Heart rhythm drug also helps some failing hearts

March 11, 2001

DALLAS, March 13 - Individuals with heart failure may have another drug treatment option, according to a report in today's Circulation: Journal of the American Heart Association.

The drug, dofetilide, is a class III antiarrhythmic drug normally used to treat tachyarrhythmia, a condition that causes the heart to beat so fast that it can't pump blood effectively. However, class III antiarrhythmia drugs have had mixed effects on treatment of the irregular heartbeats. The drugs have sometimes resulted in an increased occurrence of irregular heartbeats or arrhythmias.

"Patients with congestive heart failure (CHF) have an extremely poor prognosis and a high risk of sudden cardiac death," says lead researcher Bente Brendorp, M.D. Many of these patients might benefit from preventative treatment with an antiarrhythmic drug. However, because of uncertainty about the benefits of using dofetilide and other class III antiarrhythmic medications in treating CHF and other cardiac diseases, cardiologists have been cautious about using them in some heart patients.

In this study, researchers were able to identify a prognostic marker - the QT interval - that can be used to determine which patients can benefit from the drug. The QT interval is a measurement of a waveform on the electrocardiogram (EKG). The EKG is used to measure the heart's electrical activity and diagnose abnormalities in heart rhythm.

"In patients with moderate to severe CHF, those with a baseline QT interval within normal limits had a lower risk of death when treated with dofetilide compared to placebo-treated patients." Brendorp says. "Prolonged QT interval is a cause for caution when using antiarrhythmic drugs because the drug could further prolong the QT interval and cause a deadly arrhythmia," says Brendorp, a clinical researcher in cardiology at Copenhagen University Hospital in Gentofte, Denmark. "However, if our results are confirmed by further tests, this could mean a new line of treatment and improved survival rates in CHF patients who have normal QT intervals."

In a study of 703 individuals with CHF, researchers compared people with short and long QT intervals who were receiving dofetilide or a placebo. Those in the study with shortest QT intervals who received the drug had the lower all-cause mortality than those receiving a placebo.

Congestive heart failure is the inability of a damaged or overworked heart to pump all the blood that returns to it. The result is a back-up of blood in the veins leading to the heart and often a build up of fluids in various parts of the body.

CHF has several underlying causes, including damage from a heart attack, high blood pressure, and an infection of the heart muscle or valves. The life-threatening ailment strikes about 550,000 Americans each year. Survival after CHF diagnosis is about 1.7 years in men and 3.2 years in women.

In this study, 301 individuals received dofetilide and 402 were given a placebo. All had reduced pumping power in their left ventricle, the heart chamber that feeds blood to the rest of the body. They were tracked for an average of 18 months, with a minimum follow-up of one year. The men and women ranged in age from 49 to 84.

During follow-up, 285 (41 percent) of the patients in Brendorp's study died. The death rate was similar between the two groups: 42 percent in the placebo group and 39 percent in the drug-treated patients. However, after the researchers divided the patients into four groups, ranked according to the length of their QT intervals, they found a significant difference.

The people in Brendorp's study had participated in a larger study called the Danish Investigations of Arrhythmia and Mortality on Dofetilide-Congestive Heart Failure (DIAMOND-CHF). This 1,518-patient, randomized, double-blind trial at 34 Danish hospitals sought to determine dofetilide's effectiveness in treating moderate to severe CHF. Half received dofetilide and half a placebo.

The DIAMOND-CHF study produced neutral survival findings - death rates were no different among drug-treated patients compared to those on placebo.

"Our study raises the intriguing question of whether other studies that have had neutral or negative results regarding preventative use of class III antiarrhythmic drugs in high-risk CHF patients, could have had different outcomes had the patients been grouped according to QT intervals," the researchers write.

"If our results hold true in a separate clinical trial, mortality in some patients with CHF can be markedly reduced with the prescription of dofetilide, and perhaps other antiarrhythmic drugs of the same class," Brendorp says.
Co-authors are Hanne Elming, M.D., Ph.D.; Li Jun, M.D.; Lars Køber, M.D., D.M.Sc.; Marek Malik, M.D., Ph.D., D.M.Sc.; Gorm Boje Jensen, M.D., D.M.Sc.; and Christian Torp-Pedersen, M.D., D.M.Sc.CONTACT:
For journal copies only,
please call: 214-706-1396

For other information, call:
Carole Bullock: 214-706-1279 caroleb@heart.org
Bridgette McNeill: 214-706-1135

American Heart Association

Related Heart Failure Articles from Brightsurf:

Top Science Tip Sheet on heart failure, heart muscle cells, heart attack and atrial fibrillation results
Newly discovered pathway may have potential for treating heart failure - New research model helps predict heart muscle cells' impact on heart function after injury - New mass spectrometry approach generates libraries of glycans in human heart tissue - Understanding heart damage after heart attack and treatment may provide clues for prevention - Understanding atrial fibrillation's effects on heart cells may help find treatments - New research may lead to therapy for heart failure caused by ICI cancer medication

Machining the heart: New predictor for helping to beat chronic heart failure
Researchers from Kanazawa University have used machine learning to predict which classes of chronic heart failure patients are most likely to experience heart failure death, and which are most likely to develop an arrhythmic death or sudden cardiac death.

Heart attacks, heart failure, stroke: COVID-19's dangerous cardiovascular complications
A new guide from emergency medicine doctors details the potentially deadly cardiovascular complications COVID-19 can cause.

Autoimmunity-associated heart dilation tied to heart-failure risk in type 1 diabetes
In people with type 1 diabetes without known cardiovascular disease, the presence of autoantibodies against heart muscle proteins was associated with cardiac magnetic resonance (CMR) imaging evidence of increased volume of the left ventricle (the heart's main pumping chamber), increased muscle mass, and reduced pumping function (ejection fraction), features that are associated with higher risk of failure in the general population

Transcendental Meditation prevents abnormal enlargement of the heart, reduces chronic heart failure
A randomized controlled study recently published in the Hypertension issue of Ethnicity & Disease found the Transcendental Meditation (TM) technique helps prevent abnormal enlargement of the heart compared to health education (HE) controls.

Beta blocker use identified as hospitalization risk factor in 'stiff heart' heart failure
A new study links the use of beta-blockers to heart failure hospitalizations among those with the common 'stiff heart' heart failure subtype.

Type 2 diabetes may affect heart structure and increase complications and death among heart failure patients of Asian ethnicity
The combination of heart failure and Type 2 diabetes can lead to structural changes in the heart, poorer quality of life and increased risk of death, according to a multi-country study in Asia.

Preventive drug therapy may increase right-sided heart failure risk in patients who receive heart devices
Patients treated preemptively with drugs to reduce the risk of right-sided heart failure after heart device implantation may experience the opposite effect and develop heart failure and post-operative bleeding more often than patients not receiving the drugs.

How the enzyme lipoxygenase drives heart failure after heart attacks
Heart failure after a heart attack is a global epidemic leading to heart failure pathology.

Novel heart pump shows superior outcomes in advanced heart failure
Severely ill patients with advanced heart failure who received a novel heart pump -- the HeartMate 3 left ventricular assist device (LVAD) -- suffered significantly fewer strokes, pump-related blood clots and bleeding episodes after two years, compared with similar patients who received an older, more established pump, according to research presented at the American College of Cardiology's 68th Annual Scientific Session.

Read More: Heart Failure News and Heart Failure Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.