ventricular tachycardia
"I take atenolol to treat tachycardia caused by Dysautonomia. Like some others with my condition, there are many beta-blockers I cannot tolerate. I also have asthma (potentially caused by dysautonomia) which is a concern when taking beta blockers. Atenolol is cardioselective and less likely to affect respiratory function. In my case, this has been true. It is the only beta blocker I have been able to use without having horrible, debilitating and/or life threatening side effects. It has brought my resting HR down from 120-130 to 80-90.  Now my HR only goes above 120 with strenuous exercise or infections. Side Effects: Cold extremities, slight worsening of asthma symptoms, insomnia if taken within 6 hours of bedtime."