Ventricular Tachycardia

Ventricular tachycardia is an abnormally fast heart rhythm that starts in the heart’s lower chambers, called the ventricles. This ventricular arrhythmia can make the heart beat too quickly to pump blood effectively to the body. Severity varies from brief episodes with few symptoms to a medical emergency involving cardiac arrest. Ventricular tachycardia, sometimes called ventricular tachycardia or V-tach, can affect people with heart disease or, less often, people without an obvious heart problem.

Some episodes cause few or no symptoms. Even so, a known diagnosis or an abnormal rhythm found on a heart monitor needs prompt medical follow-up, because a stable episode can sometimes become sustained or progress to pulseless ventricular tachycardia.

Symptoms depend on how fast the rhythm is, how long it lasts, and whether the heart can pump enough blood. A brief, nonsustained ventricular tachycardia episode may cause little or no noticeable change, while a longer or faster episode can reduce blood flow and cause collapse.

Abnormal electrical circuits or irritable ventricular tissue can produce rapid ventricular impulses. This is more likely when heart muscle has been damaged or when the heart’s electrical pathways have been altered. The cause may be a chronic heart condition, an acute trigger, an inherited syndrome, or no identifiable problem.

Ventricular tachycardia can occur without an obvious risk factor. A clinician should assess risk individually based on medical history, heart structure and function, medicines, family history, and any documented ventricular arrhythmia.

The risk depends on the rhythm’s duration and rate, the underlying heart condition, and whether a pulse is present. Pulseless ventricular tachycardia is a form of cardiac arrest and requires immediate CPR and defibrillation.

An electrocardiogram (ECG) is the key test for identifying ventricular tachycardia. Clinicians assess how long the rhythm lasts, how fast it is, the QRS pattern, and whether it has one consistent shape, called monomorphic ventricular tachycardia, or varying shapes. They also determine whether the episode is sustained or nonsustained and look for an underlying cause.

Emergency treatment for unstable rhythms

Unstable ventricular tachycardia may require immediate synchronized cardioversion. Pulseless ventricular tachycardia is treated with CPR and defibrillation, along with emergency care for reversible triggers such as electrolyte abnormalities or medication toxicity. Stable episodes may be treated with antiarrhythmic medicines, correction of electrolytes, and management of coronary disease or heart failure. Catheter ablation can target an abnormal electrical circuit, and an implantable cardioverter-defibrillator (ICD) may be recommended when the risk of life-threatening recurrence is high.

Prevention focuses on treating coronary artery disease, heart failure, and electrolyte problems. Avoid stimulant or recreational drugs, review rhythm-affecting medicines with a clinician, and follow an ICD or ablation plan when prescribed. Managing cardiovascular risk factors may reduce triggers, but inherited syndromes and structural causes cannot always be prevented.

The outlook varies widely. Brief nonsustained episodes may have a different significance from sustained or pulseless episodes, and coexisting structural heart disease, reduced heart function, or an inherited syndrome can increase risk. Prognosis also depends on the cause, episode duration, symptoms, response to treatment, and risk of recurrence.