Related Experiment Video
Updated: Jun 5, 2026
In Vivo Surface Electrocardiography for Adult Zebrafish
Published on: August 1, 2019
Qtc interval as a guide to select those patients with congestive heart failure and reduced left ventricular systolic
1Copenhagen University Hospital, Gentofte, Denmark.
Insights
Patients with normal baseline QTc intervals receiving dofetilide, a class III antiarrhythmic drug, experienced reduced mortality in heart failure. This finding suggests dofetilide may benefit specific heart failure patients based on QTc interval.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Prolonged QTc interval is a contraindication for class III antiarrhythmic drugs.
- The impact of normal or slightly increased baseline QTc on class III drug efficacy is unclear.
Purpose of the Study:
- To investigate the relationship between baseline QTc interval and mortality risk in patients with moderate to severe congestive heart failure (CHF) treated with dofetilide.
Main Methods:
- A substudy of 703 patients from the DIAMOND-CHF trial with moderate to severe CHF and reduced left ventricular systolic function.
- Baseline QTc interval was measured before randomization to dofetilide or placebo.
- Median follow-up was 18 months.
Main Results:
- In dofetilide-treated patients, a baseline QTc <429 ms was linked to a significant mortality risk reduction (RR 0.4).
- Mortality risk increased with higher baseline QTc intervals in dofetilide recipients.
- Baseline QTc had no prognostic value in placebo-treated patients.
Conclusions:
- A normal baseline QTc interval is associated with significantly reduced mortality in CHF patients treated with dofetilide.
- This suggests dofetilide may offer prophylactic benefits to specific CHF patients.
- Baseline QTc interval could guide antiarrhythmic drug selection in heart failure.
Background:
A prolonged QTc interval is considered a contraindication for class III antiarrhythmic drugs, but the influence of a normal or a slightly increased baseline QTc interval on the risk or benefit of treatment with a class III antiarrhythmic drug is not sufficiently clarified.
Methods And Results:
This prospectively defined substudy included 703 patients enrolled in the Danish Investigations of Arrhythmia and Mortality on Dofetilide-Congestive Heart Failure (DIAMOND-CHF) study. Patients included had moderate to severe CHF and reduced left ventricular systolic function. Baseline QTc interval was measured before randomization to either dofetilide, a new class III antiarrhythmic drug, or placebo. During a median follow-up of 18 months (minimum 1 year), 285 patients (41%) died. Baseline QTc interval had no prognostic value on survival in placebo-treated patients. In dofetilide-treated patients, a baseline QTc interval <429 ms was associated with a significant risk reduction (risk ratio 0.4, 95% CI 0.3 to 0.8). With increasing QTc interval, the risk increased gradually, and for QTc interval >479 ms, risk ratio was 1.3 (0.8 to 1.9).
Conclusions:
A baseline QTc interval within normal limits is associated with a marked reduction of mortality in patients with CHF and left ventricular systolic dysfunction treated with dofetilide. This is a potentially important indication of which patients with CHF might benefit from prophylactic treatment with an antiarrhythmic drug.
Related Concept Videos
01:22Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers
Class 1A Antiarrhythmic Drugs: These drugs work by moderately blocking sodium channels,...
01:12Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers
01:28Dysrhythmias II: Classification of Tachyarrhythmias
01:30Dysrhythmias V: Evaluating Dysrhythmias
01:25Dysrhythmias VI: Management of Dysrhythmias
01:25ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias