A 63-year-old woman presented to the emergency department with a 3-h history of dizziness and palpitations, which awoke her from sleep. She had had one similar episode a year earlier that resolved spontaneously after 1 h and for which she did not seek medical attention. She had no significant past medical history and was not taking any regular medications.

At the time of examination the patient was asymptomatic and no longer complaining of palpitations. Examination was unremarkable except for a resting tachycardia of 130 beats per minute (bpm), there were no signs of cardiovascular compromise. A 12-lead ECG showed a regular narrow complex tachycardia with either P or flutter waves. The patient was placed on continuous ECG monitoring and it was noted that the heart rate remained fixed at 130 bpm. The probability of atrial flutter at a rate of 260 and a 2 : 1 block was considered.

The valsalva manoeuvre was performed to attempt to differentiate between atrial flutter and sinus tachycardia but was unsuccessful.

After auscultation of her right carotid artery and hearing no bruits, carotid sinus massage (CSM) was performed by firmly massaging the right common carotid artery in a longitudinal plane for 10 s.

This gradually slowed her heart rate and revealed obvious flutter waves.

The patient then complained of feeling unwell and it was immediately noted that she had slurred speech. CSM was stopped and a full neurological examination revealed an obvious dysarthria, a marked left facial droop and a dense monoplegia of the left arm. The power in her left leg was also reduced to 4/5.

It was explained to the patient that she had had a stroke caused by the CSM. In light of the presumed embolic nature of her stroke she was given clopidogrel, because she was genuinely allergic to aspirin.

After 1 h she spontaneously reverted to sinus rhythm and after a further 2 h her dysarthria and facial droop had almost entirely resolved. The power in her left leg returned fully, but some weakness remained in her left arm when asked to lift it against resistance.

Carotid ultrasound 24 h later revealed a moderate plaque in the right common carotid artery and a small plaque in the left and a magnetic resonance imaging scan of the brain was normal. The patient required 4 days in hospital while she regained further power in her right arm and at follow-up 3 months later she had made a full recovery.

DISCUSSIOIN

Neurological deficit following CSM has previously been described as a complication of the procedure. A number of studies have specifically looked at complications of CSM in patients being investigated for carotid sinus hypersensitivity. Two large prospective studies looking at complications following CSM for the investigation of carotid sinus hypersensitivity have reported a neurological complication rate between 0.17%1 and 1.0 %.2 The neurological complications reported range from mild dysarthria to visual field defects to dense hemiplegia.

However, there are only a few case reports that note neurological complications following the use of CSM to terminate a supraventricular tachycardia.

It is thought that CSM causes fissuring of atherosclerotic plaques overlying the endothelium of the common carotid artery and subsequent cholesterol emboli are thrown off into the distal circulation. One case report had a postmortem study that demonstrated cholesterol emboli in the territory of brain corresponding to the clinical deficit.3 The transient nature of the deficit also supports this being an embolic phenomenon. However, neurological complication secondary to CSM has been reported in a patient with carotid digital subtraction and carotid angiogram negative for carotid artery disease.4 It has also been proposed that the reduction in blood flow with resulting cerebral ischaemia is responsible for the neurological deficit.

It is known that the presence of a carotid bruit is a poor indicator of the presence or severity of carotid artery stenosis.

Currently, the UK Resuscitation Council guidelines still recommend CSM as a vagal manoeuvre for the termination of non-compromising narrow complex tachycardia.

Given the 1% risk of neurological complication associated with CSM and the safer alternatives available, such as the valsalva manoeuvre or the use of adenosine, it is our recommendation that CSM no longer be used for the termination of non-compromising narrow complex tachycardia in the elderly population.