Brief Answer:
Can be due to congestive cardiac failure.

Detailed Answer:
Hi,
Thanks for asking query.
I've gone through your query in details,

Most likely her symptoms can be due to congestive cardiac failure.

Cardiac failure is not indicative of a defect in heart; but it's a situation when the heart pumps weaker than what is generally deemed as natural. Therefore the blood flows at a slower rate to the heart and the body that in turn increases pressure in the heart.

In an attempt to hold more blood, heart stretches its chambers. Though this strenuous effort may keep the blood moving, it would gradually and inevitably weary the heart with all the effort.

Subsequently, the kidney responds by retaining more salt and fluid in the body. These fluids may accumulate in different parts of the body like lungs leading to congestion.

This congestion can cause breathlessness. As cardiac output decreases(due to inability of heart to pump blood out);patient can not maintain blood pressure and blood pressure will fall. This very condition in medical terminology is referred to as congestive heart failure.

Though her stress test was normal as mentioned by you, but during stress test we cannot see the mobility or any wall motion abnormality neither can valvular stenosis or regurgitation be appreciated. Even Left ventricle ejection fraction can not be calculated by it.

Therefore i would suggest you some of the baseline tests of cardiology to rule out CHF--

2D echocardiography- Most important test to see wall and valves functioning, Left ventricle ejection fraction can be calculated.Any motion abnormality or valvular dysfunction can be easily seen (Most imp. in her case)

Carotid doppler- To see if blood supply to brain is normal(dizziness).
Pulmonary function test- To rule out lungs as a cause of breathlessness.


Thanks and please follow up with reports.
Feel free to ask further.
Regards

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