My last blood test showed low potassium, just under the range, I feel as if I can hear my heart pulsing in my ears I also have long standing tinnitus in both ears. Do I need to take potassium, could this be the cause of my palpitations and heart pounding in my ears feeling? I'm so confused. The potassium result was 3.3, ref range is (3.3-5.3), also Serum bicarbonate was low, 23, range (24-32). GP just says mildly abnormal, no action needed! Any ideas please?