Palpitation

Palpitation

Palpitation is the term used to describe an abnormal subjective awareness of the heart beat. Palpitation is an abnormality of heartbeat that ranges from often unnoticed skipped beats or accelerated heartrate to very noticeable changes accompanied by dizziness or difficulty breathing. Palpitations are common and occur in most individuals with healthy hearts. Palpitations without underlying heart disease are generally considered benign. However, heart palpitations can be symptoms of illnesses such ascoronary heart disease, asthma, or emphysema.

Aetiology: Palpitation is usually benign and even if the patient’s symptoms are due to an arrhythmia the outlook is good if there is no underlying structural heart disease.

Most cases are due to:

·         Awareness of normal heart beat.

·         A sinus tachycardia.

·         Benign extrasystoles (Triggered by stress)

·         An intercurrent illness.

·         Effects of caffeine, alcohol & nicotine.

Causes: Palpitations can be attributed to one of four main causes:

1. Extra-cardiac stimulation of the parasympathetic nervous system(inappropriate stimulation of the parasympathetic nervous system, particularly thevagus nerve (which innervates the heart), can be caused by anxiety and stress due to acute or chronic elevations in glucocorticoids and catecholamines. Gastrointestinal distress such as bloating or indigestion, along with muscular imbalances and poor posture, can also irritate the vagus nerve causing palpitations)
2. Sympathetic overdrive (panic disorders, hypoglycemia, hypoxia, antihistamines(i.e. levocetirizine), anemia, heart failure, mitral valve prolapse).^[3]
3. Hyperdynamic circulation (valvular incompetence, thyrotoxicosis, hypercapnia,pyrexia, anemia, pregnancy).
4. Cardiac dysrhythmias (ectopic beat, premature atrial contraction, junctional escape beat, premature ventricular contraction, atrial fibrillation, supraventricular tachycardia, ventricular tachycardia, ventricular fibrillation, heart block).

Symptoms: Many times, the person experiencing palpitations may not be aware of anything apart from the abnormal heart rhythm itself. But palpitations can be associated with other things such as tightness in the chest, shortness of breath, dizziness or light-headedness. Depending on the type of rhythm problem, these symptoms may be just momentary or more prolonged. Actual blackouts or near blackouts, associated with palpitations, should be taken seriously because they often indicate the presence of important underlying heart disease. Another symptom is pain in arms or legs sometimes lasting through the night after the palpitation.

 

Treatment: Treating palpitations will depend on the severity and cause of the condition. Palpitations that are caused by heart muscle defects will require specialist examination and assessment. Palpitations that are caused by vagus nerve stimulation rarely involve physical defects of the heart. Such palpitations are extra-cardiac in nature, that is, palpitations originating from outside the heart itself. Accordingly, vagus nerve induced palpitations are not evidence of an unhealthy heart muscle.

Treatment of vagus nerve induced palpitations will need to address the cause of irritation to the vagus nerve and/or the parasympathetic nervous system generally. It is of significance that anxiety and stress are strongly associated with increased frequency and severity of vagus nerve induced palpitations. Anxiety and stress reduction techniques such as meditation and massage may prove extremely beneficial to reduce or eliminate symptoms temporarily. Supplementation with certain nutrients such as taurine, citrulline (or arginine), GABA, and magnesiummay also provide some reduction in nervous tension and anxiety,^[6] which in turn can help reduce symptoms. Changing body position (e.g. sitting upright rather than lying down) may also help reduce symptoms due to the vagus nerve's innervation of several structures within the body such as the GI tract, diaphragm and lungs.

With respect to the hyperstimulation of the vagus nerve, anticholinergic agents such anti-histamine or tricyclic antidepressant may inhibit the effect ofacetylcholine in activating the vagus nerve thereby reducing its interference on the heart's normal rhythm.

Reference:

1.      Davidson’s Principle and Practice of Medicine, 21^st edition.

2.      Wikipedia the free encyclopedia.

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