II. Pathophysiology
- Pathognomonic for Pericarditis
- Occurs when heart rubs against pericardial sac
III. Signs
- Three phase sound (classic triphasic sound in only 50% of cases)
- Atrial systole
- Ventricular systole
- Ventricular diastole
- Transient scratching sound
- Rasping sound of leather rubbing against leather
- Timing
- Transient - requires multiple attempts at auscultation
- Locations to best hear friction rub
- Apply stethoscope diaphragm to left lower sternal border
- Patient leaning forward
- At end of exhalation
IV. Differential Diagnosis
- Pleuritis
- Monophasic rub during respiration
V. Efficacy
- Test Sensitivity: 85%
- Test Specificity: 100% for Acute Pericarditis