ADRENALINE-RESPONSIVE ELECTROMECHANICAL DISSOCIATION

Electromechanical dissociation (EMD) occurs when there is no detectabl e blood pressure in the presence of organised electrocardiographic act ivity. This condition excludes pulseless ventricular tachycardia, and traditionally was thought to result from a failure of electrical depol arisation in the myocardium to elicit mechanical contraction. It is no w understood from echocardiographic evidence that 'pseudo-EMD' is more common - where electrical activity is associated with myocardial cont ractions too weak to sustain a detectable blood pressure [1]. Three ca ses of EMD in association with subarachnoid haemorrhage (SAH) are desc ribed. This form of cardiovascular collapse appears to respond readily to the use of adrenaline. To our knowledge, this has not been reporte d previously. We suggest that this form of EMD occurs despite adequate myocardial function and results from sympathetic failure with loss of peripheral vascular resistance.