In the last 15 years we have had the opportunity to teach Electrocardiography to many different types of student: doctors preparing to become cardiologists, cardiologists attending weekly 'refresher' sessions at our hospital, general practitioners who wish to become adept at electrocardiography and attend our yearly courses and, finally, the medical students of the Universidad Aut6noma of Barcelona. We cover everything with these students from the basics of electrophysiology to applied electrocardiographic semiology. This quadruple experience has proved stimulating, constantly motivating the search for better and more precise material, and the most appropriate didactic presentation for each type of student, each of whom has different requirements. I have always felt that didactic capability is not related to the intelligence of the professor, or to the amount of knowledge this person possesses, but really depends on the 'quality' of this knowledge, the 'desire' to transmit it and the 'capacity' to adapt to each teaching situation.

1 Cardiac electrophysiology.- 1.1 Heart cells.- 1.1.1 Types.- 1.1.2 Properties.- 1.2 Cellular activation.- 1.2.1 Diastolic polarization phase.- 1.2.2 Systolic cellular depolarization phase.- 1.2.3 Systolic cellular repolarization phase.- 1.2.4 TAP morphology in different heart structures.- 1.3 Cell electrogram.- 1.4 Concept of dipole.- 1.4.1 Depolarization dipole.- 1.4.2 Repolarization dipole.- 1.4.3 Depolarization and repolarization dipole in an ischemic cell.- 1.5 Concept of hemifield.- 1.6 Cardiac activation.- 1.6.1 Atrial activation: P loop.- 1.6.1.1 Atrial depolarization: P loop.- 1.6.1.2 Atrial repolarization.- 1.6.2 Ventricular activation: QRS and T loops.- 1.6.2.1 Ventricular depolarization: QRS loop.- 1.6.2.2 Ventricular repolarization: T loop.- 1.6.3 The domino theory.- 1.7 Correlation between the TAP curve and ECG curve.- 2 The normal electrocardiogram.- 2.1 Wave nomenclature.- 2.2 Inscription system.- 2.3 Leads.- 2.3.1 Frontal plane leads.- 2.3.1.1 Bipolar limb leads: triaxial system of Bailey.- 2.3.1.2 Unipolar limb leads: hexaxial system of Bailey.- 2.3.2 Horizontal plane leads.- 2.4 Hemifields.- 2.4.1 Positive and negative hemifields of the frontal and horizontal plane leads.- 2.4.2 Loop-electrocardiographic morphology correlation.- 2.5 Interpretation routine.- 2.5.1 Heart rate.- 2.5.2 Rhythm.- 2.5.3 PR interval and segment.- 2.5.4 QT interval.- 2.5.5 Calculation of the electrical axis of the heart.- 2.5.5.1 Indeterminate electrical axis.- 2.5.6 The normal P wave.- 2.5.6.1 Axis in the frontal plane (AP).- 2.5.6.2 Polarity and morphology.- 1 Polarity.- 2 Morphology.- 2.5.6.3 Duration and voltage.- 2.5.7 The normal QRS complex.- 2.5.7.1 Axis on the frontal plane (AQRS).- 2.5.7.2 Polarity and morphology: modifications with different rotations.- 1 Heart rotations.- 1. a Rotation on the anteroposterior axis.- 1. b Rotation on the longitudinal axis.- 1. c Rotation on the transversal axis.- 1. d Combined rotations.- 2 Normal notches and slurrings.- 3 Normal 'Q' wave.- 2.5.7.3 QRS duration and voltage.- 2.5.8 ST segment and T wave.- 2.5.8.1 ST segment.- 2.5.8.2 T wave.- 1 Axis on the frontal plane (AT).- 2 Normal polarity and morphology.- 3 Voltage.- 2.5.9 U wave.- 2.6 Electrocardiographic variations with age.- 2.6.1 Infants, children and adolescents.- 2.6.2 Elderly people.- 2.7 Other normal variants.- 2.7.1 P wave and atrial repolarization wave (ST-Ta).- 2.7.2 Ventricular depolarization.- 2.7.2.1 Hyperdeviation of AQRS in the frontal plane.- 2.7.2.2 Morphology of first degree right or left ventricular block.- 1 Morphology with r? in V1 with QRS lt; 0.12 sec.- 2 Morphology of first degree left ventricular block.- 2.7.3 Repolarization alterations.- 2.7.4 Arrhythmias.- 2.8 Sensitivity and specificity of the ECG.- 3 Other electrocardiological techniques.- 3.1 Vectorcardiography: x,y,z leads.- 3.1.1 Methodology.- 3.1.2 Clinical utility of vectorcardiography and the orthogonal leads.- 3.2 Exercise ECG test.- 3.2.1 Methodology.- 3.2.2 Utility.- 3.2.3 Interpretation.- 3.2.3.1 Physiologic responses to exercise.- 3.2.3.2 Abnormal responses to exercise.- 1 Alterations of the ST Segment.- 1. a Normal basal ECG.- 1. b Altered basal ECG.- 2 Other repolarization alterations.- 3 Increase in R wave voltage.- 4 Appearance of ventricular block.- 5 Arrhythmias.- 3.2.4 Comparison with other tests.- 3.2.5 Limitations.- 3.3 Holter ECG and allied techniques.- 3.3.1 Methodology.- 3.3.2 Utility.- 3.3.2.1 Arrhythmias.- 1 Evaluation of the electrophysiologic mechanism of the arrhythmias.- 2 Arrhythmia-symptom correlation.- 3 Investigation of the prevalence of arrhythmias.- 4 Frequency and duration of supraventricular or ventricular tachycardia crises.- 5 Noninvasive evaluation of antiarrhythmic therapy.- 6 Control of pacemaker function.- 7 Patients with syncope or near-syncope.- 3.3.2.2 Repolarization alterations.- 1 Repolarization alterations other than in coronary heart disease.- 2 Repolarization alterations due to coronary heart disease.- 2. a Secondary versus primary angina.- 2. b Sensitivity and specificity of the Holter ECG for the diagnosis of coronary disease.- 2. c Control of antianginal treatment.- 3.3.3 Limitations.- 3.3.4 Allied techniques.- 3.3.4.1 Alteration analyzer.- 3.3.4.2 Transtelephonic ECG: SAMTI system.- 3.4 Intracavitary electrocardiography.- 3.4.1 Methodology.- 3.4.2 Utility.- 3.4.2.1 To measure functional and effective refractory period.- 3.4.2.2 Topographic localization of AV block.- 1 Suprahisian AV blocks.- 1. a Intraatrial block.- 1. b Intranodal block.- 2 Intrahisian blocks.- 3 Infrahisian blocks.- 3.4.2. 3 Study of the characteristics of AV conduction.- 3.4.2. 4 Study of the sinus function.- 3.4.2. 5 Study of the characteristics of the accessory bundles.- 3.4.2. 6 Study of the characteristics of a tachycardia.- 3.4.2. 7 Topographic localization of right ventricular block.- 3.4.2. 8 Pharmaco-electrophysiology.- 3.4.2. 9 Other therapeutic uses.- 3.4.2.10 Differentiating patients with high risk of sudden death (SD).- 3.4.2.11 Enhancing the diagnostic precision of the conventional ECG.- 3.4.2.12 When intracavitary electrophysiologic study should be realized.- 3.4.3 Limitations.- 3.5 Unified ECG interpretation.- 3.5.1 Minnesota Code.- 3.5.2 Interpretation by computer.- 3.6 Other electrocardiologic techniques.- 3.6.1 Spatial velocity technique.- 3.6.2 Cardiac mapping.- 3.6.3 External techniques to record late potentials.- 3.6.4 Other techniques.- 4 Alterations in the atrial electrocardiogram.- 4.1 Alterations in the P wave.- 4.1.1 Atrial enlargement.- 4.1.1.1 Right atrial enlargement (RAE) (dilation).- 1 Changes in the P wave.- 2 Changes in the QRS complex.- 3 Diagnostic criteria: ECG and VCG.- 4.1.1.2 Left atrial enlargement (LAE) (dilation).- 1 Changes in the P wave.- 2 Diagnostic criteria: ECG and VCG.- 4.1.1.3 Biatrial enlargement.- 1 Electrocardiogram.- 2 Vectorcardiogram.- 4.1.2 Atrial block.- 4.1.2.1 Sinoatrial block.- 4.1.2.2 Interatrial block.- 4.1.2.3 Intraatrial block.- 4.2 Alterations in atrial repolarization.- 4.2.1 Depressed ST-Ta.- 4.2.2 Elevated ST-Ta.- 5 Ventricular enlargement.- 5.1 Preliminary considerations: definition of terms.- 5.2 Left ventricular enlargement (LVE).- 5.2.1 Left ventricular hypertrophy (LVH).- 5.2.1.1 Electrocardiographic alterations.- 1 Changes in the QRS complex.- 2 Changes in ST segment and T wave.- 5.2.1.2 Diagnostic ECG criteria.- 1 Limitations of the diagnostic criteria.- 1. a Methodological considerations.- 1. b Limitations conditioned by constitutional factors.- 5.2.1.3 Diagnostic VCG criteria.- 5.2.1.4 Value of the echocardiogram in the diagnosis of left ventricular enlargement (LVE).- 5.2.1.5 Value of other electrocardiologic techniques.- 5.2.1.6 Special characteristics of some types of left ventricular enlargement (LVE).- 1 LVE in children.- 2 Left ventricular dilation associated with LVH.- 3 Indirect signs of LVE.- 5.2.1.7 Diffe…