I have had mild heart palpitations and slight shortness of breath over the past few years. It was finally bothering me so much that I went to a doctor and had an ECG and 24 Holter Monitor. Both came back fine with only rare PVC's (on the holter). I still have the symptoms and it seems to occur more when lying on my back, bending down or lying or my side. Sometimes it will occur when I start walking after sitting for a long period. I am wondering if I should have an echocardiogram to rule out hypertrophic cardiomyopathy. I don't have a family history of any heart related problems, but want to make sure it's not HCM.