Experimental & Clinical Cardiology最新文献

Objectives: To evaluate whether pacing or sensing configuration has an effect on pacing parameters or their time progression. Three left ventricular (LV) pacing parameters were monitored - the LV pacing threshold, pacing impedance and intrinsic R-wave amplitude.

Methods: DATA WERE COLLECTED AT THREE INTERVALS: during implantation; between the second and fifth month after implantation (first follow-up); and between the eighth and 15th month after implantation (second follow-up). Repeated-measures ANOVA was used for the statistical analysis.

Results: The impedance, but not its time progression, was significantly higher for the LV tip to LV ring configuration than for other configurations. R-wave amplitude and impedance increased significantly (without dependance on configurations) between implantation and first follow-up, as expected. The time progression of any parameter was not dependent on configuration of the LV lead.

Conclusions: LV tip to LV ring is the best configuration for maintaining a high impedance level. It is better to maintain an individual approach for pacing threshold and R-wave amplitude, and their settings.

Background: Pacemakers have long been used to assist the heart under pathological conditions, and they are the first choice in the treatment of systematic bradyarrhythmias. However, the effect of percutaneous coronary intervention (PCI) in patients with coronary artery disease as well as bradyarrhythmias remains unknown.

Methods: In the present study, 42 patients with chest pain and/or abnormal stress test results were surveyed. Before coronary angiography, patients underwent complete examination, including a 24 h dynamic electrocardiogram, which was used to diagnose bradyarrhythmias that were not suitable for pacemaker implantation due to a lack of arrhythmia-related symptoms. All patients underwent PCI but did not undergo pacemaker implantation. Forty-one patients with chest pain and/or abnormal stress test results, as well as symptom-free bradyarrhythmias, were selected as the control group. All of the patients in the control group were committed to treatments without PCI.

Results: During a mean (±SD) of 3.3±0.5 years of follow-up (range 2.5 to 4.5 years), 24 of 42 patients who received PCI underwent pacemaker implantation for arrhythmia-related symptoms, eight were shown by Holter monitoring to have worsened but still exhibited no symptoms, and the remainder did not show any changes according to the examinations performed. In the control group, 31 patients underwent pacemaker implantation for arrhythmia-related symptoms, eight were shown by Holter monitoring to have worsened but still exhibited no symptoms, and two did not show any changes according to the examinations performed. Nevertheless, the rates of pacemaker implantation each year (from the first to the third year) between the two groups were 7.1% versus 39.0% (P=0.001); 33.3% versus 63.4% (P=0.006); and 57.1% versus 75.6%, (P=0.075), respectively.

Conclusions: The present study found that PCI delayed the demand for pacemaker implantation among coronary artery disease patients.

Objective: To investigate the effect of the stellate ganglion (SG) and its left-right asymmetry on atrial fibrillation (AF) inducibility, AF duration and atrial electrophysiological properties.

Methods: Sixteen adult mongrel dogs were randomly assigned to three groups. The control group (n=4) underwent 6 h rapid atrial pacing (RAP) only; the right SG (RSG) group (n=6) underwent 6 h RSG stimulation plus RAP; and the left SG (LSG) group (n=6) underwent 6 h LSG stimulation plus RAP. AF induction rate, AF duration, effective refractory period (ERP) and dispersion of ERP (dERP) were measured.

Results: In the RSG group, the induction rate of AF was significantly increased in sites in the right atrium (RA) compared with baseline (P<0.05). In the LSG group, the induction rate of AF was significantly increased (P<0.05) compared with baseline in the left atrium (LA), left superior pulmonary vein and left inferior pulmonary vein, respectively. Compared with RSG stimulation, right stellate ganglionectomy markedly decreased the AF induction rate of the RA (P<0.05). Compared with LSG stimulation, left stellate ganglionectomy markedly decreased the AF induction rate of the LA, the left superior pulmonary vein and the left inferior pulmonary vein (P<0.05). In the RSG group, the ERP was significantly shortened (P<0.05) and the dERP was significantly increased (P<0.05) in RA sites (P<0.05). The ERP was significantly shortened in the LSG group (P<0.05). The dERP was significantly increased (P<0.05) in LA and pulmonary vein sites (P<0.05).

Conclusions: Unilateral electrical stimulation of the SG in combination with RAP can successfully establish a canine model of acute AF mediated by excessive sympathetic activity. SG stimulation facilitates AF induction and aggravates electrical remodelling in sites in the atrium and pulmonary vein. Inhibiting sympathetic nerve activation through unilateral stellate ganglionectomy can reduce AF initiation.

A 66-year-old man with a history of coronary artery disease, stage V chronic kidney disease, peripheral arterial disease and a dual-chamber pacemaker experienced persistent chest and shoulder discomfort following his daily hemodialysis treatment. Treatment with clopidogrel had been discontinued three days previously due to impending vascular surgery. Electrocardiography revealed a right ventricular-paced rhythm with ST abnormalities indicative of posterior ST elevation myocardial infarction. The patient underwent urgent cardiac catheterization and required percutaneous coronary intervention for an acutely occluded coronary artery. The present case report emphasizes the importance of careful and timely review of the electrocardiogram of any patient with a ventricular-paced rhythm who experiences signs and symptoms consistent with acute coronary syndrome. Certain characteristic electrocardiographic abnormalities have been demonstrated to predict acute myocardial infarction in such patients.

Acute pulmonary embolism (PE) bears a significant burden on health and survival. Rapid and accurate risk stratification and management are of paramount importance to ensure the highest quality of care. This present article summarizes currently available and emerging management strategies for the disease. The authors not only review current evidence regarding early therapy of acute PE, including supportive care, anticoagulation, thrombolysis, surgical and catheter-based treatment, but also the possible role of mechanical circulatory support in PE. The authors also discuss complications related to PE and its management.

Reports of incidental coronary artery abnormalities range from 0.6% to 1.3% during routine angiography, and 0.3% in autopsies. An isolated single coronary artery is a particularly rare congenital anomaly. Clinical presentation is usually nonspecific; patients with an isolated single coronary anomaly may present with symptoms such as angina, myocardial infarction or sudden cardiac death. The therapeutic options depend on origin, course and termination. It is dangerous and potentially lethal if a single coronary artery is associated with obstructive coronary artery disease. Two cases of anomalous origin of a coronary artery from a single Valsalva sinus without any other visible coronary artery detected by aortography are reported.

Noncompaction of the left ventricular myocardium has gained increasing recognition over the past 25 years. This rare disease is caused by the arrest of myocardial morphogenesis. The classical triad of complications are heart failure, arrhythmias, including sudden cardiac death, and systemic embolic events. There is a paucity of data regarding women with left ventricular noncompaction cardiomyopathy and pregnancy outcome. The first report of an uneventful vaginal delivery without deterioration of left ventircular noncompaction cardiomyopathy is presented.

Congenital coronary artery fistulae may be isolated or may be associated with complex congenital cardiac abnormalities. In patients with complex congenital heart disease, multiple fistulous or sinusoidal communications with a cardiac chamber can occur. The treatment strategy includes surgery, coil embolization and covered stent deployment. The present article describes a case involving a 20-year-old patient with complex congenital heart lesions and multiple sinusoidal coronary to right ventricle fistulous communications, which remained patent despite coil embolization in childhood. Further coil or device embolization was deemed unlikely to be successful due to the presence of multiple communications; therefore, covered stents were deployed across the previously coiled segment of the coronary artery. The patient had an excellent clinical outcome on follow-up nine months later, with significant improvement of symptoms.

Background: The protective effects of 17-beta estradiol (E2) on cardiac tissue during ischemia/reperfusion (I/R) injury have not yet been fully elucidated.

Objective: To assess the protective effects of short- and long-term E2 treatments on cardiac tissue exposed to I/R, and to assess the effects of these treatments in combination with ischemic preconditioning (IPC) on cardiac protection from I/R injury.

Methods: SPRAGUE DAWLEY RATS WERE ASSIGNED TO THE FOLLOWING TREATMENT PROTOCOLS: control (no preconditioning); IPC (isolated hearts were subjected to two cycles of 5 min global ischemia followed by 10 min of reperfusion); E2 preconditioning (E2PC; isolated hearts were subjected to E2 pharmacological perfusion for 15 min); short-term in vivo E2 pretreatment for 3 h; long-term in vivo E2 pretreatment or withdrawal (ovariectomy followed by a six-week treatment with E2 or a placebo); combined IPC and E2PC; combined IPC and short- or long-term E2 pretreatments or withdrawal. All hearts were isolated and stabilized for at least 30 min before being subjected to 40 min of global ischemia followed by 30 min of reperfusion; left ventricular function and vascular hemodynamics were then assessed.

Results: IPC, E2PC and short-term E2 pretreatment led to the recovery of left ventricle function and vascular hemodynamics. Long-term E2 and placebo treatments did not result in any protection compared with untreated controls. The combination of E2PC or short-term E2 treatments with IPC did not block the IPC protection or result in any additional protection to the heart. Long-term E2 treatment blocked IPC protection; however, placebo treatment did not.

Conclusions: Short-term treatment with E2 protected the heart against I/R injury through a pathway involving the regulation of tumour necrosis factor-alpha. The combination of short-term E2 treatment with IPC did not provide additional protection to the heart. Short-term E2 treatment may be a suitable alternative for classical estrogen replacement therapy.

Background: Supervised cardiac rehabilitation provided at dedicated centres ameliorates exercise intolerance in patients with chronic heart failure.

Objective: To correlate the amount of physical activity outside the hospital with improved exercise tolerance in patients with limited access to centre-based programs.

Methods: Forty patients (median age 69 years) with stable heart failure due to systolic left ventricular dysfunction participated in cardiac rehabilitation once per week for five months. Using a validated single-axial accelerometer, the number of steps and physical activity-related energy expenditures on nonrehabilitation days were determined.

Results: Median (interquartile range) peak oxygen consumption was increased from 14.4 mL/kg/min (range 12.9 mL/kg/min to 17.8 mL/kg/min) to 16.4 mL/kg/min (range 13.9 mL/kg/min to 19.1 mL/kg/min); P<0.0001, in association with a decreased slope of the minute ventilation to carbon dioxide production plot (34.2 [range 31.3 to 38.1] versus 32.7 [range 30.3 to 36.5]; P<0.0001). Changes in peak oxygen consumption were correlated with the daily number of steps (P<0.01) and physical activity-related energy expenditures (P<0.05). Furthermore, these changes were significantly correlated with total exercise time per day and time spent for light (≤3 metabolic equivalents) exercise, but not with time spent for moderate/vigorous (>3 metabolic equivalents) exercise.

Conclusions: The number of steps and energy expenditures outside the hospital were correlated with improved exercise capacity. An accelerometer may be useful for guiding home-based cardiac rehabilitation.