Ventricular tachycardia

Ventricular tachycardia
Other names	V-tach,[1] Vtach, VT
A run of ventricular tachycardia as seen on a rhythm strip
Specialty	Cardiology
Symptoms	Lightheadedness, palpitations, chest pain, shortness of breath, Decreased level or total loss of consciousness[2]
Complications	Cardiac arrest, ventricular fibrillation[2][3]
Types	Non-sustained (NSVT), sustained[2]
Causes	Coronary heart disease, aortic stenosis, cardiomyopathy, electrolyte problems, heart attack[2][3]
Diagnostic method	Electrocardiogram[2]
Differential diagnosis	Supraventricular tachycardia with aberrancy, ventricular pacing, ECG artifact[4]
Prevention	Implantable cardiac defibrillator, calcium channel blockers, amiodarone[2]
Treatment	Procainamide, cardioversion, cardiopulmonary resuscitation[2][5]
Frequency	~7% of people in cardiac arrest[2]

Ventricular tachycardia (V-tach or VT) is a cardiovascular disorder in which fast heart rate occurs in the ventricles of the heart.^[3] Although a few seconds of VT may not result in permanent problems, longer periods are dangerous; and multiple episodes over a short period of time are referred to as an electrical storm.^[3][6][7] Short periods may occur without symptoms, or present with lightheadedness, palpitations, shortness of breath, chest pain, and decreased level of consciousness.^[2] Ventricular tachycardia may lead to coma and persistent vegetative state due to lack of blood and oxygen to the brain. Ventricular tachycardia may result in ventricular fibrillation (VF) and turn into cardiac arrest.^[2][3] This conversion of the VT into VF is called the degeneration of the VT. It is found initially in about 7% of people in cardiac arrest.^[2]

Ventricular tachycardia can occur due to coronary heart disease, aortic stenosis, cardiomyopathy, electrolyte imbalance, or a heart attack.^[2][3] Diagnosis is by an electrocardiogram (ECG) showing a rate of greater than 120 beats per minute and at least three wide QRS complexes in a row.^[2] It is classified as non-sustained versus sustained based on whether it lasts less than or more than 30 seconds.^[2] The term ventricular arrhythmia refers to the group of abnormal cardiac rhythms originating from the ventricle, which includes ventricular tachycardia, ventricular fibrillation, and torsades de pointes.^[2]

In those who have normal blood pressure and strong pulse, the antiarrhythmic medication procainamide may be used.^[2] Otherwise, immediate cardioversion is recommended, preferably with a biphasic DC shock of 200 joules.^[2] In those in cardiac arrest due to ventricular tachycardia, cardiopulmonary resuscitation (CPR) and defibrillation is recommended.^[5] Biphasic defibrillation may be better than monophasic.^[5] While waiting for a defibrillator, a precordial thump may be attempted (However reserved to those who have the prior experience of doing so) in those on a heart monitor who are seen going into an unstable ventricular tachycardia.^[5] In those with cardiac arrest due to ventricular tachycardia, survival is about 75%.^[2] An implantable cardiac defibrillator or medications such as calcium channel blockers or amiodarone may be used to prevent recurrence.^[2]