Woo-Baek Chung

Early Cardiac Function Monitoring for Detection of Subclinical Doxorubicin Cardiotoxicity in Young Adult Patients with Breast Cancer

Purpose As doxorubicin cardiotoxicity is considered irreversible, early detection of cardiotoxicity and prevention of overt heart failure is essential. Although there are monitoring guidelines for cardiotoxicity, optimal timing for early detection of subclinical doxorubicin cardiotoxicity is still obscure. The purpose of this study is to determine optimal timing of cardiac monitoring and risk factors for early detection of doxorubicin cardiotoxicity in young adult patients with breast cancer. Methods Medical records of 1,013 breast cancer patients diagnosed from January 2009 to December 2010 is being reviewed and analyzed. Properly monitored patients are defined as patients who underwent transthoracic echocardiography before and after the chemotherapy. The definition of subclinical cardiotoxicity (SC) either decreases left ventricular ejection fraction (LVEF) more than 10% or the LVEF declines under 55% from baseline without heart failure symptoms. Results Twenty-nine out of 174 (16.7%) properly monitored young adult female patients (mean age, 52±10 years old) developed SC. The mean interval of cardiac evaluation of SC group was 5.5±3.0 months. Among the risk factors, the history of coronary artery disease, cumulative dose of doxorubicin ≥300 mg/m2 and use of trastuzumab after doxorubicin therapy were associated with development of SC. At cumulative dose of doxorubicin 244.5 mg/m2, SC can be predicted (sensitivity, 71.4%; specificity, 70.9%; area under the curve, 0.741; 95% confidence interval, 0.608-0.874; p=0.001). Conclusion In young adult patients with breast cancer, SC was common at cumulative dose of doxorubicin <300 mg/m2 and early performance of cardiac monitoring before reaching the conventional critical dose of doxorubicin might be a proper strategy for early detection of SC.

A Case of Chloroquine-Induced Cardiomyopathy That Presented as Sick Sinus Syndrome

A 52-year-old woman with rheumatoid arthritis who had been treated with prednisone and hydroxychloroquine for >12 years presented with chest discomfort and a seizure. She was diagnosed with restrictive cardiomyopathy combined with sick sinus syndrome. A myocardial muscle biopsy was performed to identify the underlying cardiomyopathy, which showed marked muscle fiber hypertrophy, fiber dropout, slightly increased interstitial fibrous connective tissue, and extensive cytoplasmic vacuolization of the myocytes under light microscopy. Electron microscopy of the myocytes demonstrated dense, myeloid, and curvilinear bodies. The diagnosis of hydroxychloroquine-induced cardiomyopathy was made based on the clinical, hemodynamic, and pathologic findings. This is the first case report describing chloroquine-induced cardiomyopathy involving the heart conduction system.

Effect of Angiotensin Converting Enzyme Inhibitors and Angiotensin Receptor Blockers on Patients Following Ablation of Atrial Fibrillation

Background and Objectives It is known that angiotensin converting enzyme inhibitors and angiotensin II type 1 receptor blockers (ACEIs and ARBs, respectively) are effective in preventing atrial fibrillation (AF) in high-risk patients. However, it is not known whether ACEIs and ARBs are effective in preventing the recurrence of AF after catheter ablation. Subjects and Methods One hundred fifty-two patients (mean age, 57±10 years; M : F=94 : 58) who underwent catheter ablation due to drug-refractory paroxysmal (mean age, 57±10 years; M : F=58 : 43) or persistent AF (mean age, 56±10 years; M : F=36 : 15) were enrolled. We compared the recurrence rates between the groups with and without ACEIs or ARBs use in paroxysmal and persistent AF. The mean duration of follow-up was 18±14 months. Results The overall recurrence rate after ablation therapy was 26% (n=39). The recurrence rate was significantly decreased in the patients with persistent AF with the use of ACEIs or ARBs (12.1% vs. 61.1%, p<0.01), but this difference was not observed in the patients with paroxysmal AF (24.2% vs. 22.9%, p=0.87). In patients with persistent AF with and without recurrence, the size of the left atrium (44.2±8.4 mm vs. 44.3±5.8 mm, respectively, p=0.45) and the ejection fraction (62±6.5% vs. 61.5±6.2%, respectively, p=0.28) were not significantly different. In multivariate analysis, the use of ACEIs or ARBs was independently associated with recurrence after adjusting for the size of the left atrium and the ejection fraction {odds ratio (OR)=0.078, 95% confidence interval (CI)=0.02-0.35, p<0.01}. Conclusion ACEIs and ARBs were shown to be effective in preventing AF recurrence after catheter ablation in patients with persistent AF.

Estimation of Coronary Flow Velocity Reserve Using Transthoracic Doppler Echocardiography and Cold Pressor Test Might Be Useful for Detecting of Patients with Variant Angina

Purpose: The cold pressor test (CPT) has been used to detect variant angina, but its sensitivity in predicting vasospasm is low. The aim of this study was to determine whether estimates of the coronary flow velocity reserve (CFVR) in the distal left anterior descending coronary artery (dLAD) using transthoracic echocardiography (TTE) and CPT are useful tool to predict variant angina. Methods: 65 patients (mean age = 52 ± 10 years; male:female = 41:24) who had normal coronary artery on angiography and underwent acetylcholine provocation test were enrolled and divided into the spasm group (n = 31) and the no spasm group (n = 34). During CPT, the peak (PDV) and mean diastolic flow velocity (MDV) of the dLAD were estimated using TTE with a high‐frequency transducer, and electrocardiography, blood pressures, heart rate, and symptoms were monitored every 30 seconds. CPT%PDV and CPT%MDV were defined as the percentage changes in PDV and MDV during CPT, respectively. Results: CPT%PDV was 4.99 ± 23.62% in the spasm group and 52.75 ± 24.78% in the no spasm group (P < 0.001). CPT%MDV was 6.83 ± 23.81% in the spasm group and 50.22 ± 27.83% in the no spasm group (P < 0.001). CPT%PDV<31.1% had a sensitivity of 93.5% and a specificity of 82.4% in predicting variant angina (95% confidence interval [CI]: 0.939–0.979, P < 0.001). CPT%MDV<30.55% had a sensitivity of 90% and a specificity of 76.5% in predicting variant angina (95% CI: 0.884–0.950, P < 0.001). Conclusion: The measurement of changes in the coronary flow velocity of the dLAD using TTE and CPT might be useful for the estimation of endothelial dysfunction in patients with variant angina. (ECHOCARDIOGRAPHY 2010;27:435‐441)

Prehypertension is associated with early complications of atherosclerosis but not with exercise capacity

BACKGROUND Prehypertension has a high risk of progression to hypertension, and intensive lifestyle modification including regular exercise is recommended for the management of prehypertensive individuals. However, data on the association between exercise capacity and hypertension status are limited. Therefore, we aimed 1) to define the characteristics of prehypertension, focusing on metabolic aspects and exercise capacity, and 2) to elucidate determinants of exercise capacity in healthy individuals without hypertension. METHODS We retrospectively identified 741 normotensive healthy subjects (mean age, 52.6±8.8years; 57.9% men) who underwent consecutive cardiopulmonary exercise testing. The participants were categorized into two groups: the optimal blood pressure (BP) (systolic BP<120mmHg and diastolic BP<80mmHg, n=364) and prehypertension (systolic BP 120-139mmHg and/or diastolic BP 80-89mmHg, n=377) groups. Exercise capacity was assessed with peak oxygen consumption. RESULTS The prehypertension group showed metabolic syndrome characteristics, and had increased left ventricular mass index and impaired diastolic function. However, no significant differences in exercise capacity were found between the optimal BP and prehypertension groups (peak VO2, 25.3±7.2 vs. 25.8±7.3mL/kg/min, p=0.327). Age, resting heart rate, and fat percentage were identified as independent determinants of exercise capacity (p<0.001 for all). CONCLUSIONS Prehypertension is associated with metabolic disarrangement and preclinical target organ damage but not with exercise capacity. Exercise capacity is determined by age, resting heart rate, and body composition in relatively healthy individuals who do not have hypertension.

Pathophysiology and preventive strategies of anthracycline-induced cardiotoxicity

Cardiotoxicity is a well-known complication following treatment with anthracyclines. However, they are still widely used in chemotherapy for breast cancer, lymphoma, leukemia, and sarcoma, among others. Patient clinical characteristics, such as age, sex, comorbidities, anthracycline dose and infusion schedule, and the combined anti-cancer agents used, are diverse among cancer types. It is difficult to recommend guidelines for the prevention or management of anthracycline-induced cardiotoxicity applicable to all cancer types. Therefore, anthracycline-induced cardiotoxicity remains a major limitation in the proper management of cancer patients treated with an anthracycline-combined regimen. Efforts have been extensive to determine the mechanism and treatment of anthracycline-induced cardiotoxicity. Because cardiotoxicity causes irreversible damage to the myocardium, prevention is a more effective approach than treatment of cardiotoxicity after symptomatic or asymptomatic cardiac dysfunction develops. This article will review the pathophysiological mechanisms of anthracycline-induced cardiotoxicity and strategies for protecting the myocardium from anthracycline.

Serum Osteoprotegerin Is Associated With Calcified Carotid Plaque: A Strobe-Compliant Observational Study.

AbstractOsteoprotegerin (OPG) is a kind of tumor necrosis factor, which is related to bone metabolism and vascular calcification. The increase of Osteoprotegerin concentration in serum is related to cardiovascular diseases in humans. The purpose of this study was to figure out the relevance between osteoprotegerin in serum and carotid calcification.Serum OPG concentrations were compared in 145 patients who underwent carotid sonography (average age: 68 ± 9 years old, male: female = 81:64). A calcified plaque (CP) (37 people [27%]), a noncalcified plaque (NCP) (54 people [37%]), and a nonplaque (NP) (54 people [37%]) were classified for this study.No significant differences among 3 groups were demonstrated in the distribution of age, diabetes, high blood pressure, and hyperlipidemia. Serum osteoprotegerin concentrations were significantly increased in CP group rather than NCP group or NP group; (median [interquartile range], 4016 [1410] vs 3210 [1802] pg/mL, P < 0.05 and 4016 [1410] vs 3204 [1754] pg/mL, P < 0.05). Serum osteoprotegerin concentrations did not indicate a significant difference between NCP Group or NP Group.This study had proved that patient group accompanied with carotid calcification in carotid artery disease had an increased serum OPG concentration, so it could consider that OPG plays an important function on calcification related to arteriosclerosis.

Change of Coronary Flow Velocity During the Cold Pressor Test Is Related to Endothelial Markers in Subjects With Chest Pain and a Normal Coronary Angiogram

Several studies demonstrated that endothelial or atherosclerotic biomarkers, including plasma free insulin‐like growth factor‐I(IGF‐I), soluble CD40 ligand (sCD40L), adiponectin, and leptin have an influence on coronary endothelial function.

It Is Not Mandatory to Use Triple Rather Than Dual Anti-Platelet Therapy After a Percutaneous Coronary Intervention With a Second-Generation Drug-Eluting Stent.

AbstractIt has been shown that triple antiplatelet therapy with cilostazol results in better clinical outcomes than dual therapy in patients treated with a first-generation drug-eluting stent (DES); however, it is unclear whether triple antiplatelet therapy has a similar efficacy after the implantation of second-generation DES.In the COACT (Cath Olic medical center percutAneous Coronary in Tervention) registry, 1248 study subjects who underwent percutaneous coronary intervention with an everolimus- or zotarolimus-eluting stent (Endeavor, Xience V, or Promus) were analyzed. The patients were divided into 2 groups after propensity score matching (n = 724; M = 422 [58.3%]; mean age = 66.1 ± 11.0 years): Group 1: patients treated with dual antiplatelet drugs (aspirin and clopidogrel; n = 362; M = 213 [58.8%]; mean age = 65.6 ± 11.7 years); Group 2: patients treated with triple antiplatelet drugs (aspirin, clopidogrel, and cilostazol; n = 362; M = 209 [57.7%]; mean age = 65.6 ± 11.7 years). The mean follow-up duration was 13 ± 10 months, and the cumulative incidence of major cardiovascular events (MACE) was 6.3% in Group 1 and 7.7% in Group 2. There were no significant differences in MACE (death, nonfatal myocardial infarction, and stroke) between the 2 groups (OR, 1.210; 95% CI: 0.772–1.898; P = 0.406). Kaplan–Meier curves for MACE did not show any survival benefit for triple antiplatelet therapy, even in patients with acute coronary syndrome.In patients treated with a second-generation DES implantation, there is no added clinical benefit to using triple rather than dual antiplatelet therapy.

Usefulness of the parameters of quantitative myocardial perfusion contrast echocardiography in patients with chronic total occlusion and collateral flow.

Microvascular obstruction becomes more severe with longer duration of ischemia, such as chronic total occlusion (CTO) which used to have collateral flow. In this study, we explored the correlation between parameters measured using quantitative myocardial perfusion contrast echocardiography (MCE) and the angiographic collateral flow grades in patients with CTO. Furthermore, we investigated the usefulness of the parameters of quantitative MCE for the measurement of microvasculature changes after revascularization of CTO lesions.