Valve Motion In Normal Subjects

The mitral valve closes a few milliseconds before the tricuspid valve. Also remember, the tricuspid valve is located slightly more apically than the mitral valve.

The cardiac cycle is a complex set of events. It has been summarised in the table below -

Phase of contraction	Physiological features	Duration of phase (seconds)	Corresponding ECG wave
Diastasis	Passive ventricular filling prior to atrial systole	0.19	P wave
Atrial contraction	Ejection of blood into ventricle	0.11	Beginning of QRS complex
Isometric ventricular contraction	Onset of ventricular contraction. Semilunar valves are closed and AV valves are just about closed.	0.50	Just after the onset of QRS complex
Rapid ventricular ejection	Increased pressure in ventricles causes opening of semilunar valves.	0.09	Onset of T wave
Slow ventricular ejection	This is the end of ventricular ejection. Atria start to fill up.	0.13	End of T wave
Isovolumetric relaxation	Closure of semilunar valves. AV valves closed as well. Ventricles relaxed.	0.08	Between the end of T wave and the start of P wave
Ventricular filling	AV valves open, ventricles fill with blood.	0.11	Between the end of T wave and the start of P wave

Based on this, the isovolumetric relaxation time is the time when both the mitral and aortic valves are closed and ends when the mitral valve opens. The ventricle is empty during this period. The atrium passively fills the ventricle by emptying 80% of its volume and only requires to contract to empty the remaining 20%.

Keep this table in mind, it is possible there will be a question based on this.