Can thyroid dysfunction cause irregular heartbeat?

Hello doctor,

Elevated blood pressure was first detected at age 18 and runs in the family on my maternal grandmother’s side. It was never really treated until age 72 when it became a requirement for cataract surgery (as per the anesthesiologist's request). I was prescribed Lisinopril 20 mg and Amlodipine 10 mg, which continued until age 76. During this period, the doctor altered the dosage and frequency as the medication gradually seemed to lose its effectiveness.

At that point, intermittent episodes of a racing heartbeat and arrhythmia began to develop, accompanied by a total loss of stamina, sometimes with near-fainting and nausea, after only five minutes of physical exertion. Based on an ECG, my PCP diagnosed this as atrial fibrillation (a-fib) and referred me to a cardiologist. However, the cardiologist reviewed the same ECG and disagreed, stating that it was not a-fib and that it could be one of several other conditions. He advised that, if it happens again, I should go straight to my PCP to have them perform another ECG and bring it back to him. This suggestion didn’t seem very logical.

Suspecting that the long-term use of Amlodipine might have contributed, my PCP switched the medications to Verapamil 180 mg and Carvedilol 6.2 mg. For a while, these symptoms seemed to subside. During this time, I also experienced a ruptured Achilles tendon and a minor Lacunar stroke, which permanently disrupted the pressure sensitivity in the skin on my left side, from head to toe.

About a year ago, the racing heartbeat and arrhythmia started to return intermittently. I subsequently discontinued all medication. The racing condition has now become more or less constant, with arrhythmia coming and going (I can observe this using a mirror to view the right side of my neck). The lack of stamina seems permanent, and I also have slight swelling in my lower legs and feet, shortness of breath when reclining, and chronic insomnia.

I am reluctant to involve my PCP again, as I expect the same routine: a rushed examination (they give him 11 minutes), a series of laboratory tests at the local hospital, and possibly another referral to the cardiologist, all likely resulting in the same outcome. While well-intentioned, these providers are often not given enough time to thoroughly evaluate the problem and make a considered diagnosis.

Please advise.