The condition describe is termed a persistently split S2. This is typically seen in patients with right bundle branch block and may also be seen in patients with pulmonic stenosis, pulmonary embolus, ectopic or pacemaker beats originating in the left ventricle - all of which cause delayed function of the right ventricle. A fixed split S2 is heard with atrial septal defect.
In a normal heart, A2 closes before P2. A delay of aortic closure causes a paradoxically split S2 with P2 occurring before A2. A paradoxically split S2 is caused by a left bundle branch block or ectopic or pacemaker beats originating in the right ventricle-causing delayed contraction of the left ventricle and hence, delayed aortic closure.
A short PR interval causes a loud S1 (the mitral valve slams shut).