Risk factors, clinical features and outcome of acute myocardial infarction in Sana'a, Yemen.

To the Editor: According to the World Health Organization, developing countries contributed to 85% of cardiovasuclar disease (CVD) deaths.1–3 A particular cause for concern is the relatively early age of CVD deaths compared with those in developed regions. Since there are few data on the incidence and clinical course of acute myocardial infarction (AMI) in the Middle East,4–12 we retrospectively studied the demographic and clinical characteristics of patients, the prevalence of major risk factors and factors associated with morbidity and mortality during hospitalization in the intensive care unit (ICU) of the Al-Thawra University Hospital in Sana’a. All patients with confirmed AMI who were admitted and treated at the intensive care unit (ICU) during 36 consecutive months were enrolled in the study. The diagnosis of AMI was based on a history of typical chest pain or its equivalent, ECG changes plus an increase in peak serum creatine kinase (CK) activity from a minimum to twice the normal level. During the 3-year study period 386 patients with AMI were admitted to the ICU. Of all patients, 348 (90.2%) were men with a mean (±SD) age 54±11 years (range, 27–82 years) and 38 (9.8%) were women with a mean age of 59±11 years (range, 38–80 years). Almost all patients (97.9%) were Yemeni. The prevalence of risk factors was as follows: khat chewing (88%), smoking (81%), total serum cholesterol (29%), diabetes mellitus (25%) and hypertension (18%). When classified according to site, recurrence and severity of AMI, in 57.0% there was an anterior infarction, in 35.2% an inferior infarction, in 7.0% an inferoseptal infarction, in 1.8% a lateral infarction and location was undetermined in 2.5%. Only 34 (8.8%) patients had a previous history of AMI; in 352 (91.2%) patients, it was the first AMI. In 341 (88.3%) it was a Q-wave infarction while a non Q-wave infarction was found in 35 (9.1%) and in 10 (2.6%) it was undetermined. The complications of AMI were heart failure in 94 cases (24.6%), primary ventricular fibrillation or tachycardia in 18 cases (4.7%), and second or third degree atrioventricular block in 17 (4.4%). The ICU mortality rate was 11.4% (44 patients) and the total in-hospital mortality was 14.2% (55 patients). Causes of death during hospitalization were cardiogenic shock (62%), sudden death (18%), resistant arrhythmia (13%), brain embolization (5%), and hypoxic brain damage after CPR (2%).

Compared with studies from the Arabian Gulf, the incidence of admission for AMI was similar, but differed from that in Western countries. 1–3 We found that the mean age of patients was approximately 5 to 10 years younger than in Europe and the USA, which could be due to ethnicity or genetic predisposition, but also to changes in lifestyle (especially in the last 40 years), which have become more stressful and sedentary,1,10 with excessive smoking and eating of very high-calorie and fatty food. In patients with AMI, there was a very high rate of smoking (81%), but diabetes mellitus (25%), hypertension (18%) and hyperlipoproteinemia (29%) were similar in incidence to that in Middle East and Western countries. The rate of smoking was similar to that in other developing countries and Europe (range of 49–81%),4–14 and includes the chewing of khat (Catha edulis Forsk), especially in men. The leaves of this plant contain cathine and cathinone, an amphetamine-like substance with a strong sympathomimethic effect, which increases heart rate and blood pressure.15,16 This factor could be critical in some patients, especially in patients with CVD, as was found with other amphetamines. 17 Inadequacies in the evaluation of CVD before the occurrence of AMI and preventive care in Yemen due to the lack of diagnostic or therapeutic facilities may also be a factor in the incidence of AMI admissions. Another significant influence in this area has been the lack of practical health education in Yemen. Many elderly patients do not seek medical care or wait for a long time and die before reaching a hospital. More frequent and atypical clinical signs and symptoms in inferior AMI could explain the high frequency of anterior AMI. The only explanation for the very low rate of non-Q wave AMI is less marked ECG changes and symptoms.

Our study was limited in being a retrospective analysis carried out in only one hospital in Sana’a. We hope our finding will serve as a baseline for other epidemiological studies in the field of coronary heart disease and studies related to the prevalence of cardiovascular risk factors, including khat. This should provide an impulse for initiating the primary prevention of cardiovascular diseases, especially coronary heart disease.