Which are life-threatening arrhythmias?

I saw something re: the recent death of Joan Rivers in the NYT. The article said “Despite her appearance enhanced by plastic surgery, she was 81 years old and had admitted to a history of bulimia and heart arrhythmia”.

My question is what types of heart arrhythmias (avnrt, junctional/accelerated, A-Tach, LBBB, RBBB, etc.) are just annoying and which are more life-threatening…And, which rhythms are more dangerous if undergoing a medical procedure not related to heart (i.e., endoscopy, colonoscopy, etc.).

Submitted by Richard from Pennsylvania

by Ali Massumi, MD    

None of the arrhythmias that you listed are life threatening. Ventricular fibrillation, ventricular tachycardia and prolonged pauses or asystole are dangerous. Arrhythmias associated with very low potassium or magnesium or those associated with inherited causes such as QT prolongation are also serious. The ones you mentioned are supra- ventricular and generally not lethal.