Heart Health Heart Health Basics

Arrhythmias: An Introduction

A cardiac arrhythmia refers to any abnormality in the heart's rate or rhythm. There are many different types of arrhythmias, some much more serious than others. A minor arrhythmia may cause you to feel a single "skip" in your heartbeat. Almost all people have felt this type of sensation at some point in their lives and this generally does not need special treatment.

On the other end of the spectrum, much more dangerous arrhythmias may cause cardiac arrest (sudden death). In the United States, more than half of all deaths from heart disease occur suddenly. In total, it is estimated that more than 300,000 Americans die each year from sudden death related to heart disease.
 

Symptoms of an Arrhythmia

The symptoms of cardiac arrhythmias are highly variable from person to person. My patients usually complain about heart palpitations, lightheadedness, and fainting spells. In some cases, there may be no symptoms at all. A palpitation is a sensation of the heart beating within your chest. You may feel palpitations during a normal heart rhythm, particularly when nervous or exercising. They can vary in intensity, speed, and regularity. If palpitations seem unusually fast, frequent, or are accompanied by other symptoms such as dizziness, it is important to mention them to your primary care provider.

Lightheadedness and fainting are symptoms that may or may not be due to an arrhythmia. When the cause is an arrhythmia, these symptoms signify that the heart is not pumping enough blood to the brain. Cardiac arrest is the most severe symptom of any arrhythmia. In general, survival is only possible if someone immediately present knows cardio-pulmonary resuscitation (CPR). Prompt attention of an ambulance (in the United States dialing 911) and transport to a nearby hospital is essential. Even today, the chances of surviving a cardiac arrest is only about two percent in most large American cities.
 

Types of Cardiac Arrhythmias

Abnormalities of heart rate are classified as those that are too fast (called tachycardia) and those that are too slow (called bradycardia). Arrhythmias are also classified by the region of the heart that gives rise to the rhythm. Normally, your heartbeat arises from the sinus node, a tiny area on the upper right side of the heart; therefore, the normal heart rhythm is called normal sinus rhythm. Places where abnormal heart rhythms can start include the atrium (thin chambers at the top of the heart) and the ventricles (muscular chambers at the bottom of the heart).

Several common arrhythmias include:

Page 1 of 4 Next Page >>