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Anticoagulants: To prevent embolization.. Beta blockers: To block the effects of certain hormones on the heart to slow the heart rate.. Calcium Channel Blockers: Help slow the heart rate by blocking the number of electrical impulses that pass through the AV node into the lower heart chambers (ventricles).
Ectopic beat is a disturbance of the cardiac rhythm frequently related to the electrical conduction system of the heart, in which beats arise from fibers or group of fibers outside the region in the heart muscle ordinarily responsible for impulse formation (i.e., the sinoatrial node).
Premature ventricular contraction in an ECG (arrows) of a dog, caused by dilated cardiomyopathy. Premature ventricular contractions occur in healthy persons of any age, but are more prevalent in the elderly and in men. [3] In a very significant proportion of people they occur spontaneously with no known cause. [citation needed]
A premature heart beat or extrasystole [1] is a heart rhythm disorder corresponding to a premature contraction of one of the chambers of the heart. Premature heart beats come in two different types: premature atrial contractions and premature ventricular contractions. Often they cause no symptoms but may present with fluttering in the chest or ...
Ventricular pacemaker cells discharge at a slower rate than the SA or AV node. While the SA node typically initiates a rate of 70 beats per minute (BPM), the atrioventricular node (AV node) is usually only capable of generating a rhythm at 40-60 BPM or less. Ventricular contraction rate is thus reduced by 15-40 beats per minute. [3]
Electrical waves track a systole (a contraction) of the heart. The end-point of the P wave depolarization is the start-point of the atrial stage of systole. The ventricular stage of systole begins at the R peak of the QRS wave complex; the T wave indicates the end of ventricular contraction, after which ventricular relaxation (ventricular diastole) begins.
A Wiggers diagram modified from [1]. A Wiggers diagram, named after its developer, Carl Wiggers, is a unique diagram that has been used in teaching cardiac physiology for more than a century.
The isovolumetric contraction phase lasts about 0.05 seconds, [1] but this short period of time is enough to build up a sufficiently high pressure that eventually overcomes that of the aorta and the pulmonary artery upon opening of the semilunar valves. This process, therefore, helps maintain the correct unidirectional flow of blood through the ...