Background Torsade de pointes (TdP) is a ventricular tachycardia. The risk of TdP increases when the QT interval is markedly prolonged (>500 msec) or when it is combined with other risk factors such as: bradycardia, females, congenital QT prolongation, age (>65 years), hypokalaemia <3.5 mg/dl, hypomagnesaemia <1.5 mg/dl and with drugs that prolong the QT.
Purpose To identify the patients at greatest risk to develop TdP and establish a protocol to minimise such risk.
Material and methods Prospective observational study in which 140 patients were recruited from a residential centre. The TdP risk factors described by an independent nonprofit organisation CredibleMeds®Centre for Education and Research on Therapeutics (CERT) were reviewed. Patients with one or more drugs from the list ‘www. QTdrugs. org’ in risk of TdP using the computer program ‘Farmatools’ and reviewing the medical history and blood tests for other risk factors, were selected. The need for the drug and/or possibility of an alternative, if scheduled periodic monitoring of the QT interval, potassium and magnesium have been programmed, was determined, if the patient recognised the signs or symptoms. We carried out our analyses using SPSS version 22.0.
Results Of the 140 residents, 35 were on chronic treatment with one drug on the list, of whom (18=51.4%) females, (17=48.6%) males, (33=94%) were ≥65 years-old, all patients were between (33 to 96 years old, mean: 84), one with bradycardia and (four=11%) were at high risk. All residents undergo an ECG when they enter the centre, potassium levels were between (3.9–5.4 meq/L, mean=4.51, SD=0.34) and there were no determinations of magnesium. After consultation with the responsible physician in one patient, it would be possible to permanently stop donepezil (one drug on the QT list) due to lack of response, and in the remaining three there was the possibility of an alternative drug. Finally, these four patients were scheduled a new ECG.
Conclusion Patients at high risk of TdP should be identified for assessing the need or possibility of an alternative if there is a prescribed drug on the list, monitoring of the QT interval, potassium and magnesium, considering the list in future prescriptions and training the patient to recognise the alarm signs or symptoms of the arrhythmia.
References and/or Acknowledgements www.QTdrugs.org
No conflict of interest
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