Neurological or cardiological assessment of transient altered consciousness?

Cardiac arrhythmias are a recognized cause of transient alteration of consciousness and unless suspected, a cardiac aetiology for apparent neurological symptoms may be overlooked. We retrospectively assessed the variation in the investigations of 122 patients who were referred to our hospital over a twelve month period for assessment of transient alteration of consciousness and we attempted to identify any factors which might have influenced the clinical outcome for these individuals. Eighteen patients were initially referred for cardiological opinion and 104 for neurological assessment. Sixty-one patients presented with syncope, 43 with seizures, and 18 with presyncope. A baseline electroencephalogram (EEG) was obtained in 104 (85%) and 65 (53%) were also subjected to a stress EEG. Cerebral dysrhythmia was documented in 14 patients. A standard electrocardiogram (ECG) was recorded in only 71 (58%) and sinus bradycardia (heart rate < 60/min) was observed in 34. Twenty-four hour (Holter) ECGs were recorded in only 58 (48%). Ventricular pauses (at least 1.84 seconds) and/or profound bradycardia (heart rate < 40/min) occurred during waking hours in 10 patients and were more likely to be detected in individuals who also exhibited bradycardia on standard ECG (8 patients) (p < 0.05). After six months, 35 (29%) of the 122 patients still lacked a diagnosis and although cerebral dysrhythmia had been diagnosed with equal frequency in the bradycardia and non-bradycardia groups, 21 (62%) of those with bradycardia were still symptomatic compared with 11 (30%) of the non-bradycardia group (p < 0.02). Our findings indicate that, at present, investigation of patients with transient altered consciousness lacks a coordinated approach and bradycardia may influence the diagnosis and morbidity of these individuals. We suggest that greater attention should be paid to possible cardiac causes of transient altered consciousness and that only under joint direction of a cardiologist and a neurologist can efficient and thorough investigation of these patients be realised.