As an MD/MBA who investigated job opportunities in this field, I must disagree with the statement that you need to develop a strong finance background before entering VC. These funds are very interested in finding new associates who can intelligently evaluate the merit of the technology/ideas underlying investment opportunities and who can operational support to funded entrepreneurs. As someone with a strong medical background, you will be able to help fill this role better than most of the people coming out of business school. You obviously will not be of the same caliber of the fund's dedicated advisors, but you will be one of few full-time day-to-day employees with this sort of extensive knowledge.
VC firms were eager to speak to MD/MBAs without finance background...
If anything, I would argue that you need OPERATIONAL experience more than a finance background. I say this because (1) the depth of finance knowledge required for VC is not as substantial as it might be in other financial sector jobs; (2) as a person with extensive medical knowledge, most companies would not have you running the numbers -- you will never be as good as the guy who spend years at JP Morgan; and (3) ops experience helps you learn how companies survive in the industry.
Don't be discouraged! If you are interested, go after it... But definitely be sure you know what venture capital entails. Just my thoughts.