Some Theoretic Aspects

Because every physician, and even more so, every student in medicine, is aware of the important theoretic basics of Electrocardiology [as anatomy and the impulse conduction system, correlation between ion flows and the intracellular action potential (AP) of a single myocardial working cell, lead systems, and the nomenclature of the heart cycle], repetition in this short ECG Manual is renounced. Only some lesser-known basics are provided. Moreover, the reader will find a section about the determination of the frontal QRS axis (ÅQRS_F).

Atrial vectors are discussed in Chapter 3, “The Normal Electrocardiogram and Its (Normal) Variants.” The ventricular vectors, however, are discussed in this chapter, and a simplified scheme of the left ventricular vectors is provided that is especially useful in understanding bundle-branch blocks and the fact that the human electrocardiogram (ECG) generally represents a “levogram.”