Brugada Syndrome• Discovered by the Brugada brothers in 1992.• Inherited defect of sodium channels (SCN5A gene).• Epicardial area of the RV has repolarization abnormality.• Prone to spontaneous Ventricular Arrhythmias.
Inherited Long QT Syndromes• Jervell and Lange-Nielsen Syndrome – Congenital defect affecting K+ channels in heart and ears. – Results in congenital deafness and sudden cardiac death• Romano Ward Syndrome – Group of at least six genetic defects. – Only symptoms are syncope and sudden cardiac death.
Psych patient in triage “needs to be medically cleared”.• Patient is somnolent, suicidal.• Not forthcoming with history.• Triage note: “Patient is faking syncope”.• Records indicate that patient is taking antipsychotics.
EKG changes in WPW• Characterized by a short PR interval and a delta wave.
EKG changes in WPW• Delta wave is caused by early aberrant depolarization of the ventricles starting at the Kent bundle.• Soon the normal conduction via the Ventricular Conduction system depolarizes the rest of the ventricles.• This causes a widening of the QRS at the beginning of the QRS. Last part of the QRS is normal.
Significance of WPW• While WPW is generally benign on a day to day basis, two major problems may arise.• 1) A reentrant circuit may form with the AV node and the bundle of Kent, leading to SVT.• 2) In the pressence of atrial fibrillation or flutter, there is a very fast uncontrolled ventricular response.
WPW reentry circuit • Reentrant circuit leads to SVT. • Because electrical activity is passing retrogradely through Kent bundle, Delta wave may not be seen.
Treatment WPW a-fib/a-flutter with WPW• Avoid calcium channel blockers!• Calcium channel blockers decrease conduction through AV node, not through Kent bundle. By giving calcium channel blockers, you can actually increase the conduction through the Kent bundle and increase ventricular response.• The same applies with Adenosine.
Treatment WPW a-fib/a-flutter with WPW• Recommended first line treatment is cardioversion.• If cardioversion is unsuccessful, Procainamide and Amiodarone may be used.• Ultimate treatment is eblasion to get rid of the Kent bundle.
Severe Hyperkalemia • After potassium levels exceed 7.5, some very drastic changes begin to occur. • The QRS and T wave meld together into one monophasic wave that is called a sine wave. • AV blocks, V-tach, and V-fib soon follow.