Related Experiment Video
Updated: Jun 4, 2026

Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes
Published on: March 12, 2013
SCN5A variation is associated with electrocardiographic traits in the Jackson Heart Study
Janina M Jeff1, Kristin Brown-Gentry, Sarah G Buxbaum
1Center for Human Genetics Research, Vanderbilt University, Nashville, TN 37232-0700, USA.
Background:
Understanding variation in the normal electric activity of the heart, assessed by the ECG, may provide a starting point for studies of susceptibility to serious arrhythmias such as sudden cardiac death during myocardial infarction or drug therapy. Recent genetic association studies of one ECG trait, the QT interval, have identified common variation in European-descent populations, but little is known about the genetic determinants of ECG traits in populations of African descent.
Methods And Results:
To identify genetic risk factors, we have undertaken a candidate gene study of ECG traits in collaboration with the Jackson Heart Study, a longitudinal study of 5301 blacks ascertained from the Jackson, Mississippi, area. Nine quantitative ECG traits were evaluated: P, PR, QRS, QT, and QTc durations, heart rate, and P, QRS, and T axes. We genotyped 72 variations in the predominant sodium channel gene expressed in heart, SCN5A, encoding the Na(v)1.5 voltage-gated sodium channel in 4558 subjects. Both rare and common variants in this gene have previously been associated with inherited arrhythmia syndromes and variable conduction. Adjusting for age, sex, and European ancestry, we performed tests of association in 3054 unrelated participants and identified 14 significant associations (P<1.0×10(-4)), of which 13 are independent, based on linkage disequilibrium. These variants explain up to 2% of the variation in ECG traits in the Jackson Heart Study.
Conclusions:
These results suggest that SCN5A variation contributes to ECG trait distributions in blacks, and these same variations may be risk or protective factors associated with susceptibility to arrhythmias.
Related Concept Videos
Electrocardiogram
Three major waveforms are present in a typical ECG recording: the P wave, the QRS complex, and the T...
Electrophysiology of Normal Cardiac Rhythm
Mechanism of Cardiac Arrhythmias
Electrocardiogram Fundamentals
An electrocardiogram (ECG) is a diagnostic tool for identifying cardiac conditions such as arrhythmias, conduction abnormalities, and myocardial ischemia.
Definition
An electrocardiogram (ECG) visualizes the heart's electrical activity by tracing the electrical movement associated with each heartbeat on a graph or monitor. As the heart beats, an electrical wave passes through it, correlating with the cardiac cycle events.
Parts of an ECG
An ECG utilizes electrodes on the skin to...
Cardiomyopathy III: Hypertrophic Cardiomyopathy
Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...

