What Does The X-ray Indicate Regarding Breathlessness?

You just return from lunch and the charge nurse reports that you are getting an admission. The ER nurse calls report five minutes later. Mr. Johnson is a 55 year old African American being admitted to your telemetry unit with complaints of increasing shortness of breath and fatigue. He has a history of hypertension for the past 20 years. He quit smoking 6 months ago. He had a chest x-ray which showed mild atelectasis in bilateral bases and mild cardiomegaly. His VS are 156/98, P 92, R 20, T 97.4. He is in Sinus rhythm, O2 sats low 90’s upper 80’s on room air. ER placed O2 on 2 L/NC, sats increased to 94%. Labs in ER were Troponin 1.3, CBC normal, Lytes normal, BUN 26, and Creat 1.2. The ER nurse has already given the ASA, Nifedipine, and Inderal while waiting for a room to become available. Would this be kidney failure, pneumonia, or CHF? Thank you