Palpitations are a common symptom in all age groups, more commonly in women than men. Some of the palpitations are not related to abnormal heart rhythms per se, and may be provoked by stimulant medication (such as weight loss products or decongestants), caffeine, fear or stress. In these cases, the pulse rate increases due to adrenalin and a change in physiology is apparent.
Some individuals have a sensation of heart pounding and actually have a normal pulse at the time that they have this feeling. This situation can be difficult to assess, since the patient is certain that something must be wrong, but the objective data shows normal function. This situation has been dubbed "enhanced cardiac awareness." Once it has been established that there is no heart rhythm or blood pressure disturbance to account for the sensation, the episodes tend to improve and eventually abate. Patients with disabling symptoms are sometimes treated with beta-blockers, presuming perhaps that inappropriate catecholamine tone may be, in part, responsible.
There are abnormal heart rhythms and extra heartbeats, which can cause some episodes of palpitations. These include premature atrial and ventricular beats, and atrial and ventricular arrhythmias. Premature atrial and ventricular beats are usually followed by a pause, after which the heartbeat is more forceful. It is this latter beat that is responsible for the symptoms of palpitations. Due to the pause, there is a greater stroke volume and higher level of catecholamines resulting in the perception of a "thump." In addition, many premature ventricular beats are dissociated with the activity of the atrium of the heart, leading to valvular regurgitation, and felt as a pulsation in the neck or an urge to cough. The occurrence of atrial or ventricular beats may increase during the premenstrual period, pregnancy, menopause or advancing age. Choice of therapy, if any, depends on the presence or absence of heart disease or other medical conditions that may affect the occurrence of premature beats.
Paired atrial or ventricular beats are called couplets, and any occurrence of three or more beats is called a "run." Runs of atrial or ventricular beats may be sustained (>30 sec or resulting in symptoms before 30 sec) or non-sustained. While pairs of abnormal beats are deemed somewhat significant, the occurrence of runs of atrial or ventricular beats usually requires additional evaluation and therapy. These are often accompanied by symptoms which emphasize the serious nature of the problem, such as chest pain, shortness of breath, dizziness or fainting.
The evaluation of palpitations includes a good history and physical, a basic ECG and some type of monitor to correlate symptoms with the ECG at the time of symptoms. The type of ambulatory monitor should correlate with the frequency of the symptoms. If the symptoms do not occur multiple times in a day, the 24-hour monitor (Holter) will not be adequate. Murphy's law of monitoring is that as long as the monitor is on, no symptoms occur, but as soon as it is removed, they come back.
Thirty-day event monitors come in two types: (1) Loop monitors, which constantly record the ECG and "lock" the memory when the symptom button is pushed, and (2) TAM-2 type monitors, which are placed on the chest when symptoms occur. In my experience, the TAM-2 is often not quick enough to document the symptoms. The use of these devices correctly often determines the yield in documentation of arrhythmias.
An implantable event recorder has recently become available from Medtronic, and has a one-year battery during which patients may activate the event storage using a hand held device. The information stored in the monitor can then be downloaded using a programmer in the physician's office.
The major issue with palpitations is to separate benign rhythms from potentially dangerous rhythms. Once a benign situation is identified, reassurance, avoidance of precipitating factors, and occasionally beta-or calcium channel blocker therapy is sufficient.
This page was contributed by Lou-Anne M. Beauregard, M.D., cardiologist and electrophysiologist who is in private practice in Manalapan, NJ
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