Woo Hyuk Song

Impact of obstructive sleep apnea on left ventricular diastolic function.

The aim of this study was to investigate the impact of obstructive sleep apnea (OSA) on left ventricular (LV) functional changes by using tissue Doppler imaging-derived indexes in patients with OSA. We studied 62 patients classified into 3 groups, namely 18 with mild to moderate OSA, 24 with severe OSA, and 20 control subjects without OSA according to the apnea-hypopnea index (AHI) on complete overnight polysomnogram. All underwent conventional and tissue Doppler echocardiographies. Only early diastolic velocity (Ea; -6.2 +/- 0.3 vs -7.1 +/- 0.3 vs -7.3 +/- 0.3 cm/s, respectively, for the 3 groups, p = 0.023) was significantly decreased in the severe OSA group. Other echocardiographic parameters of diastolic function such as isovolumic relaxation time, deceleration time, mitral inflow early/late wave velocity ratio, and pulmonary vein systolic/diastolic pulmonary vein velocity ratio were comparable among the 3 groups. AHI was correlated only with tissue Doppler imaging-derived indexes of LV diastolic function (Ea r = -0.382, p = 0.002; Ea/late diastolic velocity r = -0.329, p = 0.009), but not with conventional Doppler indexes. AHI remained a significant predictor of Ea after adjusting for age, heart rate, fasting glucose level, blood pressure, body mass index, and LV mass index in a multiple stepwise linear regression model (p = 0.007). In conclusion, only patients with severe OSA showed a greater impairment of LV diastolic function. Of all echocardiographic parameters of diastolic dysfunction investigated, only Ea was identified as the best index to demonstrate an association between LV diastolic dysfunction and severity of OSA independently of body mass index, diabetes mellitus, and hypertension.

Efficacy of losartan and carvedilol on central hemodynamics in hypertensives: a prospective, randomized, open, blinded end point, multicenter study.

Renin–angiotensin system (RAS) blockers have shown clinical outcomes superior to those of the beta (β)-blocker atenolol, despite similar reductions in the peripheral blood pressure (BP), perhaps because of different impacts on central hemodynamics. However, few comparative studies of RAS blockers and newer vasodilating β-blockers have been performed. We compared the central hemodynamic effects of losartan and carvedilol in a prospective, randomized, open, blinded end point study. Of the 201 hypertensive patients enrolled, 182 (49.6±9.9 years, losartan group=88 and carvedilol group=94) were analyzed. Carotid-femoral pulse wave velocity (cfPWV), aortic augmentation index (AIx), AIx corrected for a heart rate (HR) of 75 beats per minute (AIx@HR75) and central BP were measured noninvasively at baseline and after a 24-week treatment regimen with losartan or carvedilol. After 24 weeks, there were no between-group differences in the brachial BP, cfPWV, AIx@HR75 or central BP changes, except for a more favorable AIx effect with losartan. The changes in all measured metabolic and inflammatory parameters were also not significantly different between the two groups, except for uric acid. Losartan and carvedilol showed generally comparable effects on central hemodynamic indices, metabolic profile, inflammatory parameters and peripheral arterial pressure with a 24-week treatment.

Effects of cilostazol on platelet activation in coronary stenting patients who already treated with aspirin and clopidogrel.

Background : A recent study has shown that triple anti-platelet therapy (cilostazol+clopidogrel+aspirin) resulted in a significantly lower restenosis rate after coronary stenting than did conventional therapy (clopidogrel+aspirin). However, the anti-platelet effects of cilostazol, when combined with clopidogrel and aspirin, have not been evaluated. Methods : Low dose cilostazol (50 mg/BID) was given to 47 patients who had already been taking clopidogrel (75 mg/day) and aspirin (100 mg/day) for more than 1 month subsequent to coronary stenting due to AMI and unstable angina. Markers of platelet activation, P-selectin and activated GPIIb/IIIa on platelets, were measured at baseline and 2 weeks after cilostazol treatment. We empirically divided patients into tertiles (low, n=16; moderate, n=14; high group, n=17), according to the baseline P-selectin expression. We then performed a comparative assessment of the anti-platelet effects of cilostazol at baseline and after 2 weeks of cilosatzol administration. Results : P-selectin was significantly decreased after 2 weeks of cilostazol treatment in total patients (n=47, 3.2±2.4% to 2.0±1.9%, p=0.03). This inhibition of P-selectin expression was mainly achieved in the moderate and high P-selectin groups (low group; 1.4±0.5 to 1.9±1.3%, p>0.05, moderate group; 2.5±0.3 to 1.3±0.3%, p<0.05, high group; 5.4±2.7 to 2.7±2.8%, p<0.05). Activated GPIIb/IIIa was not significantly changed (13.5% to 17.6%, p>0.05). Underlying disease, cardiovascular risk factors, concomitant medication including statin, and hsCRP were not related to the degree of P-selectin expression. Conclusion : Our data demonstrated that cilostazol treatment in addition to conventional anti-platelet therapy provides more effective suppression of platelet P-selectin expression in patients with relatively high platelet activity.

Cardioprotective effects of rosuvastatin and carvedilol on delayed cardiotoxicity of doxorubicin in rats

Context: Doxorubicin is widely used anti-neoplastic drug but has serious cardiotoxicity. Long-term cardioprotective effects of statin and carvedilol against delayed cardiotoxicity of doxorubicin was not well elucidated. Objective: To evaluate long-term cardioprotective effects of co-administered rosuvastatin and carvedilol against chronic doxorubicin-induced cardiomyopathy (DIC) in rats. Methods: Sixty-one rats were assigned to six groups: group I, control; group II, doxorubicin only (1.25 mg/kg, bi-daily, I.P.); group III, doxorubicin + rosuvastatin (2 mg/kg/day, P.O.); group IV, doxorubicin + rosuvastatin(10 mg/kg/day, P.O.); group V, doxorubicin + carvedilol (5 mg/kg/day, P.O.); group VI, doxorubicin + carvedilol (10 mg/kg/day, P.O.). Drugs were administered for 4 weeks (by week 4) and rats were observed without drugs for 4 weeks (by week 8). Results: After 4 weeks discontinuation of drugs (week 8), group III showed higher +dP/dt (p = 0.058), lower −dP/dt (p = 0.009), lower left ventricular (LV) tissue malondialdehyde (MDA; p = 0.022), and less LV fibrosis (p = 0.011) than group II. Group IV showed similar results to group III. However, in group V and VI, carvedilol failed to reduce LV dysfunction, elevation of troponin or myocardial fibrosis, although group V showed lower LV tissue MDA (p = 0.004) than group II. Discussion and conclusions: Myocardial injury and LV systolic/diastolic dysfunction at week 8 was alleviated by co-administered rosuvastatin, but not by carvedilol. It is unclear whether the cardioprotective effect of rosuvastatin is attributed to a suppression of oxidative stress induced by doxorubicin, because carvedilol did not exhibit a cardioprotective effect despite its antioxidant effects.

Effects of Smoking on Coronary Blood Flow Velocity and Coronary Flow Reserve Assessed by Transthoracic Doppler Echocardiography

Background: Smoking is a well‐known risk factor for cardiovascular disease. Coronary blood flow velocity (CFV) can be measured directly with transthoracic Doppler echocardiography (TTDE) which is conducted immediately after smoking. Purpose: The purpose of this study was to evaluate the chronic and acute effects of smoking on coronary blood flow and coronary flow reserve (CFR) by the use of TTDE. Methods: Healthy volunteers (11 smokers and 9 nonsmokers) with a mean age of 27 ± 3 years were included. Smoking was abstained for at least 4 hours before the study. CFV was measured at the distal left anterior descending coronary artery by TTDE at baseline and during intravenous adenosine infusion (140 μg/kg per minute) in all participants. For smokers, CFV was measured immediately after consecutively smoking two cigarettes and during adenosine infusion. Results: CFR and coronary vascular resistance index (CVRI) showed no significant difference between nonsmokers and smokers (CFR: 3.5 ± 0.8 vs 3.6 ± 0.6, P = ns, CVRI: 0.28 vs 0.28, P = ns) at baseline. CFR significantly decreased (3.6 ± 0.6 to 2.8 ± 0.7, P = 0.008) and CVRI markedly increased (0.28 to 0.35, P = 0.012) after smoking. Conclusion: After 4 hours of abstinence from smoking, CFR and CVRI in smokers were similar to those of nonsmokers. However, consecutively smoking two cigarettes acutely reduced CFR and increased CVRI. These findings suggested that smoking could reduce coronary blood flow immediately, even in healthy people.

The Prevalence and Awareness of Hypertension and the Relationship between Hypertension and Snoring in the Korean Population

Background: Hypertension is the most important, and yet modifiable, risk factor for cardiovascular diseases. But in many countries, hypertension remains poorly controlled. Moreover, sleep apnea syndrome has shown that it is correlated with hypertension. The purpose of this study was to investigate the prevalence, awareness and control of hypertension among the Korean people and to evaluate the relationship between hypertension and snoring. Methods: A total of 640 subjects living in Ansan, a regional city in Korea, were selected randomly, and trained nursing students investigated their age, sex, medical history, blood pressure, body mass index (BMI) and snoring score. Blood pressures were measured three times with a 10-minute interval and then averaged. The degree of snoring was estimated using a questionnaire. We divided the subjects into hypertensive (BP≥140/90 mmHg) versus normotensive group and snorer versus non-snorer group, and correlated hypertension with snoring. Results: Of 640 subjects, 311 were male. The mean age was 39.7 ± 14.6 years (18–77 years), the mean BMI (body mass index) was 22.4 ± 3.0 kg/m2. The mean systolic and diastolic blood pressure was 121 ± 15.7 mmHg and 79.5 ± 11.6 mmHg. The prevalence and awareness of hypertension were 22.2% and 16.9%, respectively, and the prevalence of snoring was 35.2%. With the increment of age, in the male, the prevalence of hypertension and snoring were higher, and the snorer group showed a higher risk of hypertension than the non-snorer group (Odds ratio 2.32, CI=1.56–3.39, p = 0.0001). Conclusion: In Korea, the prevalence of hypertension was similar to that in the western countries, but the awareness of hypertension was much lower compared with western countries. The prevalence of hypertension was higher in the snorer group, so more research on the correlation between the two conditions should be advanced in the future.

Brugada-Like ST-Segment Abnormalities Associated with Myocardial Involvement of Hematologic Diseases

This is a report of Brugada‐like ST‐segment abnormalities related to acute myocarditis associated with hematologic disorders. Electrocardiographic (ECG) pattern of ST‐segment elevation in the right precordial leads mimicking Brugada syndrome may relate to pathological abnormalities due to hematologic disorders that may have genetic, infective, or inflammatory origins. We describe two cases of myocardial involvement of hemotologic disorders, manifested with Brugada‐like ECG findings.

Papillary fibroelastoma of the pulmonary valve

A papillary fibroelastoma is rare, but it is the most common primary tumor of the cardiac valves. Most papillary fibroelastomas affect the left-sided heart valves, such as the aortic and mitral valves; however, they also rarely affect the pulmonary valve. Generally, surgical removal is strongly recommended to prevent its potential thromboembolic risks, especially in cases of left-sided cardiac involvement. However, there are few reports on the treatment of asymptomatic, small, right-sided cardiac fibroelastomas. We present a rare case of an asymptomatic papillary fibroelastoma occurring on the pulmonary valve, which was detected by transthoracic echocardiography, transesophageal echocardiography, and a 64-slice cardiac computed tomography scan, and which was surgically removed.

Simultaneous and spontaneous multivessel coronary artery dissection presenting as congestive heart failure

Spontaneous coronary artery dissection (SCAD) is a rare cause of myocardial ischemia. Multivessel SCAD is much rarer than single vessel involvement and acute coronary syndrome is the most frequent clinical presentation of a patient with SCAD. The patient in this report had SCAD in both the left anterior descending and right coronary arteries at the same time. However, the clinical manifestation was not acute coronary syndrome but rather congestive heart failure. Successful angioplasty and stent placement was performed and the symptoms of congestive heart failure were successfully resolved with medical treatment.

Relationship between T-wave normalization on exercise ECG and myocardial functional recovery in patients with acute myocardial infarction

Background Several studies suggested that T-wave normalization (TWN) in exercise ECG indicates the presence of viable myocardium. But the clinical implication of this phenomenon in patients with acute myocardial infarction who received proper revascularization therapy was not determined. Precisely the aim of this study was to investigate the relationship between TWN in exercise ECG and myocardial functional recovery after acute myocardial infarction. Methods We studied 30 acute myocardial infarction patients with negative T waves in infarct related electrocardiographic leads and who had received successful revascularization therapy. Exercise ECG was performed 10–14days after infarct onset using Naughton protocol. Patients were divided into 2 groups according to presence (group I; n=14) or not (group II; n=16) of TWN in exercise ECG. Exercise parameters and coronary angiographic findings were compared between groups. Baseline and follow-up (mean 11 months) regional and global left ventricular function was analyzed by echocardiography. Results Exercise parameters were similar between groups. There was no difference in baseline ejection fraction and wall motion score between group I and II (EF; 56±12% vs 52±11%, p=ns. WMS; 21±3 vs 23±4, p=ns) and it was improved at the tenth month by similar magnitude (group I/group II, EF % change=12±12% vs 7±6%, p=ns, WMS % change=6±6% vs 7±5%, p=ns). The finding of no relation between TWN and functional recovery was observed also when the patients were analysed according to infarct location and presence or absence of Q-waves. Conclusion As the exercise-induced TWN in patients with acute myocardial infarction was not related with better functional recovery of dysfunctional regional wall motion and ejection fraction, TWN does not appear to be an indicator of myocardial viability.