<prompt> Left bundle branch block LBBB on ECG can suddenly develop in all of the following except:Acute MIAshman phenomenonHypokalemiaHyperkalemia  <response>: Ans. b. Ashman phenomenon Ref: Harrison 18e p1835 stylefont-size: 1.04761904761905em; font-weight: bold; font-family: Times New Roman, Times, serif; margin: 0 0 0 8px; text-indent: 0Ashman phenomenon:Ashman phenomenon is an intraventricular conduction abnormality caused by a change in the heart rate.Wide QRS complex on the surface ECGA RBBB pattern is more common because of the longer refractory period of the right bundle branch, although association with LBBB has been documentedCauses of Left Bundle Branch Block LBBB Aortic stenosis Dilated cardiomyopathy Acute myocardial infarction Extensive coronary artery disease Primary disease of the cardiac electrical conduction system Long standing hypertension leading to aortic root dilatation and AR Hypokalemia Hyperkalemia 