Ethnic differences in the ST segment of the electrocardiogram: a comparative study among six ethnic groups.

Deviation of the ST segment of the electrocardiogram (ECG) may signify infarction or ischemia. Prior studies suggest that normal ECG patterns may differ among ethnic groups. We retrospectively reviewed the first thousand medical files of a multiethnic community, where all individuals shared similar living conditions. Only healthy adults, aged 15 to 60 years, were included. Along with age, the most common causes for exclusion were diabetes, hypertension, and ischemic heart disease. A total of 597 subjects (349 men) were included: 350 Saudi Arabians, 39 Filipinos, 95 Indians, 17 Sri-Lankans, and 57 Caucasians. Twenty men and one woman had an ECG pattern of early repolarization (ST segment elevation with upward concavity, notching on QRS, and large symmetrical T wave), with no difference in incidence among ethnic groups. ST segment elevation (2 mm in any of the leads V1-V4, or 1 mm in any of the other leads) without criteria of early repolarization occurred in 11.58%, 13.46%, 3.57%, 4.35%, 11.76%, 7.32% of Saudi, Indian, Jordanian, Filipino, Sri-Lankan, and Caucasian men, respectively (P =.61). Only one Jordanian and 2 Indian women had this pattern. However, Filipino men had higher median ST segment levels than others in leads V1 and V3. Among women, the median ST segment level was iso-electric in all leads in all ethnic groups. Only 3 subjects had ST segment depression >1 mm. Significant ST segment elevation is common in normal healthy men but may not fulfill criteria for early repolarization; it has no ethnic predilection. ST segment elevation is uncommon in normal women. ST segment depression is a rare finding in healthy adults regardless of ethnic origin.

Ethnic differences in electrocardiographic intervals and axes.

The presence of ethnic differences in electrocardiographic (ECG) patterns is debated. We retrospectively examined the first 1,000 medical files of a multi-ethnic community, where all individuals shared similar living conditions. Only healthy adults (ages 15 to 60 years) were included. All patients had similar socioeconomic, nutritional, environmental, and occupational conditions. Interval and axes measurements were obtained through integrated computerized analysis from a standard 12-lead ECG. ECGs from 597 patients were included in the study: 350 Saudi Arabians, 95 Indians, 39 Jordanians, 17 Sri-Lankans, 39 Filipinos, and 57 Caucasians; 349 patients were men. Interval and axes were compared by analysis of variance. No statistically significant differences were found among ethnic groups in PR interval, QRS duration, QT interval, P wave axis, QRS axis, or T wave axis in men (P =.05). In women, Jordanians had longer QRS duration than Filipinos (87.69 +/- 10.4, 78.81 +/- 5.47 ms, respectively, P =.014). P-wave axis was lower in Filipino women than Saudi, Indian, and Caucasian women (36.87 +/- 26.32, 50.39 +/- 16.88, 52.23 +/- 16.67, 63.19 +/- 14.55 degrees, respectively, P =.002). QRS axis was significantly higher in Filipino than Saudi women (53.06 +/- 26.14, 32.62 +/- 28.31 degrees, respectively, P <.014). There was no ethnic difference in ECG interval measurements in men. However, in women, there were differences in QRS interval, and P and QRS wave axes. Although women had a statistically significant difference in intervals, the magnitude was not clinically significant. Current reference standards for ECG intervals and axes can be used across the ethnic groups studied.

Microscopic polyangiitis presenting as idiopathic pulmonary fibrosis: is anti-neutrophilic cytoplasmic antibody testing indicated?

We report a 55-year old woman with microscopic polyangiitis who presented with idiopathic pulmonary fibrosis and 1 year later developed hematuria and proteinuria. She had a high serum level of perinuclear anti-neutrophilic cytoplasmic antibodies. Renal angiogram was normal. The diagnosis of microscopic polyangiitis was confirmed by renal biopsy, which showed pauci-immune crescentic glomerulonephritis. The patient received immunosuppressive therapy and improved markedly. Consideration of small vessel vasculitis is important in the differential diagnosis of idiopathic pulmonary fibrosis.