Evaluating the patients on predefined subset of drugs and its association with QTc prolongation

Abstract

Introduction: Drug-induced QT prolongation is the most common cause of acquired QT prolongation. Risk factors for QTc prolongation and TdP are recorded as the following: female sex, old age, cardiac disease, electrolyte abnormalities, diabetes mellitus type II, thyroid disease, and bradycardia. Hence the present study was conducted to find out the changes in QTc readings after taking predefined subset of drugs among patients. Materials and Methodology: This study is adopted as a prospective observational study and was planned to be conducted at L.N. Medical College & Research centre and associated J.K Hospital Bhopal. . The study group was formed based on the fulfilment of the inclusion and exclusion criteria. There are certain biochemical tests to be done in order to exclude the
acquired cause. The primary test to be followed is ECG in which the QTc was calculated, measured and analysed. Baseline ECG was recorded at the time of inclusion then follow up ECG was recorded within 24 hours of completion of antibiotic treatment, and 7 days of
antidepressant and antipsychotic treatment.
Results: Theoverall distribution of study subjects according to level of QTc change according to drug class results revealed that maximum 64 subjects those were on antibiotics, 49 subjects were on antidepressants and 40 subjects were on anti-psychotics where QTc level change 1-5ms.There were significant (p<0.01) association of various drugs class with
according to level of QTc change.
Conclusion: Acquired QTc prolongation due to drugs is the most common cause for QTc prolongation observed in clinical practice. Though antipsychotics, antidepressant and antibiotics could cause significant QTc prolongation, ventricular tachycardia or Torsade De
Pointes is more common with simultaneous use of two or more other QT prolonging drugs.