2 Epidemiology of pathological electrocardiogram findings

A 12-lead electrocardiogram (ECG) allows the recognition of cardiac diseases that may have evolved without causing subjective disturbances. ST changes, bundle branch blocks or left ventricular hypertrophy as well as arrhythmias or premature ectopies are the most important findings. In younger patients the detection of a pre-excitation syndrome (especially Wolff-Parkinson-White) is essential, as it does require special therapeutic management. At our pre-operative clinic a resting ECG is part of the screening programme. The data of 18 939 patients were evaluated over a 3 year period, divided into two categories, with (category I) or without (category II) previous cardiac disturbances in their history. In comparison the resting ECGs of 10 523 healthy firemen (category III) were evaluated. The percentage of pathological ECG findings in the patients scheduled for noncardiac surgery was high. Depending on the decade of their life, 9.5–45.2% of subjects in category I (without any previous cardiac disturbances) and 13.2–80.2% in category II had a pathological ECG. In contrast, only 1.6–4.2% of subjects in category III had pathological ECG findings. The statement that the percentage of relevant pathological findings is increasing with age can be emphasized although a threshold cannot actually be defined: there is no difference in the incidence of changes in the age groups from 40 to 60 years. On the other hand, surgical patients without any cardiac history showed an incidence of pathological findings of 7.6%. The ECG is an inexpensive, easy-to-perform non-invasive procedure. In combination with an exact physical examination and a careful judgement of the impact of the findings on anaesthesia it allows a reliable pre-operative evaluation.