Hi Suresh,
I would be cautious to assume that 7-10 days will be enough recovery time to get back to work. I am a 26y female - I had a really easy recovery and was walking before my uncle was out of surgery, but I took three weeks off. I have a very physical job and had to come back on light duty. I would say I could have come back to work at 1 1/2 to 2 weeks but I would tire pretty quickly at that point. I was fortunate enough to have the financial help to stay off work for three solid weeks, and when I did get back I felt like nothing had ever happened. There were several people asking why I was filing and such when normally I am out wrestling animals (I am a licensed veterinary technician) because they recognized me as my normal energetic self and said I didn't appear to have had anything done. If you can take additional time, please do. I think you will benefit in the long run from getting a solid recovery and returning to work strong and healthy. If you really need to, I would maybe look into working shorter days at first, just to make sure your body can handle it.
As for the echocardiogram question, I did not need one. I had a normal ECG and chest x-ray, so they didn't require the ultrasound exam. There are additional tests depending on your family history and any abnormal findings - for example they had me do a fasting glucose tolerance test (FYI the orange stuff tastes disgusting) because there is a history of diabetes in my family. I was originally set to do two 24-hour urine collections for creatinine clearance testing, but due to my scheduling issues they had an alternative test for creatinine clearance (iothalamate, an injection that BURNS). So, I think if you have any issues with the testing it doesn't hurt to ask for alternatives, and they should only require additional tests if your results are wonky or your family history warrants it.
Best of luck to you!
Taryn