Basic Electrocardiography NORMAL AND ABNORMAL ECG PATTERNS Ebook PDF download
Basic Electrocardiography NORMAL AND ABNORMAL ECG PATTERNS Ebook PDF download ECG is the technique of choice in the study of patients with chest pain, syncope, palpitations and acute dyspnoea, and is crucial for the diagnosis of cardiac arrhythmias, conduction disturbances, pre-excitation syndromes and chan- nelopathies. It is also very important for assessing the evolution and response to treatment of all types of heart diseases and other diseases, and different sit- uations such as electrolytic disorders, drug administration, athletes, surgical evaluation, etc. Additionally, it is useful for epidemiologic studies and screen- ing (check-up).
Despite its invaluable usefulness if used correctly, electrocardiography may induce mistakes if one excessively trusts on an ECG recording of normal ap- pearance. Sometimes, bowing to the ‘magical’ power of ECG, physicians caring for a patient with chest pain of doubtful origin may state: ‘Let’s have an ECG recording done so that we may solve the problem’. It must be remembered that a high percentage of patients with coronary heart disease, in the absence of chest pain, show a normal ECG recording and that even in acute coronary syndromes ECG is normal or borderline in approximately 5–10% of cases, and without symptoms especially in its early phase. Furthermore, ECG may be normal months or years after a myocardial infarction. From the above, it can be inferred that a normal ECG does not imply any ‘life insurance’ as a patient may die from cardiac causes even on the same day a normal recording is taken. However, it is evident that in the absence of clinical findings or family history of sudden death, the possibility of this occurring is, in fact, very remote.
On the other hand, on occasions some subtle ECG abnormalities with no evidence of heart disease may be observed. Clearly, in such cases one must be cautious, and before considering this to be a non-specific abnormality, is- chaemic heart disease, channelopathies (long QT, Brugada’s syndrome, etc.) or pre-excitation syndromes should be ruled out. Therefore, it is necessary to read the ECG recordings while bearing in mind the clinical setting and, if necessary, taking sequential recordings.
In addition, normal variants may be observed in the ECG recording, which are related to constitutional habits, chest malformations, age, etc. Even tran- sient abnormalities may be detected owing to a number of causes (hyperven- tilation, hypothermia, glucose or alcohol intake, ionic abnormalities, effect of certain drugs, etc.).