Title : Multifactorial Etiology of QTc Prolongation: Understanding the Medication Risk and Electrolyte Imbalance
Abstract:
Prolonged QTc interval is one of the critical risk factors for torsade de pointes and sudden cardiac death. QTc prolongation can be congenital or acquired. Medication side effects and electrolyte disturbances are two major acquired causes of a prolonged QTc interval. Case presentation: A 79-year-old female, with a past medical history significant of paroxysmal atrial fibrillation, hypertension, and chronic lower extremity swelling, presented to the emergency department with a chief complaint of syncope. One of her medications, metoprolol, was discontinued recently due to persistent bradycardia. She missed her cardiologist’s appointment last month when she was scheduled for dose adjustments of amiodarone. She has been on oral amiodarone 200 mg once daily. She takes furosemide for chronic lower extremity swelling. Vitals and physical exams were within normal limits. Results: The electrocardiogram on admission showed normal sinus rhythm, and 62 beats per minute ventricular rate. The corrected QTc interval was 692 milliseconds. Her potassium level was 3.1 millimole/liter. Decision making: The patient was admitted and placed on continuous cardiac monitoring. Amiodarone and furosemide were discontinued. The patient was given oral potassium supplements and encouraged to take a potassium-rich diet. A repeat electrocardiogram 2 days later, showed a QTc interval of 501 milliseconds. The patient did not have further syncopal episodes during her hospital stay. Conclusion: Amiodarone has one of the most potent side effects of QTc prolongation. Furosemide induces hypokalemia due to its diuretic effect, which further increases the risk of prolonged QTc. These medications require close monitoring and dose adjustments. Patients should be counseled regarding these side effects, and related symptoms and seek medical care promptly.
What will audience learn from your presentation?
• Identify the symptoms and signs related to QTc prolongation.
• Understand the mechanism via which medications and electrolyte abnormalities cause prolonged QTc.
• Adopting appropriate measures to mitigate the triggering agents and perform close cardiac monitoring.
• Reversal of the prolonged QTc within normal range on correction of the risk factors.
• Realize the importance of patient education and close follow up of medication dose/side effects.
