Sanjiv M. Narayan, MD, PhD, is a cardiologist, a professor of medicine, and the director of electrophysiology research at Stanford University. He previously served as a professor of medicine at the University of California, San Diego. Dr. Sanjiv Narayan has pioneered therapies for atrial fibrillation that involved identifying localized regions or drivers, called Focal Impulse and Rotor Modulation, which is one of several 'AF Mapping" approaches to identify drivers now used in clinical practice.. Cardiac arrhythmia is a disorder that results in the heart beating irregularly, too slowly, or too quickly. The condition is caused by the malfunction of electrical impulses that coordinate or control the heartbeat. There are different types of cardiac arrhythmia, depending on the speed and the location in the heart they occur. Cardiac arrhythmia based on the rate of the heartbeat includes tachycardia and bradycardia. With tachycardia, the heart beats more than 100 times per minute. With bradycardia, the heart beats fewer than 60 times per minute. However, these heartbeat rates can occur in normal situations, such as exercise or sleep. They are a concern only when they are recurrent or they are a symptom of an underlying heart condition.

1. SANJIV NARAYAN
Forms of Cardiac Arrhythmia

2. Introduction
Sanjiv M. Narayan, MD, PhD, is a cardiologist, a professor of medicine, and
the director of electrophysiology research at Stanford University. He
previously served as a professor of medicine at the University of California,
San Diego. Dr. Sanjiv Narayan has pioneered therapies for atrial fibrillation
that involved identifying localized regions or drivers, called Focal Impulse
and Rotor Modulation, which is one of several 'AF Mapping" approaches to
identify drivers now used in clinical practice..

3. Cardiac arrhythmia is a disorder that results in the heart beating irregularly,
too slowly, or too quickly. The condition is caused by the malfunction of
electrical impulses that coordinate or control the heartbeat.

4. There are different types of cardiac arrhythmia, depending on the speed and
the location in the heart they occur. Cardiac arrhythmia based on the rate of
the heartbeat includes tachycardia and bradycardia.

5. With tachycardia, the heart beats more than 100 times per minute. With
bradycardia, the heart beats fewer than 60 times per minute. However, these
heartbeat rates can occur in normal situations, such as exercise or sleep. They
are a concern only when they are recurrent or they are a symptom of an
underlying heart condition.