Diagnostic properties of the third (S3) and fourth (S4) heart sounds detected by phonocardiography for predicting left ventricular dysfunction*
| Heart sound | Gold standard | Sensitivity (95% CI) | Specificity (CI) | +LR | −LR |
|---|---|---|---|---|---|
| *LVEDP = left ventricular end diastolic pressure; LVEF = left ventricular ejection fraction; BNP = B type natriuretic peptide. Diagnostic terms defined in glossary. LRs calculated from data in article. | |||||
| S3 | LVEDP | 41% (26 to 58) | 92% (80 to 98) | 5.13 | 0.64 |
| LVEF | 52% (31 to 73) | 87% (76 to 94) | 4.00 | 0.55 | |
| BNP | 32% (20 to 46) | 92% (78 to 98) | 4.00 | 0.74 | |
| S4 | LVEDP | 46% (31 to 63) | 80% (66 to 90) | 2.30 | 0.68 |
| LVEF | 43% (23 to 66) | 72% (59 to 82) | 1.54 | 0.79 | |
| BNP | 40% (26 to 54) | 78% (61 to 90) | 1.82 | 0.77 | |
| S3 and/or S4 | LVEDP | 68% (52 to 82) | 73% (59 to 85) | 2.52 | 0.44 |
| LVEF | 74% (52 to 90) | 64% (52 to 76) | 2.06 | 0.41 | |
| BNP | 57% (42 to 70) | 72% (55 to 86) | 2.04 | 0.60 | |