In patients who describe the palpitations as a brief flip-flopping in the chest, the palpitations are thought to be caused by extra- systoles such as supraventricular or ventricular premature contractions. The flip-flop sensation is thought to result from the forceful contraction following the pause, and the sensation that the heart is stopped results from the pause. The sensation of rapid fluttering in the chest is thought to result from a sustained ventricular or supraventricular arrhythmia. Furthermore, the sudden cessation of this arrythmia can suggest paroxysmal supraventricular tachycardia. This is further supported if the patient can stop the palpitations by using Valsalva maneuvers. The rhythm of the palpitations may indicate the etiology of the palpitations (irregular palpitations indicate atrial fibrillation as a source of the palpitations). An irregular pounding sensation in the neck can be caused by the dissociation of mitral valve and tricuspid valve, and the subsequent atria are contracting against a closed tricuspid and mitral valves, thereby producing cannon A waves. Palpitations induced by exercise could be suggestive of cardiomyopathy, ischemia or channelopathies. Diagnosis
The most important initial clue to the diagnosis is ones description of palpitation. The approximate age of the person when first noticed and the circumstances under which they occur are important, as is information about caffeine intake (tea or coffee drinking), and whether continual palpitations can be stopped by deep breathing or changing body positions.
Evidence of cardiomegaly and peripheral edema may indicate heart failure and ischemia or a valvular abnormality.Blood tests, particularly tests of thyroid gland function, are also important baseline investigations (an overactive thyroid gland is a potential cause for palpitations; the treatment, in that case, is to treat the thyroid gland over-activity).The next level of diagnostic testing is usually 24-hour (or longer) ECG monitoring, using a recorder called a Holter monitor, which can record the ECG continuously during a 24-hour or 48-hour period. If symptoms occur during monitoring it is a simple matter to examine the ECG recording and see what the cardiac rhythm was at the time. For this type of monitoring to be helpful, the symptoms must be occurring at least once a day. If they are less frequent, the chances of detecting anything with continuous 24- or even 48-hour monitoring are substantially lowered. More recent technology such as the Zio Patch allows continuous recording for up to 14 days; the patient indicates when symptoms occur by pushing a button on the device and keeps a log of the events.Other forms of monitoring are available, and these can be useful when symptoms are infrequent. A continuous-loop event recorder monitors the ECG continuously, but only saves the data when the wearer activates it. Once activated, it will save the ECG data for a period of time before the activation and for a period of time afterwards – the cardiologist who is investigating the palpitations can program the length of these periods.