Ventricular tachycardia in acute myocardial infarction: the role of hypophosphatemia.

The relationship between serum concentration of certain electrolytes and the pathogenesis of ventricular arrhythmia in myocardial infarction has been the subject of frequent review. The role of hypophosphatemia in the pathogenesis of arrhythmia in patients with acute myocardial infarction has not been as well studied. In our study group of 325 consecutive patients admitted to the coronary care unit of a community hospital, 111 were confirmed to have had a myocardial infarction. Patients were continuously monitored for ventricular arrhythmia during the first 24 hours, and the electrocardiographic records were reviewed for documentation of arrhythmia. From an admission blood sample, measurement of electrolytes included serum phosphate, calcium, bicarbonate, potassium, and magnesium. Associations between ventricular tachycardia and serum electrolyte abnormalities including magnesium, potassium, phosphate, calcium, and bicarbonate were studied. Low phosphate (less than 2.6 mg/dL) was a significant predictor of ventricular tachycardia in the myocardial infarction group. In the entire group of 325 patients prior to the confirmation of myocardial infarction, both low bicarbonate and low phosphate were significant predictors of ventricular tachycardia during the first 24 hours of hospitalization. Although management of acidosis is considered early in the hospital course, phosphate replacement therapy is usually not as often considered. We recommend further study on the effectiveness of replacement therapy in hypophosphatemic patients with chest pain to reduce the risk of ventricular tachycardia.

Pneumococcal bacteremia in three community teaching hospitals from 1980 to 1989.

STUDY OBJECTIVE: To review the clinical and laboratory findings in a large number of patients with pneumococcal bacteremia in the 1980s and identify risk factors associated with increased mortality. DESIGN: Retrospective review of medical records identified by blood culture logbooks and ICD-9 codes. SETTING: Three community teaching hospitals affiliated with a medical school in northeastern Ohio. PATIENTS: 385 inpatients with pneumococcal bacteremia admitted between Jan 1, 1980 and Dec 31, 1989. MEASUREMENTS: Important clinical and laboratory information was abstracted from patients' medical records, compiled, computerized, and analyzed. MAIN RESULTS: The patients' mean age was 48 years. The overall mortality was 25 percent. The mortality increased with age, reaching 42 percent in patients over 65 years old. For these elderly patients, the mortality was higher (55 percent) for patients admitted from nursing homes than patients from the community (36 percent). Higher mortality was also associated with congestive heart failure (p = 0.001), alcoholism/cirrhosis (p = 0.02), diabetes mellitus (p = 0.05), and malignancy (p = 0.02). A platelet count less than 150,000/mm3, renal dysfunction (serum creatinine > 2 mg/dl), and the number of lobes involved were also associated with mortality. Patients receiving standard therapy (penicillin, ampicillin, erythromycin, or cephalosporins) had lower mortality. Of the previously specified risk factors for mortality, only age, whether standard therapy was administered, the number of lobes involved, and the serum creatinine level proved to be independent risk factors according to logistic regression. CONCLUSIONS: The overall mortality from pneumococcal bacteremia has not decreased during the past 40 years. Risk factors associated with increased mortality were identified. Prevention by immunization with polyvalent pneumococcal polysaccharide vaccine should be practiced more widely.