ST Segment Elevation Besides Acute Myocardial Infarction

Abstract

Normal variant of ST segment elevationSTE is commonly observed in the electrocardiogram of normal persons (figure 1). A study done on 45 normal volunteers suggest that standard precordial leads do not accurately predict maximal torso potentials during the ST segment, thus STE may commonly be seen without acute myocardial infarction 3 . Another study conducted on 6014 healthy men in the U.S. Air Force who were 16 to 58 years old, 91% had STE of 1-3 mm in one or more precordial leads 4 . Other study by Surawicz and Parikh on 529 males and 544 females, age 5 to 96 years, showed variation of STE between normal male and female that is, prevalence of STE of at least 1 mm in one or more of leads V 1 through V 4 was 93% in the men who were 17 to 24 years old 5 . According to these studies, it is now established that the main feature of the male pattern in electrocardiograms (ECG) is ST elevation at the J-point of =0.1 mV in at least one of the leads V1-V4 with concave upward ST-segments and the prevalence of the male pattern in ECG of healthy male (mostly Caucasians or Blacks) who were 16-58 years old was high (85%) 4,5 . Much higher prevalence was observed in a recent study in Hong Kong (on 202 apparently healthy Chinese adult males, aged 20-54 years) which was 95.5% 6 . Early repolarization syndromeThe early repolarization syndrome (ERS) is a common electrocardiographic variant characterized by J-point elevation manifested either as QRS slurring (at the transition from the QRS segment to the ST segment) or notching (a positive defection inscribed on terminal S wave), STE with upper concavity and prominent T waves in at least 2 contiguous leads 7-10 . In most of the studies elevation of the J point and/or ST-segment from the baseline by at least 0.1 mV was considered definitive of ER 9,11 (figure 2).ERS is found in approximately 1% to 2% of the young adult population and in up to 13% to 48% of patients presenting with chest pain in the emergency rooms and coronary care units. It generally occurs in the absence of myocardial disease 12,13 . Its predominance is in young black males and shows disproportionate infrequency in white females 14 . This syndrome is common in people under the age of 30 years old and shows decreasing incidence with ST Segment Elevation Besides