Norfolk County Cardiologist Association
Palpitations, an unusual awareness of the heartbeat, is an extremely common symptom. Most people who complain of palpitations will describe them either as "skips" in the heartbeat (that is, a pause, often followed by a particularly strong beat,) or as periods of rapid and/or irregular heartbeats.
While many people with palpitations can essentially ignore them, others find them extremely disturbing and frightening, and often worry that they are about to die at any moment. Fortunately, the vast majority of palpitations are not associated with life threatening heart rhythm disturbances.
When a patient complains to a doctor about palpitations, it becomes the doctor's obligation to do two things: a) identify the cause of the palpitations, and b) provide optimal therapy for that cause.
What kinds of arrhythmias produce palpitations?
Most people with palpitations have one form or another of a cardiac arrhythmia. Virtually any arrhythmia can cause palpitations, but the most common causes of palpitations are premature atrial complexes (PACs), premature ventricular complexes (PVCs), episodes of atrial fibrillation, and episodes of supraventricular tachycardia (SVT).
PACs are extra electrical impulses arising in the atria. PACs are always completely benign (non-life threatening) and usually do not require therapy unless the palpitations they produce are extremely symptomatic. In most cases, reassuring patients that the palpitations are completely benign, and that there is virtually no chance they will progress to anything more serious, will significantly reduce the degree of symptoms they are experiencing.
There are several varieties of SVT, but in general SVT is also a benign arrhythmia. SVT can often be cured during an electrophysiology study by mapping the cardiac electrical system to find the abnormal region that produces the arrhythmia, and then applying radiofrequency energy through the catheter to cauterize that region. (This procedure is called radiofrequency ablation.) Most patients with the diagnosis of SVT should be referred to an electrophysiologist, who can fully discuss their therapeutic options with them.
More dangerous arrhythmias - such as episodes of ventricular tachycardia - can produce palpitations. Fortunately, only a tiny fraction of patients complaining of palpitations end up having a potentially life-threatening arrhythmia, and the majority of these also have significant underlying heart disease. Nonetheless, since palpitations can occasionally herald a dangerous arrhythmia, the doctor should always definitively identify which arrhythmia is associated with palpitations.
Because of the association between heart disease and dangerous arrhythmias, it is especially important to identify what is causing palpitations in individuals who have underlying heart disease. The same thing holds for patients with palpitations who also have significant risk factors for heart disease (family history, smoking history, high cholesterol, overweight, sedentary lifestyle).
How do you find out if there is an arrhythmia causing the palpitations?
The first order of business when a patient complains of palpitations is to find out whether (as is most often the case) the palpitations are caused by a heart rhythm disturbance, and if so, to identify the particular arrhythmia that is causing the palpitations.
This should be relatively straightforward to do, so it always amazes DrRich to see how much trouble doctors seem to have in accomplishing this feat. The trick is simply to record an electrocardiogram (ECG) at the time the patient is having symptoms. That's it. Not exactly rocket science, is it?.
But doctors commonly make two major mistakes in their attempt to determine whether an arrhythmia is causing the palpitations: they often miss the arrhythmia that is causing the palpitations, and they often attribute the palpitations to an arrhythmia that is not causing them.
Mistake 1: The doctor will order an ECG (which records the heart rhythm for 12 seconds) or a Holter monitor study (which records the heart rhythm for 24 hours), and during that time the patient will not experience palpitations. Then, not seeing an arrhythmia, the doctor will declare that there is no arrhythmia causing the palpitations. Worse, the doctor may tell the patient that the symptoms are "all in your head." But often, the arrhythmia that is causing the palpitations just happened not to occur during the arbitrary monitoring period. The doctor's workup was inadequate.
To make a correct diagnosis, the palpitations and ECG must occur at the same time. If the palpitations occur only intermittently, and especially if they do not occur every single day, instead of doing an ECG or a 24-hour Holter study, the doctor should order an event recorder study. The event recorder study can continuously record the heart rhythm for weeks at a time - however long it takes to "capture" an episode of palpitations. It's really quite simple - record the ECG for as long as it takes for the patient to have an episode of palpitations, then look to see what the heart rhythm is during the palpitations.
Mistake 2: The doctor will see an arrhythmia during monitoring that is not associated with palpitations, and blame the palpitations on that arrhythmia. This is wrong. To say an arrhythmia is causing palpitations, the arrhythmia and the palpitations must occur at the same time. Once again, monitoring must continue until palpitations occur, so that the heart rhythm can be examined at the time of the palpitations.
Since doctors frequently make these two mistakes, it is important for patients to keep in mind the simple rule: To make a correct diagnosis, the ECG must be recorded at the very time the palpitations are taking place. If this has not been accomplished, the patient must redirect the physician's efforts through gentle reminders, guile, appeals to reason, righteous indignation, or whatever it takes.
What are the non-cardiac causes of palpitations?
Occasionally individuals will perceive palpitations where no arrhythmia at all is present. The ECG during such palpitations will be completely normal.
Other times, a non-cardiac condition will cause an increase in adrenaline levels that, in turn, will cause the heart rate to increase (just as increased adrenaline levels caused by running the 100 yard dash will make the heart rate go up.) The increase in heart rate produced by adrenaline (whether in response to an appropriate stimulus or not) is called sinus tachycardia.
The most common non-cardiac conditions that produce palpitations are thyroid disease and anxiety disorders. Both of these conditions can cause sinus tachycardia, and both can cause a "hyperawareness" of the heartbeat, so that palpitations can be perceived even when the heart rhythm is normal. It is important to recognize that an anxiety disorder - just like a thyroid disorder - is a specific medical diagnosis that requires specific therapy. It is not a diagnosis that should tossed about loosely, or used to brush the patient off. Click here for an excellent site related to panic disorders.
Other, less common non-cardiac disorders associated with palpitations include hypoglycemia, pheochromocytoma and carcinoid (these latter two conditions are hormone-secreting tumors).
Palpitations are a symptom, not a diagnosis. Most often palpitations are caused by a benign cardiac arrhythmia that requires no specific therapy, aside from reassurance. However, palpitations can sometimes provide a clue that something more serious is afoot, such as previously undiagnosed underlying heart disease, a more significant cardiac arrhythmia, or a treatable non-cardiac illness. Therefore, palpitations always deserve a full medical evaluation. They should not be ignored either by the individuals experiencing them, or by their doctors, and neither patient nor doctor should rest until a specific diagnosis is made.