Ventricle P-V

Master answer

Normal P-V loop:

• Diastole
  • (D) Beginning of diastole (isovolumetric ventricular relaxation)
  • (A first 60% of vol) Early diastole (rapid ventricular filling – highly compliant Ventrical still relaxing)
  • (A 60-90% of vol) Mid-diastole (slow ventricular filling – nearly full of blood → ↓ vent compliance)
  • (A last 10% of vol)  Late diastole (atrial contraction)
• Systole
  • (B) Early systole (isovolumetric contraction)
  • (C) Ventricular Ejection
  • Early short rapid ejection phase (1st third of time)
  • Prolonged reduced ejection phase (last 2/3 of time)

Derived Values:

• Stroke volume:  SV = LVEDV-LVESV
• Ejection fraction as per eqn: EF = SV / EDV
• Measure of preload: LVEDV
• Measure of afterload
  • Line b/w end-systolic point and locus at  (LVEDV, 0)
  • ↑ slope → ↑ Afterload
• Measure of contractility (ESPVR)
  • End-systolic pressure volume relationship
  • Slope is surrogate for contractility
• Measure of elastance (or stiffness) and compliance (or distensibility) of the LV – (EDPVR)
  • End-diastolic pressure volume relationship
  • Slope of the EDPVR = elastance = 1/compliance
• Peak LV pressure
• Measure of cardiac workload
  • Total mechanical energy (or stroke work) (area of P-V loop)
  • Heat generated by the heart during contraction
  • “Diastolic work”

Gladwin 2016

Answer by Gladwin