be230cLecture8

2 druginduced lqt common concern and reason for drug

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Unformatted text preview: Q ­T interval Electrocardiogram •  P ­Q interval (or P ­R) –  Time atria depolarize & remain depolarized •  Q ­T interval –  Time ventricles depolarize & remain depolarized 4 4/25/13 Impulse PropagaGon and ECG Long QT syndrome •  Long QT interval, increase AcGon PotenGal DuraGon •  Causes syncope, sudden death and potenGally fatal arrhythmia •  Common mutaGons: –  LQT1, slow delayed recGfier K channel (KCNQ1) –  LQT2, rapid delayed recGfier K channel (hERG) –  LQT3, Na channel alpha subunit (SCN5A) –  LQT8, L ­type Ca channel (Cav1.2) •  Drug ­induced LQT –  Common concern and reason for drug failures during development in pharma Wolff ­Parkinson ­White and Artrioventricular Bypass Tract •  Accessory pathways form and fail to disappear during fetal development •  Formed near the mitral or tricuspid valves or interventricular septum •  An AV bypass tract is someGmes referred to as the bundle of Kent 5 4/25/13 Artrioventricular Bypass Tract •  •  From SA node directly to AV node AND to ventricular myocardium ParGally bypassing the bundle of His and purkinje fibers Accessory Pathways Atrioventricular Heart Blocks Degree AV Conduction Pattern 1St Degree Block Uniformly prolonged PR interval 2nd Degree, Mobitz Type I Progressive PR interval prolongation 2nd Degree, Mobitz Type II Sudden conduction failure 3rd Degree Block No AV conduction 6 4/25/13 SchemaGc Overview of ConducGng System Development Christoffels V M , and Moorman A F Circ Arrhythm Electrophysiol 2009;2:195-207 Copyri...
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