Overview of Ventricular Tachycardia
Ventricular tachycardia is one of several serious heart conditions that fall under the category of arrhythmia, or irregular heartbeat. One of the medications used to treat this condition, amiodarone, has been implicated in a number of serious side effects leading to litigation against the drug’s manufacturers.
The term “tachycardia” derives from two Greek words: takhos, referring to speed and swiftness, and kardia, meaning “heart.” Therefore, the literal meaning is “rapid heart(beat),” a condition which originates in the lower chambers of the heart, or the ventricles. A patient’s condition is considered to be tachycardia if the heartbeat exceeds 100 beats per minute for more than 3 beats. If it goes on for 30 seconds or more, it is considered to be sustained ventricular tachycardia, or “VT”.
Symptoms of VT
VT symptoms can include any or all of the following:
- lightheadedness and/or dizziness
- chest pain
- respiratory distress (breathing difficulty)
- tightness in the neck
In some cases however, there may be no symptoms at all.
Causes of VT
Ventricular tachycardia can be caused by any number of heart-related issues. Coronary heart disease caused by restricted blood flow to the heart (usually due to a buildup of arterial plaque) is one of the most common conditions leading to VT. Another cause is aortic stenosis, which is a narrowing of the left ventricle, preventing blood from exiting the chamber.
In other cases, it may be due to a chemical imbalance in the blood, such as a deficiency of magnesium or potassium, or the condition may run in families.
Dangers of VT
When the heart beats to rapidly, there is not enough time for it to fill with blood between beats. This in turn means impaired blood flow to the rest of the body and its organs even causing the heart to stop beating altogether; untreated, ventricular tachycardia can be fatal.
VT Treatments
Among the primary treatments for ventricular tachycardia are:
- cardioversion: electrical current, medication or a combination of the two may be used in order to “shock” the heart into resuming a normal beat
- defibrillation
- surgery: implantation of a pacemaker or implantable cardioverter defibrillator (ICD), or use of a robotic magnetic navigation device.
- medication, including beta blockers or magnesium sulfate. Amiodarone may be used if the patient fails to respond to other treatments.
Amiodarone as a Treatment for Ventricular Tachycardia
Amiodarone, sold under the brand names Cordarone, Nexterone and Pacerone, is used to treat various forms of arrhythmia in addition to atrial fibrillation (“a-fib”). It can be taken orally, intravenously, or injected into the bone marrow.
Because it has several serious potential side effects, amiodarone has been approved by the FDA only as a treatment of last resort. These side effects can include serious respiratory disorders, such as interstitial pneumonitis, an inflammation of the lung tissue, and liver damage. Unfortunately, some drug companies have been accused of marketing it as a first-line treatment, meaning that some doctors have possibly been prescribing it for patients who may fare better under a different drug regimen.