You need a stethoscope to tell the difference I had (presumaby) BBB when I had (presumably) viral myocarditis. A miss every 5 seconds. Day after day for weeks. Every night while walking up the stairs to go to bed, I wondered if I would wake up dead. Finally, I decided to run as fast as I could up a long steep hill at my favorite park, to decide it one way or the other.
I also once had concomitant noises during another spell of missed beats. It was like a whistling. I would never have known about it, without a stethoscope. I found auscultation sounds on a website, and I seemed to match a benign sound.