Cardiovascular Anatomy and Physiology Flashcards

Depolarization of the ventricles is represented on the ECG by which waveform?

Answer: QRS complex

The QRS complex reflects rapid ventricular depolarization, which triggers myocardial contraction.

What does the term 'cardiac output' refer to?

Answer: The volume of blood ejected by one ventricle per minute

Cardiac output (CO) equals stroke volume multiplied by heart rate and represents the volume pumped per minute.

Which phase of the cardiac cycle represents ventricular contraction?

Answer: Systole

Systole is the phase during which the ventricles contract and eject blood into the aorta and pulmonary artery.

The 'atrial kick' contributes approximately what percentage of ventricular filling at normal heart rates?

Answer: 15–30%

Atrial contraction contributes roughly 15–30% of ventricular filling, which becomes especially important when heart rate is elevated.

Which valves open during ventricular systole?

Answer: Aortic and pulmonic valves

During systole, rising ventricular pressure forces open the aortic and pulmonic (semilunar) valves to eject blood.

The refractory period of the cardiac cycle is important in telemetry because stimulation during this phase can:

Answer: Trigger a life-threatening arrhythmia (R-on-T phenomenon)

A stimulus falling on the vulnerable T wave (R-on-T) can precipitate ventricular tachycardia or fibrillation.

Stroke volume is primarily determined by which three factors?

Answer: Preload, afterload, and contractility

Stroke volume is governed by preload (filling volume), afterload (resistance to ejection), and myocardial contractility.