The S3 is the finding.
The heart-failure exam by likelihood ratio: the S3 rules in, crackles and edema barely move you, and only a normal BNP rules out.
Reviewed July 2026 · verify against current guidelines
Bedside Evidence · Heart Failure
The S3 is the finding.
In the dyspneic patient, most of what we dutifully document barely moves the needle. A few findings genuinely do.
The exam
| Finding | LR+ | Read |
|---|---|---|
| S3 gallop | 11 | Rules in. The best exam finding. |
| History of heart failure | 5.8 | Moderate. Ask for it. |
| Jugular venous distension | 5.1 | Moderate. Trust it. |
| Crackles | 2.8 | Small. Weaker than taught. |
| Lower-extremity edema | 2.3 | Small. Weak on its own. |
Beyond the exam
| Test | LR | Read |
|---|---|---|
| Chest x-ray congestion | LR+ 12 | Rules in. |
| BNP <100 pg/mL | LR- 0.11 | Rules out. |
Wang et al., JAMA 2005, dyspneic adults in the emergency department.
The S3 rules in. Nothing on the exam rules out. A normal BNP does.
LR+ positive likelihood ratioLR- negative likelihood ratioBNP B-type natriuretic peptide
Sources
Verify against current guidelines and local protocol before acting.
- Wang et al., JAMA 2005 (The Rational Clinical Examination)
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