ELECTROCARDIOGRAPHY 1893 Einthoven introduces the term 'electrocardiogram' 1895 Einthoven distinguishes five deflections - P, Q, R, S andT 1902 Einthoven publishes the first electrocardiogram 1905 Einthoven starts transmitting electrocardiograms from the hospital to his laboratory 1.5 km away via telephone cable 1924 the Nobel prize Willem Einthoven 1860- 1927 ELECTROCARDIOGRAPHY = methods enabling to register electrical changes caused by heart activity from body surface. ECG - information about: 1. Frequency disorders (changes of HR in SA node or arrhythmias, sick sinus syndrome) 2. Conduction disorders (blocks - SA, AV) 3. Rhythm disorders (ES - supraventricular, ventricular) 4. Disorders of ventricular gradient (relationship between depolarisation and repolarisation: origin - metabolic, haemodynamic, anatomic, physical.. .ischemia, hypertrophy, dilatation, cardiomyopathy, inflammations, changes in electrolytes, drugs...) ELECTRICAL DIPOLE Local currents • Maximal in dipole axis (1) • Zero in the place of the centre (0) SPREADING OF DEPOLARIZATION FRONT ELECTRICAL FIELD OF THE HEART (vector) •Consists of sum of momentary dipoles on the depolarization front •Its size is a function of number of dipoles and steepness of boundary line •Direction from depolarized (-) to (re)polarized (+) area REGIONAL VECTORS INTEGRAL VECTOR during excitation is changing: •Size of momentary dipoles •Their direction •They are spreading to body surface - ELECTROCARDIOGRAPHY PQ interv. QRS QT 0,16 0,1 0,3 - i_ ! HR - dependent Atrial depol. Ventricular complex (depol.) (repol.) 3D SMYČKY SRDEČNÍHO VEKTORU F - frontální rovina hrudníku H - horizontální rovina hrudníku 0 - elektrický střed srdce P - sinová depolarizace QRS - komorová depolarizace T - komorová repolarizace 2D PROJEKCE HLAVNÍHO SRDEČNÍHO VEKTORU F - frontální rovina hrudníku H - horizontální rovina hrudní ID PROJEKCE HLAVNÍHO SRDEČNÍHO VEKTORU Projekce na povrch hrudníku do frontální roviny (2D) a její projekce na přímku (ID), osu I. EKG svodu rozepsaná v case E - Einthovenův trojúhelník F Goldberger, 1947, aVR, aVL, aVF HEXAAXIAL SYSTEM aVF It tmrt fads I Frontal projection of vector! CHEST LEADS Horizontal projection of vector! PROJECTION PLANES OF CARDIAC VECTOR AND ECG LEADS Frontal plane limb leads L, IL, III., aVR, aVL, aVF Horizontal plane VI-V6 Both planes are shifted into the level of electrical centre of the heart (0) E - Einthoven triangle ELECTRICAL AXIS - in the frontal plane (r-q-S) in lead I., II., III. ELECTRICAL AXIS OF THE HEART Summary of all momentary vectors, which form ventricular depolarisation loop. Expresses the direction of ventricular activation. Reflects asymmetry in ventricular wall thickness and the position of the heart in the chest. LEFT DEVIATION, RIGHT DEVIATION i -rvA_ I + \ \ 7 111 i ~rc~y— v+ \ i^'-. / iii-rj\— \ v / m Normal 12-lead electrocardiogram ECG - information about: 1. Magnitude and position of the heart (electrical axis) 2. Site of impulse origin (P, QRS) 3. Conduction path (P-Q, QRS) 4. Impulse regression (T) 5. Rhythm (P-P, R-R) 6. Action potential alterations (ST, T) 7. Effect of drugs, remedies, ion composition changes. HEART ISCHEMIA A: exercise angina pectoris B: acute non-Q myocardial infarction C: acute Q myocardial infarction ARRHYTHMIAS DISTURBANCES OF IMPULSE GENERATION OR CONDUCTION RHYTHM: Regular HEART RATE (normal range: 70 - 220 bpm; effect of age) 1. Sinus tachycardia (60 - 100 bpm; exercise; aging) 2. Sinus bradycardia (below 60 bpm; athletes' heart) (nodal rhythm below 40 bpm, ventricular rhythm below 20 bpm) RHYTHM: Irregular sinus respiratory arrhythmia (physiological) extrasystoles (ES) single, coupled (bigeminy, trigeminy) sinus, atrial, junction, ventricular • Sick sinus syndrome • Syncope ARHYTMIAS SITE OF ORIGIN SINUS ATRIA JUNCTION VENTRICLES JL JL JU ju p+ p- (p-) (p-)^ •Polarity of P wave •PQ interval (QP) (physiological PQ interval: 0.12 - 0.2 s) BLOCKS SICK SINUS SYNDROM AV BLOCKS r PQ>0.2sec LBBB II O RBBB Wenckebach periods (phenomenon) in o A-V dissociation BUNDLE BRANCH BLOCK (BBB) - LEFT, RIGHT PREEXCITATION AV node is „by-passed"? fast conduction •„short nodus" •Wolf-Parkinson-White syndrome (WPW) - sensitive to paroxysmal tachycardia - see re-entry delta wave PQ<0,12s REENTRY Common mechanism of (paroxysmal) tachycardias, extrasystoles, bigeminy, etc. ES 0 1. 2. 3. 1. 2. Loops most often at the level of AV junction Determinants of re-entry: Proper dimension of the loop Proper timing of the trigger ES Double pathway Diverging and converging of excitation pathways Unidirectional block Long refractory period Slowed conduction Reentry TACHYARYTHMIA • SINUS TACHYCARDIA • PAROXYSMAL TACHYCARDIA (supraventricular, ventricular) • FLUTTER (>250/min; atrial) • FIBRILLATION (>600/bpm; atrial, ventricular; breakdown of electrical homogeneity) ATRIAL FLUTTER Frequency 250 - 600/bpm Atrioventricular block n: 1 ATRIAL FIBRILLATION Irregular ventricular rhythm + f-waves VENTRICULAR FIBRILLATION oVR VI V4 V2 V5 m V3 V6 fiHVTHM STRtPi fl 25 ami/mo; I cm/mY COOOOtWJOOO -3 Frequency above 600/bpm, LETHAL ANTIARRHYTHMICS • BLOCKERS OF Na CHANNEL - prolong inactivation of INa, e.g. refracterity, „block" fast ways • BLOCKERS OF Ca CHANNELS - „block" fast ways • BLOCKERS OF K CHANNEL - prolong refractory period • ß-SYMPATOLYTICS - slowing of heart rate Schémata a animace zpracovalo Servisní středisko pro e-learning na MU CZ. 1.07/2.2.00/28.0041 Centrum interaktivních a multimediálních studijních opor pro inovaci výuky a efektivní učení Ht -. Bfl 'KŠr C íii ^T^^ I S0Clalnl. MINISTERSTVO ŠKOLSTVÍ. OUfcWírfrf %^m^T m&^&m fondvCR evropská unie mládeže a tělovýchovy pt* h«*MUKMdiD|MiKt *4jía*^ INVESTICE DO ROZVOJE VZDĚLÁVÁNÍ V. Spaciokardiogram zdravého člověka.