[Painful left bundle branch block syndrome: an uncommon but treatable chest pain condition].

Painful left bundle branch block syndrome is an uncommon chest pain condition, which is caused by rate-dependent left bundle branch block in the absence of myocardial ischemia. The onset and resolution of the chest pain follows that of the left bundle branch block aberrancy, with an intensity ranging from mild to incapacitating, and it can be treated by pacemaker implantation (preferably with so-called conduction system pacing, since dyssynchronous myocardial contraction is thought to be the culprit). To date, roughly 70 case reports of painful left bundle branch block syndrome have been published in the literature (with none of them originating from Sweden). In this case report, we present ECG findings from repeated exercise tests in a patient who was diagnosed with painful left bundle branch block syndrome and successfully treated by pacemaker implantation.