Association Between Inappropriateness of Left Ventricular Mass and Left Ventricular Diastolic Dysfunction: A Study Using the Tissue Doppler Parameter, E/E'

BACKGROUND AND OBJECTIVES: The structural significance of the inappropriateness of left ventricular mass (iLVM) is known to be an important prognostic factor for cardiovascular events; however, the functional changes associated with iLVM have not been established. This study was performed to determine if diastolic dysfunction is associated with iLVM using a tissue Doppler technique. SUBJECTS AND METHODS: Three hundred sixty consecutive subjects, including 221 hypertension patients from the echocardiography database, were analyzed. Regarding the appropriateness of left ventricular (LV) mass, an observed/predicted ratio of LV mass (OPR) >130% was defined as inappropriate. Echocardiographic parameters, including early diastolic peak velocity (E)/late diastolic peak velocity (A), deceleration time (DT), isovolumetric relaxation time (IVRT), and E/early mitral annulus velocity (E'), were compared between the appropriate LV mass (aLVM) group and the iLVM group. RESULTS: Among transmitral flow parameters, only the E velocity was negatively correlated with the OPR when adjusted for age (adjusted r=-0.107, p=0.04). Based on multiple regression analysis, the OPR (beta=0.163, p=0.003), as well as age (beta=0.286, p=0.0001), systolic blood pressure (beta=0.120, p=0.019), fasting blood glucose (beta=0.098, p=0.042), and male gender (beta=0.157, p=0.002) were independent factors determining E/E'. The cholesterol level was not an independent factor (beta=-0.059, p=0.355). In the iLVM group (n=105), the adjusted E/E' was higher than in the aLVM group (n=255; 11.7+/-3.4 vs. 10.8+/-3.1, p=0.02), while the peak E flow velocity was significantly lower than in the aLVM group (70.9+/-15.1 vs. 75.5+/-17.6, p=0.03). CONCLUSION: Inappropriateness of LV mass is independently associated with increased E/E'. Thus, E/E' may be a useful parameter for the evaluation of diastolic dysfunction.

Prospective Study to Evaluate the Efficacy and Safety of Pitavastatin in Patients with Risk Factor of Cardiovascular Disease(PEACE Study)

BACKGROUND AND OBJECTIVES: Pitavastatin, a recently approved synthetic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, is known to effectively treat hypercholesterolemia. The goal of this study was to investigate the efficacy and safety of pitavastatin in hyperlipidemic Korean patients with coronary risk factors. SUBJECTS AND METHODS: This was an 8-week, prospective, multicenter, open-label clinical trial. The study subjects were hyperlipidemic Korean patients (triglyceride 130 mg/dL, age; 45-75 years) with at least two coronary risk factors. After a 2-week wash out period, the eligible subjects were given 2 mg of pitavastatin once daily for 8 weeks. In the case of the patients with LDL-cholesterol > or = 100 mg/dL after the first 4 weeks of treatment, the dose of pitavastatin was increased to 4 mg per day for the remaining 4 weeks. RESULTS: Of the 131 patients initially enrolled, 105 completed the study. Among the lipid profiles, the total cholesterol, triglyceride, and LDL-cholesterol levels showed a significant reduction with mean reduction rates of -30.66%, -23.92%, and -41.06%, respectively, after 8 weeks. Interestingly, the HDL-cholesterol level was significantly increased in the subjects with a low HDL-cholesterol level (HDL-cholesterol < 40 mg/dL) after 8 weeks of therapy (35.28+/-4.38 mg/dL to 40.39+/-6.45 mg/dL, 15.9%, p=0.001). The proportions of patients who achieved the LDL-cholesterol goal of the National Cholesterol Education Program Adult Treatment Panel III were 72.5% (37/51), 93.6% (44/47), and 100.0% (7/7) for the patients with goals of 100 mg/dL, 130 mg/dL, and 160 mg/dL, respectively. Five patients had mild adverse drug events, such as fatigue, itching, myalgia, and anorexia. No significant abnormalities were detected in the laboratory tests, including the liver function test and creatinine kinase level. CONCLUSION: The HMG-CoA reductase inhibitor, pitavastatin, was highly effective and generally well tolerated with an acceptable safety profile in hyperlipidemic Korean patients with coronary risk factors.

A Case of Coronary Artery-Left Ventricular Microfistulae Demonstrated by Transthoracic Doppler Echocardiography

The coronary artery-left ventricular microfistula is an extremely rare congenital anomaly. Little is known about their epidemiologic and clinical features. Moreover, to our knowledge, only two cases of coronary artery-left ventricular microfistulae demonstrated by transthoracic doppler echocardiography have been reported in the literature. Recently we experienced a case of coronary artery-left ventricular microfistulae demonstrated by transthoracic doppler echocardiography, who was a 63 year old woman and visited for evaluation of chest pain. Herein, along with a review of the pertinent literature regarding this disorder, we report a case of coronary artery-left ventricular microfistulae demonstrated by transthoracic doppler echocardiography.

Aterial Stiffness and Abdominal Obesity are Associated with the Relaxation Abnormality of Left Ventricle in Human Hypertension

BACKGROUND AND OBJECTIVES: Aging is a major factor related to a relaxation abnormality of the left ventricle. Increased arterial stiffness and central distribution of body fat are common physiologic changes observed in the elderly. To further elucidate the relationship between aging and a relaxation abnormality of the left ventricle, we investigate the relationship between the pulse wave velocity, abdominal obesity and diastolic function parameters of the left ventricle. SUBJECTS AND METHODS: In 490 subjects (153 normotensive, 128 prehypertensive, 120 untreated hypertensive and 89 hypertensive on anti-hypertensive drugs, aged 59.8+/-12.6 (21-88) years), the brachial-ankle pulse wave velocity (baPWV) and echocardiographic indices for a relaxation abnormality, i.e. transmitral E, A, E/A, DT, IVRT, were measured. A relaxation abnormality was defined by an E/A 240 ms in the young (240 ms in the old ( or =90 cm in male, > or =80 cm in female, OR: 2.34), a high baPWV (> or =1,600 cm/sec, OR: 3.96) and a high BMI (> or =25 kg/m2, OR: 0.60) to be independent deter-minants of a relaxation abnormality. The age adjusted mean baPWV (1526.9+/-119.4 vs. 1577.1+/-106.9 cm/sec, p< 0.0001) and AC (86.2+/-9.8 vs. 88.5+/-7.7 cm, p=0.005) were higher in group II than group I. CONCLUSION: Arterial stiffness is the major determinant of a relaxation abnormality of the left ventricle. Abdominal obesity and a high BMI were found to be independent of each other, and an inverse relationship was found with respect to a relaxation abnormality of the left ventricle in a rural Korean population, including hypertensive patients.

A Case of Aortic Root Abscess Causing Fatal Myocardial Infarction

Despite the major advances in diagnostic technology and improvements in antimicrobial selection and monitoring accompanied by parallel advances in surgical techniques, the morbidity and mortality of infective endocarditis(IE) still remain high. Because of this high mortality rate, it is worthy of investigating the clinical features of IE and it's complications thoroughly. The main causes of mortality in IE are congestive heart failure and septic embolization. In 9% of active IE, acute myocardial infarction(AMI) developed. AMI caused by coronary artery obliteration by occlusion or embolization is a rare but recognized complication of aortic valve endocarditis with annular abscess. We reported a case of aortic valve endocarditis with aortic root abscess which was complicated by AMI and death.

Dilated Cardiomyopathy Associated with Clozapine / 신경정신의학

Clozapine is an atypical antipsychotic agent that is more effective than the typical neuroleptics in the treatment of refractory schizophrenia. However, clozapine is also a drug associated with potentially serious adverse effects, such as cardiac complications as well as agranulocytosis. Clozapine-related agranulocytosis has been reported in Korea, whereas clozapine-related cardiac complications have not. We report a 31-year-old male schizophrenia treated with clozapine who developed a dilated cardiomyopathy. We also reviewed literatures on dilated cardiomyopathy associated with clozapine treatment. This report is an attempt to raise the awareness of clozapine-related cardiac complications.

Significance of QT Dispersion as a Prognostic Factor in Hyperkalemia

PURPOSE: To date, it has been impossible to relate the occurrence of ventricular arrhythmia to survival in hyperkalemia. QT dispersion is thought to reflect the inhomogeneity of ventricular repolarization and to be related to ventricular-arrhythmia-induced sudden cardiac death in various medical conditions. Therefore, the purpose of this study was to investigate to use QT dispersion as a prognostic marker in hyperkalemia and to suggest treatment guidelines for hyperkalemia by analyzing the correlations between the QT dispersion on the initial ECG and the treatment outcomes. METHODS: This study's population was comprised of 104 patients with serum potassium concentrations > or =5.5 mEq/L, who were divided into 2 groups; group 1 was the survival group (n=81), group 2 was the death group (n=23). We reviewed retrospectively the underlying diseases, electrolytes, treatment outcomes and the clinical and ECG findings during the initial and the recovery states. The QT interval for each lead was measured manually on an enlarged (X1.5) ECG. The QT interval was measured from the first deflection of the QRS complex to the point of the T wave offset, and the corrected QT interval was obtained by using B a z e t t's formula. The QT dispersion and the corrected QT dispersion were defined as the differences between the minimal and the maximal QT values and between the corresponding corrected QT values for each of the 12 leads, respectively. RESULTS: The treatment outcomes were not related to the initial serum potassium and the hourly serum potassium change rates. For hyperkalemia > or =7.0 mEq/L, the death group had significantly larger QT dispersion than the survival group (death group = 95.6+/-15.4 msec, survival group = 51.8+/-17.5 msec, p or =7.0mEq/L, QT dispersion above 65 msec had a 93.8% sensitivity, a 79.4% specificity, and a 68.2% positive predictive value for death. CONCLUSION: For hyperkalemia > or =7.0 mEq/L, QT dispersion above 65 msec should be considered to be a prognostic marker for prediction of the treatment outcome.

The Relationship between the Pulse Wave Velocity(PWV) and the Left Ventricular Geometry: A Community-Based Cross-Sectional Study

BACKGROUND AND OBJECTIVES: Arterial compliance is a well-known factor affecting the left ventricular structure and function. Pulse wave velocity (PWV) is a reliable indicator of arterial compliance. To elucidate the role of arterial stiffness on the geometric adaptation of LV, the relationship between the pulse wave velocity and geometric patterns of the LV were investigated in subject living in a rural area of Korea. SUBJECTS AND METHODS: The brachial-ankle pulse wave velocity (baPWV) and echocardiographic indices, i.e. left ventricular mass index (LVMI), relative wall thickness (RWT), were measured in 217 (59 hypertensive, 158 normotensive, and age of 57.7+/-12.8 (21-86)) subjects. The relationship between the baPWV and RWT was analyzed according to the presence of LVH, which was defined by >52.0 g/m2.7. Group I was defined as having a RWT0.35. RESULTS: In a multiple regression model for the relative wall thickness, the stroke volume (beta=-0.261), PWVright (beta=0.177), total peripheral resistance (beta=0.227), abdominal circumference (beta=0.317) and body mass index (beta=-0.214) were found to be independent determinants (R2=0.265, SEE=0.043, constant=0.258+/-0.043, p=0.0001). In subjects without LVH, those in group II (n=42) were older (59.3+/-13.4 vs. 52.0+/-13.0, p=0.005) and had a higher meanPWV (1590.7+/-407.3 vs. 1711.3+/-407.3 cm/sec, p=0.02) than those in group I (n=65). In subjects with LVH, those in group II (n=66) were older (62.5+/-10.9 vs. 57.5+/-11.4, p=0.03) and had a higher meanPWV (1623.7+/-385.3 vs. 1488.5+/-266.3 cm/sec, p=0.03) than those in group I (n=44). In group II, the total peripheral resistance was higher (1858.7+/-447.7 vs. 1608.0+/-347.4 dynes-sec-cm-5, p=0.0001) and the stroke volume lower (67.0+/-14.2 vs. 79.4+/-15.7 ml, p=0.0001) than in group I. CONCLUSION: Pulse wave velocity is independently associated with the concentric geometry of the left ventricle in the rural Korean population used in this study.

Influences of Body Size and Cardiac Workload on the Left Ventricular Mass in Healthy Korean Adults with Normal Body Weight and Blood Pressure

BACKGROUND AND OBJECTIVES: The left ventricular mass is known to be influenced by both hemodynamic and non-hemodynamic factors. Body size and gender are the most representative non-hemodynamic factors. This study was performed to establish the influences of these variables on the variation of the left ventricular mass in healthy Korean adults. SUBJECTS AND METHODS: 368 subjects (male=184, female=184), with a normal body mass index and blood pressure, were included in the echocardiographic analysis from the echocardiography database of the Hanyang University Hospital and of the Yangpyung Epidemiologic Survey 2004. The left ventricular mass was calculated using the equation: 1.04x(IVSd+LVDd+PWTd)3-LDVs3)x0.8+0.6. The stroke volume was calculated (mL/beat) using Teichholz's formula. The stroke work (SW in gram-meters/beat [g-m/beat]) was computed as the cuff systolic BPxstroke volumex0.0144. RESULTS: The stroke work (SW) was the most important factor associated with the LV mass (adjusted R2=0.501, p<0.001), and body weight, age and gender were independent factors (adjusted R2=0.642). In a regression model, including stroke work, gender and height2.7, the LV mass was predicted by the equation: 54.9+7.62xheight (m2.7)+0.67xSW (g-m/beat)-13.2xgender (male=1, female=2)(constant=54.9+/-14.7 g, adjusted R2=0.576, SEE=21.67, p=0.001). CONCLUSION: As with the studies in the western countries, the stroke work, gender and height2.7 were important determinants of the left ventricular mass in Korean adults with a normal weight and normal blood pressure.

Comparison of Endothelium-Dependent Vasodilation According to the Presence of Diabetes in Coronary Artery Disease

BACKGROUND AND OBJECTIVES: The purpose of this study is to evaluate endothelium dependent vasodilation in the diabetic patients suffering with coronary artery disease (CAD). SUBJECTS AND METHODS: 43 patients who presented with typical chest pain and who underwent coronary angiography were enrolled in this study. They were classified into diabetic patients with CAD (n=13), non-diabetic patients with CAD (n=13), diabetic patients without CAD (n=7), and non-diabetic patients without CAD (n=10), according to the presence of CAD and diabetes mellitus. Endothelium-dependent vasodilation of the brachial artery was measured in all the subjects by performing 7.5 MHz high-resolution ultrasound sonography. RESULTS: The endothelium-dependent vasodilation in the diabetic patients with CAD was 1.30+/-2.13% and it was 5.72+/-3.70% in the non-diabetic patients with CAD. There was a significant difference between the two groups (p=0.001). The endothelium-dependent vasodilation in diabetic patients without CAD was 2.28+/-1.88% and it was 10.70+/-10.19% in the non-diabetic patients without CAD. There was a significant difference between the two groups (p=0.029). The endothelium-dependent vasodilations in the diabetic group was 2.28+/-1.88% and it was 10.70+/-10.19% in the non-diabetic group for all the patients. There was a significant difference between the two groups (p=0.029). There was correlation between the endothelium-dependent vasodilation and the fasting blood sugar. There was negative correlation between the endothelium-dependent vasodilation and the fasting blood sugar (FBS) in the patients with CAD (r=-0.59, p=0.002). However, there was no correlation between the endothelium-dependent vasodilation and the FBS in the patients without CAD (r=-0.327, p=0.201). There was negative correlation between the endothelium-dependent vasodilation and the FBS in all subjects (r=-0.352, p=0.021). CONCLUSION: The endothelium-dependent vasodilation was decreased in the diabetic patients with CAD as compared to the non-diabetic patients with CAD. There was also was negative correlation between the endothelium-dependent vasodilation and the FBS in the patients with CAD.

Distribution of von Willebrand Factor with Angiogenesis in Neonatal Rat Heart / 체질인류학회지

To investigate the process of angiogenesis in the cardiac tissue of neonatal rats, the levels of von Willebrand factor (vWf) produced by endothelial cells were observed. At days 1 to 7 after birth, whole heart obtained from neonatal rats was frozen sectioned, stained with anti-vWf and biotinylated rabbit anti-goat IgG antibodies, followed by immunohistochemical examinations. The results were as follows: 1. At day 1 after birth, extracellular matrix of endocardium and epicardium was stained with anti-vWf at the intermediate level, but that of myocardium was at the low level. 2. At day 2 after birth, a few blood islands were detected. At day 4 after birth, blood island was formed in most parts of heart and extracellular matrix was stained with ant-vWf at the intermediate level. 3. At day 7 after birth, a few blood vessels were formed, and endothelial cells and extracellular matrix was stained with ant-vWf at the intermediate level. These results suggest that mesenchymal cells were differentiated to blood islands and myocardiac cells, which are responsible for the distribution of vWf in extracellular matirx and for angiogenesis.

Primary Sjogren's Syndrome with Renal Pseudolymphoma Featuring Interstitial Nephritis / 대한신장학회잡지

A 65 year-old woman with Sjogren's syndrome was found to have renal mass and acute renal failure. Immunopathologic analysis of renal biopsy specimens showed polyclonal lymphocytic interstitial infiltration. Gene rearrangement study of T cell receptor showed a polyclonal pattern. The degree of azotemia and the size of pseudolymphoma diminished dramatically with steroid therapy. This is a case of proven pseudolymphoma that was found as renal mass in Sjogren's syndrome.

Characteristics of QT Dispersion during Recovery Phase after Treadmill Exercise in Airlines Pilots

BACKGROUND: QT dispersion (QTD) represents the inhomogeneity of ventricular repolarization and has been suggested to predict ventricular arrhythmia in patients with coronary artery disease. The purpose of this article is to study the characteristics of QTD during recovery phase after maximal treadmill exercise in airlines pilots. METHODS: The study population included 45 healthy airlines pilots. QTpeak D (QTpD) was defined as the difference between maximum and minimum QTp interval measured on 12 lead ECG at single cardiac beat. Paired t test was used between QTpD at rest and QTpD during recovery phase after maximal treadmill exercise. RESULTS: The QTpD at early recovery phase (1 minute) after maxial treadmill exercise was significantly decreased compared to QTpD at rest (22+/-11 msec. vs 27+/-12 msec., P<0.05), but there was no significant difference between QTpD at rest and QTpD at late recovery phases (3 minutes, 5 minutes and 7 minutes). CONCLUSION: This finding suggests that antiarrhythmogenic effect is present at early recovery phase (1 minute) after maxial treadmill exercise in healthy airlines pilots.

Four Cases of Management of Congenital Coronary Arteriovenous Fistula

Four cases of congenital coronary arteriovenous fistula were diagnosed using coronary angiography. Three cases had fistula-related chest pain and the remaining case showed no symptoms but displayed electrocardiographic changes suggesting myocardial ischemia. As he was elderly and had a potential for future complications, we decided to close the fistulas of all cases. Three cases were closed with transcatheter coil embolization and one with surgical ligation due to a suspicious accompanying pericardial cyst. None of the patients demonstrated periprocedural or perioperative complications and all were relieved from symptoms during the 2 year follow-up period. We concluded that transcatheter coil embolization and surgical ligation are effective methods for use in the management of coronary arteriovenous fistula.

The Relationship between the Upright Serum aldosterone Level and the Left Ventricular Geometry in Essentioal Hypertension

BACKGROUND: Aldosterone acts as a non-hemodynamic factors on the hypertensive heart regarding sodium retension or myocardial fibrosis. To elucidate whether aldosterone is associated with the specific left ventricular geometry or not, we investigated the relationship between the upright serum aldosterone levels and the echocardiographicleft ventricular structure in the essential hypertension patients never treated. METHODS: Echocardiographic indices included M-mode measured left ventricular mass index (LVMI), relative wall thickness (RWT). Aldosterone is measured by Radioimmunoassay for the serum withdrawn from the subjects at least 3 hours upright position. 63 patients and 20 normal control subjects were evaluated. RESULTS: 1) 84.1% (63/53) of cases showed left ventricular hypertrophy. 7 patients showed normal LVMI, 3 patients showed concentric remodeling geometry. 19 patients had concentric left ventricular hypertrophy (LVH). 34 patients had eccentric LVH. 2) The serum aldosterone level has negative correlation with the RWT (r=-0.27, p=0.03) but not with LVMI (r=0.08, p=NS). There was difference among groups (ANOVA, F=0.009). Serum aldosterone is higher in eccentric LVH group than in concentric LVH group (10.5+/-1.2 ng/dL vs 5.2+/-0.6 ng/dL, p=0.0001) and than in control group (10.5+/-1.2 ng/dL vs 6.6+/-0.8 ng/dL, p=0.01). CONCLUSION: In this study, we observed that the serum aldosterone level was not correlated with the LVMI but with RWT negatively so that eccentric LVH group showed higher serum aldosterone levels than control group and concentric LVH group.

Characteristics of QT Interval Dispersion During Exercise-induced Changes of Heart Rate

BACKGROUND: QT interval dispersion (QTD) reflects the regional inhomogeneity of ventricular repolarization, and heart rate variability reflects the autonomic tone of the heart. The relation between QTD and heart rate is not clarified yet. The object of this study was to examine the influence of heart rate on QTD using exercise treadmill test in healthy subjects. METHODS: The influence of heart rate on QTD was studied in 42 young healthy pilots by evaluating the changes in QTD induced by hyperventilation and exercise. QTpeak interval dis-persion (QTp D) was defined as the difference between maximum and minimum QTpeak interval measured on 12 lead ECG at single cardiac beat. Paired t test was used between QTp D at rest, QTp D after hyperventilation and QTp D after exercise to determine the effect of heart rate on QTp D. RESULTS: The QTp D after hyperventilation (37+/-11 msec) was greater compared to QTp D at rest (35 +/-14 msec), but there was no difference (P>0.05). The QTp D after exercise was 31 +/-11 msec at stage 1, 28 +/-13 msec at statge 2 and 31 +/-12 msec at stage 3. and there was the significant difference in QTp D at statge 2 compared to QTp D at rest (P<0.05). CONCLUSION: The QTp D significantly decreased at stage 2 after graded exercise in healthy men. This finding suggests that anti-arrhythmogenic effect associated with decreased QTp D during physiologic exercise is present in apparently healthy men.

Relationship between ST segment of lateral leads and culprit arteries in acute inferior myocardial infarction

BACKGROUND AND OBJECT: We intended to assess the characteristics of ST segment deviation in lateral leads(aVL, I, V5, V6) in patients with acute inferior myocardial infarction(AIMI) and find out the relationship with culprit arteries. MATERIALS AND METHOD: The subjects were 51 patients diagnosed as AIMI by standard electrocardiogram, cardiac enzymes and typical chest pain. Subjects were devided into two groups by angiographically proven culprit arteries ; left circumflex artery(LCx) group and right coronary artery(RCA) group. We compared the frequencies of ST segment depression more than 1 mm and less than 1 mm in aVL and I, and ST segment elevation more than 0.5 mm and less than 0.5 mm in V5 and V6 in each culprit artery group. RESULTS: Among 51 patients with AIMI, 42 were RCA group and 9 were LCx group. The frequency of ST segment depression more than 1 mm in aVL was 44% in LCx group and 71% in RCA group(p=0.140). 11% of LCx group and 43% of RCA group showed more than 1 mm ST segment depression in lead I (p=0.128). 56% of LCx group showed more than 0.5 mm ST segment elevation in V5 and V6 and 81% of RCA group showed less than 0.5 mm ST segment elevation in V5 and V6 (p=0.036). CONCLUSION: Culprit arteries in patients with AIMI and ST segment deviation in V5 and V6 are significantly related with each other. ST segment elevation more than 0.5 mm in V5 and V6 was predominantly found in LCx group than RCA group. Observation for ST segment deviation in lateral precordial lead V5 and V6 would be important in predicting the culprit artery in AIMI.

Normalized Idioventricular QT Interval Variability in Patients with Q- and Non-Q Wave Myocardial Infarction

BACKGROUND AND OBJECTIVES: The aim of the study was to evaluate the difference of temporal lability in myocardial repolarization between acute non-Q (NQMI) and Q-wave myocardial infarction (QMI), and to discern whether the locations of myocardial infarction influence such temporal lability. SUBJECTS AND METHODS: Twelve patients with NQMI and 28 with QMI, including 16 anterior (AMI) and 12 inferior MI (IMI) patients were enrolled. Twenty four-hour ambulatory ECG recordings of each patient were analyzed, and the digitized data was partitioned into 30-min sections. The QT intervals were measured using a template matching strategy. We then calculated the low (LF:0.03 - 0.15 Hz) and high frequency (HF:0.15 - 0.4 Hz) power of the QT interval variability using an algorithm capable of removing the influence of the RR-interval on QT interval variability (Normalized Idioventricular QT variability Index:IV-QT). RESULTS: For patients with QMI, the low frequency IV QT (LF IV-QT) was higher than that of NQMI (1.941+/-0.101 and 1.556+/-0.114 respectively, p<0.05). No difference was seen in the high frequency IV QT (HF IV-QT) of the two groups. For QMI patients, both the LF IV-QT and HF IV-QT were higher in day time (6AM-6PM) than in night time (6PM-6AM). Comparing the differences of these indices by the location of QMI, both the LF IV-QT and HF IV-QT of AMI were higher than those of IMI patients (2.231+/-0.135 vs 1.355+/-0.131 and 2.341+/-0.161 vs 1.346+/-0.145 respectively, p<0.0005). Both indices of each group also demonstrated a circadian change. CONCLUSION: In cases of QMI, the temporal lability in myocardial repolarization is larger than that seen in NQMI. Moreover, it was worse in AMI than IMI. Finally, such temporal repolarization lability tends to have a circadian pattern in QMI.

Protective Roles of Adenosine A1 Receptor Agonist and KATP Channel Opener in Adriamycin induced Cardiac Toxicity / 체질인류학회지

Although adriamycin is a potent chemotherapeutic agent, it elicits serious adverse effects, including cardiac toxicity. Evidence suggests that congestive heart failure induced by adriamycin is mediated by oxidative stress. We investigated whether regulators of adenosine A1 receptor and KATP channel, which have been demonstrated to mediate protective effects of ischemic -preconditioning in myocardium, are able to modulate adriamicin -induced impairment of cardiomyocyte. To study the effect of antioxidant, adenosine A1 receptor agonist & antagonist and KATP channel agonist & antagonist, ICR mice were pretreated with Cu,Zn -SOD, dimethyl thiourea, RPIA (R (-)N6 -(2 -Phenylisopropropyl)- adenosine, adenosine A1 receptor agonist), 8 -CPDPX (8 -Cyclopentyl -1, 3 -dipropylxanthine, adenosine A1 receptor antagonist), Pinacidil (KATP channel opener) and glibenclamide (KATP channel closer), followed by i.p injection with adriamycin. Mice were sacrificed day 1 or day 4 after adriamycin injection and cardiac toxicity was accessed by measurement of creatine phosphokinase (CK) levels in serum, immunohistochemistry using anti -Bcl -2 antibody and TUNEL histochemical assay. As expected, pretreatment of mice with Cu, Zn -SOD and DMTU reduced the frequency of TUNEL positive cells, indicating antioxidants protected cardiocytes from adriamycin -induced apoptosis. Interestingly, pretreatment with RPIA and pinacidil induced a significant decrease in adriamycin -induced cytotoxicity, whereas 8 -CPDPX and glibenclamide generated the opposite results. In Bcl -2 immunohistochemistry, an increased expression of Bcl -2 was found in all ADR treated groups, especially in glibenclamide pretreated group, and 8 -CPDPX pretreated groups, but Bcl -2 failed to protect myocytes from apoptosis. All ADR treated groups exhibited elevated levels of serum CK, compared with nomal controls, especially mice sacrificed at day 4 than those at day 1, and showed similar patterns of TUNNEL assay, reflecting heart tissue damages. This observation implicated cytoprotective roles of RPIA and pinacidil against adriamycin -induced cardiac toxicity. In conclusion, these results demonstrated that adriamycin -induced cardiotoxicity was associated with the generation of reactive oxygen species and that regulators including SOD, DMTU, RPIA and pinacidil elicited protective effects on this toxicity. In particular, pinacidil, the KATP channel opener, was more effective than RPIA, the adenosine A, receptor agonist, to attenate the adriamycin -induced cardiac toxicity.

Mechanism of epibatidine-induced catecholamine secretion in the rat adrenal gland

The present study was attempted to investigate the characteristics of epibatidine on secretion of catecholamines (CA) from the isolated perfused model of the rat adrenal gland, and to establish the mechanism of action. Epibatidine (3X10(-8) M) injected into an adrenal vein produced a great inhibition in secretory response of CA from the perfused rat adrenal gland. However, upon the repeated injection of epibatidine (3X10(-8) M) at 15 min-intervals, CA secretion was rapidly decreased after second injection of epibatidine. However, there was no statistical difference between CA secretory responses of both 1st and 2nd periods by the successive administration of epibatidine at 120 min-intervals. Tachyphylaxis to releasing effects of CA evoked by epibatidine was observed by the repeated administration. Therefore, in all subsequent experiments, epibatidine was not administered successively more than twice only 120 min-intervals. The epibatidine-induced CA secretion was markedly inhibited by the pretreatment with atropine, chlorisondamine, pirenzepine, nicardipine, TMB-8, and perfusion of Ca2+/-free Krebs solution containing EGTA, while was not affected by diphenhydramine. Moreover, the CA secretion evoked by ACh for 1st period (0apprx4 min) was greatly potentiated by the simultaneous perfusion of epibatidine (1.5X10(-8) M), but followed by time-dependently gradual reduction after 2nd period. The CA release evoked by high potassium (5.6+/-10(-8) M) for 1st period (0apprx4 min) was also enhanced by the simultaneous perfusion of epibatidine, but those after 2nd period were not affected. Taken together, these experimental data suggest that epibatidine causes catecholamine secretion in a calcium dependent fashion from the perfused rat adrenal gland through activation of neuronal cholinergic (nicotinic and muscarinic) receptors located in adrenomedullary chromaffin cells. It also seems that epibatidine-evoked catecholamine release is not relevant to stimulation of histaminergic receptors.