QTc-time-prolongating drugs and additional risk factors for long-QT-syndrome at hospital admission of surgical patients - risk assessment by pharmacists

Drugs can cause long-QTc-syndrome (LQTS), thereby elevating the risk for palpitations, syncopes, and sudden cardiac death. Additional risk factors such as the intake of more than one QTc-prolongating drug (QTPD) and surgery (cardiac and non-cardiac) increase the risk considerably. Therefore, a good knowledge of patientś perioperative risk is important. Data concerning this issue in surgical patients is, however, scarce. We aimed to determine the number of surgical patients taking QTPD at hospital admission and to assess the presence of additional risk factors for LQTS. In addition, we determined the LQTS-risk at hospital admission by calculating the Tisdale Risk Score, enabling early detection of patients at risk. In a retrospective study, the pre-hospital medication of a 4-month cohort of surgical patients admitted to a tertiary teaching hospital was evaluated for QTPD-intake. For these patients, additional risk factors for LQTS were assessed and the Tisdale Risk Score was calculated. Of 837 surgical patients, 419 (50%) took at least one QTPD. In total, 3,376 drugs were taken and 723 (21%) classified as QTPD with a median number of 2 (range 1-8) per patient. The median number of LQTS-risk factors for these patients at hospital admission was 2 (range 0-5). The Tisdale Risk Score classified 23 patients (5%) as high, 187 (45%) as moderate, and 209 (50%) as low risk. These findings indicate a high number of surgical patients with QTPD and additional risk factors. The Tisdale Risk Score can be used as a screening instrument for patients at risk for QTc-prolongation during medication reconciliation by pharmacists at hospital admission. Patients identified as high and moderate risk should be evaluated for adjustable risk factors and monitored adequately. Medical treatment needs to be chosen carefully in view of in-hospital patient safety.