Electrical conduction through the heart provides the timing that links chamber activity to the cardiac cycle. It coordinates ventricular contraction with pressure elevation and ejection, then supports relaxation as pressure falls and filling begins. Because valve opening and closing depend on these pressure changes, disrupted timing can interfere with the orderly movement of blood through the lungs and body.
Pressure differences determine whether a cardiac valve opens or closes. As ventricular pressure rises during systole, blood is driven toward the pulmonary artery and aorta; as pressure falls during diastole, the chambers can refill. This pressure-based control links chamber activity to the direction and timing of blood flow through the heart.
The timing of heart sounds can be interpreted alongside valve movements during systole and diastole. Pressure changes cause cardiac valves to open or close at particular points in the cycle, producing transitions between ejection and filling. Comparing audible events with phase timing helps connect heart sounds to mechanical changes inside the chambers.
Blood pressure measurements contain information from both phases. The higher value corresponds to arterial pressure generated during ventricular contraction, while the lower value reflects pressure during relaxation and filling. Considering both values together shows how the recorded pressure relates to alternating pressure elevation and decline across the cardiac cycle.
Pulse pressure is understood by comparing the pressure associated with systole with that associated with diastole. The difference reflects the contrast between the heart’s pressure-generating and pressure-falling phases. Examining it alongside the two blood-pressure values helps connect a numerical measurement to the underlying cardiac cycle rather than treating the reading as a single value.
The systole-diastole framework helps distinguish problems involving pumping from those involving filling. A problem affecting systolic activity is considered in relation to contraction and ejection, whereas a diastolic problem is considered in relation to relaxation and chamber filling. This distinction provides a biological framework for interpreting disorders that disrupt effective circulation.