Mechanodefibrillator dissociation due to prolonged sinus arrest / Mecano disociación del desfibrilador debido a un paro sinusal prolongado

ABSTRACT

To the editor, Sinus arrest and cardiac arrest are two different terms which are often confused by many. This confusion often leads to inappropriate cardiopulmonary resuscitation (CPR) when patient is connected to defibrillator. Sinus arrest is defined as transient pause in Sino-atrial firing for more than 3 s1. When sinus arrest occurs, other latent pacemakers (atrial myocardium, cells nearby atrioventricular node, and His purkinje system) usually starts firing until Sino-atrial node recover. Sinus arrest can be prolonged till other pacemakers starts firing2. Cardiac arrest occurs when these latent pacemakers does not take up the job of alternate firing. Prolonged sinus arrest in a defibrillator may look like a cardiac arrest which might lead to unnecessary CPR. Here, we would like the put forward a new term “mechano - defibrillator dissociation” which occurs because of prolonged sinus arrest. We should be aware this, so that inappropriate CPR could be avoided. We, emergency physician also faced similar situation while resuscitating a patient because of mechano - defibrillator dissociation caused by prolonged sinus arrest/pseudo cardiac arrest. A 52-year-old male diabetic, hypertensive, and chronic alcoholic came to our emergency department (ED) with history of giddiness, syncope, and palpitation. On arrival to ED, patient was drowsy, diaphoretic, and hypotensive. Patient was connected to defibrillator which showed a heart rate of 35/min and saturation was 90% in room air. ECG showed complete heat block (CHB) and point of care echocardiography showed reduced ejection fraction.