Matters of the heart

By Luke Eggleston/ SUN staff writer
Local cardiologist involved in national study

A Syracuse area cardiologist co-authored an article appearing in the New England Journal of Medicine clarifying the effectiveness of dual-chamber pacemakers.

Russell Silverman, M.D. served as co-investigator in a nationwide clinical trial to determine if dual-chamber pacemakers are more efficient than single chamber pacemakers at decreasing the risk of atrial fibrillation (a common heart rhythm disruption), reducing signs and symptoms of heart failure and improving the quality of life for patients with sinus-node dysfunction.

“Dual-chamber pacemakers are not new. They’ve been around for about 20 years. When it was initially designed it was thought to be an important improvement,” Silverman said. “This study provides cardiologists with the justification to do what they have been doing.”

A dual-chamber pacemaker is an instrument implanted through surgery allowing both the top and the bottom chambers of the heart to be paced. Silverman explained that technology has progressed to the sophistication of a transmitter being able to communicate with the pacemaker to instruct it in different modes, including single-chamber or dual chamber pacing. Patients from St. Joseph’s Hospital in Syracuse and Silverman’s private practice were selected as candidates based on specific criteria, which included being afflicted with sinus-node dysfunction, a condition where the heart’s natural pacemaker malfunctions causing an irregular rhythm.

“Every patient who is an appropriate candidate is seen as a potential participant, but it’s ultimately the patient’s choice,” Silverman said. Patients who participate are required to sign informed consent documents explaining what the study is, the risks involved, the expected length of the study and the expenses involved. In addition, the patients are given numbers to call if a problem arises and options of withdrawing from the study. A review board consisting of doctors, lawyers, clergy and non-medical persons must approve this document and verify that the study is ethical, moral and scientifically based. “We have to follow the patients’ wishes. They’re given the same treatment and care regardless of their choice to participate,” Silverman said.

As part of the study, approximately 2,010 patients received a dual-chamber pacemaker capable of either single or dual-chamber pacing. The patients were then randomly assigned to either single-chamber or dual-chamber mode for an average of 33 months as doctors collected relevant data. The trials spanned six years. During this time, patients answered questions regarding their lifestyle, perception of pain or comfort, and heart rhythm problems.

St. Joseph’s Hospital provided the second highest enrollment in the study out of 91 clinic sites throughout the country by providing 95 patient participants in the cardiac clinical trials.

Silverman was asked to participate as co-investigator in the clinical trials due to his reputation as a cardiologist and his work in previous studies for which he was able to raise a high level of participation.

“Basically, Dr. Silverman has an excellent reputation of enrolling patients to be followed in clinical trials. He also has excellent clinical support. These make an ideal combination in which to carry out research,” said Gervasio Lamas, M.D., principal investigator of the national study and director of Cardiovascular Research at Mount Sinai & Miami Heart Institute, Fla. Results from the study proved that patients implanted with pacemakers in the dual-chamber mode did not live longer or have a different rate of stroke. However, these patients reportedly benefited from an improvement in their lifestyles. They also suffered from fewer episodes of heart rhythm abnormalities and fewer congestive heart failures.

“Most cardiologists always suggested similar results, but this study proves that dual-chamber pacemakers are useful for patients with sinus-node dysfunction,” Silverman said. Lamas said the results allow cardiologists to understand better the options and benefits of pacemaker implementations. “From my perspective the situations now require interpretation of the results to see whether the added money and difficulty of implementing dual-chamber pacemakers is worth it,” Lamas said. “Overall, though, this study reassures most physicians. They are encouraged that patients feel better with the dual-chamber pacemaker.”

The National Heart, Lung, and Blood Institute of Health Support provided the primary funding for the study.

St. Joseph’s Hospital in Syracuse was chosen as a participating site because of the hospital’s willingness to participate in scientifically based investigations and becuase of a long history of allowing physicians to participate in studies. In addition, St. Joseph’s heart surgery program has been consistently ranked number one in the state by the New York State Department of Health.

“Hospitals don’t always make money on research studies. They have to have an open minded approach when presented with the opportunity,” Silverman said. “St. Joseph’s is also very generous on how they allow doctors to practice. St. Joseph’s is a good place to practice for physicians who are scientifically orientated. It’s also a good place for patients to be part of research. It was the only hospital above New York City to take part in the study.”

Currently, Silverman is working with St. Joseph’s Hospital in conducting studies regarding the usefulness of sophisticated pacemakers.

“There are pacemakers which have not only dual-chamber action, but also rate response systems which work according to whether the person is in motion or just resting,” Silverman said. “The study is looking into whether the added features are truly needed and how they help patients.”

Silverman practices at private locations in East Syracuse, Liverpool and Fayetteville, as well as at St. Joseph’s Hospital and Crouse Hospital in Syracuse. He received certification from the North American Society of Electrophysiology-Special Competency in Pacing in 1986.

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