Phases of the PV Loop:
Phase l - Ventricular filling: This phase starts with the opening of the mitral valve and ends with its closure.
Phase ll - Isovolumetric contraction: This phase begins with the closure of the mitral valve and ends with the opening of the aortic valve.
Phase lll - Ventricular ejection: This phase starts with the opening of the aortic valve and ends with its closure.
Phase lV - Isovolumetric relaxation: This phase begins with the closure of the aortic valve and ends with the opening of the mitral valve.