Brief Answer:
Might be due to anti-hypertensive therapy you use.

Detailed Answer:
Hi my dear,

I have gone through your medical history and understood your worries.

Having a low diastolic blood pressure(bp) is an uncommon complication of antihypertensive treatment.

However, there are other causes to be ruled out first, to my opinion:
- problems with arteries (atherosclerosis or narrowing)
- heart problems (evaluate the stage of heart failure, if present)
- I also want to know when do you measure blood pressure (relation with eating, activity, etc.)
- if you are using a digital blood pressure monitor, please make sure that it is functioning properly and you are using it properly according to the manufacturer's instructions. Some of my patients who were used to such bp monitors have reported lower bp numbers as compared to the ones when measured by a mercury bp monitor.

So, as you may see, if all these other causes are excluded, then, we can conclude that low diastolic blood pressure might be caused by antihypertensive therapy (hydrochlorothiazide).

I highly recommend to keep monitoring your blood pressure when resting, record the results and pass them to your doctor. Further cardiac tests are necessary to evaluate your heart condition:
- ECG
- stress test
- cardiac echo
- holter monitoring

I would suggest to run EEG and ct-scan of head to rule out brain problems. Angiography might also be necessary upon your cardiologist judgement.

Hope it was of help! Do write me back if you need further clarifications!
Dr.Albana

---