Premature Ventricular Complexes: Causes and Treatments
What are PVCs?
Premature ventricular complexes are irregular heartbeats caused by the ventricles (the lower heart chambers) contracting earlier than normal. When the heart beats normally, the sinoatrial node in the right atrium (upper chamber) sends an electrical impulse across the atria to the ventricles, causing them to contract. When the ventricles contract, blood is pumped out of the heart and throughout the body. With PVCs, the ventricles contract before the atria. PVCs can be thought of as a sort of a ‘hiccup’ in the heart.
In the above rhythm strip, the second and fourth beats are PVCs.
It’s possible to have PVCs and never know it. However, some people will get the sensation of a “fluttering” or racing heart. If you notice skipped beats or “flip-flops”, you should see your doctor to have the symptoms evaluated. Anemia, infections, anxiety, and other rhythm problems can cause PVC symptoms. Your doctor can determine the cause and proper treatment.
PVCs are not unusual in a healthy, normal heart. They are of no concern in a healthy heart, but may be serious in a diseased heart. Coronary artery disease, high blood pressure, and myocarditis (infection of the heart muscle) can cause PVCs. Other causes include chemical imbalances in the body, alcohol or illegal drugs, and some medications, such as asthma medications. Thyroid disease and high levels of adrenaline caused by caffeine, anxiety, or exercise may also cause PVCs.
An EKG is a quick, noninvasive way to show PVCs by displaying the electrical activity of the heart on a monitor. In a patient complaining of symptoms, a special monitor called a Holter monitor may be worn at home over a longer period of time to monitor the heart’s rhythm. The monitor can record and transmit the information back to the physician. If PVCs are noted, blood work may be ordered to check potassium and magnesium levels in the blood. These two electrolytes are vital for proper functioning of the body’s electrical system. If levels are too low, supplements may be given in pill form for minor deficiencies, or as an IV in the vein for significant deficiencies.
In healthy individuals, no treatment may be needed. In those with frequent PVCs or cardiac disease, medication such as beta blockers, calcium channel blockers, or anti-arrhythmic drugs may be prescribed. If PVCs are severe or potentially life-threatening, an implantable defibrillator may be placed. Depending on the type of defibrillator used, the PVCs are not prevented, but are stopped within seconds. This is often used in patients who have more than one type of arrhythmia.
When PVCs are Dangerous
Certain patterns of PVCs can be dangerous. Bigeminy and trigeminy, in which PVCs occur every other beat or every third beat can result in ventricular tachycardia (VT or V tach) or ventricular fibrillation (VF or V fib). Two PVCs in a row, known as a couplet, can also cause V tach. Three PVCs in a row are considered a run of V tach.
V tach is dangerous because it often precedes V fib. In V tach, the ventricular rate is fast, from 100 to 250 beats a minute. When V tach is sustained, immediate treatment is needed to prevent death, as it can quickly morph into V fib. In V fib, the electrical activity in the heart is chaotic, and the ventricles quiver instead of contracting. When this occurs, the heart can no longer pump blood efficiently throughout the body. In V tach where there is no pulse present, and in V fib, treatment includes shocking the heart back into rhythm. V fib is one of the most common causes of a code blue in the hospital setting.
Living with PVCs
Your doctor will decide if your PVCs need any further treatment. If medication is ordered, be sure you understand what drug you are taking, the brand and generic names, dosage, and how often to take. Know what side effects to look for, or indications that you should contact your doctor. If lifestyle changes, such as avoiding alcohol, controlling stress, and limiting caffeine is recommended, follow your doctor’s guidelines. For most healthy people, PVCs are nothing to be concerned about. But if you have any kind of cardiac disease, be aware of warning signs that require immediate medical attention.
Health Central - https://www.healthcentral.com/encyclopedia/408/643.html
Heart Health Center, About.com - https://heartdisease.about.com/cs/arrhythmias/a/PVC.htm
Mayo Clinic - https://www.mayoclinic.com/health/premature-ventricular-contractions/DS00949