| Fact | Explanation |
|---|---|
| Asymptomatic | Some patients are asymptomatic especially if the VF is non-sustained. VF is common in patients who are 45 to 75 years old. |
| History of coronary artery disease | Patients with coronary artery disease and a history of myocardial infarction are at high risk of VF. Presence of cardiovascular risk factors (obesity, unhealthy dietary practices, physical inactivity, smoking) should also be looked for. [3,6] |
| Syncope | Patients experience syncope or near syncope. Ventricular tachycardia causes rapid and unproductive ventricular contractions, leading to reduced cerebral perfusion and syncope. [2] |
| Sudden cardiac death | VF is the commonest cause of sudden cardiac death. Sudden cessation of cardiac output leads to sudden death. Presence of family history of sudden cardiac death is also an important risk factor of VF. [1,2] |
| History of arrhythmia | History of frequent ventricular ectopy, premature ventricular contractions or rapid ventricular tachycardia are risk factors of VF. Patients may develop VF after therapeutic cardioversion as well. [1,8] |
| History of cardiomyopathy | Patients with dilated cardiomyopathy and hypertrophic cardiomyopathy are at risk of VF. [4,5,7] |
| History of myocarditis | Myocarditis is another cause for the development of VF. [10] |
| History of structural heart diseases [9] | Structural heart diseases, surgical repair of congenital heart diseases (Tetralogy of Fallot, Ebstein’s anomaly, single ventricle, transposition of the great arteries carry the highest risk of VF. Atrial septal defect and valvar pulmonary stenosis carry a small risk of VF. ) and valvular heart diseases can lead to VF. Sarcoidosis and other infiltrative heart diseases and right ventricular dysplasia are other causes of VF. [14] |
| History of ECG abnormalities | Patients with ECG evidence of long QT syndrome, Wolff-Parkinson-White syndrome and Brugada syndrome can have VF. [11,12] |
| Triggering factors | VF can be triggered by antiarrhythmic drugs, hypoxia, electrolyte imbalances, myocardial ischemia, cardioversion, and competitive ventricular pacing. [13] |
| Fact | Explanation |
|---|---|
| Level of consciousness | Most patients are unconscious at the time of presentation. [2] |
| Pulse | In the emergency setting patient can be pulseless. More than ten seconds should not be spent trying to palpate the pulse because life saving measures should be immediately carried out. [1,3] |
| Blood pressure | Hypotension is commonly observed. This is due to diminished cardiac output which occurs secondary to unproductive ventricular contractions. |
| Cardiac auscultation | No heart sounds are audible during a VF. This is due to uncoordinated atrial and ventricular contractions. [3] |
| Fact | Explanation |
|---|---|
| Ventricular tachycardia | VT is another cause for broad QRS complexes. But the QRS complexes are regular and the ventricular rate is more than 100 beats/minute in VT. [3] |
| Aortic stenosis | Aortic stenosis may lead to acute coronary syndrome and development of VF. |
| Cardiomyopathy | Hypertrophic cardiomyopathy can cause ventricular tachycardia which later develops in to ventricular fibrillation. [4] |
| Ebstein anomaly | Ebstein anomaly is a rare congenital heart disease. The tricuspid valve is malformed and the right ventricle is partially incorporated in to the right atrium. [5] |
| Long QT syndrome | An abnormality in the ion channels in the ventricles causes slow transmission of the signals for ventricular repolarization, leading to long QT interval. This can propagate into VF. [6] |
| Lown-Ganong-Levine syndrome | An abnormal atrioventricular node transmits most of the atrial impulses to the ventricle leading to rapid ventricular excitation and VF. [7] |
| Myocardial infarction | Myocardial infarction can lead to VF. [8] |
| Torsade de pointes | Torsade de pointes is one of the polymorphic ventricular tachycardia. ECG shows marked prolongation of the QT interval. [2] |
| Wolff-Parkinson-White syndrome | In Wolff-Parkinson-White syndrome there is an aberrant conduction pathway connecting the atria and the ventricle leading to rapid ventricular rate. VF is one of the rhythm abnormalities associated with Wolff-Parkinson-White syndrome. [8] |
| Pulseless electrical activity | Pulseless electrical activity can cause sudden cardiac death, commonly seen in elders and in females. [1] |
| Fact | Explanation |
|---|---|
| ECG [2,3] | There are few characteristic features of the ECG. The waves are bizarre and irregular. The QRS complexes and P waves can not be clearly identified and the baseline is irregular. |
| Exercise ECG | Exercise induced arrhythmia can be detected by the exercise ECG. [4] |
| Holter monitoring [5] | Holter monitoring is indicated if VF is strongly suspected and if the ECG is normal. |
| Echocardiography | Reduced ejection fraction and abnormal left ventricular wall motion predicts the risk of VF. Transesophageal echocardiogram demonstrates irregular ventricular oscillations. [1] |
| Fact | Explanation |
|---|---|
| ECG | VF can recur even after treatment, so ECG monitoring is necessary. [1] |
| Fact | Explanation |
|---|---|
| Basic life support | Cardiopulmonary resuscitation should be immediately started. Assessment of the airway, breathing and circulation should be carried out but it should not delay cardiac defibrillation. Oxygen should be delivered via a face mask and if the patient is unconscious immediate intubation and bag and mask ventilation is necessary. Patient should be connected to a cardiac monitor. Administration of intravenous fluid is considered if necessary. Some patients with severe cardiac failure and cardiogenic shock may require mechanical cardiac support. Intravenous adrenaline is also helpful because it is a vasoconstrictor and increases the cerebral perfusion. [3] Patients should be given intensive care because of the high risk of recurrence. [1] |
| Correct any electrolyte imbalances | Electrolyte imbalance especially hypomagnesaemia and hypokalemia can precipitate arrhythmia and it is reversible. If present magnesium supplementation should be done. [1,2] |
| Fact | Explanation |
|---|---|
| Defibrillation | Defibrillation is the most important management option in managing VF. Early defibrillation is lifesaving in emergencies. Ideally it should be done within two minutes in the emergency department. The two paddles should be kept over the right upper sternum and over the cardiac apex or over the tip of the left scapula and anterior left chest. [3] |
| Implantation of defibrillator [1] | Insertion of internal cardioverter-defibrillator (ICD) is recommended in all patients with VF even in the absence of non-sustained VF. [1,2] |
| Catheter ablation | Catheter ablation of the premature ventricular contraction triggers are useful in some patients. [1] |
| Medical management | Isoproterenol and quinidine are used in the acute and long term management of VF respectively. Beta blockers are proven to reduce the risk of recurrence of VF. Amiodarone is the drug of choice if defibrillation fails. [1,3,4] |