Conventional echocardiography measurements on day 1
| Term group n=50 | Preterm group n=50 | P value | |
| Heart rate | 128±15 | 156±12 | <0.01 |
| Systolic time (ms) | 190±20 | 139±15 | <0.01 |
| Diastolic time (ms) | 193±45 | 122±17 | <0.01 |
| SD ratio | 1.0±0.2 | 1.2±0.2 | <0.01 |
| Pulmonary artery acceleration time (ms) | 62±15 | 41±9 | <0.01 |
| Right ventricular ejection time (ms) | 211±23 | 151±22 | <0.01 |
| PAATi | 0.29±0.06 | 0.28±0.06 | 0.15 |
| Left ventricular length (mm) | 31±2 | 18±2 | <0.01 |
| LV s′ (cm/s) | 4.9±1.1 | 2.8±0.8 | <0.01 |
| LV e′ (cm/s) | 6.5±1.5 | 3.7±1.4 | <0.01 |
| LV a′ (cm/s) | 5.7±1.7 | 4.5±1.8 | <0.01 |
| LV ea′ ratio | 1.2±0.3 | 0.9±0.3 | <0.01 |
| Ejection fraction (%) | 60±5 | 60±6 | 0.64 |
| Mitral valve E:A | 1.1±0.3 | 0.7±0.1 | <0.01 |
| RV s′ (cm/s) | 6.3±1.5 | 3.8±0.9 | <0.01 |
| RV e′ (cm/s) | 8.7±1.6 | 4.3±1.4 | <0.01 |
| RV a′ (cm/s) | 8.9±2.2 | 7.4±1.9 | <0.01 |
| PDA | 26 (52) | 47 (94) | <0.01 |
| PDA diameter (mm) | 1.9 (1.6–2.5) | 2.4 (2.1–2.9) | <0.01 |
| PDA maximum systolic velocity (m/s) | 1.1 (−1.1–2.0) | 1.1 (0.8–1.6) | 0.64 |
| LA:Ao | 1.4±0.2 | 1.4±0.2 | 0.93 |
| Bidirectional shunting | 10/26 (39) | 19/47 (40) | 1.00 |
Values are presented as means (SD), medians (IQR) or count (%).