Restenosis is not associated with stent length in a pig model of coronary stent implantation

Background: The aim of this study was to determine if stent length is by itself a risk factor for intimal proliferation and restenosis. Long lesions represent an independent risk factor for restenosis after coronary stent implantation. A longer stented segment might result in a higher probability of restenosis. Methods: Twenty-two 7-month-old male farm pigs underwent implantation of two steel stents, one short (8 mm length) and one long (16 mm length), in the right coronary artery. The pigs were sacrificed 28 days after stent implantation and histomorphometric analysis of the coronary arteries was performed for neointimal area proliferation and area stenosis evaluation. Results: Seventeen short stents and 19 long stents were finally implanted. There were no differences in neointimal proliferation (1.84 ± 0.64 mm2 vs. 1.81 ± 0.94 mm2, p = 0.84), area stenosis (40 ± 9% vs. 41 ± 19%, p = 0.86) and lumen area (2.96 ± 1.30 mm2 vs. 2.51 ± ± 1.18 mm2, p = 0.21) between the short stent group and the long stent group, respectively. Conclusions: These data suggest that stent length by itself does not influence restenosis extent in the porcine model

Proarrhythmic Effect of ICD Function

The implantable cardioverter ??? defibrillator (ICD) is a device that treats ventricular tachyarrhythmias (VT), when they appear in a sustained form. The device???s programming can deliver the following therapies: 1) antitachycardia pacing (ATP), 2) cardioversion and 3) defibrillation. Today???s devices also have the capability of every mode of cardiac pacing, i.e. atrial, ventricular, atrio-ventricular and biventricular pacing.It is well known that the antiarrhythmic drug therapy can exhibit proarrhythmic effects. Likewise, the antiarrhythmic apparatus can possibly aggravate an existing VT or cause the appearance of a new arrhythmia, attempting to convert the clinical tachyarrhythmia. A case of proarrhythmic effect related to the therapeutic sequences delivered by an ICD, is delineated in the following continuous recording of an arrhythmic event,as it was stored in the Holter function of the device

Proarrhythmic Effect of Implantable Defibrillator Function

Proarrhythmia usually refers to the worsening of an arrhythmia from an antiarrhythmic medication. However, implantable cardioverter defibrillator (ICD) devices can also be proarrhythmic as is shown in the case herein presented

Systemic hypertension augments, whereas insulin-dependent diabetes down-regulates, endothelin A receptor expression in the mammary artery in coronary artery disease patients

Background: Endothelin (ET) A receptor antagonism causes decreased vasodilation in hypertensive coronary arteries and decreased effects on coronary artery compliance in diabetic patients. Methods: We investigate the mRNA expression of ET-1, ETA and ETB receptors, using real time RT-PCR, in biopsies from the internal mammary artery obtained from 49 patients, 18 diabetics and 34 hypertensives, all undergoing coronary artery bypass grafting. Results: Hypertensive patients had higher ET-1 mRNA expression (16438 [8417, 23917]), than normotensive patients (2974 [2283, 18055], p=0.008). Diabetic patients had significantly lower ETA receptor levels than non-diabetic patients (455 [167, 1496] vs. 1660 [700, 3190], respectively, p = 0.003). Conclusions: Multivariate analysis demonstrated that the presence of systemic hypertension was the only independent predictor of log ETA receptor expression and log ET-1 expression, while insulin-dependent diabetes was negatively correlated with ETA receptor expression. ETB receptor expression was not correlated with any predictor. Systemic hypertension is associated with increased ET-1 and ETA receptor mRNA expression, whereas insulin-dependent diabetes down-regulates ETA receptor mRNA expression in the internal mammary artery in patients with coronary artery disease undergoing bypass grafting

Implantable Loop Recorder and Syncope-Rhythm Correlation

A case of syncope-rhythm correlation is presented in a patient with a history of unexplained loss of consciousness and an implantable loop recorder. A permanent pacemaker was implanted due to the bradycardia event revealed by the recorder device and the patient remained asymptomatic in the follow up period

Endothelin-B Receptors and Left Ventricular Dysfunction after Regional versus Global Ischaemia-Reperfusion in Rat Hearts

Background. Endothelin-1 (ET-1) is implicated in left ventricular dysfunction after ischaemia-reperfusion. ETA and ETB receptors mediate diverse actions, but it is unknown whether these actions depend on ischaemia type and duration. We investigated the role of ETB receptors after four ischaemia-reperfusion protocols in isolated rat hearts. Methods. Left ventricular haemodynamic variables were measured in the Langendorff-perfused model after 40-and 20-minute regional or global ischaemia, followed by 30-minute reperfusion. Wild-type (n = 39) and ETB-deficient (n = 41) rats were compared. Infarct size was measured using fluorescent microspheres after regional ischaemia-reperfusion. Results. Left ventricular dysfunction was more prominent in ETBdeficient rats, particularly after regional ischaemia. Infarct size was smaller (P = 0.006) in wild-type (31.5 ± 4.4%) than ETBdeficient (45.0 ± 7.3%) rats after 40 minutes of regional ischaemia-reperfusion. Although the recovery of left ventricular function was poorer after 40-minute ischaemia-reperfusion, end-diastolic pressure in ETB-deficient rats was higher after 20 than after 40 minutes of regional ischaemia-reperfusion. Conclusion. ETB receptors exert cytoprotective effects in the rat heart, mainly after regional ischaemia-reperfusion. Longer periods of ischaemia suppress the recovery of left ventricular function after reperfusion, but the role of ETB receptors may be more important during the early phases