On Monday, I took Louie for a cardiac ultrasound because his formerly nightly coughing incidents have worsened and have been occurring several times throughout the day and night. He was very stoic when he was being shaved before the procedure:
Previous to the ultrasound he was diagnosed with asthma and put on Theophylline to open up the bronchioles in his lungs to ease his breathing. It seemed to help, but a side effect of that medication made him a bit hyperactive so I stopped it. Of course something had to be done about the coughing so my vet suggested the cardiac ultrasound to find out what was going on with his heart. The test revealed "moderate" thickening of the heart walls. It was explained to me that the coughing may be caused by the thickening pressing against his trachea.
Other than the coughing he shows no other heart defect symptoms so he won't be given any heavy duty medication. I've gone back to the Theophylline which I thought might help, but last night he had a really bad coughing spell. It is sad watching and listening to him fight for breath at these times.