Mahaim type preexcitation
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Mahaim type pre-excitation is a form of ventricular pre-excitation characterized by a normal PR interval and a long QRS interval with initial slurring of or slow deflection of the QRS complex (a delta wave is present).  
In Mahaim type pre-excitation, the atrial impulse travel to the ventricle via the Mahaim fibers which connect the atrioventricular node directly to the right ventricular wall (nodoventricular pathway) or to the right bundle branch of the His bundle (nodofascicular pathway).
Epidemiology and Demographics
- There is a delta wave with a normal PR interval.
- In older patients there can be a prolonged conduction down the accessory pathway resulting in a normal PR interval in the presence of WPW which is tough to distinguish from Mahaim fibers.
Shown below is an EKG of a 24 years old man with Mahaim type of preexcitation.
Shown below is an EKG of the same patient after Mahaim bundle ablation
- ↑ Sternick EB. Mahaim Fibre Tachycardia: Recognition and Management, Indian Pacing Electrophysiol J. 2003 Apr–Jun; 3 (2): 47–59.
- ↑ Hanon S, Shapiro M, Schweitzer P. Early history of the pre-excitation syndrome, Europace (2005) 7, 28-33.
- ↑ Silva MA, Berardi G, Kraemer A, Nadalin E, Jorge JCM, Catheter Ablation of Atriofascicular Mahaim Fibers Guided by the Activation Potential, Arq Bras Cardiol, volume 80 (no 1), 66-70, 2003.