Where would the S1 heart sounds correlate with EKG waves?

The S1 heart sound, also known as the "lub" sound, corresponds to the closing of the mitral and tricuspid valves at the beginning of ventricular contraction (systole). This event is primarily associated with the end of the depolarization phase of the heart, which is represented by the peak of the R wave on an electrocardiogram (EKG).

During the cardiac cycle, the R wave marks the point when the ventricles are fully depolarized and are about to contract. As the pressure in the ventricles rises and exceeds that of the atria, the valves close, creating the S1 sound. Thus, the timing of S1 closely aligns with the peak of the R wave, reflecting the mechanical activity that occurs during this phase of the cardiac cycle.

The other options relate to different phases of the EKG and heart sounds. The start of the T wave corresponds to the repolarization of the ventricles, which does not relate to the S1 sound. The end of the T wave represents ventricular repolarization right before diastole, while the start of the P wave corresponds to atrial depolarization, which is prior to the ventricular contraction that causes S1. Therefore, the correlation