Effects of the Ikr-blocker almokalant and predictors of conversion of chronic atrial tachyarrhythmias to sinus rhythm. A prospective study.

Abstract

PURPOSE:

To assess the efficacy of the Ikr-blocker almokalant attempting to convert chronic atrial tachyarrhythmias, and to find predictors of conversion, to sinus rhythm.

METHODS:

The electrophysiological effects of a 6-hour infusion of almokalant, to a total dose of 25 +/- 4 mg, were assessed by ECG and transesophageal atrial electrograms (TAE) in 100 consecutive patients with atrial fibrillation/flutter (n = 95/5) of 8 +/- 12 months' duration (range 1 to 99 months).

RESULTS:

The conversion rate was 32%. The time to conversion was 3.5 +/- 2.2 hours. During infusion increases in QTtop (292 +/- 35 to 335 +/- 44 ms, p < 0.001, after 30 minutes), QT (387 +/- 40 to 446 +/- 60 ms, p < 0.001), corrected QT (425 +/- 30 to 487 +/- 44 ms, p < 0.001), and QT dispersion (21 +/- 12 to 29 +/- 31 ms, p = 0.02), were paralleled by decreases in T wave amplitude (0.31 +/- 0.19 to 0.23 +/- 0.16 mV, p < 0.001), and atrial rate (425 +/- 78 to 284 +/- 44 beats per minute (bpm) on ECG, and 396 +/- 72 to 309 +/- 44 bpm on TAE), with no differences between converters to sinus rhythm and non-converters. Patients with aberrantly conducted beats, and T wave variation, also increased. Calcium antagonists were more common among converters. A decreasing T wave amplitude predicted conversion. Four patients developed torsades de pointes.

CONCLUSIONS:

This study demonstrates class III action of almokalant, with a conversion rate of 32% of long-standing, chronic atrial tachyarrhytmias. An early decrease in T wave amplitude was associated with conversion to sinus rhythm.

• Authors: B Houltz, B Darpö, K Swedberg, P Blomström, J Brachmann, H J Crijns, S M Jensen, E Svernhage, H Vallin, N Edvardsson
• Journal: Cardiovascular drugs and therapy (Cardiovasc Drugs Ther) Vol. 13 Issue 4 Pg. 329-38 (Jul 1999) ISSN: 0920-3206 [Print] United States
• PMID: 10516869 (Publication Type: Clinical Trial, Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't)

Chemical References

• Anti-Arrhythmia Agents
• Propanolamines
• almokalant

Topics

• Aged
• Anti-Arrhythmia Agents (therapeutic use)
• Atrial Fibrillation (diagnosis, drug therapy, genetics)
• Electrocardiography (drug effects)
• Female
• Heart Rate
• Humans
• Male
• Propanolamines (therapeutic use)
• Time Factors
• Torsades de Pointes (etiology)