Cardiac cycle one-liners
High-yield rapid revision facts and one-liners covering the phases, pressures, volumes, and heart sounds of the cardiac cycle for medical and allied healthcare exams.
Cardiac Cycle One-Liners
For MBBS, nursing, pharmacy, paramedical, and physiotherapy students preparing for exams, mastering cardiac cycle one-liners is crucial for quick viva and MCQ success. The cardiac cycle covers all mechanical and electrical events occurring from the start of one heartbeat to the beginning of the next.
Key Points & Timings
- Total duration of a normal cardiac cycle is 0.8 seconds at a heart rate of 72 beats per minute.
- Atrial systole lasts for 0.1 seconds.
- Ventricular systole lasts for 0.3 seconds.
- Joint diastole lasts for 0.4 seconds.
- Isovolumetric contraction and isovolumetric relaxation are periods where all heart valves are closed.
- End-Diastolic Volume (EDV) is approximately 120-130 mL.
- End-Systolic Volume (ESV) is about 50-60 mL.
- Stroke Volume (SV = EDV – ESV) averages around 70 mL per beat.
Rapid Revision Lines & Heart Sounds
- Total cycle time = 0.8s at 72 bpm.
- S1 (Lubb) marks start of ventricular systole (AV valves close).
- S2 (Dubb) marks start of ventricular diastole (Semilunar valves close).
- Normal Stroke Volume = ~70 mL.
- Ejection fraction normal range = 55% – 70%.
Remember This: Exam Pearl
Wiggers diagram questions frequently test the exact timing of heart sounds and valve openings/closures. Remember that isovolumetric contraction follows the QRS complex.
Related Study Link
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Frequently Asked Questions
What is the total duration of a normal cardiac cycle?
The total duration of a normal cardiac cycle is 0.8 seconds at a resting heart rate of 72 beats per minute.
What is the normal Stroke Volume (SV) during a cardiac cycle?
The normal Stroke Volume averages around 70 mL per beat, calculated as End-Diastolic Volume minus End-Systolic Volume (EDV – ESV).
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