Search results
Results From The WOW.Com Content Network
An impulse (action potential) that originates from the SA node at a relative rate of 60–100 bpm is known as a normal sinus rhythm. If SA nodal impulses occur at a rate less than 60 bpm, the heart rhythm is known as sinus bradycardia. If SA nodal impulses occur at a rate exceeding 100 bpm, the consequent rapid heart rate is sinus tachycardia ...
The movements of cardiac muscle are coordinated by a series of electrical impulses produced by specialized pacemaker cells found within the sinoatrial node and the atrioventricular node. Cardiac muscle is composed of myocytes which initiate their internal contractions without receiving signals from external nerves—with the exception of ...
The blood supply of the AV node is from the atrioventricular nodal branch. The origin of this artery is most commonly (80–90% of hearts) a branch of the right coronary artery, with the remainder originating from the left circumflex artery. [4] [5] [6] This is associated with the dominance of the coronary artery circulation.
These cells produce an electrical impulse known as a cardiac action potential that travels through the electrical conduction system of the heart, causing it to contract. In a healthy heart, the SA node continuously produces action potentials, setting the rhythm of the heart (sinus rhythm), and so is known as the heart's natural pacemaker.
Cardiac physiology or heart function is the study of healthy, unimpaired function of the heart: involving blood flow; myocardium structure; the electrical conduction system of the heart; the cardiac cycle and cardiac output and how these interact and depend on one another.
The PR interval is measured from the beginning of the P wave to the beginning of the QRS complex. This interval reflects the time the electrical impulse takes to travel from the sinus node through the AV node. A PR interval shorter than 120 ms suggests that the electrical impulse is bypassing the AV node, as in Wolff-Parkinson-White syndrome.
It employs pacemaker cells that produce electrical impulses, known as cardiac action potentials, which control the rate of contraction of the cardiac muscle, that is, the heart rate. In most humans, these cells are concentrated in the sinoatrial (SA) node, the primary pacemaker, which regulates the heart’s sinus rhythm.
The cardiac pacemaker is the heart's natural rhythm generator. It employs pacemaker cells that generate electrical impulses, known as cardiac action potentials.These potentials cause the cardiac muscle to contract, and the rate of which these muscles contract determines the heart rate.