What are the indications, contraindications, and step‑by‑step technique for performing carotid sinus massage to terminate paroxysmal supraventricular tachycardia safely?

Carotid Sinus Massage for Supraventricular Tachycardia

Primary Recommendation

Carotid sinus massage should NOT be used as first-line therapy for terminating paroxysmal supraventricular tachycardia—the modified Valsalva maneuver is 2.8-3.8 times more effective and safer, followed by adenosine if vagal maneuvers fail. 1

Indications

For SVT Termination (Limited Role)

• Carotid sinus massage may be attempted for hemodynamically stable narrow-complex SVT only when modified Valsalva maneuver has failed and before pharmacologic therapy 1, 2
• Efficacy for SVT termination is only approximately 20%, compared to 43% for modified Valsalva and 90-95% for adenosine 3, 4
• The American College of Cardiology notes that carotid sinus massage is less effective than Valsalva techniques 1

For Diagnostic Purposes (Primary Indication)

• Carotid sinus massage remains important for diagnosing carotid sinus hypersensitivity in patients >40 years with unexplained syncope of suspected reflex mechanism 5, 6
• This diagnostic indication requires reproduction of spontaneous symptoms (the "method of symptoms") in addition to abnormal hemodynamic response 5

Absolute Contraindications

Critical safety screening must be performed before any carotid sinus massage: 5, 1, 3

• Carotid bruits present on auscultation (unless carotid Doppler excludes ≥70% stenosis) 5, 1, 3
• History of TIA or stroke within past 3 months 3
• Suspected ventricular tachycardia or pre-excited atrial fibrillation (must confirm narrow-complex SVT first) 1, 7
• Myocardial infarction within recent weeks 5

Step-by-Step Technique

Pre-Procedure Setup

1. Position patient supine with continuous ECG monitoring 5
2. Establish continuous beat-to-beat blood pressure monitoring (non-invasive device preferred, as vasodepressor response is rapid and cannot be adequately detected otherwise) 5
3. Ensure resuscitation equipment immediately available (defibrillator ready, as ventricular fibrillation can occur in 0.08% of cases) 3, 8
4. Auscultate both carotid arteries to confirm absence of bruits 5, 1

Massage Technique

1. Locate the carotid sinus at the site of maximum carotid pulse, between the angle of the jaw and cricoid cartilage on the anterior margin of the sternocleidomastoid muscle 5
2. Rotate patient's face contralaterally 5, 6
3. Apply firm manual compression with the tips of the second, third, and fourth fingers of one hand, massaging up and down the carotid artery 5
4. Duration: 5-10 seconds (10 seconds preferred for diagnostic purposes to allow symptoms to develop) 5
5. Begin with right carotid artery first 5
6. Wait 1-2 minutes for heart rate and blood pressure to return to baseline before proceeding 5
7. Repeat on left side if right-sided massage unsuccessful 5

For Diagnostic Purposes Only

• Repeat in upright position (on tilt table) if supine massage negative, as diagnosis may be missed in one-third of cases if only supine position used 5, 6
• Administer atropine 1 mg IV after asystolic response to assess vasodepressor component 5

Interpretation of Results

Abnormal Response (Carotid Sinus Hypersensitivity)

• Cardioinhibitory: Asystole ≥3 seconds 5
• Vasodepressor: Fall in systolic blood pressure ≥50 mmHg 5
• Mixed: Both criteria met 5

Diagnostic Criteria for Carotid Sinus Syncope

• Requires reproduction of spontaneous symptoms (syncope or presyncope) during massage in addition to abnormal hemodynamic response 5

Safety Profile and Complications

Neurologic Complications

• Stroke or TIA occurs in 0.2-1% of patients undergoing carotid sinus massage 3, 4
• These are potentially devastating complications that can be avoided by using alternative interventions 3, 4

Cardiac Complications

• Ventricular fibrillation can occur (incidence 0.08%), even without preceding bradycardia or predisposing heart disease 3, 8
• Requires immediate defibrillation capability 8

Recommended Treatment Algorithm for SVT

The American College of Cardiology and American Heart Association recommend the following sequence for hemodynamically stable SVT: 1, 7

1. First-line: Modified Valsalva maneuver (patient supine, bearing down for 10-30 seconds generating ≥30-40 mmHg pressure) 1
2. Second-line: Adenosine 6 mg rapid IV push through large vein followed by saline flush (90-95% success rate) 1, 7
3. Third-line: IV calcium channel blockers or beta-blockers (80-98% success rate) 1, 7
4. Rescue: Synchronized cardioversion 50-100J if medications fail 1, 7

Common Pitfalls

• Never perform carotid sinus massage without first auscultating for carotid bruits 5, 1, 3
• Never use as first-line therapy for SVT when safer, more effective alternatives exist 3, 4
• Never perform without continuous ECG and blood pressure monitoring 5
• Never perform in patients under general anesthesia (adenosine is first-line as vagal maneuvers not feasible) 7
• Avoid bilateral simultaneous massage (perform sequentially with adequate time interval) 5, 6