Ventricular tachycardia (VT) is a type of cardiac arrhythmia caused by abnormal firing of a group of cells in one of the bottom chambers of the heart (ventricles). The cells fire at a higher rate than that of the sinus node in the top right chamber (atria), which causes the heart to beat 100 times per minute or higher.
“Idiopathic” ventricular tachycardia conveys that other than an abnormal heart rhythm (arrhythmia), the heart is functioning normally, as opposed to ventricular tachycardia associated with cardiomyopathy. Idiopathic VT is caused by an electrical short circuit in the heart.
Ventricular tachycardia associated with cardiomyopathy is caused by an electrical short circuit in one of the heart’s bottom chambers (ventricles). Symptoms can include lightheadedness, sensations that the heart is racing, chest tightness, shortness of breath and fainting. This dangerous condition can result in sudden cardiac death.
When the heart muscle weakens, scar tissue can form, creating a place for electrical short circuits to occur. The short circuits can result in a rapid heart rhythm that weakens the heart’s already compromised pumping function, causing a near-complete lack of blood flow to the body.
Immediate defibrillation (shock from a defibrillator) is commonly required to stop the abnormal rhythm. Ventricular tachycardia associated cardiomyopathy is even more serious than idiopathic ventricular tachycardia that occurs in patients with otherwise normal heart muscle function.
Long QT syndrome (LQTS) is a genetic condition where a heart’s abnormal electrical system may short circuit spontaneously causing dangerous ventricular tachycardia.
Brugada syndrome is a related genetic condition of a heart’s abnormal electrical system. These both can result in dizziness, fainting, or death. Symptoms may also include lightheadedness, sensations that the heart is racing, chest tightness and shortness of breath.
Doctors use an electrocardiogram to detect and diagnose ventricular tachycardia. An electrocardiogram is an electrical tracing of the heart.
Because most VT episodes happen intermittently, patients may be required to wear a heart monitor (also known as mobile telemetry). The monitor records heart activity around the clock and can detect abnormal heart rhythms, which are recorded and provided to your physician for review in making a diagnosis.
An electrophysiology study (also known as EP study or EPS) is another way to diagnose VT. Doctors insert catheters in a patient’s veins in the upper leg to reach the heart and record electrical activity. They also send signals to make the heart beat at different rates, as part of the procedure. Patients commonly receive sedation and anesthesia to make them comfortable and pain-free during an electrophysiology study.
For VT associated with cardiomyopathy, the newest 3-D mapping equipment is available at Scripps for proper diagnosis and frequent care.
Patients may also be asked to provide a blood sample so genes can be screened for inherited abnormalities.
Treatment may include:
- Antiarrhythmic medications that suppress the abnormal rhythm.
Minimally invasive procedure
- Radiofrequency ablation where a catheter emitting heat energy is advanced into the heart to cauterize the abnormal electrical circuit or focus. The procedure is performed in conjunction with an electrophysiology study.
- Implantable cardioverter defibrillator (ICD) to keep the heart beating at a healthy rate. The ICD is implanted under the skin and delivers silent pacing treatment or a shock to stop abnormal heart rhythms.