Paul McCartney wrote this as Hey Jules, a song meant to comfort John Lennon's 5-year-old son Julian as his parents were getting a divorce. The change to Jude was inspired by the character Jud in the musical Oklahoma! (McCartney loves show tunes)
The medical term for a slow heart rate is bradycardia; generally defined as a heart rate below 60 bpm (beats per minute). In contrast, tachycardia means fast heart rate above 100 bpm.
Bradycardia (slow heart beat) in Dog or Canine. A common form of heart arrhythmia canine is called Bradycardia or a slower than normal heartbeat. A slower heartbeat means there is a slower blood flow that reduces the amount of oxygen in your dogs body. With less oxygen your dog will act tired.