Does Your Heart Skip a Beat?Nadim Nasir, M.D., Cardiac Electrophysiologist
Nearly every second, from the moment we are born until death, our life is sustained by the regular rhythmic contractions of our heart, pumping life-giving blood to all our vital organs. This remarkable pump will beat more than 2.5 billion times by age 70. What controls this amazing pump and allows it to meet the needs of our bodies?
Our heart's rhythm is controlled by a variety of factors, but primarily an intrinsic "computer" system that slows the heart beat during sleep and increases it during periods of stress or exercise. Abnormalities of heart rhythm can often be noted by patients resulting in a variety of symptoms from a sense of hard pounding to very rapid racing of the heart."Generally, abnormalities of heart rhythm are called arrhythmia, but this is not a specific diagnosis," says Nadim Nasir, M.D., cardiac electrophysiologist on staff at Methodist Sugar Land Hospital. "There are many different diagnoses that can lead to symptoms, and one individual's arrhythmia is not necessarily the same as someone else's. For example, your arrhythmia is not necessarily the same as your mother's."
Electrophysiology Gets to the Heart of the Matter
Cardiologists (specialists who are involved in the diagnosis and therapy of cardiac disorders), and more specifically, cardiac electrophysiologists (experts in the diagnosis and management of heart rhythm disorders), typically try to determine if complaints or symptoms of arrhythmia are serious or more of a nuisance and are benign.
"Common benign arrhythmias include premature contractions that interrupt the natural rhythm of the heart and can originate in the upper (atria) or lower (ventricular) chambers of the heart," Dr. Nasir says. "However, these symptoms may be identical to more serious conditions. Other common rhythm abnormalities include atrial fibrillation, a more sustained irregular and rapid rhythm with symptoms that may vary from mild breathlessness to severe chest pain or syncope (fainting)."
More serious arrhythmias that can lead to fainting or even cardiac arrest include rapid rhythms originating in the lower chambers, such as ventricular tachycardia or ventricular fibrillation. Unless treated emergently with external shock therapy (as frequently seen on such TV shows as "ER"), these dangerous rhythm problems can lead to death. Very rapid rhythms can originate in the upper chambers as well.
Diagnosing ArrhythmiasTypically, an evaluation to discover the type of arrhythmia includes an electrocardiogram (EKG), a 24- or 48-hour monitor of every heart beat. This monitor is then examined for abnormal rhythms and for a correlation with symptoms. For less frequent episodes, event recorders can be applied for several weeks to document the heart rhythm changes that relate to the symptoms. This is key to both diagnosis and therapy. Patients may frequently have asymptomatic premature beats that are only noted during an exam or a routine EKG.
"Additional evaluations might include a cardiac echocardiogram (ultrasound of the heart) or stress test, especially if symptoms tend to occur with physical stress," Dr. Nasir says.
If initial noninvasive evaluations do not show conclusive results, a more invasive electrophysiologic evaluation may be used to discover the cause of symptomatic heart rhythm issues. Often, arrhythmias can be corrected during electrophysiology but it depends on the specific rhythm abnormality.
Keep in mind that underlying heart disease such as coronary artery disease or conditions that affect the heart can lead to the development of heart rhythm abnormalities. If you have significant heart disease or congestive heart failure, make sure your doctors are aware of symptoms that might be related to your rhythm and then seek an appropriate medical evaluation.
For a physician referral to Dr. Nasir or a cardiac electrophysiologist in your area, call 281-274-7500.
