Carotid sinus massage

Carotid Sinus Massage (CSM) is a medical procedure used to diagnose and treat certain conditions related to the heart and its rhythm. The carotid sinus is a region located near the bifurcation of the carotid artery, which is a major blood vessel that supplies blood to the brain. This area contains baroreceptors that are sensitive to changes in blood pressure. By massaging the carotid sinus, healthcare providers can influence the heart rate and blood pressure, providing valuable diagnostic information and, in some cases, therapeutic benefits.

Indications

Carotid sinus massage is primarily indicated for the diagnosis and treatment of certain types of supraventricular tachycardia (SVT), a group of conditions characterized by abnormally fast heart rates originating above the heart's ventricles. It is particularly useful in cases of atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT), where it can help to terminate the tachycardia. CSM is also used diagnostically in patients with unexplained syncope (fainting), as it can provoke a response in those with carotid sinus hypersensitivity.

Contraindications

Carotid sinus massage should not be performed in patients with known or suspected carotid artery disease, including those with a history of transient ischemic attack (TIA) or stroke, due to the risk of dislodging plaque and causing a stroke. It is also contraindicated in patients with recent myocardial infarction or those with significant carotid bruits, indicating turbulent blood flow due to narrowing of the artery.

Procedure

The procedure should be performed by a healthcare professional trained in the technique. The patient is typically placed in a supine position with the head slightly elevated. The provider then locates the carotid sinus on one side of the neck, at the level of the cricoid cartilage. Gentle, circular pressure is applied for 5 to 10 seconds, while continuously monitoring the patient's heart rate and blood pressure. If no adverse effects are observed, and the desired effect is not achieved, the massage may be repeated on the opposite side after a brief interval.

Mechanism of Action

Carotid sinus massage exerts its effects through the stimulation of baroreceptors in the carotid sinus. This stimulation leads to increased parasympathetic (vagal) tone and decreased sympathetic activity, resulting in a decrease in heart rate (negative chronotropic effect) and a reduction in the conduction velocity through the atrioventricular (AV) node. These effects can interrupt the reentrant circuits responsible for certain types of SVT, restoring normal heart rhythm.

Risks and Complications

While generally safe when performed correctly, CSM can lead to adverse effects, including transient ischemic attack, stroke, or profound bradycardia (slow heart rate). Therefore, it is crucial to properly select patients for this procedure and to perform it in a controlled setting where immediate medical intervention is available.

Conclusion

Carotid sinus massage is a valuable diagnostic and therapeutic tool in the management of certain cardiovascular conditions. However, due to its potential risks, it should be performed by experienced healthcare professionals, with careful patient selection and appropriate monitoring.