Only $35.99/year

Mechanical Activity of the Heart and the Cardiac Cycle

Terms in this set (17)

Ventricular systole:
1.) QRS: ventricular depolarization, contraction
2.) Onset: AV valve closes when ventricular pressure exceeds atrial pressure (its heart sound) all valves are closed
3.) isovolemic contraction causes a steep increase in pressure
4.) ventricular ejection


Ventricular diastole:
1.) T wave: ventricular repolarization; relaxation. Onset of diastole when T waves completed
2.) drop in ventricular pressure
3.) falls below aortic pressure and aortic valve closes (seconds heart sound)
4.) falls below atrial pressure, AV valves open
5.)P wave: atrial depolarization- atrial contraction, small rise in ventricular pressure

1.) During the atrial systole: the p wave occurs, there is a slight increase in atrial ventricular pressure and the AV valves open and a slight increase in ventricular volume (ventricular kick or topping off)

2.) During the ventricular systole: the QRS wave occurs, there is an immediate rise in ventricular pressure (when it supersedes the atrial pressure, the AV valve closes); this marks the first sound

Then:
a.) Isovolemic contraction begins, resulting in a sharp increase in pressure but no change in volume
b.) Rapid ejection begins in which the ventricular pressure is greater than the aortic pressure and the aortic semilunar valve opens resulting in a sharp decrease in ventricular pressure and volume
c.) Reduced ejection corresponds with the T wave, as a repolarization occurs, aortic and ventricular pressures begin to decrease as ventricles begin to relax and blood continues to leave ventricle leave (continues decrease in ventricle volume)

3.) ventricular diastole: the onset of a diastole is marked by the completion of repolarization (end of the T wave)

A.) Isovolemic relaxation occurs when the ventricular pressure drops below aortic pressure and the aortic valve closes (this is the second heart sound): with both valves closed there is a big drop in pressure, but no change in volume

b.) rapid filing: pressure in the ventricle drops below atria and the AV opens allowing blood to passively pour into the ventricle... leading to a large increase in volume and a decrease in aortic (simultaneously) as blood is carried to the periphery
1.) atrial systole (during ventricular diastole): pa wave atrial contraction; slight increase in atrial-ventricular pressure (AV valves open); slight increase in ventricular volume

2.) ventricular systole:
QRS/ventricular contraction. Immediate rise in ventricular pressure above atrial. V valve closes. 1st heart sound

A.) isovolumetric contraction: against two closed valves, sharp increase in pressure, no change in volume

B.) Rapide ejection: ventricular pressure is greater than aortic pressure and the aortic valve opens, leading to a rapid decrease in ventricular volume

C.) Reduced ejection: T wave: repolarization spreading over ventricles; aortic and ventricular pressure begin to decrease as ventricles begin to relax and blood continues to leave ventricles. Continued decrease in ventricular volume.

3.) ventricular diastole: Onset of diastole marked by completion of repolarization (end of T wave)

A.) Isovolumic relaxation: ventricular pressure drops below aortic pressure so the aortic valve closes and the second heart sound can be heard when both valves are closed and there is a big drop in pressure but no change in volume

B.) rapid filling: pressure in ventricles drops below atria- AV valve opens- blood passively pours into ventricle; big increase in volume (aortic pressure decreases

The Wigger's diagram is crucial to know

It is the simultaneous depiction of several parameters related to blood flow and volume, the EKG and the echocardiogram through one cycle of a diastole and systole