An Overview of Cardiac Arrhythmias

What You Need to Know about Heart Rhythm Disorders


It's with you your entire life, yet you probably don't notice it much: your heartbeat. When normal, the heartbeat is nice and regular, and has just the right rate. But when things aren't quite right -- when the heartbeat is too fast or too slow, or just too irregular -- it's known as a cardiac arrhythmia (heart rhythm problem), which is among the most common of the heart disorders.

Most people, in fact, have occasional cardiac arrhythmias.

The importance of cardiac arrhythmias can vary tremendously. Many are completely benign and inconsequential, while others are extremely dangerous and life-threatening. And many of them, while not particularly dangerous, produce symptoms that can be quite disruptive to your life.

This article gives a brief overview of the major cardiac arrhythmias - the symptoms they cause, and how they are evaluated and treated - with links to articles that describe specific arrhythmias in much more detail.

The Basics: The Heart's Normal Electrical System

A cardiac arrhythmia is a disruption of the heart’s normal electrical system, which regulates the heart rate and heart rhythm. To understand arrhythmias, it often helps to have a basic idea of how the normal electrical system works. You can read about the normal electrical system of the heart here.

Symptoms Caused By Cardiac Arrhythmias

Despite the fact that there are many different cardiac arrhythmias, the symptoms caused by these arrhythmias generally fall into only four major categories.

Follow the links to learn more about these symptoms, and what kinds of arrhythmias may cause them.

The Various Types of Cardiac Arrhythmias

There many specific cardiac arrhythmias, and to treat an arrhythmia appropriately it is important for your doctor to figure out which specific type you have.

However, the arrhythmias all can be classified into three general types (click on the links for more details about each arrhythmia):

1) Extra heart beats, also known as premature heart beats. These extra beats can arise in the atria of the heart - premature atrial complexes (PACs) . They can also arise in the ventricles - premature ventricular complexes (PVCs). PACs and PVCs are usually benign, but they can produce significant palpitations that some people find very disruptive.

2) Bradycardia, or arrhythmias that make the heart rate too slow. There are two general causes of bradycardia:

3) Tachycardia, or arrhythmias that make the heart rate too fast.

There are two general categories of tachycardia:

    Diagnosing and Evaluating Cardiac Arrhythmias

    Making the correct diagnosis of a cardiac arrhythmia generally requires "capturing" it on an electrocardiogram (ECG). Today there are several sophisticated ways to do so. If understanding the specific mechanism of a particular arrhythmia is important for deciding on therapy (as is the case if ablation is being contemplated), an electrophysiology study is often useful.

    Treating Cardiac Arrhythmias

    Just as there are many types of heart rhythm problems, many different treatment options are available. Deciding which treatment to use for which arrhythmia can be challenging even for cardiologists. The most common options for treating cardiac arrhythmias include:

    If making the right diagnosis or deciding on the best therapy turn out to be difficult, patients with arrhythmias will often be referred to a cardiac electrophysiologist - a cardiologist who specializes in heart rhythm disorders.


    Blomström-Lundqvist C, Scheinman MM, Aliot EM, et al. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias--executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Supraventricular Arrhythmias). Circulation 2003; 108:1871.

    Zipes DP, DiMarco JP, Gillette PC, et al. Guidelines for clinical intracardiac electrophysiological and catheter ablation procedures. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Clinical Intracardiac Electrophysiologic and Catheter Ablation Procedures), developed in collaboration with the North American Society of Pacing and Electrophysiology. J Am Coll Cardiol 1995; 26:555.