when does isovolumetric relaxation and ventricular filling take place
Cardiac cycle "Ventricular diastole," begins when the ventricles starts to relax. At this point, some blood of the previous cycle's systole is still flowing out of the ventricles through the semilunar valves, due to the inertia of the moving blood column, which overcomes the higher pressure in the aorta/pulmonary trunk with respect to the pressure in the ventricles. This short lasting phase, called "protodiastole" ends with the closure of the semilunar valves, producing the second heart sound (S2). Now that both the AV valves and the semilunar valves are closed, the ventricles are now closed chambers. Hence, this phase is known as isovolumetric (also called isovolumic, isometric) relaxation phase. Then the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, allowing blood to fill the ventricles. This ventricular inflow phase can be sub-divided into the 'first rapid filling phase' as blood rushes in from the atria as a result of ventricular dilation; a phase of slow ventricular filling called 'Diastasis', and the 'last rapid filling phase' due to atrial contraction (systole).
First-degree atrioventricular block The management includes identifying and correcting electrolyte imbalances and withholding any offending medications. This condition does not require admission unless there is an associated myocardial infarction. Even though it usually does not progress to higher forms of heart block, it may require outpatient follow-up and monitoring of the ECG, especially if there is a comorbid bundle branch block. If there is a need for treatment of an unrelated condition, care should be taken not to introduce any medication that may slow AV conduction. If this is not feasible, clinicians should be very cautious when introducing any drug that may slow conduction; and regular monitoring of the ECG is indicated.