I'm with halcyon, small poison dart, CIA style https://www.google.com.au/search?q=heart+attack+poison+dart&rlz=1C1NOOH_enAU532AU532&oq=heart+attack+poison+dart&aqs=chrome..69i57j69i60.9351j0j4&sourceid=chrome&ie=UTF-8
gave the google ref because they're all shitty sources. Ethical though....probably not.