, once afflicted, heavier heart disease patients fare better than their slimmer counterparts.
Study author Valentina Kutyifa, M.D., postdoctoral research associate at URMC, says that with heart failure, the body has a much higher energy demand. “Patients who maintain their weight have more reserves, while those who lose weight may be exposed to more harm because they don’t have such backup,” she noted.
The finding doesn’t mean that patients with an implanted defibrillator should pack on the pounds, Kutyifa cautions. She says physicians and patients should be aware that even a small amount of weight loss is a warning sign and patients with unintended weight loss should be followed more closely.
Kutyifa presented two other studies at the meeting, focused on better identifying patients who will respond to and get the most benefit from CRT-D therapy.
Beta Blockers in Defibrillator Patients
Martin H. Ruwald, M.D., postdoctoral research fellow at the Medical Center and the University of Copenhagen in Denmark, conducted the first study to compare the efficacy of the most commonly used beta blockers – metoprolol and carvedilol – in heart failure patients with an implantable cardioverter defibrillator (ICD) or CRT-D. He found that treatment with carvedilol was superior and led to a decreased risk of heart failure or death when compared to metoprolol.
In a second study, Ruwald examined the influence of metoprolol and carvedilol on inappropriate therapies – potentially painful and anxiety-provoking defibrillator shocks delivered for rhythms that aren’t dangerous or life threatening. Once again, he found that carvedilol prevailed; it was associated with a significantly decreased risk of inappropriate therapy when compared to metoprolol.
Ruwald says this is the first time these drugs have been compared in defibrillator patients and that carvedilol may be the drug of choice for physicians and patients moving forward.
Arrhythmias in Defibrillator Patients
Studies have shown that patients with chronic arrhythmias – abnormal heart rhythms – do not benefit from CRT-D therapy. In contrast, little is known about patients with intermittent arrhythmias. Anne-Christine Huth Ruwald, M.D., postdoctoral research fellow at the Medical Center and the University of Copenhagen in Denmark, found that such patients do derive benefit from CRT-D therapy.
“Instead of eliminating patients with sporadic arrhythmias from receiving CRT-D therapy, our analysis suggests that they should be treated,” said Ruwald. In patients with intermittent arrhythmias, CRT-D therapy was associated with close to a 60 percent reduction in the risk of heart failure or death compared with ICD therapy. She adds that the findings will help doctors improve the selection of patients for CRT-D therapy.
Beta Blockers in LQTS
Beta blockers are effective in reducing the risk of fainting, cardiac arrest or death in patients with Long QT syndrome. But, no one has compared the different types of beta blockers to determine which is best at treating the disease.
In an analysis that that won “Best Poster” at ACC 2013 – an award given to posters that scored in the top 3 percent of those accepted – Abeer Abu-Zeitone found that different beta blockers are equally effective in reducing the risk of cardiac events in Long QT patients. “This study suggests that factors other than efficacy, such as side effects, should be considered to determine which drug is to be used,” concluded Abu-Zeitone, a Ph.D. candidate in the Translational Biomedical Science Program at the University of Rochester School of Medicine and Dentistry and the Clinical and Translational Science Institute.
LQTS Risk and Life Insurance
Long QT syndrome patients often have trouble getting life insurance because they are predisposed to cardiac arrest and sudden cardiac death. Using the International Long QT Syndrome Registry, Claire Zhang, a fourth year medical student at the University of Rochester, identified low-risk adult LQTS patients with a 45-year survival similar to unaffected family members.
“We found that about 27 percent of Long QT patients don’t have symptoms by age 20 and have a three percent risk of death during the next 45 years, which is no different than their siblings without the disorder,” said Zhang, who is taking a year out of medical school to conduct research. “These low risk patients function normally and should qualify for normal, age-related life insurance.”