A disturbance of the normal synchronized rhythm of the heartbeat so that the heart does not pump blood is fatal if not reversed, arrhythmia.
Abnormal rate of muscle contraction in the heart, caused by malfunction of impulse-conducting fibers in the heart or inability of the heart to respond to stress (e.g., fever, excessive exercise, altered metabolic balance). Types of arrhythmia include bradycardia, heart block, and tachycardia.
A disturbance or abnormality in the rhythm of the heartbeat. Cardiac arrhythmias vary in severity from annoying to life-threatening.
Abnormal rhythm of the heartbeat. Most commonly seen after someone has had a myocardial infarction, but also present in some normal individuals — especially if they have taken a lot of coffee or other stimulant — and in those with a congenital abnormality of the conducting system of the heart muscle. The cause is interference in the generation or transmission of electrical impulses through the heart’s conducting system. Occasional isolated irregular beats (ectopic beats) do not necessarily mean that conduction is faulty. Arrhythmias can be classified as tachycardias (more than 100 beats a minute) or bradycardias (slower than 60 beats a minute). Heartbeats may be regular or irregular.
Any abnormal heart rhythm caused by physiological or pathological disturbances in the discharge of cardiac impulses from the sinoatrial node or their transmission through conductive tissue of the heart.
Arrhythmia refers to an abnormality in the rhythm or rate of the heartbeat. These irregularities arise from disruptions in the electrical impulses within the heart. When an irregular beat occurs in isolation, it is referred to as an ectopic heartbeat. It is important to note that the presence of ectopic beats does not necessarily indicate an underlying abnormality.
Arrhythmias can be classified into two primary categories: tachycardias, where the heartbeat rate is faster than the normal range, and bradycardias, where the heartbeat rate is slower. The rhythm of the heartbeats may be regular, with each atrial beat (from the upper chambers called atria) followed by one ventricular beat (from the lower chambers called ventricles).
Sinus tachycardia refers to an elevated heart rate with a regular rhythm, originating from the sinoatrial node. Supraventricular tachycardia is a faster form of tachycardia with a regular rhythm. It may occur due to an abnormal electrical pathway that allows continuous circulation of an impulse in the heart, taking over from the sinoatrial node. Ventricular tachycardia is a rapid and irregular heartbeat that originates in the ventricles. Atrial flutter is characterized by rapid and regular beating of the atria, with not every impulse reaching the ventricles, which beat at a slower rate. Atrial fibrillation, on the other hand, involves uncoordinated and fast beating of the atria, resulting in completely irregular ventricular beats. Ventricular fibrillation, a type of cardiac arrest, occurs when the ventricles exhibit rapid and disorganized twitching, preventing the heart from effectively pumping blood.
Sinus bradycardia refers to a slow and regular heartbeat. In cases of heart block, there is a partial or complete blockage of electrical impulse conduction through the heart muscle, resulting in a slow and irregular heartbeat. Periods of bradycardia may alternate with periods of tachycardia due to a fault in impulse generation.
Coronary artery disease, characterized by the narrowing of coronary arteries due to atherosclerosis (buildup of fat deposits on the artery walls), is a common underlying cause of arrhythmia. This association is particularly significant following a myocardial infarction (heart attack). Additionally, certain tachycardias may arise as a result of congenital defects in the heart’s conducting system, which are present from birth.
In certain individuals, caffeine consumption can induce tachycardia, a rapid heartbeat. High doses of amitriptyline, as well as certain other antidepressant medications, can potentially lead to severe cardiac arrhythmias, posing a significant risk to the individual’s heart rhythm.
Arrhythmias can manifest as palpitations, which refers to the perception of an unusually rapid heartbeat by the individual. However, in certain instances, arrhythmias can result in fainting and dizziness due to decreased blood flow to the brain. Chest pain and breathlessness may also occur if there is a reduction in blood flow to the lungs. These symptoms, including fainting, dizziness, chest pain, and breathlessness, may serve as initial indicators of an underlying arrhythmia.
Arrhythmias are typically diagnosed through the use of an electrocardiogram (ECG), a diagnostic test that reveals the electrical activity pattern within the heart muscle. In cases where the arrhythmia occurs intermittently, it may be necessary to perform a continuous recording using an ambulatory ECG, allowing for an extended monitoring period.
Treatment options for arrhythmias encompass the use of antiarrhythmic drugs, which aim to prevent or slow down episodes of tachycardia. In cases where an arrhythmia occurs suddenly, it may be feasible to restore a normal heart rhythm by applying an electric shock directly to the heart. This procedure, known as cardioversion, can help reset the heart’s electrical activity.
For recurring episodes of tachycardia, radiofrequency ablation, a procedure involving the removal of damaged or abnormal tissue in the heart’s conduction pathway, can be employed as a treatment option. This procedure is often performed during cardiac catheterization. In certain cases, a pacemaker may be implanted to restore a normal heartbeat by overriding the heart’s abnormal rhythm. The pacemaker serves to regulate the heart’s electrical impulses and maintain a healthy heart rate.