From the Guidelines
Yes, both amiodarone and pasireotide can prolong the QT interval on an electrocardiogram (ECG), which represents the time it takes for the heart to repolarize between beats. Amiodarone, an antiarrhythmic medication used to treat various cardiac arrhythmias, is well-known for causing QT prolongation as one of its primary pharmacological effects, as seen in a case study where a 76-year-old woman experienced a ventricular-fibrillation-arrest due to QT prolongation caused by amiodarone and other medications 1. This occurs because amiodarone blocks potassium channels in cardiac cells, delaying repolarization. Pasireotide, a somatostatin analog used to treat Cushing's disease and acromegaly, also carries a risk of QT prolongation, though this effect is less prominent than with amiodarone. When these medications are used, especially in combination, patients should undergo baseline and periodic ECG monitoring to assess the QT interval, as recommended by the European Heart Rhythm Association (EHRA) consensus document on the management of supraventricular arrhythmias 1. Risk factors that may increase the danger of QT prolongation include:
- Electrolyte abnormalities (particularly low potassium or magnesium)
- Female gender
- Advanced age
- Structural heart disease
- Concomitant use of other QT-prolonging medications Significant QT prolongation (typically QTc >500 ms) increases the risk of developing torsades de pointes, a potentially life-threatening ventricular arrhythmia, as noted in the 2016 ESC guidelines for the management of atrial fibrillation 1 and the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. Therefore, it is crucial to monitor patients taking amiodarone and pasireotide for QT prolongation and adjust their treatment accordingly to minimize the risk of torsades de pointes and other cardiac complications.
From the Research
Amiodarone and QT Interval Prolongation
- Amiodarone is known to prolong the QT interval, as it is a class III antiarrhythmic drug that prolongs phase III of the cardiac action potential 2, 3, 4.
- The prolongation of the QT interval is a marker for the therapeutic antiarrhythmic effect of amiodarone 3.
- Amiodarone therapy can result in a significant increase in the maximal QTc interval 5.
- The QTc interval should be monitored during amiodarone up-titration to prevent proarrhythmia 2.
Pasireotide and QT Interval Prolongation
- There is no evidence in the provided studies to suggest that pasireotide prolongs the QT interval.
- The studies provided are focused on amiodarone and its effects on the QT interval, with no mention of pasireotide 2, 3, 4, 6, 5.
Drug-Induced QT Interval Prolongation
- Drug-induced QT interval prolongation is a common acquired cause of Long QT syndrome (LQTS) 6.
- Antiarrhythmic drugs such as amiodarone, sotalol, quinidine, procainamide, verapamil, and diltiazem are associated with the prolongation of the QTc interval 6.
- Other non-cardiovascular drugs, such as ondansetron, macrolide and fluoroquinolone antibiotics, and typical and atypical antipsychic agents, are also frequently associated with the prolongation of the QTc interval 6.