Ventricular fibrillation – ECG

Ventricular fibrillation – ECG

Ventricular fibrillation - ECG
Ventricular fibrillation – ECG

Ventricular fibrillation (VF) is a life threatening arrhythmia, which leads to death unless promptly corrected by electrical defibrillation (direct current or DC shock). Cardiopulmonary resuscitation (CPR) is initiated while the defibrillator is being made available. Automatic external defibrillators (AED) in public places have automatic diagnostic algorithms and gives audible prompts to the resuscitator so that shocks can be delivered even by the minimally trained persons.

VF is recognized on the electrocardiogram (ECG) as a highly disorganized electrical activity. Each wave has a different morphology. When multiple simultaneous leads are available as in this case, it can be seen that the morphology is different between the leads as well. It may be noted that VF also has an electrical axis so that it has high amplitude in one lead and low amplitude in another. Here lead I shows a low amplitude and lead III shows a high amplitude.

VF has been divided into fine VF and coarse VF. This ECG shows coarse VF. Usually VF is thought to be coarse at the onset and becomes fine VF as time passes. Fine VF is likely to be more resistant to defibrillation. Hence an additional role for early defibrillation. Read on the 3-phase model of CPR.

Some authors have suggested that coarse VF may be seen in some leads, but may appear fine in other leads due to the lead orientation to the axis of VF [1]. But as time passes, VF becomes fine due to metabolically induced degeneration of cellular excitability.

When the electrical activity is so disorganized, no ventricular contraction is possible and ventricle remains still in a state of cardiac arrest which leads to circulatory arrest and hypoxemia. Only a short time window of about four minutes is available for initiation of CPR, beyond which irreversible cerebral damage may ensue.

A review of 10 year experience with prehospital coarse VF as the initial rhythm has been published by K M Hargarten et al. Of  their 1,497 patients, 25% survived [2]. These were nontraumatic, non-poisoned, witnessed cardiac arrests in adults.

Cases of VF due to direct inhalation of air freshener has been reported [3,4]. It was due to the inhalation of short chain aliphatic hydrocarbons butane and isobutane. Senthilkumaran S et al [3] have suggested that epinephrine may be avoided during early resuscitation of cardiac arrest in these cases of catecholamine-sensitized heart. They used esmolol infusion for ventricular ectopy instead.

References

  1. Jones DL, Klein GJ. Ventricular fibrillation: the importance of being coarse? J Electrocardiol. 1984 Oct;17(4):393-9. doi: 10.1016/s0022-0736(84)80077-1. PMID: 6502056.
  2. Hargarten KM, Stueven HA, Waite EM, Olson DW, Mateer JR, Aufderheide TP, Darin JC. Prehospital experience with defibrillation of coarse ventricular fibrillation: a ten-year review. Ann Emerg Med. 1990 Feb;19(2):157-62. doi: 10.1016/s0196-0644(05)81801-3. PMID: 2301793.
  3. Senthilkumaran S, Meenakshisundaram R, Michaels AD, Balamurgan N, Thirumalaikolundusubramanian P. Ventricular fibrillation after exposure to air freshener-death just a breath away. J Electrocardiol. 2012 Mar;45(2):164-6. doi: 10.1016/j.jelectrocard.2011.05.002. Epub 2011 Jun 21. PMID: 21696756.
  4. LoVecchio F, Fulton SE. Ventricular fibrillation following inhalation of Glade Air Freshener. Eur J Emerg Med. 2001 Jun;8(2):153-4. doi: 10.1097/00063110-200106000-00014. PMID: 11436914.