Israel Medical Association Journal

Background: The etiology of chest pain with normal epicardial coronary arteries (cardiac syndrome X) seems to be related to endothelial cell dysfunction. Multiple factors are implicated in the pathophysiology, including evelated levels of homocysteine in the blood. Mutations in the MTHFR gene are associated with evelated levels of homocysteine.

Objectives: To test whether abnormal homocysteine metabolism is associated with syndrome X.

Methods: Forty-two women with chest pain, positive stress test and normal coronary arteries (syndrome X) and 100 asymptomatic women (controls) were studied for the C677T mutation. Vitamin B12, folic acid, and plasma levels of homocysteine were also measured. Endothelial cell function was studied in 10 patients with syndrome X and homozygosity for C677T mutation, and in 10 matched healthy controls. Folic acid (5 mg daily) was prescribed to syndrome X patients after initial measurements of ECF[1]. Following 13 weeks of treatment, ECF and blood tests were repeated and compared to baseline measurements.

Results: Homozygosity for C677T mutation was doubled in syndrome X vs. control (33%, 14/42 vs. 16%, 16/100, P < 0.02), and homocysteine levels were increased (9.16 ± 2.4 vs. 8.06 ± 2.6 μmol/L, P = 0.02). In the 10 homozygous patients, homocysteine levels decreased significantly after treatment with 5 mg/day folic acid (10 ± 3.3 vs. 5.4 ± 1.1 µmol/L, P = 0.004). Abnormal baseline ECF improved after treatment with folic acid: flow-mediated dilatation was greater (11.3 ± 7.9% vs. 0.7 ± 4.5%, P < 0.002), as was nitroglycerin-mediated dilatation (15.2 ± 9.0% vs. 5.6 ± 6.4%, P < 0.003). Frequency of chest pain episodes was significantly reduced after 13 weeks of folic acid treatment.

Conclusion: Our findings establish the association between the C677T mutation, endothelial cell dysfunction and cardiac syndrome X, and provide a novel and simple therapy for a subset of patients with syndrome X and homozygosity for the C677T mutation.

Background: Emergency room triage of patients presenting with chest pain syndromes may be difficult. Under-diagnosis may be dangerous, while over0diagnosis may be costly.

Objectives: To report our initial experience with an emergency room cardiologist-based chest pain unit in Israel.

Methods: During a 5 week pilot study, we examined resource utilization and ER [1] diagnosis in 124 patients with chest pain of uncertain etiology or non-high risk acute coronary syndrome. First assessment was performed by the ER physicians and was followed by a second assessment by the CPU[2] team. Assessment was based on the following parameters: medical history and examination, serial electrocardiography, hematology, biochemistry and biomarkers for ACS[3], exercise stress testing and/or 64-slice multi-detector cardiac computed tomography angiography. Changes in decision between initial assessment and final CPU assessment with regard to hospitalization and utilization of resources were recorded.

Results: All patients had at least two cardiac troponin T measurements, 19 underwent EST[4], 9 echocardiography and 29 cardiac MDCT[5]. Fourteen patients were referred for early cardiac catheterization (same/next day). Specific working diagnosis was reached in 71/84 patients hospitalized, including unstable angina in 39 (31%) and non-ST elevation myocardial infarction in 12 (10%). Following CPU assessment, 40/124 patients (32%) were discharged, 49 (39%) were admitted to Internal Medicine and 35 (28%) to the Cardiology departments. CPU assessment and extended resources allowed discharge of 30/101 patients (30%) who were initially identified as candidates for hospitalization after ER assessment. Furthermore, 13/23 (56%) of patients who were candidates for discharge after initial ER assessment were eventually hospitalized. Use of non-invasive tests was significantly greater in patients discharged from the ER (85% vs. 38% patients hospitalized) (P < 0.0001). The mean ER stay tended to be longer (14.9 ± 8.6 hours vs. 12.9 ± 11, P = NS) for patients discharged. At 30 days follow-up, there were no adverse events (myocardial infarction or death) in any of the 40 patients discharged from the ER after CPU assessment. One patient returned to the ER because of chest pain and was discharged after re-assessment. 

Conclusions: Our initial experience showed that an ER cardiologist-based chest pain unit improved assessment of patients presenting to the ER with chest pain, and enhanced appropriate use of diagnostic tests prior to decision regarding admission/discharge from the ER.