From the Guidelines
An ECG should be performed at baseline and repeated 7 days after initiation of SSRI therapy, as well as after any dosing changes, to monitor for QT interval prolongation, particularly in patients with risk factors for QT prolongation 1. When initiating SSRI therapy, it is essential to consider the potential risk of QT interval prolongation, which can increase the risk of developing a dangerous heart rhythm called torsades de pointes.
- Key factors that warrant ECG monitoring include:
- Pre-existing heart conditions
- Electrolyte abnormalities
- Concomitant use of other QT-prolonging medications
- Advanced age
- Family history of sudden cardiac death
- The frequency of ECG monitoring should be individualized depending on the patient's characteristics and the causative drug, with more frequent monitoring recommended for patients experiencing diarrhea or receiving treatment with certain medications like arsenic trioxide 1.
- If the QTc interval is > 500 ms, treatment should be temporarily interrupted, electrolyte abnormalities corrected, and cardiac risk factors for QT prolongation controlled, with treatment resumed at a reduced dose once the QTc normalizes 1.
- In cases of torsades de pointes, management should include intravenous administration of magnesium sulphate, and in some acute situations, overdrive transvenous pacing or isoprenaline titrated to a heart rate > 90 beats per minute to prevent new episodes 1.
From the Research
ECG Monitoring After Initiating SSRI Therapy
- The timing of an electrocardiogram (ECG) after initiating Selective Serotonin Reuptake Inhibitor (SSRI) therapy is not explicitly stated in the provided studies, but the importance of ECG monitoring is highlighted in certain situations 2, 3, 4, 5, 6.
- According to the study by 5, an ECG should be performed if the initial evaluation suggests increased cardiac risk or if the prescribed medication has been established to have an increased risk of torsade de pointes and sudden death.
- The study by 3 suggests that ECGs be performed to monitor the effects of SSRIs, specifically citalopram, on the QTc interval, particularly in older adults or those with high-risk factors.
- In the study by 6, ECG records were reviewed to examine the effects of citalopram, bupropion, sertraline, and tricyclic antidepressants on QTc, but no specific guidance on the timing of ECG monitoring after initiating SSRI therapy was provided.
Considerations for ECG Monitoring
- The presence of co-existing risk factors, such as cardiovascular disease or electrolyte disturbances, may necessitate ECG monitoring after initiating SSRI therapy 5.
- The study by 4 highlights the importance of monitoring the QT interval in patients receiving a combination of antipsychotic and antidepressive agents, as this combination may increase the risk of QT prolongation.
- The U.S. Food and Drug Administration's safety warning limiting the maximum dose for citalopram due to the risk of QTc prolongation is noted in the study by 6, but no specific guidance on ECG monitoring timing is provided.