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An Interindividual Variability in the Sensitivity of Atrioventricular Node to Diltiazem in Patients with Paroxysmal Supraventricular Tachycardia
Author(s) -
Fukuhara Shunichi,
Echizen Hirotoshi,
Naito Masahito,
Ishikawa Shinichiro,
Toyama Masako,
Nagoshi Hideki,
Honda Masasada,
Ishizaki Takashi
Publication year - 1989
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1002/j.1552-4604.1989.tb03294.x
Subject(s) - diltiazem , medicine , paroxysmal supraventricular tachycardia , atrioventricular node , cardiology , tachycardia , antagonist , supraventricular tachycardia , anesthesia , calcium , receptor
To study the sensitivity of atrioventricular (AV) node to diltiazem in seven patients with paroxysmal supraventricular tachycardia (PSVT), we analyzed the plasma concentration‐response relationship of this Ca‐antagonist using AH interval as an index for assessing its Ca channel blocking effect on the AV node after an IV infusion (0.4 mg/kg). The postdose AH intervals were prolonged compared with the baseline, and their percentage changes correlated significantly (P < 0.01) with log‐diltiazem concentrations in all patients. However, drug concentrations associated with a 20% prolongation of AH interval differed considerably among the patients (range; 65 to 260 ng/ml), indicating a large interindividual variability in the sensitivity of AV node to diltiazem. These results suggest that the interindividual difference in the responsiveness of AV node to diltiazem‐induced Ca channel blocking effect may be one of the possible explanations for the therapeutic failure of this Ca‐antagonist for terminating PSVT or preventing its recurrences in certain patients.