Ventricular Arrhythmias

What are ventricular arrhythmias?

Ventricular arrhythmias are abnormal heart rhythms that start in the ventricles. The ventricles are the two lower pumping chambers. Normally the electrical signal begins in the upper chambers and travels down. Sometimes it fires from the ventricles instead. The beat then arrives early, or the rhythm runs away at high speed. There are three main types. Premature ventricular contractions, or PVCs, are single early beats that feel like a skip or a thump. They are common even in healthy hearts. Ventricular tachycardia is a run of fast beats from the ventricles that can drop blood pressure. Ventricular fibrillation is chaotic electrical activity in which the heart cannot pump at all. It causes cardiac arrest within seconds. Risk depends heavily on the underlying heart. Occasional PVCs in a structurally normal heart are usually benign. The same beats in a weakened heart matter far more, as the National Heart, Lung, and Blood Institute explains.

Symptoms to watch for

Many ventricular arrhythmias are felt as a skipped beat followed by a forceful one. Others cause no sensation and appear only on a tracing.

Call the office if you have:

• Frequent skipped beats, thumps or a flip flop feeling in the chest.
• Palpitations that increase with rest, caffeine or stress.
• New shortness of breath or reduced exercise tolerance.
• Mild lightheadedness with an episode.
• Known heart disease and any new palpitations.

Call 911 for any of these:

• Fainting, or nearly fainting, with a racing heartbeat.
• Chest pain or pressure with palpitations.
• A sustained racing heartbeat that will not slow down.
• Severe shortness of breath, confusion or gray, clammy skin.

If someone collapses and is unresponsive without normal breathing, call 911. Begin CPR and use an AED if one is nearby. The American Heart Association notes that immediate bystander CPR can double or triple the chance of survival.

How Dr. Nanavati diagnoses it

Two questions guide the workup. What is the rhythm? Is the heart muscle underneath it normal? Both must be answered.

• Electrocardiogram (ECG or EKG) identifies the shape of the extra beats. It also screens for prior heart muscle injury.
• Holter monitoring counts how many PVCs occur in 24 to 48 hours. The burden, as a percentage of total beats, guides treatment.
• 7 to 10 day ambulatory rhythm monitoring captures episodes that are less frequent.
• Loop recorder implantation and interrogation is used for unexplained fainting or very rare events.
• Echocardiogram measures the ejection fraction. It also looks for scar, weakness or a thickened muscle.
• Treadmill stress testing shows whether the beats increase or suppress with exercise. That is an important clue.
• Nuclear stress testing and advanced stress testing look for reduced blood flow as the trigger.
• Ischemic heart disease evaluation is used when coronary artery disease is the suspected cause.
• Defibrillator interrogation downloads stored episodes if you already have a device.

Blood work rounds out the evaluation. It covers electrolytes, magnesium, thyroid function and advanced lipid testing.

Treatment options

Treatment depends on the burden of extra beats. It also depends on your symptoms and the strength of your heart muscle.

Correct the triggers. Low potassium or magnesium can provoke ventricular beats. So can caffeine, alcohol, nicotine, stimulants and decongestants. Poor sleep and untreated sleep apnea do the same. Correcting them often reduces the burden substantially. The heart healthy living steps from NHLBI support the rest.

Observation. Infrequent PVCs with a normal echocardiogram usually need no drug at all. Periodic monitoring confirms the burden stays low.

Medication. Beta blockers are the usual first choice for symptomatic PVCs. Antiarrhythmic drugs are reserved for higher burden or sustained rhythms. Treating the underlying disease matters as much as the antiarrhythmic itself. That disease may be coronary artery disease, high blood pressure or a weak heart muscle. This approach keeps with American College of Cardiology guidelines.

Procedures. Catheter ablation can eliminate the focus producing frequent PVCs or ventricular tachycardia. An implantable defibrillator is recommended when the risk of sudden cardiac arrest is high. That is typically the case with a significantly weakened pumping function. Both are done at affiliated hospitals, with cardiac rehabilitation afterward to rebuild exercise capacity safely.

What to expect at your visit

Bring your medication list, recent blood work and any prior ECGs or monitor reports. Those older records allow direct comparison. Describe when the beats occur. Say whether rest or exercise makes them worse, and whether you have ever fainted. The visit includes an exam, blood pressure and an ECG. Monitors are fitted in the office and echocardiography is performed on site. You leave knowing your PVC burden if it has been measured. You also learn whether your heart muscle is normal and what your risk actually is. Vague reassurance is not the goal. The FAQs page covers preparation.

When to see a cardiologist

See a cardiologist for frequent skipped beats or fainting of unknown cause. Come in for palpitations with any chest pain or breathlessness. Also come in for PVCs found on an ECG when you have known heart disease. A family history of sudden death before age 50 warrants prompt evaluation. 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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