What's to be expected? might ventolin work at all if you have an asthma attack whilst taking beta blockers?

Less so: Ventolin may still work but would likely be less effective. It is also important to choose a cardio-selective beta blocker if there is no other alternative. One study showed that taking a cardio-selective beta blocker reduced the fev-1 (the one-second airflow which is reduced in airway obstruction) by about 7% but made the lung more responsive to bronchodilators . Avoid beta blocker if possible.