Heart Sounds Flashcards
(19 cards)
What is S1 caused by?
Closure of mitral and tricuspid valves
What causes a loud S1?
- Mitral stenosis
- Left-to-right shunts
- Short PR interval, atrial premature beats
- Hyperdynamic states
What causes a quiet S1?
Mitral regurgitation
What is S2 caused by?
Closure of aortic and pulmonary valves
What causes a soft S2?
Aortic stenosis
What causes a loud S2?
- Hypertension: systemic (loud A2) or pulmonary (loud P2)
- Hyperdynamic states
- Atrial septal defect without pulmonary hypertension
What causes a fixed split S2?
Atrial septal defect
What causes a widely split S2?
- Deep inspiration
- RBBB
- Pulmonary stenosis
- Severe mitral regurgitation
What causes a reversed (paradoxical) split S2?
- LBBB
- Severe aortic stenosis
- Right ventricular pacing
- WPW type B (causes early P2)
- Patent ductus arteriosus
What is S3 (third heart sound) caused by?
Diastolic filling of the ventricle
Is S3 considered normal in individuals under 30 years old?
True
In which conditions can S3 be heard?
- Left ventricular failure (e.g. dilated cardiomyopathy)
- Constrictive pericarditis (called a pericardial knock)
- Mitral regurgitation
What is S4 (fourth heart sound) caused by?
Atrial contraction against a stiff ventricle
In which conditions may S4 be heard?
- Aortic stenosis
- HOCM
- Hypertension
What does S4 coincide with on the ECG?
The P wave
What may be felt in HOCM as a result of a palpable S4?
A double apical impulse
What is the normal finding for splitting during inspiration in S2?
Normal
What is the significance of a loud S2 in systemic hypertension?
Loud A2
What is the significance of a loud S2 in pulmonary hypertension?
Loud P2
