Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Procedure for irregular heartbeat gives long-lasting relief & improves quality of life

02.03.2006


Catheter ablation for chronic atrial fibrillation returns 74 percent of patients to normal rhythm



People who have endured the effects and risks of an irregular heartbeat for years can get long-lasting relief from a procedure that takes less than two hours, a definitive new study shows.

In the March 2 issue of the New England Journal of Medicine, researchers from the University of Michigan Cardiovascular Center and the San Raffaele Hospital in Milan, Italy report the results of a rigorous study of radiofrequency catheter ablation for the chronic form of the most common heart-rhythm disorder: atrial fibrillation.


Although the treatment has shown promise for several years in studies by U-M researchers and others, the new paper gives conclusive evidence of catheter ablation’s positive effects on heart rhythm, symptoms, quality of life and heart function -- even in the most difficult-to-treat chronic atrial fibrillation patients.

In all, 74 percent of study participants who had the procedure were free of their irregular heartbeat a year afterward, and did not need rhythm-regulating drugs. They reported a steep drop in the severity of symptoms, and their hearts’ left upper chambers returned to normal size. No side effects were reported, though some of the patients needed a second procedure to fully treat their heart rhythm disturbance.

"We have shown objectively, and with rigorous follow-up, that this procedure is a very good option for patients with symptomatic, chronic atrial fibrillation who otherwise may have to live with atrial fibrillation for the rest of their lives," says lead author Hakan Oral, M.D., an associate professor of medicine at the U-M Medical School and member of a U-M Cardiovascular Center team that has treated more than 2,000 atrial fibrillation patients using catheter ablation.

The study was a randomized, controlled trial, and used long-term automatic daily monitoring of heart rhythm, to assess the efficacy of ablation. It involved 146 patients, 77 of whom were randomized to receive a left atrial catheter ablation procedure known as circumferential pulmonary-vein ablation. The remaining 69 patients were randomized to a control group.

The study was supported by U-M’s Ellen and Robert Thompson Atrial Fibrillation Research Fund, founded in 2001 by a Detroit philanthropist who has the condition.

More than 2.3 million Americans live with atrial fibrillation, which is caused by electrical "misfires" in the heart muscle that make the upper chambers of the heart quiver and pump erratically. This causes weakness and other debilitating symptoms, and encourages the formation of clots, putting patients at much higher risk of stroke.

Some patients have rhythm problems only occasionally, but most, like those in the study, have them all the time. Usual treatments for atrial fibrillation include electric-shock procedures called transthoracic cardioversions, which requires sedation, and drugs to regulate rhythm and thin the blood, which can cause side effects and often lose effectiveness. Moreover, these measures often are only temporarily effective, and the majority of the patients develop recurrences of atrial fibrillation sooner or later.

Catheter ablation aims to counteract the irregular electrical impulses in the heart muscle by delivering tiny bursts of intense radiofrequency waves to areas of disorganized and rapid electrical activity, thereby short-circuiting the aberrant electrical impulses. The catheters that record electrical signals in the tissue and deliver the radiofrequency energy are inserted through the groin of a sedated patient, and snaked through the major blood vessels into the heart. Then, the catheter head pokes through the septum that divides the heart vertically, and enters the left atrium, where ablation takes place. The radio wave heats the targeted areas of tissue, a process called ablation, but spares nearby tissue.

The new study was the first ever designed specifically to separate the ablation procedure’s effects from those of medications and cardioversion, which are often used temporarily after ablation.

All study participants took amiodarone, a rhythm-regulating medicine, for six weeks before and three months after they were randomized to either the ablation group or the control group. Ablation patients were allowed to have a cardioversion during their ablation procedure and as needed in the first three months after the procedure, and they were allowed to take amiodarone for up to three months. Control-group patients had a cardioversion after being randomized, and were allowed to have a second one anytime in the next the three months. During those three months, they took amiodarone daily, then stopped. If their atrial fibrillation came back, control patients were allowed to resume amiodarone or have an ablation procedure. Fifty-three control patients opted for ablation.

For a year, all patients used a portable monitor to record their heart rhythm several times a day and any time their heartbeat became irregular. Those recordings were transmitted by phone to a central location and the rhythm patterns were analyzed by cardiologists who did not know which patients had had ablation. The patients also had several clinic visits, and electrocardiogram and echocardiogram heart tests, during the year, at which they completed questionnaires about the severity of their symptoms.

Although the study was not designed to compare the efficacy of catheter ablation with long-term use of rhythm-regulating medications, only 4 percent of the patients who didn’t have the ablation procedure and stopped their medication after three months were still free of their atrial fibrillation after one year.

Senior author Fred Morady, M.D., a professor of cardiovascular medicine who directs the U-M CVC’s Clinical Electrophysiology Laboratory, notes that after one year, ablation patients in the study experienced a decrease in the size of their left atrium, which is often enlarged in AF patients, and an improvement in the ejection fraction, or pumping ability, of their left ventricle. The patients who received ablation reported significant reductions in the severity of their symptoms, compared with those who did not receive ablation.

In the ablation group, 20 patients needed one more ablation procedure to address remaining atrial fibrillation, and four had a second ablation after developing a less-serious rapid-heartbeat condition called atrial flutter. There were no complications related to the ablation procedure.

Kara Gavin | EurekAlert!
Further information:
http://www.umich.edu

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Camera on NASA's Lunar Orbiter survived 2014 meteoroid hit

29.05.2017 | Physics and Astronomy

Strathclyde-led research develops world's highest gain high-power laser amplifier

29.05.2017 | Physics and Astronomy

A 3-D look at the 2015 El Niño

29.05.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>