A 52 year old man with history of ant MI 3 weeks ago developed sudden onset of dyspnea. Examination: BP 100/60mmHg, pulse 100bpm, SaO2 88%, chest bilateral crackles. Which inv would you do to find the underlying cause?

The key is b. Echo. [The question does not want to know the features of pulmonary oedema rather it is clearly mentioned “which investigation would you do to find out the UNDERLYING CAUSE”. As in this patient sudden papillary muscle rupture or VSD may be the likely cause (ventricular aneurism may take a more slower course) so echo seems to be more logical approach].