The risk of treatment-induced QT interval prolongation

QT interval prolongation can increase patients' hospital stay and  mortality rate. This study aims to determine the incidence of drug-induced QT  interval prolongation and establish which QT interval measurement method is  the most appropriate for electrocardiographic monitoring.

A retrospective observational study was conducted of patients admitted to the Clínica Bíblica Hospital during 2018. The electronic  medical records of patients hospitalized for longer than 48 hours and whose drug regimen included at least one drug potentially able to prolong the  QT interval were reviewed. Manually-measured QT intervals were corrected using Fridericia's and Rautaharju's formulae, while automatically- measured QT intervals were corrected with Bazett's formula. Risk was assessed  using the RISQ-PATH scale.

Of the 141 patients analyzed, 23 had arrhythmia as per their clinical  history and 14 suffered a complication during their stay in hospital. A total of  113 (80%) had a high RISQ-PATH score and only 64 were subjected to an  electrocardiogram on admission. Patients received a mean of three potentially  QT interval prolonging drugs. Most of the QT intervals measured automatically  were shorter than those obtained manually. Of all corrections, the longest QTc  interval values were obtained with Bazett's formula, and the shortest with  Rautaharju's formula. None of the patients developed TdP or complex  ventricular tachycardia.

Every effort should be made to implement strategies conducive to more effective monitoring of the QT interval to prevent QT  nterval prolongation related complications in hospitalized patients.