Can cardiomyopathy lead to low oxygen saturation levels?

Hello doctor,

My husband was recently diagnosed with cardiomyopathy with 15 % EF by an echocardiogram at a hospital. He is 37 years old, with no medical history problems, such as high blood pressure, diabetes, or thyroid issues. During his stay at the hospital, he received countless tests. He battled stabilizing his oxygen (O2) and would go as low as 80. He received a heart catheter but showed no signs of blockages. The night before the heart catheter, he went into Vtech for nine beats. The doctors are all confused. All blood work, urine, and vitals (other than O2) show normal. They also mentioned his rhythm was perfect during the echocardiogram except for the fact the echocardiogram showed that his only concern was the 15 % EF. They mentioned he should be discharged and continue outpatient care. Would this be a normal request for someone who is experiencing this? I wanted to note that I rushed him to the ER due to coughing up foamy pink stuff and his O2 was 83. Kindly suggest.