All are ECG findings in Wolf Parkinson's white syndrome, except :
Answer is A (Narrow QRS complexes) WPW syndrome is characteristically associated with a wide QRS complex. WPW Syndrome : Features Wolf Parkinson White syndrome is caused by the presence of on additional / accessory pathway (connection) between the atria and ventricle. Normally the AV node is the only pathway that allows electrical connection between atria and ventricles and allows some delay in conduction of impulses from atrial to ventricles. Accessory bundles do not have an AV node to delay conduction and form such a direct connection between atrium and ventricle -- This constitutes WPW syndrome. A depolarization wave reaches the ventricle early and causes premature excitation of ventricles -- preexcitation.Q Paroxysmal tachycardias Q are produced as a result of such preexcitation. The acessary pathway (called bundle of Kent) may be present as a connection between the left atrium and left ventricle (Left sided) or as a connection between the right atrium and right ventricle (Right sided). Pre excitation resulting from left sided accessory pathways is called Type A Pre-excitation Pre excitation resulting from right sided accessory pathway is called Type B Pre-excitation The most common accessary pathways leading to pre-excitation syndromes (WPW) are left sided (connecting left atrium to left ventricle)e Left free wall accessory pathways are most common. `Left free wall accessary pathways are most common followed by posteroseptal, right free wall and anteroseptal locations' -Braunwald Hea Diseases: Review & Assessment' by Lilly (2012)/Q249 The most common macro-reentrant tachycardia associated WPW syndrome is ohodromic AV reentry. The most common macro-reentrant tachycardia associated with WPW syndrome is referred to as Ohodromic AV reentry' -- Harrison's 18th/1889 WPW Syndrome has a charachteristic ECG Patern Typical ECG pattern includes Sho PR interval Q Slurred upstroke of QRS complex Q i.e. Delta wave. The second pa of QRS complex is normal as conduction through bundle of His catches up with preexcitation. Wide QRS complex Q
Narrow QRS complexes
Normal QT interval
Slurred and tall QRS
Sho PR interval