Nearly everyone has experienced the unsettling feeling of an irregular heartbeat, or cardiac arrhythmia. Typically, the occasional fluttering of the heart and rapid pulse are considered inconsequential; however, there are times when an underlying cause must be diagnosed and treated.
Cardiac Arrhythmia-Common and Treatable
By Mike Haskew
According to the American Heart Association, the term “arrhythmia” refers to any changes from the normal sequence of electrical impulses. The electrical impulses may happen too fast, too slowly or erratically – causing the heart to beat too fast, too slowly or erratically.
Millions of Americans experience irregular heartbeats, and approximately 850,000 are hospitalized each year due to arrhythmias. Any time a cardiac event occurs, the most prudent course of action is to visit a primary care physician, which may be followed by a referral to a specialist for further evaluation and testing.
“Appropriate evaluation is critical to define what type of arrhythmia leads to the symptoms,” explains Dr. Gregory Keith Bruce, a cardiologist with The Chattanooga Heart Institute. “We sort things out to determine if we have a benign prognosis or something more worrisome. Evaluations are done with recordings such as EKGs (electrocardiograms) or outpatient monitors.
“The other issue is to determine whether there is an underlying cardiac disorder,” Bruce continues. “You determine this through taking a good patient history and doing a physical examination that may include the EKG and an echocardiogram, which is a cardiac ultrasound. Sometimes things such as a stress test or heart catheterization are needed, and occasionally advanced imaging techniques such as a cardiac CT or MRI are required. On occasion, genetic testing may also be used.”
A normal human heart rate falls somewhere within the range of 50 to 100 beats per minute. Arrhythmias can occur in hearts beating at normal, slow or accelerated rates. While arrhythmias can occur in healthy hearts, they may also indicate serious problems and can lead to heart disease, stroke or sudden cardiac arrest.
“Arrhythmias affect a wide spectrum of patients, from even young people and babies to the very old,” says Bruce, a native of Cleveland, Tenn. who completed undergraduate studies at the University of Tennessee at Chattanooga, medical training at Emory and Johns Hopkins universities, and further training at the Mayo Clinic.
“The risk tends to increase with age and the co-existence of such conditions as heart disease, high blood pressure, sleep apnea and lung disease,” Bruce says. “Some arrhythmias, like atrial fibrillation, become more common as we age; by the eighth decade of life, 10 percent to 20 percent of the population will have it.”
According to Bruce, arrhythmias may occur in the upper chambers of the heart (the atria) or the lower chambers (the ventricles). They can occur in a defined circuit, which is called re-entry; an automatic focus, which may be likened to a hot spot; or as random chaotic electrical activity, which is known as fibrillation.
“The conditions do vary with age groups, and there is wide variation and some overlap,” Bruce says. “One condition, called supraventricular tachycardia, occurs in the upper chambers of the heart and is frequent in younger patients when they present with palpitations or a racing heartbeat. Sometimes arrhythmias come from the lower chambers, which is called ventricular tachycardia. In older patients, we tend to see more atrial fibrillation and atrial flutter. Whether these are only a nuisance or are actually dangerous depends on the type of arrhythmia and whether there are underlying disorders.”
Although an arrhythmia may be virtually unnoticed by an individual and cause few symptoms, if any, certain symptoms should be investigated fully and a course of treatment determined. These symptoms include:
• Palpitations, which are generally the feeling of skipped heartbeats, fluttering and a sensation that the patient’s heart is “taking off”
• Weakness or fatigue
• Chest discomfort or tightness
• Pounding in the chest
• Shortness of breath
• Dizziness or a lightheaded feeling
The medical specialty that deals with the study and treatment of cardiac rhythm disorders is called electrophysiology. Treatment options for arrhythmias fall into three main categories: medication, ablation and implantable cardiac devices.
Drugs such as beta-blockers have proven effective in controlling some arrhythmias, and some anticoagulant or antiplatelet medications are often prescribed to decrease the possibility of blood clots.
Ablation involves the use of high frequency electrical energy, which is delivered to the affected section of the heart to destroy troublesome tissue and return the heart to normal rhythm. Such a procedure is often effective in the treatment of supraventricular tachycardia, atrial fibrillation and atrial flutter.
In some cases, heart surgery is required in combination with ablation. One such surgical technique is the maze procedure, which involves a series of incisions in the right and left atria to direct the heart’s electrical impulses into defined areas.
The implantation of a pacemaker or defibrillator is sometimes required to control arrhythmias. A pacemaker emits a small electrical impulse that keeps the heart beating at an appropriate rate, most often preventing it from beating too slowly. The defibrillator is capable of detecting irregular heart rhythms -particularly ventricular tachycardia and ventricular fibrillation, both of which are serious – and correcting the irregularities.
In certain cases a procedure called cardioversion, which delivers a low-level electrical shock to the heart to synchronize its rhythm, may be employed.
“Courses of treatment are very patient specific,” says Bruce. “Some young people respond well to ablation. Sometimes older people need medication and an implanted device or even all three main types of treatment.
“Palpitations are what we see the most – when someone comes in and says that they feel their heart racing,” Bruce says. “You really don’t know what the cause is until you start looking, and a lot of people don’t have an underlying cause. Some arrhythmias can be caused by excessive caffeine intake or stress. People can be born with a condition, or they can develop a weak heart or poor blood flow. There is a big group of young people in which arrhythmia in an upper chamber just happens; they respond well to ablation, and there is a 95 percent chance they won’t have it again.”
Individuals can take simple steps to minimize or prevent the onset of cardiac arrhythmias, including the following:
• Avoid any activities that cause an irregular heartbeat
• Stop smoking
• Limit the intake of alcohol
• Reduce consumption of caffeine
• Avoid cough and cold medications, which include stimulants that may cause the onset of an irregular heartbeat
The field of electrophysiology is continuing to develop more effective treatments for arrhythmias. “Over the last 10 to 15 years, there have been significant changes,” asserts Bruce. “Today, we can use ablation to treat some arrhythmias in which this was not an option a few years ago. We have also seen significant improvements in equipment – it is better, safer and more efficient in terms of the technology available. Several clinical studies have educated us on the best ways to program devices such as defibrillators and pacemakers for patients. Clinical trials have also helped us define patients most at risk for cardiac arrest and appropriately apply defibrillator technology to those patients.”
Cardiac arrhythmia is common and very treatable. However, the first step in successful treatment is recognizing that the condition exists. From there, diagnosis and a course of action may be well defined.