Symptoms of Arrythmia
Symptoms related to cardiac arrhythmias can vary from a relatively harmless sensation of missed heartbeat to the occurrence of sudden cardiac death.
Palpitations or "Racing of the Heart" is a term that is loosely applied. It is important to differentiate a feeling of skipped beats or flip-flop or periodic thumping (usually caused by Premature Atrial Contractions (PAC) or Premature Ventricular Contraction (PVC)) from a continuous racing of the heart (often seen with Paroxysmal Atrial Tachycardia (PAT), Atrial Flutter, Atrial Fibrillation, or Ventricular Tachycardia (VT)). Skipped heartbeats are usually benign and seldom require work-up. However, patients with recurrent racing heartbeats may have abnormal electrical short-circuits in their heart that can be identified precisely with an electrophysiology study and treated with medications or cured with radiofrequency catheter ablation.
Syncope (fainting) is one of the most common medical ailments encountered in clinical practice. Although frequently considered a neurological problem, it usually has a cardiovascular cause (arrhythmia or neurocardiogenic syncope). The final common pathway for both major cardiovascular causes is decreased circulation of blood to the brain resulting in temporary loss of consciousness. Neurological work-up is seldom rewarding.
Arrhythmias causing syncope can be fast (tachycardia) or slow (bradycardia). Tachycardias, especially ventricular tachycardia (VT), are the usual culprit. VTs often occur in people with known previous heart disease. Such individuals are at high risk for sudden cardiac death (SCD) in the future. However, SCD can be prevented if the cause of the syncope is appropriately identified and managed as early as possible. An electrophysiology study is the preferred test to evaluate these disorders.
Neurocardiogenic (vasovagal, vasodepressor) syncope occurs as a result of malfunctioning of a complex network of nerves that links the brain to the heart and controls the heart rate. This system is instrumental in increasing your heart rate when you see something exciting or frightening. A disturbance in this finely controlled network can lead to pooling of blood in your lower extremities, thereby reducing blood flow to the heart. This phenomenon causes patients to experience symptoms ranging from lightheadedness, dizziness, fatigue, sweating, nausea, or palpitations to more serious loss of consciousness. Several triggers have been implicated in bringing on symptoms in this disorder including pain, alcohol intake, dehydration, blood loss, etc. One of more of these factors may play a dominant role in an individual patient. A head-up tilt test helps establish this diagnosis. Medications are usually effective in treating this disorder.
Sudden Cardiac Death/Cardiac Arrest
Sudden cardiac death (SCD) is a death occurring within one hour of the onset of an arrhythmia. SCD is responsible for at least 300,000 deaths in the United States every year.
Most cases of SCD are due to a rapid heartbeat originating in the ventricles, called ventricular tachycardia (VT) or ventricular fibrillation (VF). These life-threatening arrhythmias are usually the result of electrical "short circuits" in a heart that has previously been scarred by some form of heart disease.
If a person survives a cardiac arrest (via the intervention of paramedics, rescue squads, in-hospital defibrillation, etc.), he or she is at high risk of recurrence in the future. Such recurrences can be prevented or reduced by appropriate diagnosis and treatment in high-risk patients.
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