Yes, I am a myth-buster and this time it is about heart and lung medical care.
If you have heart failure BUT you also have a preserved ejection fraction (as seen on heart cath or echo), consider NOT taking a long-acting nitrate pill as this may decrease your level of activity and increase adverse events.
If you have community acquired pneumonia, your doctor may discontinue antibiotics (if deemed clinically stable) after five days. Make sure your doctor thinks you are medically stable, do not stop medication without their okay.
We, doctors, are decreasing our prescribing of antibiotics during acute asthma attacks. Oral (or a shot of) steroids may help you and antibiotics may not improve your outcome.