A case of papillary fibroelastoma in the left ventricle

Cardiac papillary fibroelastoma (CPF) is a rare and benign primary cardiac neoplasm of unknown prevalence. The incidence of CPF in the left ventricle is lower than that in other parts of the heart. A 65-year-old female was referred to our cardiology department for evaluation of a cardiac mass of the left ventricle. Transthoracic echocardiography revealed a 1.8 x 1.7 cm highly mobile round mass attached by a stalk to the apical inferior wall of the left ventricle with an echolucent area. The mass was successfully removed without any postoperative complications and was identified as a CPF.

A Case of a Pulmonary Arteriovenous Malformation With Ebstein's Anomaly

A pulmonary arteriovenous malformation (PAVM) is a rare pulmonary vascular anomaly presenting as dyspnea or recurrent epistaxis. Ebstein's anomaly (EA), a congenital cardiac malformation, is also a rare condition. There have been no reports concerning the co-existence of PAVM with hereditary hemorrhagic telangiectasia (HHT) and EA. A 40-year-old woman was admitted with a 2-month history of increasing dyspnea and several years of recurrent epistaxis. On transthoracic echocardiography, she was diagnosed with EA and agreed to undergo surgical treatment. A chest CT angiography showed a 12-mm serpiginous vascular structure suspicious for a PAVM and a liver CT suggested HTT. Although it is unclear whether or not a concurrent PAVM and EA have an embryologic or genetic relationship, we report a case of a PAVM with EA. Further genetic and embryonic studies are needed to identify a possible relationship of the two medical conditions.

Effects of Granulocyte-Colony Stimulating Factor and Bone Marrow Mononuclear Cells on Cardiac Function and Remodeling in the Porcine Reperfused Myocardial Infarction Model

BACKGROUND: Granulocyte stimulating factor (G-CSF) and bone marrow mononuclear cells (BM-MNC) were reported to improve cardiac function after myocardial infarction (MI). This study was to examine their combined beneficial effects and mechanisms of actions in reperfused MI, which have not been verified yet. METHODS:Fifteen pigs were divided into 3 groups after a 1-hour balloon occlusion and reperfusion of the left anterior descending coronary artery. G1 (n=5) was a control, G2 (n=5) was a G-CSF injected group (10 ug/kg/day, from day1 to day7 after MI), and G3 (n=5) was an autologous intracoronary BM-MNC infused group after G-CSF treatment RESULTS:Modified wall motion indices by echocardiography were similar among 3 groups at 24 hours after MI. However, they improved significantly in G2 and G3 at 35days after MI (p<0.05). The percentage of infarct area/left ventricular myocardial area measured from a triphenyltetrazolium chloride (TTC) stain was lower in G3 than in G1 or G2 (p=0.026). The number of vWF-positive vessels and the expressions of vWF and VE cardherin by RT-PCR were higher in G3 and G2 than in G1 (p<0.05). The number of TUNEL-positive cells and bcl2/bax ratio were not significantly different among 3 groups. CONCLUSION: This study suggests that intracoronary BM-MNC infusion with G-CSF treatment in reperfused MI reduced infarct size, improved left ventricular function and prevented ventricular remodeling.

A Case of Hepatopulmonary Syndrome in a Patient with Child-Pugh Class A Liver Cirrhosis / 결핵및호흡기질환

Hepatopulmonary syndrome (HPS) is characterized by a defect in arterial oxygenation that's induced by pulmonary vascular dilatation in the setting of liver disease. Some studies have shown the relationship between the presence of the HPS and the severity of liver disease, but there are only rare cases of HPS inpatient with Child-Pugh class A liver cirrhosis. We report here on a case of a 58 years-old male who suffered from progressive dyspnea for the previous few years. He was diagnosed with alcoholic liver cirrhosis 5 years previously. There was no significant abnormality on the chest radiograph and transthoracic echocardiography, but the arterial blood gas analysis revealed severe hypoxemia. Contrast-enhanced transesophageal echocardiograpy with agitated saline demonstrated a delayed appearance of microbubbles in the left cardiac chambers. Thus, he was finally diagnosed with HPS. This case suggests that we should consider HPS when a patient with compensated liver cirrhosis has unexplained dyspnea.

Deep Vein Thrombosis and Pulmonary Embolism in the 8th Week of Pregnancy

A 29-year-old woman in her 8th week of pregnancy was referred to our hospital for swelling in the lower extremities, rapid onset of dyspnea (1 hr) and pre-syncope. Severe right ventricular dysfunction and moderate pulmonary hypertension were detected using 2-dimentional Doppler echocardiography. In addition, left calf vein and proximal thromboses were detected by venous compression ultrasound imaging. After successful thrombolytic treatment, the patient quickly recovered and was discharged from hospital on subcutaneous low-molecular-weight heparin. She delivered a normal, healthy infant at full-term (40 weeks).

Decrease in Plasma Adiponectin Concentrations in Patients with Vasospastic Angina

BACKGROUND AND OBJECTIVES: Plasma adiponectin, which decreases the progression of atherosclerosis and insulin resistance, as well as suppressing lipid accumulation in macrophages, is decreased in patients with acute myocardial infarction and unstable angina pectoris; however, the correlation between plasma adiponectin and vasospastic angina pectoris (VAP) remains to be verified. We compared the plasma adiponectin concentration between patients with VAP and other coronary artery diseases; moreover, we investigated the association between the plasma adiponectin concentration and VAP. SUBJECTS AND METHODS: Following coronary angiography for the evaluation of chest pain, 395 subjects (180 women and 215 men) were divided into 4 groups: acute coronary syndrome (ACS)(n=117), VAP (n=94), stable angina pectoris (SAP)(n=108) and angiographically normal coronary artery (n=76). The acetylcholine provocation test was used to confirm VAP, and plasma adiponectin concentrations were measured in all participants. RESULTS: The plasma adiponectin concentrations in patients with VAP and ACS were significantly lower than that of the normal coronary artery group (6.6+/-5.4 vs. 5.2+/-4.0 vs. 9.0+/-6.2 microgram/mL, p<0.001, respectively). A multivariate analysis indicated that plasma adiponectin [odd ratio (OR) 0.744, 95% confidence interval (CI) 0.645 to 0.858, p=0.001], smoking (OR 2.054, 95% CI 1.027 to 4.106, p=0.042) and age (OR 0.966, 95% CI 0.935 to 0.997, p=0.031) were independently correlated in patients diagnosed with VAP. CONCLUSION: Our results suggest that a decreased plasma adiponectin concentration may be associated with VAP.

Percutaneous Coronary Intervention versus Coronary Artery Bypass Grafting for Diabetics with Multivessel Coronary Artery Disease: The Korean Multicenter Revascularization Registry (KORR)

This study was designed to assess the relative merits of percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) in multivessel coronary artery disease (MVCAD), particularly for Korean diabetics. Among 3,279 patients with MVCAD who were recommended for revascularization were enrolled from nine centers in Korea, 2,154 were selected after statistical adjustments for the disparities between two groups. Survival rates were not significantly different for three years between two groups. Among diabetic patients, the three-year mortality rate in PCI group was 1.9-fold higher than that of CABG group, although it was not statistically significant (PCI 19.8%, CABG 11.4%, p=0.14). The three-year mortality rate was similar between the two groups in non-diabetics (PCI 8.3%, CABG 10.0%, p=0.50). The 30-day rate of cerebrovascular event was higher in CABG group, for both diabetic (CABG 3.6%, PCI 0.0%, p<0.001) and non-diabetic patients (CABG 2.4%, PCI 0.0%, p<0.001). Short- and long-term revascularization rates were higher in PCI group than in CABG group. As a conclusion, this Korean registry demonstrates that PCI was associated with comparable survival rates and lower short-term morbidity, but a greater requirement for repeated revascularization compared with CABG in Korean diabetics.

Changes of Coronary Blood Flow in Vasospastic Angina under Cold Stimulation by Transthoracic Doppler Echocardiography

This study was done to evaluate changes of microvascular function under cold stimulation by measuring coronary flow velocities (CFVs) in vasospastic angina (VA) patients using transthoracic Doppler echocardiography (TTDE). 14 patients with VA and 15 healthy controls were included. CFVs were measured at the distal left anterior descending coronary artery by TTDE at baseline and under cold stimulation. Hyperemia was induced by intravenous adenosine infusion (140 microgram/kg/min). At baseline, CFVs and coronary flow reserve (CFR) were not different between controls and VA patients. Under cold stimulation, the degree of increment of CFV with adenosine was lower in VA patients than in controls. Comparing baseline with cold stimulation, coronary flow reserve (CFR) increased (3.1 +/-0.7 to 3.8 +/-1.0, p=0.06) in controls. In contrast, in VA patients, CFR was decreased (2.8 +/-0.9 to 2.6 +/-0.7, p=0.05) and coronary vascular resistance index markedly increased (0.35 to 0.43, p=0.01). Throughout the study, no patient experienced chest pain or ECG changes. In VA patients, CFR was preserved at baseline, but coronary blood flow increase in response to cold stimulation was blunted and CFR was decreased. These findings suggest that endothelial dependent vasodilation is impaired at the coronary microvascular and the epicardial artery level in VA under cold stimulation.

Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery in an Elderly Patient Visualized by Three-Dimensional Multidetector Computed Tomograph Coronary Angiography

An anomalous origin of the left coronary artery (LCA )from the pulmonary artery (ALCAPA syndrome )or Bland-White-Garland syndrome is a rare congenital cardiac anomaly. We report a 65-year old female patient who presented with atypical chest discomfort. Coronary angiography and three-dimensional multidetector computed tomography coronary angiography demonstrated the ectatic right coronary artery (RCA )arising from the aorta, rich collaterals from the RCA to LCA and the ectatic tortuous LCA that originated from the pulmonary trunk.

Antifibrillatory and Proarrhythmic Effects of d,l-Sotalol Mediated by the Action Potential Duration Restitution Kinetics

BACKGROUND AND OBJECTIVES: The action potential duration (APD) restitution kinetics has been known to play a crucial role in the initiation and maintenance of ventricular tachycardia (VT)/fibrillation (VF). We hypothesized that "the anti-arrhythmic and proarrhythmic effects of d,l-sotalol are mediated by changing the APD restitution (APDR) kinetics". MATERIALS AND METHODS: The purposes of this study were: 1) to assess the effects of d,l-sotalol on the APDR kinetics, and 2) to correlate the anti-arrhythmic and proarrhythmic action using the APDR kinetics. We recorded the transmembrane potentials (TMPs), using the microelectrode technique, in seven isolated perfused swine right ventricles, at the baseline, and with 1, 5, 10 and 20 mg/L of d,l-sotalol, with a washout period of 1 hour. The ventricular effective refractory periods (VERP), APD at 90% repolarization (APD90), spontaneous defibrillation rate and VF inducibility were measured at each concentration. We plotted APDR curves of S1-S2 pacing against VF, and calculated the maximal slopes (Smax) of the APDR. RESULTS: Sotalol (10 mg/L) prolonged the APD90 (p<0.001) by reducing the Smax of the APDR (by S1-S2 pacing, p<0.01; during VF, p<0.05). Accordingly, 41.7% of the VT/VF was terminated spontaneously, and VT/VF inducibility reduced from 91.1% at the baseline to 25% with 10 mg/L sotalol. A higher dose of sotalol (20 mg/L) increased the Smax, despite continuous prolongation of the VERP and APD90, resulting in the increase in the VT/VF inducibility (36.4%). CONCLUSION: Sotalol produces its anti-fibrillatory effect by APD prolongation in parallel with a flattening of the Smax at therapeutic doses. However, a higher concentration of sotalol increased the Smax and VF inducibility in isolated swine ventricular tissue.

The Source of Inflammatory Response and Platelet Activation in Patients with Acute Myocardial Infarction

BACKGROUND AND OBJECTIVES: Studies on the stability of atheromatous plaques, as a determinant of the cause of complications, have been reported. Among the functional features of plaques related with vulnerability, inflammation has emerged as a leading cause of clinical presentation. The purpose of this study was to find the source of the inflammatory response in the patients with acute myocardial infarction (AMI). SUBJECTS AND METHODS: Patients with AMI, whose lesion of in either the left anterior descending artery (LAD group, n=13) or the right coronary artery (RCA group, n=11), were selected. The levels of interleukin-6 (IL-6) and P-selectin were measured in blood from the aortic root (A), great cardiac vein (G) and peripheral vein (V). The control group (n=15) included patients with either stable or variant angina. RESULTS: The levels of IL-6 were 4.77+/-6.0 (A), 11.32+/-7.8 (G) and 4.39+/-5.0 pg/mL (V) in the LAD group, and 3.64+/-2.1 (A), 6.05+/-4.9 (G) and 3.84+/-3.2 pg/mL (V) in the RCA group. Unrelated to the infarction related artery, the level of IL-6 in the great cardiac vein was significantly increased in patients with AMI. The percentages of platelet expressed P-selectin were 6.03+/-7.0 (A), 8.14+/-8.1 (G) and 8.83+/-7.9 (V) in the LAD group and 6.46+/-8.4 (A), 5.80+/-6.0 (G) and 5.91+/-6.9 (V) in the RCA group. CONCLUSION: These findings suggest that the generalized inflammatory response is activated across the coronary vascular bed in patients with AMI, regardless of the infarction related artery site. Therefore, systemic therapy, as well as local management for vulnerable plaque, would be required.

Plasma Renin Activity and Clinical Implication in Korean Hypertensive Patients

BACKGROUND AND OBJECTIVES: Angiotension II, the active component in the renin angiotensin system, modulates blood pressure via vasoconstriction and sodium retention. In normal subjects, the active level of the RAS is reflected by the plasma renin activity (PRA). Importantly, when blood pressure is elevated, the level of RAS is reactively suppressed, and that of PRA approaches zero. Therefore, this study was conducted to find the characteristics of hypertensive patients according to the level of circulating renin. SUBJECTS AND METHODS: The subjects were 275 essential hypertensive patients, with a mean age of 53.2+/-11.9 years, 9.5% of which had diabetes. Patients were classified into 3 groups: low, normal and high renin (high PRA>4.5 ng/mL/h, normal PRA: 0.75-4.5 ng/mL/h and low PRA55 year-old) compared to younger patients (58.7 vs. 36.2%, both p<0.001). However, there were no significant differences in the hemodynamics (SBP, DBP and heart rate), LVMI and cardiovascular risk factors (obesity, dyslipidemia and diabetes) between the 3 groups. CONCLUSION: Women and elderly people are more likely to have LREH compare to men and younger people, who are more likely to have HREH.

Effect of Human Bcl-2 Gene Expression on the Peripheral Atherosclerotic Lesions of Apolipoprotein E-Deficient Mouse

BACKGROUND AND OBJECTIVES: Bcl-2 protein is related to the inhibition of apoptosis via the mitochondrial pathway and Bcl-2's anti-oxidant effect. During the development of atherosclerosis, apoptosis is known to play an important role in the pathophysiologic behavior of atherosclerotic vascular disease in the medium-sized arteries. Apoptosis may be a compensatory reaction to regulate the cellular density of various tissues during the cellular proliferation process such as happens with tissue injury and during the development of atherosclerosis. The consequences of apoptosis in atherosclerosis may be related to the formation of an acellular lipid core, plaque instability and the loss of vascular wall integrity and remodeling. We sought to determine the effect of Bcl-2 gene expression on the development of primary atherosclerosis in apolipoprotein E deficient mouse, which is one of the typical animal models that are used for the development of peripheral atherosclerosis. MATERIALS AND METHODS: Bcl-2 transgenic mice were cross hybridized with apolipoprotein E deficient mice. Systemic analysis of the distribution and severity of their atherosclerotic lesions was done by dissecting microscopy, and the histological characteristics of the lesions were evaluated in normal chow-fed, 9-month-old apolipoprotein-E deficient/Bcl-2 transgenic mice (n=6) and apolipoprotein-E deficient mice (n=6). RESULTS: The distribution and severity of atherosclerotic lesions at the peripheral arteries were less in the apolipoprotein-E deficient/Bcl-2 transgenic mice. Acellular lipid core formation, destruction of the smooth muscle cell layers in the media and infiltration of inflammatory cells in the adventitia were much less in the apolipoprotein-E deficient/Bcl-2 transgenic mice. The lipid profile was similar in both groups. CONCLUSION: The effect of Bcl-2 gene expression on the peripheral atherosclerosis was related with the inhibition or the delay of atherosclerotic lesion progression, such as the reduction of amount of the acellular lipid core, maintenance of vascular smooth muscle cell integrity and the reduction of adventitial inflammation, and this was achieved regardless of serum cholesterol level.

An Appraisal of the Electrocardiographic Criteria for Diagnosis of Left Ventricular Hypertrophy in Koreans: Comparison to Echocardiographic Measurement of Left Ventricular Mass

BACKGROUND AND OBJECTIVES: Left ventricular hypertrophy (LVH) is associated with an increased risk of cardiovascular morbidity and mortality. Electrocardiography (ECG) is a widely available, simple and cost-effective screening method for the diagnosis of left ventricular hypertrophy. Since all the ECG criteria for LVH used for Koreans are based on ECG data from Caucasians, i.e., people whose body size is generally bigger than Koreans, its test accuracy may be low. The purpose of this study was to investigate by ECG the best cut-off value for LVH in terms of the left ventricular mass, as determined by echocardiogram. SUBJECTS AND METHODS: We investigated ECG and echocardiograms of 200 consecutive patients who visited the Korean University Anam Hospital. The sensitivity, specificity and diagnostic accuracy of the left ventricular mass for LVH, by the Sokolow-Lyon voltage criteria and Romhilt-Estes point score, were calculated and compared according to the cut-off values of 35, 40 and 45 mm and 3, 4 and 5 points, respectively. RESULTS: The sensitivities of the Sokolow-Lyon voltage criteria at 40 mm were slightly decreased (42.5, 37.5 and 8.8%; > or =35, > or =40, > or =45 mm), but the specificities and diagnostic accuracies were increased (specificities of 84.2, 95.0 and 99.2%, and diagnostic accuracies of 67.5, 72.0 and 63%; > or =35, > or =40, > or =45 mm). The sensitivities of a Romhilt-Estes point score of 4 points were slightly decreased (43.8, 37.5 and 13.8%; > or =3, > or =4, > or =5 points), but the specificities and diagnostic accuracies were increased (specificities 85.8, 94.2 and 98/3%, and diagnostic accuracies 69.0, 71.5 and 64.5%; > or =3, > or =4, > or =5 points). CONCLUSION: The Sokolow-Lyon voltage criteria at 40 mm or more and a Romhilt-Estes point score 4 points or more are appropriate ECG criteria for LVH in Koreans.

Effect of Central Losartan on DOCA-Salt Hypertension Rats

BACKGROUND: The purpose of this study was to investigate whether brain AT1 receptor stimulation contributes as a hypertensive mechanism to deoxycorticosterone acetate (DOCA)-salt hypertension. METHODS: 1) Acute injection:Losartan (1 mg/4 uL) or artificial cerebrospinal fluid (aCSF) was injected into the lateral cerebral ventricle (icv) of conscious control uninephrectomized Wistar rats or rats with DOCA-salt at 2 or 4 weeks, and mean arterial pressure (MAP) and heart rates (HR) were recorded. 2) Chronic injection:Using osmotic minipump, losartan (1 mg/kg/d) or aCSF was injected to a sham group or three DOCA-salt rat groups [icv-aCSF, icv-losartan, sc-losartan (subcutaneous) groups] for 4 weeks, after which the MAP and HR were recorded in addition to the weights of the left (LV) and right ventricles (RV) and kidneys. RESULTS: 1) Acute injection: In rats treated with DOCA-salt, resting MAP significantly increased compared to the control group [144+/-6 mmHg (2 weeks), 170+/-5 mmHg (4 weeks) vs 115-120 mmHg (controls)]. MAP decreased significantly (2 weeks, 4 weeks) at 4, 8, 24 hours after icv injection of losartan to the level of the control group. 2) Chronic injection: The general trend showed that MAP decreased more in the icv-losartan group than in the icv-aCSF group (127+/-15.2 mmHg vs 141.1+/-5.5 mmHg, p=0.0578). In all DOCA-salt groups, no differences in RV weight were found. In the icv-aCSF and sclosartan groups, the kidney weight increased compared to the control group, but there was no difference in LV and kidney weight between the icv-losartan group and the control group. CONCLUSION: Normalization of MAP after acute or chronic icv administration of the AT1 receptor antagonist suggests that the stimulation of the brain AT1 receptor plays a significant role in the development and maintenance of hypertension in the DOCA-salt hypertensive rat model. Losartan icv injection appeared to have a protective effect on the heart and kidney.

5-azacytidine induces cardiac differentiation of P19 embryonic stem cells

The P19 embryonal carcinoma cell line is a useful model cells for studies on cardiac differentiation. However, its low efficacy of differentiation hampers its usefulness. We investigated the effect of 5-azacytidine (5-aza) on P19 cells to differentiate into a high-efficacy cardiomyocytes. Embryoid-body-like structures were formed after 6 days with 1 micrometer of 5-aza in a P19 cell monolayer culture, beating cell clusters first observed on day 12, and, the production of beating cell clusters increased by 80.1% (29 of 36-wells) after 18 days. In comparison, the spontaneous beating cells was 33.3% (12 of 36-wells) for the untreated control cells. In response to 1 micrometer of 5-aza, P19 cells expressed bone morphogenetic protein-2 (BMP-2), BMP-4, Bmpr1a and Smad1 at day 6 or 9, and also cardiac markers such as GATA-4, Nkx2.5, cardiac troponin I, and desmin were up-regulated in a time-dependent manner after induction of BMP signaling molecules. Immunocytochemistry revealed the expression of smooth muscle a-actin, sarcomeric a-actinin, cardiac myosin heavy chain, cardiac troponin T and desmin, respectively. The proportion of sarcomeric a-actinin positive cells accounted for 6.48% on day 15 after 5-aza exposure as measured by flow cytometry. This study has demonstrated that 5-aza induces differentiation of P19 cells into cardiomyocytes in a confluent monolayer culture in the absence of prior embryoid formation and dimethyl sulfoxide exposure, depending in part on alteration of BMP signaling molecules. These results suggest that 5-aza treatment could be used as a new method for cardiac differentiation in P19 cells.

Relation of Blood Pressure Components to Left Ventricular Hypertrophy and Coronary Heart Disease with Aging

BACKGROUND AND OBJECTIVES: There is still uncertainty regarding the relative importance of systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP) in predicting the risk of cardiovascular disease. The relative importance of the BP components, as markers of left ventricular hypertrophy (LVH) and coronary artery disease (CAD), were examined in relation to age. SUBJECTS AND METHODS: In 257 subjects receiving no antihypertensive medication, LVH was determined using the M-mode echocardiography when left ventricular mass index (LVMI) was >or =129 g/m2 in men or >or =118 g/m2 in women. In a further 265 subjects, CAD was determined using the coronary angiography when stenosis of the coronary arterial diameter was >or =70%. The most important BP component was determined using a logistic regression analysis. RESULTS: With respect to LVH, in the group 0.10) for DBP, SBP and PP respectively. In the group 50 to 59 years of age, ORs were 1.65, 1.35, 1.36 (all por =60 years of age, ORs were 1.56 (p0.10), 1.07 (p>0.10), 1.21 (por =60 years of age, no BP component had a statistical significance. CONCLUSION: With increasing age, there was a gradual shift from DBP to SBP and then to PP as the marker with the greatest relation to LVH. In all age group, PP was the strongest marker of CAD.

Cardiac Rhythm Disturbance in Sleep Apnea Syndrome: Effect of Nasal Continuous Positive Airway Pressure(nCPAP) Therapy

BACKGROUND AND OBJECTIVES: It has been demonstrated that sleep apnea syndrome predisposes to cardiac rhythm disturbances and cardiovascular risks such as systemic hypertension. This study was conducted to investigate the types and frequency of cardiac arrhythmias which occurred during sleep and the effects of nasal continuous positive airway pressure (nCPAP) therapy in the patients with sleep apnea syndrome. SUBJECTS AND METHODS: The subjects were 197 patients who were referred to the Sleep Research Center of Korea University Medical Center for polysomnography due to snoring and sleep apnea from Jan. 1st 2000 to July 31st 2002. Of the 197 patients, 44 with severe sleep apnea syndrome, whose respiratory disturbance index (RDI) exceeded 40/hr, were enrolled. Their electrograms on polysomnography before and after nCPAP therapy were analyzed. RESULTS: Of the 44 subjects, 32 (72.8%) showed cardiac arrhythmias. The types of arrhythmias were atrial premature beats (APBs, n=17), premature ventricular complexes (PVCs, n=15), sinus bradycardia (heart rate less than 40 per minute, n=6), sinus pause (n=1), and sinoatrial block (n=5). No fatal arrhythmias were identified. Most, 93.2%, of these arrhythmias arose immediately after hypopneic or apneic episodes, and were accompanied by a significant decrease in SaO2, from 91.4% to 84.7% (p<0.05). After nCPAP therapy, these arrhythmias were completely disappeared in 11 patients (34.4%) and diminished in 15 (46.9%). Hypopneic or apneic episodes were preceded by cardiac arrhythmias in only 36.4% with nCPAP (p<0.05 vs. before). CONCLUSION: Cardiac arrhythmias were demonstrated in 72.8% of cases of severe sleep apnea syndrome, which were mostly benign and preceded by hypopneic or apneic episodes. nCPAP therapy decreased the frequency of hypopnea and apnea with elevated arterial O2 saturation, and effectively eliminated cardiac arrhythmias.

Initiation and Maintenance Mechanism of Atrial Fibrillation Assessed by 3-Dimensional Non-Contact Mapping System

BACKGROUND AND OBJECTIVES: We undertook this study to assess the initiation and maintenance mechanisms of atrial fibrillation (AF) and their relationships with the anatomical structures of the left atrium (LA) and pulmonary veins (PVs). SUBJECTS AND METHODS: Thirty-seven patients (33 men, mean age 50, range 25-68 years) with paroxysmal AF (n=29) and persistent AF (n=8) who underwent mapping of the LA and PV using 3D non-contact endocardial mapping system (EnSite 3000) were enrolled. The multielectrode array and ablation catheter were positioned in the LA via the double transseptal approach. Atrial premature beats (APBs) which triggered initiation of AF that lasted longer than 1 min were mapped and the activation sequence was analyzed on isopotential color maps. Wave front dynamics and the relationship with the underlying structures were assessed. RESULTS: More than half, 56.4%, of APBs from PV were related to the initiation of AF, but not related to the maintenance of AF. A quarter, 25.6%, of APBs from PV not only initiated AF, but also maintained AF without continuous triggering. Mixed type and indeterminate type of AF was 5.0% and 12.8%, respectively. During AF, the mean number of wavelets was 1.45 (maximum 3 in 76.5%). Anatomical structures showing slow conduction and wavebreaks were mostly located at the septopulmonary bundle (86.5%) and the posterior roof of the LA between the left superior PV and right superior PV (54.1%). CONCLUSION: Focal repetitive activity from PV played an important role in both the initiation and maintenance of AF. Specific anatomical structures such as septopulmonary bundle or posterior roof of the LA were related to the heterogeneous conduction delay and spontaneous wavebreak, which was also important in the maintenance of AF.

Time-Related Alterations of Endogenous Ouabain in DOCA-Salt Hypertensive Rats

BACKGROUND AND OBJECTIVES: Controversy exists regarding the role of endogenous ouabain in the pathogenesis of DOCA-salt induced hypertension. The purpose of this study was to investigate the role of endogenous ouabain in the development of hypertension in DOCA-salt rats. MATERIALS AND METHODS: The mean blood pressure and heart rate were recorded in 1, 2 and 4 week old control and DOCA-salt treated rats. The endogenous levels of ouabain in the plasma, hypothalamus, pituitary and adrenal glands of the 1, 2 and 4 week old control and DOCA-salt treated rats were also measured using a radioimmunoassay. RESULTS: The mean blood pressures in the 2 and 4 week old DOCA-salt treated rats were significantly higher than those of the controls. There was no significant change in the heart rate between the DOCA-salt treated and control groups. In the 4 week old DOCA-salt treated rats, the endogenous level of ouabain in the adrenal glands was higher than that in the control rats, but this was only weakly significant. The endogenous level of ouabain in the hypothalamus was significantly higher in the 1 week old DOCA-salt treated rats than in the control, but this significance disappeared in the 2 and 4 week old DOCA-salt treated rats. CONCLUSION: These results suggest that the endogenous level of ouabain contributes to the development and maintenance of high blood pressure in DOCA-salt rats. Further studies will be required to elucidate the relationship between the endogenous level of ouabain and DOCA-salt hypertension.