睏睴睴睴瞤睴 人用人人 Cardiac Arrhythmia C: AFib 量目 D: VT E: VT-TdP
Cardiac Arrhythmia
A normal rhythm ORS premature ventricular beat 人人人入人 C paroxysmal supraventricular tachycardia arrhythmias (PSVT) D atrial fibrillation Abnormal pacemaker, -y rhythm and Ay E atral flutter with variable AV conduction coordination ofheart beats. +++++++++++4+++++ all arrhythmias result from F atrial flutter with 1: 1 AV conduction (1)disturbances in impulse ormation G monomorphic ventricular tachycardia (2)disturbances in impulse conduction H Torsades de Pointes (3)both. ventricular fibrillation
arrhythmias Abnormal pacemaker, rhythm and AV coordination of heart beats. all arrhythmias result from (1) disturbances in impulse formation, (2) disturbances in impulse conduction, (3) both
A. Electrophysiological basis of arrhythmias o 1. Normal cardiac electrophysiology u Excita bility: ability to produce action potentials maximal diastolic potentialS(MDP) threshold levels u Automaticity: pacemaker phase 4 slope u Conductivity: ability to conduct impulse conduction pathways, phase 0 amplitude
A. Electrophysiological basis of arrhythmias 1. Normal cardiac electrophysiology Excitability: ability to produce action potentials maximal diastolic potentials (MDP) threshold levels Automaticity: pacemaker phase 4 slope Conductivity: ability to conduct impulse conduction pathways, phase 0 amplitude
0 mV Fast response cell 100ms Ca Ca Outside Membrane ATP Diastolic channel Channel currents Pump Exchanger currents Action potential and ion transport
Action potential and ion transport Fast response cell
inward outward 13 Phase 4 Gene/protein Na’ current SCN5A/Nav 1.5 Ca L-typ CACNA∥Cav1.2 Action current L T-type CACNA1G.∥cav3.1.32 potential transient KCND3/Ky 4.3 and ion outward current KCNA4/Kv 1.4 transport KCNA1/KVLQT 1 delayed rectifiers KCNH2/hERG (k) KCNA5/Kv 1.5 CFTR/CFTR Fast response cell inward rectifier, IK1 三 KCNJ1/Kir 2.1 pacemaker current↓ J HCN2,4/HCN2,4 Na*-Ca2* exchange SLC8A1/NCX 1 Na*, K+-ATPase NKAIN1-4/Na, K-pump
Action potential and ion transport Fast response cell