Fouh hea sound is caused by: March 2013
Ans. C i.e. Ventricular fillingFouh hea soundThe S4 sound occurs, by definition, immediately before S1, while the atria of the hea are vigorously contracting.It is manifest as a vibration of 20 to 30 Hz within the ventricle.While the mechanism is not absolutely ceain, it is generally accepted that S4 is caused by stiffening of the walls of the ventricles (usually the left), which produces abnormally turbulent flow as the atria contract to force blood into the ventricle.
Closure of the aoic and pulmonary valves
Vibrations in the ventricular wall during systole
Ventricular filling
Closure of the mitral and tricuspid valves