PURPOSE: Reduced heart rate variability significantly increases cardiovascular mortality. Metabolic syndrome increases the cardiac autonomic dysfunction. Recently, increasing cardiovascular mortality has been reported in patients with schizophrenia. This study was done to compare heart rate variability between adults with and without schizophrenia and to compare the relationship of heart rate variability to metabolic syndrome in hospitalized patients with schizophrenia. METHODS: This was a descriptive and correlational study in which 719 adults without schizophrenia and 308 adults with schizophrenia took part between May and June 2008. We measured the following: five-minute heart rate variability; high-frequency, low-frequency, the ratio of low-frequency to high-frequency, and the Standard Deviation of all the normal RR intervals. Data was also collected on metabolic syndrome, abdominal obesity, triglycerides, HDL cholesterol, blood pressure and fasting glucose. RESULTS: The Standard Deviation of all the normal RR intervals values of heart rate variability indices were 1.53+/-0.18. The low-frequency and high-frequency values of heart rate variability indices were significantly higher in hospitalized patients with schizophrenia (3.89+/-1.36; 3.80+/-1.20) than those in the healthy participants (2.20+/-0.46; 2.10+/-0.46). There were no significant differences between the schizophrenic patients with and without metabolic syndrome. CONCLUSION: The results of this study indicate that schizophrenia patients have significantly lower cardiac autonomic control, but they have significantly higher low-frequency and high-frequency values than those of healthy adults. Use of antipsychotic drug may affect the autonomic nervous system in schizophrenic patients. Metabolic syndrome was not associated with cardiac autonomic control in schizophrenia patients.
Adult ; Autonomic Nervous System/physiopathology ; Blood Glucose/analysis ; Blood Pressure ; Cardiovascular Diseases/complications/diagnosis/mortality ; Cholesterol, HDL/blood ; Female ; *Heart Rate ; Hospitalization ; Humans ; Male ; Metabolic Syndrome X/*complications/*physiopathology ; Middle Aged ; Obesity/etiology ; Schizophrenia/*complications/mortality/*physiopathology ; Triglycerides/blood

BACKGROUND/AIMS: Identification of patients at high risk for perioperative cardiac events (POCE) is clinically important. This study aimed to determine whether preoperative measurement of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) could predict POCE, and compared its predictive value with that of conventional cardiac risk factors and stress thallium scans in patients undergoing vascular surgery. METHODS: Patients scheduled for non-cardiac vascular surgery were prospectively enrolled. Clinical risk factors were identified, and NT-proBNP levels and stress thallium scans were obtained. POCE was the composite of acute myocardial infarction, congestive heart failure including acute pulmonary edema, and primary cardiac death within 5 days after surgery. A modified Revised Cardiac Risk Index (RCRI) was proposed and compared with NT-proBNP; a positive result for ischemia and a significant perfusion defect (> or = 3 walls, moderate to severely decreased, reversible perfusion defect) on the thallium scan were added to the RCRI. RESULTS: A total of 365 patients (91% males) with a mean age of 67 years had a median NT-proBNP level of 105.1 pg/mL (range of quartile, 50.9 to 301.9). POCE occurred in 49 (13.4%) patients. After adjustment for confounders, an NT-proBNP level of > 302 pg/mL (odds ratio [OR], 5.7; 95% confidence interval [CI], 3.1 to 10.3; p < 0.001) and a high risk by the modified RCRI (OR, 3.9; 95% CI, 1.6 to 9.3; p = 0.002) were independent predictors for POCE. Comparison of the area under the curves for predicting POCE showed no statistical differences between NT-proBNP and RCRI. CONCLUSIONS: Preoperative measurement of NT-proBNP provides information useful for prediction of POCE as a single parameter in high-risk patients undergoing noncardiac vascular surgery.
Aged ; Biological Markers/blood ; Chi-Square Distribution ; Female ; Heart Diseases/blood/*etiology/mortality ; Heart Failure/etiology ; Humans ; Logistic Models ; Male ; Middle Aged ; Multivariate Analysis ; Myocardial Infarction/etiology ; Natriuretic Peptide, Brain/*blood ; Odds Ratio ; Peptide Fragments/*blood ; Predictive Value of Tests ; Preoperative Period ; Prospective Studies ; ROC Curve ; Risk Assessment ; Risk Factors ; Sensitivity and Specificity ; Surgical Procedures, Elective ; Time Factors ; Tomography, Emission-Computed, Single-Photon ; Treatment Outcome ; Vascular Diseases/blood/mortality/radionuclide imaging/*surgery ; Vascular Surgical Procedures/*adverse effects/mortality