Heart Block The heart rate is controlled by a natural pacemaker called the sinoatrial node, a group of specialized cells in the wall of the right atrium (the upper right chamber of the heart). The sinoatrial node transmits electrical impulses…
Ectopic Heartbeats Ectopic heartbeats are irregular beats among otherwise normal heartbeats that feel as though the heart has either missed or gained a beat. This condition is common and usually does not require treatment. If you are bothered by an…
Atrial Fibrillation and Flutter In atrial fibrillation and flutter, the atria (the two upper chambers of the heart) contract (beat) irregularly and are not synchronized with the contractions (beating) of the ventricles (the two lower, pumping chambers of the heart).…
Cardiac Arrest Cardiac arrest means that the heart is beating ineffectively or has stopped beating. Possible causes of cardiac arrest include ventricular tachycardia (a rapid, ineffective heartbeat originating in the ventricles), ventricular fibrillation (a disorganized, ineffective attempt by the ventricles…
Arrhythmias A normal heart rate for a person who is resting is between 60 and 100 beats per minute, with some minor variations. The two major types of arrhythmias are bradycardias, in which the resting heartbeat is slower than 60…
High Blood Pressure Blood pressure is produced by the heart as it pumps blood through the arteries and as the arteries resist blood flow. It is measured in millimeters of mercury (mm Hg) with an instrument called a sphygmomanometer. Blood…
Congestive Heart Failure Congestive heart failure develops when the heart is weakened and is no longer able to pump an adequate supply of blood to the lungs and other body tissues. Heart failure does not mean that the heart stops…
Heart Attack The heart needs a continuous supply of oxygen-rich blood from the coronary arteries to function properly. A heart attack occurs when a coronary artery is blocked, depriving part of the heart muscle of blood. The resulting damage to…
