Hello!
Thank you for asknig on HCM!
Regarding the above resting ECG parameters, they do not show any abnormalities. So nothing to worry about presented parameters of your wife's resting ECG. But, it is also necessary to consider possible ST-T changes for any evidences of 
myocardial ischemia.
Nevertheless, facing the fact that your wife is a diabetic (a high risk factor for coronary artery disease), exertional shortness of breathing should be considered an equivalent of chest angina, unless proven different.
So, arriving at this point, I would recommend a medical check up by her cardiologist to perform a comprehensive physical exam anda  complains history review, coupled with cardiac 
ultrasound, lab tests (cardiac enzymes, 
complete blood count, fasting 
glucose, etc), and if suspicions are raised, followed by an exercise cardiac 
stress test (to rule out exertional cardiac ischemia).
Hope to have been helpful to you! Greetings! Dr. Iliri