Today's Medical Fact
Eating breakfast helps to burn calories throughout the day.
Paul Nadler, MD
San Francisco, California
Associate Clinical Professor of Medicine
University of California San Francisco
By Paul Nadler, MD
Most of us are not aware of our heart beating steadily throughout the day, but sometimes our hearts can seem to “skip a beat.” It may happen when we narrowly miss hitting a car that runs a stop sign. Perhaps it happened when you first saw your beloved. But for some people, their heart seems to pound, flutter or race for no apparent reason. This is called having “palpitations.”
Palpitations are a general term defined as an unpleasant awareness of the forceful, rapid, or irregular beating of the heart. They are common, and rarely indicate significant disease. In a few cases however, palpitations are a symptom of a serious problem with the heart. For this reason, palpitations should never be dismissed or ignored, even in otherwise healthy patients.
Common Symptoms of Palpitations
The symptoms of palpitations can be experienced in many different ways. In some cases, the heart is beating at the normal speed and with a regular rhythm, but the patient feels it more strongly than usual. Other times, a patient can feel their heart beating faster than usual, but in a regular manner. In some cases, the heart seems to be beating irregularly; some feel this irregular rhythm while their heart is beating faster than usual, others experience the irregular rhythm at a normal speed. Either way, it feels very distressing, and many patients may be concerned that their heart may suddenly stop.
In addition to feeling a rapid heart beat, irregular heart beat, or a “pounding in the chest” some patients report the pattern of their palpitations as:
What causes palpitations
A healthy heart beats in a steady rhythm. This steady beating is initiated and regulated by a conduction system in the heart. This conduction system automatically generates a recurrent, regular electrical impulse in a specialized area in an upper chamber of the heart. These specialized cells function as a natural “pacemaker” and collectively are called the sinoatrial node (also called the SA node). The impulse, after it is generated, is then conducted through the heart muscle by a network of special cells. In a normal heart, the heart muscle is stimulated by this impulse to beat in a synchronized, organized manner. Some palpitations occur when this process is altered in the ways described below.
For one, the speed (or rate) of heart beating varies throughout the day, and can be increased by exercise, stress, caffeine, and over-the-counter medications such as pseudoephedrine. In addition, the heart beat usually slows down during sleep or if the patient is taking beta-blocker medication (often prescribed for high blood pressure). In some cases, the sinoatrial node will stop generating impulses if it becomes diseased by infection, or other inflammatory illnesses, or damaged by a heart attack. Other times, the SA node will generate impulses at an abnormally rapid rate. Another type of problem occurs when the impulse generated by the sinoatrial node is normal, but the conducting system is damaged from disease or a previous heart attack. This can cause the impulse to be blocked, or not spread through the heart in a coordinated sequential way. This will also lead to the heart muscle contracting in a disorganized way.
Although it is logical to assume that symptoms of palpitations are always caused by the heart beating abnormally, this is often not the case. Quite often the symptoms of palpitations are caused when the sensation of a normal heartbeat, usually ignored, is suddenly felt strongly.
So, in summary, the symptoms of palpitations can be experienced in two ways:
To make a proper diagnosis, a clinician must do enough tests to be sure the symptoms are benign, yet avoid invasive and costly diagnostic procedures that have little value. Consider that in one study, 54% of patients who later turned out to have a significant abnormality of their heart rhythm were initially wrongly diagnosed as having an anxiety disorder, with women making up a disproportionate share of these misdiagnosed patients.
When a patient comes to a clinician complaining of the symptom of palpitations, four questions are considered immediately:
Fortunately, in many cases the heart is beating normally, and the problem is that the patient perceives their heart beat more sensitively than usual. Still, the clinician must always take the symptoms seriously and assess the patient for the rare, but potentially serious causes of palpitations.
Patient History and Symptom Review
Evaluation for of a patient should start with a general history and symptom review. Many other diseases of the body can affect the heart, and these can be diagnosed with a careful history. For instance, change in body weight may suggest thyroid disease. (An overactive thyroid can cause the heart to beat faster and pound.) Vomiting or diarrhea can lead to changes in the concentration of sodium or potassium in the blood that can then disrupt the normal heartbeat. Fluid loss from dehydration can speed up the heart. In a few cases, the membrane that covers the heart (the pericardium) can become inflamed and cause an irregular heartbeat and palpitations. This is suggested by chest pain that is relieved by leaning forward.
In cases where the heartbeat is normal and regular, anxiety can cause palpitations by increasing the sensitivity of the patient to their normal heartbeat, or by actually speeding the heart when adrenaline is released because of stress. Palpitations associated with hyperventilation, hand tingling, and nervousness are common when anxiety or panic disorder is the root cause.
Other important questions include a full review of all medications used: prescription, over-the-counter, and herbal. The patient should discuss honestly any use of stimulant drugs such as cocaine.
Common Medications Or Drugs That Can Cause Palpitations
Important questions that focus on the symptoms of palpitations include the age of first episode, situations that cause the symptoms, and the rate, duration, and degree of regularity of the palpitations.
Palpitations that start at a young age suggest a congenital (from birth) problem. The rate, duration, and degree of regularity can help identify the specific problem in the heart conduction system. To help identify the pattern, the patient should try to “tap out” the rhythm with their fingers for the clinician. Also, it is important to note whether the palpitations go away on their own, or if they only go away if the patient bears down with the abdominal muscles or coughs. (Some patients become so adept at terminating the palpitations that they may react to their symptoms nearly automatically and forget to tell the examining clinician how they self-treat their problem).
A more serious symptom is chest pain associated with palpitations. This may represent ischemic heart disease such as angina or a myocardial infarction (heart attack). Light-headedness, pre-syncope or syncope (passing out) associated with palpitations suggests sudden loss of blood pressure, and may signify a life-threatening cardiac arrhythmia. If a benign cause for these concerning symptoms cannot be ascertained during the office visit, continuous cardiac monitoring after admission to the hospital may be warranted.
It is important to note whether the palpitations occur only with physical exertion. This may be caused by a congenital (from birth) condition in which the heart muscle is enlarged and can be a clue to a dangerous condition called hypertrophic cardiomyopathy. In other cases, palpitations with exercise may be a sign of a heart conduction system that only fails at higher heart rates, or even ischemia (too little blood reaching the heart muscle because of blocked coronary arteries).
As part of the general history, it is important for the clinician to obtain a full family history. A patient with close relatives who had certain kinds of heart disease, palpitations, syncope, or suffered sudden death may be more likely to have inherited a serious cause of their symptoms.
It is uncommon that the clinician has the opportunity to examine a patient during an actual episode of palpitations, but a careful physical exam can yield clues that will help make a diagnosis. It is important to thoroughly examine the entire body before focusing on the heart. Tremulousness, brisk reflexes, or a fine hand tremor can suggest hyperthyroidism (too much thyroid hormone) causing a fast heart rate. A rapid heart rate can also be caused by fever, anemia, or dehydration.
Even if the heart is beating normally when evaluated, a careful cardiovascular exam can reveal abnormalities that would increase the likelihood of specific cardiac arrhythmias. In some cases, a murmur heard with a stethoscope points to a type of valvular disease associated with rapid beating of the upper chambers of the heart. Another type of murmur that increases after a patient is asked to contract their lower abdominal muscles and bear down can suggest thickened heart muscle caused by hypertrophic cardiomyopathy.
This will be guided by a thorough knowledge of a patient’s history and after a physical exam. Common tests include: a complete blood count to assess for anemia; electrolytes such as sodium, potassium, glucose, calcium; and thyroid studies. In cases of suspected infection, cultures may be taken. The patient’s blood oxygen may also be measured.
The two cardiac studies that are commonly used in the initial evaluation of a patient with palpitations are the 12-lead electrocardiogram (ECG) and ambulatory monitoring devices such as the Holter monitor or the event recorder.
A 12 lead ECG should be performed on all patients reporting palpitations as it can provide evidence for a wide variety of diseases. Although in most instances a specific arrhythmia will not be detected on the tracing, a careful evaluation of the ECG can still help the clinician to determine a likely cause in some circumstances.
In most cases, a careful history, physical exam, selected labs, and an ECG is all that is needed to assure that the palpitations are benign or to make the diagnosis. In some cases, however, it is important to record the heart rhythm at the exact time the patient is having symptoms, so that the symptoms and the electrocardiogram tracing can be directly compared. To do this, the patient is asked to wear a portable ECG machine that records the rhythm on a continuous basis. This type of portable ECG is called the Holter monitor. It is worn from 48 to 72 hours and records every heartbeat. The patient then brings the machine back to the medical center and the rhythm is analyzed to see if there are examples of arrhythmias (abnormal rhythms) captured. These can be correlated with the patient’s symptoms to either confirm that a transitory arrhythmia is the cause of palpitations or to exclude it. A Holter monitor is best used when the palpitations occur relatively frequently so they are likely to be captured by wearing the device for two or three days. If the palpitations are less frequent (or rare), another type of monitor may be recommended. It is called an event monitor, and can be worn for extended times. The device will allow the patient to trigger an ECG recording during symptoms or to “mark” the problem in some similar way.
ECG exercise testing (“treadmill test”) is appropriate in patients who have palpitations with physical exertion and patients with suspected coronary artery disease. Exercising the heart and increasing the heart rate reveal problems that only show up with increased rate or blood demand.
Echocardiography, which takes a moving picture of the heart with sound waves, is useful when physical exam or EKG suggests structural abnormalities, leaky heart valves, or decreased contraction of the heart muscle.
For the relatively few patients with palpitations caused by dangerous arrhythmias, or patients with known heart disease that might have a dangerous arrhythmia, testing may include a referral for electrophysiologic testing. This highly specialized form of testing involves the careful application of an electrical stimulus to the heart to either test or provoke the heart in very specific ways. It can also be used to test whether a patient who has an arrhythmia (with or without palpitations) is getting adequate benefit from prescribed medications.
Treating Palpitations Without Medicine
For most otherwise healthy patients, the symptoms of palpitations are caused by a transient minor arrhythmia, increased sensitivity to their heartbeat, or both. Their health is not threatened, but the symptoms of palpitations are annoying or distressing. Common ways to decrease the unpleasant symptoms of palpitations caused in this way include increased sleep, light exercise, relaxation techniques such as deep breathing or meditation. During this time, it may be very helpful to eliminate all caffeine from the diet (eliminate coffee, tea, soft drinks, energy drinks, or supplements). For those who want a hot beverage before going to work, limited amounts of decaffeinated coffee or tea may be tried. In my experience, minor bouts of palpitations go away on their own in two or three weeks, and limited amounts of regular coffee, tea, and soft drinks may be reintroduced into the diet if desired.
Treating Palpitations With Medicine
There is no one medicine that treats palpitations, and in many cases, no medication is necessary. The treatment depends on a careful determination of whether the palpitations are caused by a general condition in the body, or an abnormality of the heart conduction system.
If a patient is dehydrated, increasing fluids by mouth (or by intravenous drip for the very dehydrated) may eliminate the symptoms. Replacement of potassium lost by vomiting or diarrhea may resolve the problem. Treating an underlying infection may be required, sometimes with antibiotics. If the patient has an overactive thyroid, it may be controlled by medication, radioactive iodine, or surgery. If the heart is normal, but the patient is more sensitive to their heartbeat because of stress, anxiety or panic disorder, treatment of these psychological problems with therapy and/or medication may solve the problem. For patients with a recurrent arrhythmia that is not dangerous but causes annoying palpitations, a beta-blocker may be prescribed for symptom control. For the relatively few patients with a serious arrhythmia causing palpitations, certain medications (called anti-arrhythmics) may be prescribed. This may be recommended after specialized testing if the initial ECG does not show the problem.
Treating Palpitations with Surgery
For patients with certain types of serious fast arrhythmias, “ablation” surgery may cure or significantly help the problem. In this procedure, specialists in this surgery will pass a catheter through the patient’s blood vessels and alter an area of the heart that is firing abnormally or conducting abnormally. Needless to say, this is very specialized therapy done by clinicians experienced in this technique.
A more common procedure is to place an artificial pacemaker for certain rhythm problems. This artificial pacemaker either supplements a weak sinoatrial node, or overcomes the aberrant conduction of electrical impulses in the heart.