Journal of cardiovascular electrophysiology
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J. Cardiovasc. Electrophysiol. · Apr 2001
Clinical TrialProblems of heart rate correction in assessment of drug-induced QT interval prolongation.
Estimation of QT interval prolongation belongs to safety assessment of every drug. Among unresolved issues, heart rate correction of the QT interval may be problematic. This article proposes a strategy for heart rate correction in drug safety studies and demonstrates the strategy using a study of ebastine, a nonsedating antihistamine. ⋯ Use of published heart rate correction formulas in the assessment of drug-induced QTc prolongation is inappropriate, especially when the drug might induce heart rate changes. Correction formulas optimized for pooled drug-free data are inferior to the formulas individualized for each subject. Measurement imprecision and natural variability can lead to mean QTc interval changes of 4 to 5 msec in the absence of drug treatment.
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J. Cardiovasc. Electrophysiol. · Apr 2001
Diagnosis of amiodarone pulmonary toxicity with high-resolution computerized tomographic scan.
Amiodarone pulmonary toxicity is a serious adverse effect that can be fatal. The diagnosis is difficult due to the nonspecificity of symptoms, clinical findings, and test results. Because of its high iodine content, amiodarone deposition can be detected by sensitive high-resolution computed tomographic (CT) scan techniques. We hypothesized that pulmonary toxicity can be diagnosed more readily when these scans indicate the presence of increased attenuation of either pleural or pulmonary densities representing high iodine amiodarone deposits. ⋯ High-resolution CT may be a valuable noninvasive test to aid in the diagnosis of amiodarone pulmonary toxicity in symptomatic patients.