The heart is encased in two protective layers. The outer layer, the pericardial sac, covers the heart. It folds in on itself at the aorta

Modified Central Lead (MCL1) – The modified central lead is created by placing the positive electrode at the 4th intercostal space just to the right

Every lead view of an ECG has a positive electrode. The heart is viewed electrically from the vantage point of the positive electrode. The positive

Locating the positive electrode is crucial to determining which area of the heart is viewed electrically. Metaphorically, the positive electrode serves as a mini-video camera

A major artery that serves the left ventricle, travelling along the left anterior epicardial surface of the heart. In order to beat over 100,000 times

A notched P wave in lead II with increased amplitude to the latter aspect of the P wave (left atrium) suggests left atrial enlargement. Atrial

A bundle branch block must satisfy two criteria – a wide QRS complex and a notch in the QRS complex. To distinguish between a RBBB

Several major vessels enter and exit the heart. The arteries carry blood away from the heart while the veins bring blood to the heart. While

The right ventricle ejects blood through the main branches of the left and right pulmonary arteries to the lungs. The main vessel feeding the right

Within the arch, the coronary arteries branch off first followed by three main arteries that branch to the brain (carotids) and the upper thorax (subclavian

The left ventricle ejects blood into the aortic arch to the body. Within the arch, the coronary arteries branch off first followed by three main

The 12-lead ECG provides 12 views of the heart. The 12 views are generated through only 10 electrodes. Four limb electrodes attach to the inner

The PR interval is the time from the beginning of the atrial wave to the beginning of myocardial depolarization of the ventricles. Normally this takes