Intravenous dantrolene does not exhibit calcium channel blocking effects on the cardiac conduction system in humans

• Published in: Anesthesiology (Philadelphia) 1991-10, Vol.75 (4), p.583-587
• Main Authors: KENTSCH, M, ROEWER, N, KUNZE, K.-P, KUCK, K.-H
• Format: Article
• Language: English
• Subjects: Adult; Anti-Arrhythmia Agents - administration & dosage; Anti-Arrhythmia Agents - pharmacology; Anti-Arrhythmia Agents - therapeutic use; Antiarythmic agents; Biological and medical sciences; Calcium Channel Blockers - administration & dosage; Calcium Channel Blockers - pharmacology; Calcium Channel Blockers - therapeutic use; Cardiovascular system; Dantrolene - administration & dosage; Dantrolene - pharmacology; Dantrolene - therapeutic use; Female; Heart Conduction System - drug effects; Humans; Injections, Intravenous; Male; Malignant Hyperthermia - drug therapy; Medical sciences; Middle Aged; Pharmacology. Drug treatments; Tachycardia, Atrioventricular Nodal Reentry - drug therapy
• ISSN: 0003-3022; 1528-1175
• DOI: 10.1097/00000542-199110000-00007

In malignant hyperthermia, dantrolene, a drug assumed to possess calcium channel blocking properties, effectively suppresses supraventricular and ventricular arrhythmias. To investigate antiarrhythmic properties of dantrolene, six patients (three women and three men, age 42 +/- 18 yr) with symptomatic atrioventricular (AV)-nodal reentry tachycardia were studied. Electrocardiographic measurements included sinus cycle length, PQ-interval, width of the QRS-complex, and QT- and rate-corrected QT-interval. During the electrophysiologic study, effective refractory periods of the right atrium, AV node, right ventricle, and AV-nodal conduction intervals were determined, and AV-nodal reentry tachycardia was induced in all patients. Dantrolene was administered intravenously over a period of 15 min at doses of 1.0, 1.5, or 3.0 mg/kg in two patients each. The dosage was not further increased because of side effects at the dose of 3.0 mg/kg. After the infusion of dantrolene, the electrocardiographic measurements and electrophysiologic study were repeated. The plasma concentrations of dantrolene ranged from 1.69 to 6.61 micrograms/ml at the time of the electrophysiologic study. After dantrolene administration, the sinus cycle length shortened from 686 +/- 80 to 622 +/- 55 ms (P less than 0.05). No significant changes of any other parameter could be demonstrated after intravenous dantrolene. AV-nodal reentry tachycardia remained inducible in all patients without change of the tachycardia cycle length and without change in coupling intervals of tachycardia-inducing extrastimuli. Antiarrhythmic properties of dantrolene could not be demonstrated in patients with AV-nodal reentry tachycardia at therapeutic doses.