Ventricular Tachycardia

What is ventricular tachycardia?

Ventricular tachycardia is a fast heart rhythm that starts in the ventricles. The ventricles are the heart's two lower pumping chambers. Doctors often shorten the name to VT. VT means three or more beats in a row from the ventricles at a rate above 100 beats per minute. The signal bypasses the heart's normal wiring. The chambers do not fill properly between beats, so less blood reaches the body with each contraction. Short runs lasting a few seconds are called non sustained VT and may cause only a flutter. Runs lasting longer than 30 seconds are called sustained VT. So is any run that drops your blood pressure. Sustained VT is a medical emergency. VT most often occurs in a heart scarred by a previous heart attack, weakened by cardiomyopathy, or affected by an inherited electrical disorder. Untreated sustained VT can deteriorate into ventricular fibrillation and cardiac arrest. That is why the American Heart Association classifies it among the most serious arrhythmias.

Symptoms to watch for

VT often announces itself abruptly. How it feels depends on two things. One is how fast it runs. The other is how strong your heart muscle is.

Call the office if you have:

• Brief flutters or a run of rapid beats that stops on its own.
• Palpitations with mild dizziness that resolve quickly.
• Reduced exercise tolerance or new fatigue.
• Known heart disease and any new rhythm sensation.
• Shocks or beeping from an implanted defibrillator, which need prompt review.

Call 911 immediately for:

• A sustained racing heartbeat that does not slow down.
• Fainting or near fainting
• Chest pain or pressure with a racing heart.
• Severe shortness of breath, confusion or clammy, gray skin.
• More than one defibrillator shock in 24 hours.

If someone collapses and is not breathing normally, call 911. Start CPR and use an AED. Survival from cardiac arrest depends on how quickly CPR and defibrillation begin.

How Dr. Nanavati diagnoses it

VT must be documented on a tracing. The heart muscle underneath it must also be assessed. Both parts drive treatment.

• Electrocardiogram (ECG or EKG) captures the rhythm. It also shows evidence of a prior heart attack that could be the source.
• Holter monitoring records every beat for 24 to 48 hours. It finds non sustained runs.
• 7 to 10 day ambulatory rhythm monitoring extends the search for episodes that are less frequent.
• Loop recorder implantation and interrogation monitors long term after unexplained fainting.
• Echocardiogram measures the ejection fraction. That is the single most important number for judging risk.
• Nuclear stress testing and advanced stress testing look for reduced blood flow that provokes the rhythm.
• Ischemic heart disease evaluation assesses coronary artery disease as the underlying cause.
• Defibrillator interrogation and pacemaker interrogation read stored episodes. They also check device settings.

A transradial angiogram defines the coronary anatomy when a blockage is suspected. It is done at an affiliated hospital. Electrolyte, magnesium and thyroid testing complete the picture. So does advanced lipid testing.

Treatment options

Treatment has two aims. It stops episodes and prevents sudden cardiac arrest. Nearly every patient needs both addressed.

Reverse the triggers. Low potassium and magnesium can provoke VT. So can stimulants, alcohol and certain decongestants. Some prescription drugs that prolong the QT interval do the same. Reviewing every medication and supplement is part of the first visit.

Treat the underlying heart. Ischemia is sometimes the cause. Blood flow is restored with angioplasty and coronary stenting. That removes the trigger. Other medications strengthen and protect a weakened heart muscle. They reduce episodes over time, following American College of Cardiology guidelines.

Medication. Beta blockers are the foundation. Antiarrhythmic drugs such as amiodarone or sotalol are added for recurrent episodes. Dr. Nanavati monitors them closely.

Devices and ablation. An implantable cardioverter defibrillator monitors your rhythm continuously. It delivers a shock to stop a lethal rhythm. It is the standard protection for patients with a significantly weakened pumping function. Catheter ablation targets the scar tissue circuit driving VT. It can markedly reduce episodes and shocks. A temporary pacemaker may be used in urgent hospital settings. Cardiac rehabilitation follows, so you can return to activity under supervision.

What to expect at your visit

Bring your medication list, any hospital discharge paperwork and prior ECGs. Bring your device card too if you have a pacemaker or defibrillator. Describe every episode. Say how it started, how long it lasted, whether you fainted and what stopped it. The visit includes an exam, blood pressure and an ECG. Device interrogation and echocardiography are performed in the office. You will leave with a specific plan. It covers medication, monitoring, activity limits and exactly when to call 911. Family members are welcome, and CPR training is encouraged. The FAQs page answers common questions.

When to see a cardiologist

Seek prompt evaluation after any fainting episode or a documented run of VT. Do the same after a defibrillator shock. Also call for palpitations with chest pain or breathlessness. Get assessed if you have had a prior heart attack or have a weakened heart muscle. The same applies to a family history of sudden death before age 50. The ventricular arrhythmias page covers related rhythms. Request an appointment online or call the Bonita office at (619) 585-0476.

Dr. Vimal Nanavati, MD, FACC is board certified in cardiology and interventional cardiology. He has 32 years of experience. He founded Advanced Heart Care, Inc. in 1997. He sees patients at three locations. The Bonita office is in South San Diego. It serves Chula Vista, Eastlake, Otay Ranch, National City, Spring Valley, Imperial Beach, San Ysidro and Coronado. The North San Diego office at 5190 Governor Dr serves University City, La Jolla, Clairemont and Mira Mesa. The Redding office serves Shasta County, Anderson, Red Bluff, Palo Cedro and Cottonwood.

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