What are the top venture capitals on medicine in USA?
There are many venture capital firms that invest in medicine and healthcare startups in the US. Some of the top healthtech venture capital firms in the US are:

NEA: One of the world’s largest medical venture capital companies with $25bn in committed revenue.
MedTech Innovator: As the name suggests, specializes in accelerating innovative medtech products to market profitability.
Versant Ventures: Focuses on biotechnology, medical devices, and healthcare services.
USVP: Invests in early-stage companies across healthcare and technology sectors.
Deerfield Management: Provides flexible financing to biotechnology and pharmaceutical companies.
SV Health Investors: Invests across biotechnology, medical devices, digital health, and healthcare services.
Domain Associates: Partners with entrepreneurs to create and grow companies that transform human health.
Johnson & Johnson Innovation - JJDC: The strategic venture capital arm of Johnson & Johnson that invests across pharmaceuticals, medical devices, consumer health, and digital health.
There are many other venture capital firms that are active in the healthcare space. You can find more information by searching online or by looking at some of the recent funding rounds for healthcare startups.
Can you tell me more about NEA? What kind of medicine and healthcare startups do they invest in?
According to NEA's website, they invest in four sectors. Here is the list of sectors, along with example companies that NEA has invested in at the seed stage.

Technology - Enterprise
    -- Aigen (soil regeneration)
    -- BoxC (e-commerce logistics)
Technology - Consumer
    -- Block (renovation)
    -- FabFitFun (beauty, fitness, and wellness products)
Healthcare - Life Sciences 
    -- Acrivon (oncology drug development)
    -- code bio (gene therapy)
Healthcare - Digital Health
    -- omada (chronic disease prevention)
    -- Tempus (molecular and clinical data analysis)