-Systolic dysfunction-Occurs during early diastole. As blood flows passively from atria to ventricles, it hits the walls of the ventricles causing vibration, and thus the S3 sound.
-Normal in children, young adults, and pregnant women
-Can occur in heart failure, or regurgitation. Called S3 ventricular gallop.
Heart sound S4?
--Diastolic dysfunction--The rare fourth heart sound S4 is sometimes audible in healthy children, but when audible in an adult is called a presystolic gallop --It occurs just after atrial contraction and is the sound of blood being forced into a stiff/hypertrophic LV--Poorly controlled htn, recurrent MI
What might a renal artery bruit indicate?
-renal artery stenosis,
can cause secondary htn
-usually d/t atherosclerosis and may indicate stenosis elsewhere
Look for the leader to direct activities that have the most ________ influence
◦Historical cohort study
◦Nonconcurrent prospective study
◦Use historical data in order to speed up results
◦Exposure is ascertained from past records
◦E.g. Breast Cancer and Progesterone deficiency –Cowan et al. (1978)