Palpitations


Palpitations occur when a person becomes aware of their heartbeat. The heartbeat may feel hard, fast, or uneven in their chest.
Symptoms include a very fast or irregular heartbeat. Palpitations are a sensory symptom. They are often described as a skipped beat, a rapid flutter, or a pounding in the chest or neck.
Palpitations are not always the result of a physical problem with the heart and can be linked to anxiety. However, they may signal a fast or irregular heartbeat. Palpitations can be brief or long-lasting. They can be intermittent or continuous. Other symptoms can include dizziness, shortness of breath, sweating, headaches, and chest pain.
There are a variety of causes of palpitations not limited to the following:
Palpitation may be associated with coronary heart disease, perimenopause, hyperthyroidism, adult heart muscle diseases like hypertrophic cardiomyopathy, congenital heart diseases like atrial septal defects, diseases causing low blood oxygen such as asthma, emphysema or a blood clot in the lungs; previous chest surgery; kidney disease; blood loss and pain; anemia; drugs such as antidepressants, statins, alcohol, nicotine, caffeine, cocaine and amphetamines; electrolyte imbalances of magnesium, potassium and calcium; and deficiencies of nutrients such as taurine, arginine, iron or vitamin B12.

Signs and symptoms

Three common descriptions of palpitation are:
Palpitations often come with other symptoms. Knowing these links can help determine if they are dangerous or harmless. However, these links are not definitive and should be evaluated by a licensed healthcare provider to ensure an accurate diagnosis and proper care.
Palpitations associated with chest discomfort or chest pain suggests coronary artery disease. Palpitation associated with light-headedness, fainting or near fainting suggest low blood pressure and may signify a life-threatening cardiac dysrhythmia. Palpitation that occurs regularly with exertion suggests a rate-dependent bypass tract or hypertrophic cardiomyopathy.
If a benign cause for these symptoms isn't found at the first visit, then prolonged heart monitoring at home or in the hospital setting may be needed. Noncardiac symptoms should also be elicited since the palpitations may be caused by a normal heart responding to a metabolic or inflammatory condition. Weight loss could suggest hyperthyroidism. Palpitation can be precipitated by vomiting or diarrhea that leads to electrolyte disorders and hypovolemia. Hyperventilation, hand tingling, and nervousness are common when anxiety or panic disorder is the cause of the palpitations.

Causes

The responsibility for the perception of heartbeat by neural pathways is not clear. It has been hypothesized that these pathways include different structures located both at the intra-cardiac and extra-cardiac level. Palpitations are a widely diffuse complaint and particularly in subjects affected by structural heart disease. The list of causes of palpitations is long, and in some cases, the etiology is unable to be determined. In one study reporting the etiology of palpitations, 43% were found to be cardiac, 31% psychiatric, and approximately 10% were classified as miscellaneous.
The cardiac etiologies of palpitations are the most life-threatening and include ventricular sources, atrial sources high output states, structural abnormalities, and miscellaneous sources. Palpitations can be a symptom of mast cell activation syndrome.
Palpitation can be attributed to one of five main causes:
  1. Extra-cardiac stimulation of the sympathetic nervous system
  2. Sympathetic overdrive.
  3. Hyperdynamic circulation.
  4. Abnormal heart rhythms.
  5. Pectus Excavatum, also known as funnel chest, is a chest wall deformity. When the breastbone and attached ribs are sunken in enough to put excess pressure on the heart and lungs which can cause tachycardia and .
Palpitations can occur during times of catecholamine excess, such as during exercise or at times of stress. The cause of the palpitations during these conditions is often a sustained supraventricular tachycardia or ventricular tachyarrhythmia. Supraventricular tachycardias can also be induced at the termination of exercise when the withdrawal of catecholamines is coupled with a surge in the vagal tone. Palpitations secondary to catecholamine excess may also occur during emotionally startling experiences, especially in patients with a long QT syndrome.

Psychiatric problems

Anxiety and stress elevate the body's level of cortisol and adrenaline, which in turn can interfere with the normal functioning of the parasympathetic nervous system resulting in overstimulation of the vagus nerve. Vagus nerve induced palpitation is felt as a thud, a hollow fluttery sensation, or a skipped beat, depending on at what point during the heart's normal rhythm the vagus nerve fires. In many cases, the anxiety and panic of experiencing palpitations cause a patient to experience further anxiety and increased vagus nerve stimulation. The link between anxiety and palpitation may also explain why many panic attacks involve an impending sense of cardiac arrest. Similarly, physical and mental stress may contribute to the occurrence of palpitation, possibly due to the depletion of certain micronutrients involved in maintaining healthy psychological and physiological function. Gastrointestinal bloating, indigestion and hiccups have also been associated with overstimulation of the vagus nerve causing palpitations, due to branches of the vagus nerve innervating the GI tract, diaphragm, and lungs.
Many psychiatric conditions can result in palpitations including depression, generalized anxiety disorder, panic attacks, and somatization. However one study noted that up to 67% of patients diagnosed with a mental health condition had an underlying arrhythmia. There are many metabolic conditions that can result in palpitations including, hyperthyroidism, hypoglycemia, hypocalcemia, hyperkalemia, hypokalemia, hypermagnesemia, hypomagnesemia, and pheochromocytoma.

Medication

The medications most likely to result in palpitations include sympathomimetic agents, anticholinergic drugs, vasodilators and withdrawal from beta blockers.
Excessive consumption of caffeine, commonly found in coffee, tea, and energy drinks, is a well-known trigger. Recreational drugs such as cocaine, amphetamines, and MDMA are also associated with palpitations and pose significant cardiovascular risks. These substances can lead to serious health issues, including vasospasm-related angina, heart attacks, and strokes. Understanding the impact of these substances is crucial for both prevention and management of palpitations.

Pathophysiology

The sensation of palpitations can arise from extra-systoles or tachyarrhythmia. It is very rarely noted due to bradycardia. Palpitations can be described in many ways. The most common descriptions include a flip-flopping in the chest, a rapid fluttering in the chest, or pounding in the neck. The description of the symptoms may provide a clue regarding the etiology of the palpitations, and the pathophysiology of each of these descriptions is thought to be different. 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 arrhythmia 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. 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

To diagnose palpitations, patient description is of notable importance, and a complete history and physical exam are essential. Key details are the age symptoms began, the presence of other symptoms such as chest pain, dizziness, or fainting and the situations in which they occur. It may also be helpful to know about their caffeine intake, if deep breathing or changing positions can stop the palpitations, or how the palpitations start and stop - do they begin and end suddenly or gradually, does the heartbeat feel regular or irregular, how fast does the pulse get during an episode, etc. It is useful to know whether the person has found a way to stop the palpitations.
Along with medical and family history, the patient should be asked about all medications, including over-the-counter drugs, their habits such as exercise, caffeine or alcohol and drug.
Diagnosing palpitations can be arduous as it is rare for symptoms to occur during a routine medical exam or an ECG. However, if a heart murmur or abnormal ECG is found, it can provide important clues, and as such a thorough physical exam and ECG are essential.
The physical exam should include checking vital signs and a position based blood pressure measurement, listening to the heart and lungs and examining the arms and legs. If the person is not displaying symptoms during the exam, they can tap out the rhythm to show what their heartbeat felt like.
Palpitations that start in childhood are often caused by supraventricular tachycardia. Palpitations that appear later in life are more likely linked to structural heart problems. A rapid, regular heartbeat is usually due to paroxysmal SVT or ventricular tachycardia. A rapid, irregular rhythm might be due to atrial fibrillation, atrial flutter, or tachycardia with a variable block. Supraventricular and ventricular tachycardias often cause sudden palpitations, beginning and ending rapidly. If someone can stop their palpitations with the Valsalva maneuver, it may indicate SVT. Palpitations with chest pain could mean reduced blood flow to the heart. If the person feels lightheaded or faints, arrhythmias should be considered.
Positive orthostatic vital signs may indicate dehydration or an electrolyte abnormality. A mid-systolic click and heart murmur may indicate mitral valve prolapse. A harsh holo-systolic murmur best heard at the left sternal border which increases with Valsalva may indicate hypertrophic obstructive cardiomyopathy. An irregular rhythm indicates atrial fibrillation or atrial flutter. Evidence of cardiomegaly and peripheral edema may indicate heart failure and ischemia or a valvular abnormality.