atrial systole

systole /sys·to·le/ (sis´to-le) the contraction, or period of contraction, of the heart, especially of the ventricles.systol´ic

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aborted systole  a weak systole, usually premature, not associated with pulsation of a peripheral artery.

atrial systole  the contraction of the atria by which blood is propelled from them into the ventricles.

extra systole  extrasystole.

ventricular systole  the contraction of the cardiac ventricles by which blood is forced into the aorta and pulmonary artery.

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atrial systole,

the contraction of the atria of the heart, which precedes ventricular contraction by a fraction of a second.

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atrial

pertaining to an atrium.

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atrial contraction

contraction of the atrial muscle; plays a part in ventricular filling and opening and closing of the A-V valves.

atrial filling

return of blood via the venae cavae and the pulmonary veins to the atria. Too slow a return means inadequate cardiac output, too slow emptying means an increase in central venous pressure and possibly the development of congestive heart failure. The rate varies normally with the cardiac cycle, being fastest during atrial diastole and slowest during atrial systole.

atrial natriuretic factor (ANF)

a peptide hormone found in cardiocytes of the right and left atria and released in response to increases in plasma volume. Plays a role in the regulation of blood pressure and volume, and in the excretion of water, sodium and potassium. Closely related or possibly identical substances include auriculin, atriopeptin, cardionatrin.

atrial rupture

most often is a complication of endocardiosis and valvular insufficiency in dogs. The resulting acute pericardial hemorrhage may cause death from cardiac tamponade.

atrial septal defect

a congenital heart defect in which there is persistent patency of the atrial septum, owing to failure of closure of the ostium primum or ostium secundum.

atrial standstill

complete lack of atrial contraction; ventricular function remains normal. Caused by hyperkalemia, extreme sinus bradycardia, digitalis toxicity and a congenital muscle disorder of dogs and cats.

atrial systole

see atrial contraction (above).

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systole

the contraction, or period of contraction, of the heart, especially of the ventricles, during which blood is forced into the aorta and pulmonary artery.

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atrial systole

contraction of the atria by which blood is forced into the ventricles; it precedes the true or ventricular systole.

extra systole

see extrasystole.

ventricular systole

contraction of the ventricles, forcing blood into the aorta and pulmonary artery.