Basic Electrophysiology Michael Eldar, M.D. Heart Institute Sheba Medical Center Caesaria 2010
Transmembrane Ion-Transfer Modes Ion Channel Pump Exchanger Opie LH, The Heart 1998:75
Voltage-Gated Sodium channel Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:64
Channel Pore Model Opie LH, The Heart 1998:76
Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:43
The Sodium Channel Whalley DW et al, PACE 1995;18:1561
The Action Potetial Berne & Levy,Physiology 1998:30
Electro-Mechanical Relation Opie LH, The Heart 1998:74
Berne & Levy,Physiology 1998:335
Berne & Levy,Physiology 1998:330
Ik,ur Whalley DW et al, PACE 1995;18:1565
Normal Automaticity I k decay I I f f Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:55
Normal Automaticity Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:199
ACh and Automaticity Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:202
Catecholamines & Normal Automaticity MDP Slope Phase 4 Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:201
Abnormal automaticity - Depolarized myocytes (-60-10 mv) - ph - [O 2 ] - [K+] o
Depolarization-induced induced Automaticity Low High Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:206
Abnormal automaticity Clinical Arrhythmias - Myocardial infarction - 15-30 minutes - 24-72 hours - AIVR - [K+] o - Ischemia - Injury currents
Triggered Activity - activity arising from membrane potential oscillations during or immediately following an AP - Should occur following a previous AP (spontaneous or driven)
Triggered Activity Zipes & Jaliffe, Cardiac Electrophysiology1995:208
Digoxin induced DAD Rate-Dependence of DAD s Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:211
DAD Clinical Arrhythmias - Dig. Intoxication - atrial tach - VT - Accelerated VT during AMI - Reperfusion induced arrhythmias - CPVT - Exercise (catecholamine, camp dependent) induced RVOT VT
Early Afterdepolarization Pathophysiology (EAD) Outward current and/or Inward current
Quinidine-induced induced EAD s Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:215
EAD Clinical arrhythmias - TDP - acquired LQTS - congenital LQTS
LQTS- net outward current I,II,V,VI III Viskin, Lancet 99;354:1625
Acquired EAD - hypokalemia ( K K conductance) - Acidosis - Bradycardia - Ikr blockers - AAD - Phenothiazine - Antihistamines - Antibiotics - antidepressants
Circus Movement Reentry 1. Intact anatomic circuit 2. Unidirectional block (onset) 3. Area of slow conduction 4. Wavelength of tach. < length of circuit
Wavelength=Conduction Velocity x Refractory Period
AVNRT
slow fast
WPW Syndrome
Reentry EPS-Diagnosis 1. Continuous electric activity 2. Inducibility/termination by electrical stimulation 3. Inverse relationship of C.I. of initiating extrastimulus/1 st tachycardia beat 4. Entrainment (resetting) by external stimuli
Viskin, Prog Cardiovasc Dis 1998;41:17
Phase II Reentry Di Diego, Circulation 1993;88:1177
Phase II Reentry
Clinical Reentry Tachyarrhythmias Definite SANRT AVNRT AVRT A Flutter Post MI VT BBR VT Probable A Fibrillation PVT VF
Na Channel
OT VT
LVOT VT
K + channel opener rate Yan Gan-Xin, Circulation 1999;100:1660
Berne & Levy,Physiology 1998:330
מי מהתעלות הבאות האחר אית העיקרית 2. לשלב ה ח ד רי? של פו טנצ יאל הפ עולה II I ca,l I na I k I k1 I k,ach א- ב- ג- ד- ה- א' התשובה
Inward Rectifier Ik 1 Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:69
Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:40
מהבאים יוצא דופן? 1.מי I ca I k Ryanodin receptor Na/K ATPase pump Ca/Na exchanger א- ב- ג- ד- ה- התשובה ג' THE HEART INSTITUTE
4. המשפטים הבאים מתייחסים ל Activity-.Triggered אחד אינו נכון, מהו? א- ב- ג- ד- ה- DAD גדלים עקב טכיקרדיה LQT3 נגרם בשל מוטציה בתעלת אשלגן TdP מתרופות נגרם מחסימת תעלת אשלגן מחויב להיגרם ע"י פוטנציאל פעולה קודם עודף יונים חיוביים בתא גורם להארכת QT התשובה הנכונ ה ב'
3. אחת מהפרע ות הקצב להלן נגרמת עק ב..Abnormal automaticity איזו הי א? א- PAT עקב הרעלת דיגוקסין ב- TdP מקינידין ג- RVOT VT במאמץ ד- AVNRT ה- AIVR התשובה הנכונ ה ה'
5. המשפטים הבאי ם מתיי ח סים ל.REENTRY אח ד אי נו נכ ון, מהו? א- המנגנ ו ן השכ י ח בי ותר ב- א ח ר אי ג- לא ר יתמיות באדם ל א רי תמיה בתסמונת ברו ג דה א ח ר אי ע י ק ר י ל VT לא ח ר אוט ם ישן ד- חסם ח ד כי ו ונ י א ינ ו תנאי ה כ ר ח י לה תחל תו ה- בטכי ק ר ד יה, או ר ך ה ג ל קצ ר מ או ר ך המסל ול התשובה הנכונ ה ד'
EAD Pathophysiology -AP prolongation Ik,, Ik1, Ito I NA, Ica, electrogenic Na Ca exchanger AP Plateau - Currents sensitivity - Net depolarizing current - Ica, L (window) -
Genotype and ECG
Reentry Unidirectional block 1. Increase in sinus rate 2. Rapid or premature atrial pacing 3. Retrograde activation from VPC 4. Autonomic influence 5. AAD 6. Ischemia
Resetting
Leading Circus Reentry 1. Cannot be interrupted by disrupting the circuit 2. No fully excitable gap - unstable - insensitive to electrical stimulation 3. Short cycle length
Leading Circle Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:237
APC in WPW
Atrial flutter circuit SVC CT FO His TV IVC CS
Reentry circuit
Tetrodotoxin effect on Action Potential 100 mv Berne & Levy,Physiology 1998:339
Channels Open in Bursts Opie LH, The Heart 1998:81
Berne & Levy,Physiology 1998:285
Characteristics DAD - Induction - fast train -1 ES - CI / CL of initiating stimulus/li CI of triggered response - Termination - 1 ES - ODP
Berne & Levy,Physiology 1998:330
Jalife et al. Basic Cardiac Electrophysiology for the Clinician, 1998:70