I think you might learn more if you were to wear a digital device like a smart watch and have it record your HR and an ECG when you feel the faint coming on...if you can manage to set your watch in time. Or set the watch to record continuously, but live with having to charge the watch twice a day or more often due to the large draw on the battery. Or, if it is becoming more intrusive with time, and more worrying, have a Loop Recorder implanted and it will monitor you for signs of arrhythmia 24/7.

Consult a 'great' electrophysiologist about this.