I am a doctor, I don't play one on TV though. Please take this as general advice only, usual disclaimers regarding medical advice from strangers on the internet who only have a partial history should apply.

I agree with the above poster that this sounds like a supraventricular tachycardia (SVT, possibly atrial flutter). It is important to have an ECG or recording of the fast heart rate, normal one at rest is relatively meaningless. A Holter monitor or event recorder is useful if the symptoms are infrequent, if very often just go for an ECG when they are happening.

Hypokalemia and hypomagnesemia are common on diuretics (though less so on such low dose). Rarely if ever associated with SVT to my knowledge. HypoMg is rarely associated with serious ventricular arrythymia (Torsades de Pointes) but your ECG should have shown clues to that (long QT) and it wouldn't likely give those symptoms. Not assoicated with SVT. I wouldn't treat the potassium or magnesium without lab confirmation of the problem and lab followup of the treatment. It sounds like the success of the self treatment was short-lived and MAY well have been coincidental. In this situation I usually would recommend a Holter monitor, echocardiogram and stress test, depending obviously on other symptoms and risks and whether those tests had been done previously or not. Thyroid function also relevent if not previously checked.

I don't know how things work in the states but in Canada we can't bill if we haven't seen and examined the patient, for that and confidentiality/legal reasons I do not respond to faxes or Emails from patients, I also do not wish to give preferential access to my time to the technologically gifted or the anxious.

Good luck

I won't reply to specific questions for legal reasons.