How did the Shot heard around the world lead to the revolutionary war?

Because it was where the first shots of the American Revolution were fired. The first battle was actually at Lexington, then it continued onto Concord. This was the beginning of the end of British rule around the world. Until this time, Britain was a major world sea power and ruled in India and The New World. It would be a long time until the USA would become a super power, but this was the start.