Loud S2
The common causes of a loud S2 include high systemic (A2) or pulmonary (P2) pressures and closure of a prosthetic valve (usually in the aortic position). If the S2 is split, try to decipher which component is loudest. A2 should always be louder than P2, except over the pulmonic area where they may be equal. If P2 is louder than A2 anywhere in the chest, pulmonary hypertension should be suspected. Look for other signs of pulmonary hypertension, such as giant a waves in the jugular venous waveform or the presence of a right ventricular heave.
Patient 1:
This patient has severe pulmonary hypertension. Note the split S2, with P2 being significantly louder than A2.
Loud S2
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