Experimental & Clinical Cardiology最新文献

Background: Peak oxygen consumption (VO2) is the gold standard measure of cardiorespiratory fitness and a reliable predictor of survival in chronic heart failure patients. Furthermore, any form of physical training usually improves cardiorespiratory fitness, although the magnitude of improvement in peak VO2 may vary across different training prescriptions.

Objective: To quantify, and subsequently rank, the magnitude of improvement in peak VO2 for different physical training prescriptions using data from published meta-analyses and randomized controlled trials.

Methods: Prospective randomized controlled parallel trials and meta-analyses of exercise training in chronic heart failure patients that provided data on change in peak VO2 for nine a priori comparative analyses were examined.

Results: All forms of physical training were beneficial, although the improvement in peak VO2 varied with modality. High-intensity interval exercise yielded the largest increase in peak VO2, followed in descending order by moderate-intensity aerobic exercise, functional electrical stimulation, inspiratory muscle training, combined aerobic and resistance training, and isolated resistance training. With regard to setting, the present study was unable to determine whether outpatient or unsupervised home exercise provided greater benefits in terms of peak VO2 improvment.

Conclusions: Interval exercise is not suitable for all patients, especially the high-intensity variety; however, when indicated, this form of exercise should be adopted to optimize peak VO2 adaptations. Other forms of activity, such as functional electrical stimulation, may be more appropriate for patients who are not capable of high-intensity interval training, especially for severely deconditioned patients who are initially unable to exercise.

Background: Patients with ST-segment elevation myocardial infarction (STEMI) and a patent infarct-related artery (IRA) experience lower mortality and better clinical outcome, but little is known about the predictors of IRA patency before primary percutaneous coronary intervention (PCI) in the setting of STEMI.

Objective: To assess possible predictors of patency of IRA before primary PCI in patients with STEMI.

Methods: A total of 880 patients with STEMI undergoing primary PCI were prospectively included (646 male, 234 female; mean [± SD] age 58.5±12.4 years). Blood samples were obtained on admission to investigate biochemical markers. Preinterventional thrombolysis in myocardial infarction (TIMI) flow was assessed in all patients. The patients were divided into two groups according to the pre-PCI TIMI flow as impaired flow group (TIMI flow 0, 1 and 2) and normal flow group (TIMI flow 3). Transthoracic echocardiography was performed in all patients.

Results: Eighty-three (9.43%) patients had pre-PCI TIMI 3 flow in IRA. Uric acid levels and neutrophil to lymphocyte (N to L) ratio in the normal flow group were lower than in the impaired flow group (P<0.001 for both). However, ejection fraction (EF) was higher in the normal flow group than in the impaired flow group. Multivariate logistic regression analysis showed that IRA patency was independently associated with serum uric acid level (β 0.673 [95% CI 0.548 to 0.826]; P<0.001), N to L ratio (β 0.783 [95% CI 0.683 to 0.897]; P<0.001) and EF (β 1.033 [95% CI 1.006 to 1.061]; P=0.016).

Conclusion: Serum uric acid level, N to L ratio and EF are independent predictors of the pre-PCI patency of IRA in patients with STEMI undergoing primary PCI.

Background: Systemic thromboembolism is a serious, major complication in patients with an atrial septal aneurysm (ASA). Atrial dysfunction resulting from paroxysmal atrial fibrillation is more common in patients with ASA than in the general population. The autonomic nervous system plays an important role in the initiation of atrial fibrillation.

Objective: To investigate autonomic function and its impact on ventricular and atrial arrhythmia in a group of ASA patients compared with a control group of healthy volunteers.

Methods: The study group consisted of 40 patients with ASA; the control group consisted of 30 age-, sex- and body mass index-matched healthy volunteers. All patients and control subjects underwent echocardiographic examination. Autonomic function was assessed by determining heart rate variability (HRV) indexes.

Results: HRV time and frequency domain indexes were lower in patients with ASA compared with healthy controls (188±32 ms(2) and 323±42 ms(2) for low-frequency HRV; 195±39 ms(2) and 377±43 ms(2) for high-frequency HRV; P<0.001 for all). Statistically significant differences with respect to other HRV indexes were also found between the two groups.

Conclusion: ASA appears to be associated with cardiac autonomic dysfunction; however, the mechanisms of this association are not known in detail.

Background: Vitronectin (VN) is an abundant acute-phase plasma protein that regulates cell adhesion and migration as well as interactions with components of the plasminogen activator/plasmin system, specifically plasminogen activator inhibitor type 1. This system plays a major role in tissue remodelling regulating wound healing after myocardial infarction.

Objectives: To investigate the feasibility of using VN knockout mice (VN(-/-)) to study the role of VN on ventricular remodelling following myocardial infarction.

Methods: Specifically bred VN(-/-) mice and normal wild-type (VN(+/+)) mice underwent coronary artery ligation and were assessed 28 days postligation using echocardiography and morphometric histology.

Results: No difference was observed between VN(-/-) mice and VN(+/+) mice with respect to gross phenotype, weight, coronary anatomy or echocardiographically measured ejection fraction (56%). Following myocardial infarction, VN(-/-) mice exhibited less ventricular dilation and less impairment in echocardiographic ejection fraction compared with VN(+/+) mice (48% versus 41%; P=0.01). VN(-/-) mice also exhibited smaller infarcts on morphometric analysis.

Conclusions: The results of the present study confirmed the feasibility of using coronary artery ligation in VN knockout mice to investigate the role of VN in post-myocardial infarction remodelling. The absence of VN appears to result in favourable effects on wound healing. These data suggest that this model may offer novel insights into the role of VN in the regulation of myocardial remodelling.

Background/objectives: Coronary artery anomalies are present at birth, but relatively few are symptomatic. The majority are discovered incidentally. In the present study, coronary angiograms performed in the authors' centre (Ondokuz Mayis University Hospital, Samsun, Turkey) were analyzed to determine the prevalence and types of coronary artery origin and course anomalies.

Methods: Coronary angiographic data of 16,573 patients were analyzed. Anomalous origins and courses of coronary arteries were assessed.

Results: Anomalous coronary arteries were detected in 48 (0.29%) of 16,573 patients. The origin of the circumflex (Cx) artery from the right coronary artery (RCA) or right sinus of Valsalva was the most common anomaly (28 patients [58.3%]). An anomalous RCA originating from the left anterior descending artery (LAD) or Cx artery was observed in six patients (12.5%). The left coronary artery originated from the right sinus of Valsalva in five patients, and the LAD originated from the RCA or the right sinus of Valsalva in five patients. The RCA originated from the left sinus of Valsalva in three patients and from an ectopic ostium in the ascending aorta in one patient.

Conclusions: The most frequent anomaly observed in the present study was related to the Cx artery, which is consistent with previous reports. Although coronary artery anomalies are rare, they may cause difficulties during coronary interventions or cardiac surgery and may occasionally result in sudden cardiac death. Therefore, the recognition and diagnosis of these anomalies is important and requires specialization in coronary angiographic techniques and other imaging modalities.

Background: The gold standard treatment for multivessel coronary revascularization is coronary artery bypass grafting. The internal mammary artery and saphenous vein grafts are the conduits most frequently used for these operations. Spasm of arterial and venous grafts is a significant problem during the operation.

Objectives: To evaluate the acute in vitro effects of L-carnitine on internal mammary artery and saphenous vein grafts using a tissue bath.

Methods: Ten consecutive patients who underwent elective coronary artery bypass grafting were enrolled in the present study (nine men, one woman; mean [± SD] age 62±9.1 years). Samples from left internal mammary artery and saphenous vein grafts were collected from each patient. Submaximal smooth muscle contraction was achieved by adding 1 μM phenylephrine, and L-carnitine was then added to the solution. The concentration-response curves of the vasodilation response were obtained.

Results: In the internal mammary graft samples, the vasodilation response to L-carnitine was 64.3±11.1% at a concentration of 5 mM. In the saphenous vein graft samples, the vasodilation response to L-carnitine was 41.5±11.4% at a concentration of 5 mM. There was a statistically significant difference (P<0.001) between the response of the internal mammary artery and saphenous vein grafts in the in vitro tissue bath system.

Conclusions: These results indicate that L-carnitine is a potential vasodilatory drug for internal mammary artery and saphenous vein grafts.

Background: C-reactive protein (CRP) is a marker of systemic inflammatory activity and may be modulated by physical fitness. Treadmill exercise testing is used to evaluate cardiovascular health through different variables including exercise capacity, heart rate and blood pressure responses. It was hypothesized that CRP levels are associated with these variables in men and women without overt heart disease.

Methods: A total of 584 asymptomatic subjects (317 [54.3%] women and 267 [45.7%] men) were enrolled in the present study and underwent clinical evaluation. CRP levels in men and women were examined relative to clinical characteristics and to variables of treadmill exercise testing: peak heart rate, exercise systolic blood pressure, exercise time, chronotropic reserve and heart rate recovery at the first and second minutes after exercise. Multivariate analysis was performed using a log-linear regression model.

Results: In women, exercise time on the treadmill exercise test (P=0.009) and high-density lipoprotein cholesterol levels (P=0.002) were inversely associated with CRP levels. Body mass index (P<0.001) and total cholesterol levels (P=0.005) were positively associated with CRP levels. In men, exercise time on the treadmill exercise test was inversely associated with CRP levels (P=0.015). Body mass index (P=0.001) and leukocyte count (P=0.002) were positively associated with CRP levels. CRP levels were not associated with peak heart rate, chronotropic reserve, heart rate recovery at the first and second minutes, or exercise systolic blood pressure.

Conclusions: These findings contribute to the evidence that CRP is lower in individuals with better exercise capacity and demonstrate that this relationship is also apparent in individuals without overt heart disease undergoing cardiovascular evaluation through the treadmill exercise test. Lowering inflammatory markers may be an additional reason to stimulate sedentary individuals with low exercise capacity in the treadmill exercise test to improve physical conditioning through regular exercise.

Background: The clinical outcome of patients with myocardial infarction (MI) complicated by cardiogenic shock (CS) who require mechanical ventilation (MV) is poor.

Objective: To analyze the impact of abciximab pretreatment in this high-risk population of MI patients.

Methods: The present study was a retrospective subanalysis of the multicentre randomized Routine Upfront Abciximab Versus Standard Peri-Procedural Therapy in Patients Undergoing Percutaneous Coronary Intervention for Cardiogenic Shock (PRAGUE-7) study, which included 80 MI patients in CS undergoing primary percutaneous coronary intervention (PCI). Patients were randomly assigned into group A (routine pretreatment with an abciximab bolus followed by a 1 h abciximab infusion) and group B (standard therapy). The subanalysis included 37 patients requiring MV. Seventeen patients were in group A and 20 were in group B. The primary end point (death/stroke/reinfarction/new severe renal failure) at 30 days, procedural success (thrombosis in myocardial infarction [TIMI] flow) and frequency of bleeding were assessed. The χ(2) and Student's t tests were used for statistical analysis; P<0.05 was considered to be statistically significant.

Results: The primary end point occurred in nine (53%) patients in group A and 12 (60%) patients in group B (P=0.66). TIMI flow after primary PCI was higher in group A (2.75 versus 2.31; P<0.05). Major bleeding occurred in 12% of patients in group A versus 10% of patients in group B (P=0.86). Minor or minimal bleeding was more common in group A (29%) compared with group B (5%; P<0.05).

Conclusion: The results of the present study suggest that routine pretreatment with abciximab before primary PCI in mechanically ventilated patients with MI complicated by cardiogenic shock was associated with better angiographic results but also with a higher incidence of bleeding.

Background: Hypertension has become prevalent among young and middle-age individuals. Many studies have identified a variety of risk factors for cardiovascular diseases, yet there have been few reports focusing on the young and middle-age hypertensive population.

Objective: To investigate the epidemiological characteristics of conventional risk factors of premature coronary artery disease (PCAD) in patients with hypertension.

Methods: The clinical and laboratory data of 267 hypertensive patients with PCAD and 96 hypertensive patients without any visible coronary disease according to angiography were compared. Potential coronary risk factors were analyzed using logistic regression.

Results: The PCAD group had lower levels of high-density lipoprotein cholesterol (HDL-C) (P<0.05). Multivariate logistic analysis showed positive family history, low HDL-C, hypertriglyceridemia, duration of diabetes mellitus and male sex were significantly associated with PCAD (P<0.05), with ORs of 12.317, 3.267, 2.894, 1.140 and 0.088, respectively. Plasma renin activities in PCAD patients were significantly higher than in control hypertensive patients (P=0.027), but there was no significant difference in angiotensin II and aldosterone levels between the two groups.

Conclusion: Low HDL-C and hypertriglyceridemia are important coronary risk factors in Chinese individuals with hypertension.

Background: Intravenous infusion of prostaglandin E1 (PGE1) has been used to treat pulmonary arterial hypertension (PAH); however, the efficacy and safety of inhaled PGE1 is unclear.

Objectives: To investigate the effect of inhaled PGE1 on PAH following corrective surgery for congenital heart disease.

Methods: Sixty patients with postoperative residual PAH following corrective surgery for congenital heart disease were randomly assigned to a control group, a PGE1 infusion group (intravenous PGE1 infusion; 30 ng/kg/min daily for 10 days) or a PGE1 inhalation group (100 μg nebulized PGE1 every 8 h for 10 days). Systolic blood pressure, mean pulmonary arterial pressure, arterial oxygen pressure, oxygen saturation and serum endothelin-1 level were measured before and after the treatment.

Results: At the end of the study, the mean pulmonary arterial pressure in the two PGE1 groups were lower than in the control group (P<0.01), whereas the mean arterial oxygen pressure was higher (P<0.01). Compared with the PGE1 infusion group, the mean pulmonary arterial pressure in the PGE1 inhalation group was lower (P<0.01) whereas the arterial oxygen pressure was higher (P<0.01). The mean endothelin-1 levels in the two PGE1 groups were lower than in the control group (P<0.01), but there was no statistically significant difference in endothelin-1 levels between the PGE1 inhalation and infusion groups (P>0.05).

Conclusions: In pediatric patients with PAH, PGE1 inhalation was associated with a reduction in pulmonary arterial pressure and improvement in arterial blood oxygen levels.