For about 3 years now, i have had random episodes in which i become so dizzy that i cannot walk. My breathing gets slow and heavy, my heart starts beating very fast then becomes very slow. As my hear slows, my vision starts to blur and becomes fuzzt and fades to pitch black. While my vision Is fading, i hear a ringing in my ears and as soon as my visiom goes to black i absolutely cannot hear anything. This lasts anywhere from 2 to 5 minutes per episode.