Cardiomyopathy in my young male cat - clarification? Any other options for treatment other than Atenolol?

My 2.5 year old male cat, Henry, has been diagnosed with Hypertrophic Obstructive Cardiomyopathy. On 12/31 he had a sudden paralysis episode that lasted a minute on the left side of his body. After an ER visit, a murmur was detected and then the cardiologist visit confirmed this disease. He has been on 1/2 of pill of Atenolol every day since. About 6 weeks later on 2/11, I noticed another paralysis episode that seemed to affect all legs and lasted for about a minute. Other than these 2 episodes, he seems fine, eats as much as he used to, plays, is affectionate, etc. I am taking him to the cardiologist every few weeks for updated echocardiograms. My questions are: will these paralysis episodes become more frequent as the disease progresses? And, is my kitty in pain when these episodes happen? Also, when these episodes happen, what is exactly going on - does his limbs fall asleep, or is it a blood clot? I am just devastated this is happening to my little baby. Thank you.

Asked by Henry on Feb 13th 2012 Tagged heart, disease, cardiomyopathy in Illness & Disease