Flashcards in Examination Features (Med Secrets p59) Deck (18):
Explain normal splitting of the second heart sound
S2 normally split into Aortic (A2) and pulmonary (P2). Degree of splitting varies with respiratory cycle
How does inspiration affect splitting of the second heart sound?
With inspiration, negative intrathoracic pressure INC venous return to RA and DEC to LHS. Thus:
- P2 occurs slightly later
- A2 to occur slightly earlier
How does expiration affect splitting of the second heart sound?
Negative intrathoracic pressure is eliminated and A2 and P2 occur almost simultaneously
What is paradoxical S2 splitting?
Widening with expiration and shortening with inspiration (opposite of normal)
Causes of paradoxical S2 splitting?
- Aortic insufficiency
- Aortic stenosis
- Hypertrophic cardiomyopathy
Generally conditions that delay A2 by delaying ejection of blood from the LV
What is the significance of a loud P2?
Usually indicated pulmonary HTN
What is S3?
Low frequency heart sound just after S2; also called ventricular gallop
How is S3 best heard?
With bell. Does not change with respiration
What is a pathologic S3?
S3 occurring in a variety of pathologic conditions including:
- mitral valve prolapse
- coronary artery disease
- pericardial constriction
- mitral or aortic insufficiency
What is the mechanism behind S3?
Controversial: may be due to increase in the blood entering the ventricle (rapid ventricular filling). Usually indicates ventricular decompensation associated with heart disease.
What is S4?
Sound occurring just before S1. Reflects decreased ventricular compliance (stiff ventricle).
What is an opening snap?
High frequency early diastolic sound associated with mitral or tricuspid valve opening.
What causes a pericardial knock?
Sudden slowing of LV filling in early diastole associated with the restriction of a rigid pericardium acting as a "rigid shell" such as in chronic constrictive pericarditis
What are the physical examination findings in MR?
- Apical holosystolic murmur
- Quick upstroke and short duration of peripheral pulses
- Widened pulse pressure
- Hyperdynamic praecordium
What are the 3 waves composing the JVP?
- A wave: produced by RA contraction, occurring just before S1
- C wave: caused by bulging upward of the close tricuspid valve during RV contraction
- V wave: caused by RA filling just before opening of the tricuspid valve
What are cannon A waves?
Very large and prominent A waves occurring when the atria contract against a closed tricuspid valve.
Define pulsus paradoxus
Drop of more than 10mmHg in sBP during normal inspiration