Second Degree Atrioventricular Block – Mobitz II

Mobitz II occurs when the infranodal conduction system intermittently fails, resulting in intermittently “dropped” P waves but consistent PR intervals when conducted. Mobitz II usually occurs with preexisting conduction disease (e.g., combination of bundle branch and fascicular blocks), is always pathologic, and more likely to progress to complete heart block.



  1. Costa D Da, Brady WJ, Edhouse J. Bradycardias and Atrioventricular conduction block. Br Med J. 2002;324(March):535-538.
  2. de Pádua F, Pereirinha A, Marques N, Lopes MG, Macfarlane PW. Conduction Defects. In: Macfarlane PW, van Oosterom A, Pahlm O, Kligfield P, Janse M, Camm J, eds. Comprehensive Electrocardiology. London: Springer London; 2010:547-604.
  3. Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhyth. Circulation. 2019;140(8):e382-e482.