Do beta blockers cause prolonged QT?

As a medical professional with expertise in pharmacology, I can provide you with information regarding the relationship between beta blockers and the QT interval on an electrocardiogram (ECG). Beta blockers are a class of drugs that are commonly used to treat a variety of conditions, including hypertension, heart failure, and certain arrhythmias. They work by blocking the effects of adrenaline and other similar substances on the heart and blood vessels, which can slow heart rate, reduce blood pressure, and decrease the workload on the heart. The QT interval on an ECG represents the time between the start of the Q wave and the end of the T wave, which corresponds to the duration of the depolarization and repolarization of the ventricles. A prolonged QT interval is associated with an increased risk of a type of irregular heartbeat called torsades de pointes, which can be life-threatening. While most beta blockers do not typically cause a prolonged QT, there are exceptions. Some beta blockers, particularly those with "membrane-stabilizing" properties or "Class III antiarrhythmic" effects, such as sotalol and ibutilide, can indeed cause a prolongation of the QT interval. It is important for healthcare providers to be aware of this potential effect when prescribing these medications, and to monitor patients accordingly. In summary, while most beta blockers are not associated with a prolonged QT, certain ones can have this effect. Patients taking these medications should be monitored for any changes in their ECG readings.

Beta-blockers are drugs of choice for patients with LQTS. The protective effect of beta-blockers is related to their adrenergic blockade, which diminishes the risk of cardiac arrhythmias. They may also reduce the QT interval in some patients.