Explicit analytical tuning rules for digital PID controllers via the magnitude optimum criterion.

Analytical tuning rules for digital PID type-I controllers are presented regardless of the process complexity. This explicit solution allows control engineers 1) to make an accurate examination of the effect of the controller's sampling time to the control loop's performance both in the time and frequency domain 2) to decide when the control has to be I, PI and when the derivative, D, term has to be added or omitted 3) apply this control action to a series of stable benchmark processes regardless of their complexity. The former advantages are considered critical in industry applications, since 1) most of the times the choice of the digital controller's sampling time is based on heuristics and past criteria, 2) there is little a-priori knowledge of the controlled process making the choice of the type of the controller a trial and error exercise 3) model parameters change often depending on the control loop's operating point making in this way, the problem of retuning the controller's parameter a much challenging issue.

Sealing of coronary artery aneurysm by using a new stent graft.

Coronary stenting has begun to play an increasingly important role in the management of coronary artery aneurysms. A case of successful and complete sealing of a coronary aneurysm by using a new stent graft is described. Further studies in a large patient population are required to confirm the safety and efficacy of this method.

Elective intracoronary Micro-Stent II implantation without quantitative coronary angiography or intravascular ultrasound guidance and without subsequent anticoagulation: short- and long-term results.

Intracoronary stenting has been shown to reduce acute closure and restenosis rate in patients treated with coronary angioplasty. The use of high inflation pressures and intravascular ultrasound guidance allowed the substitution of anticoagulants with antiplatelet agents but increased the cost. The aim of this study was to investigate the effectiveness, safety, and long-term outcome of the elective implantation of a relatively new type of stent (Micro-Stent II), without the use of quantitative coronary angiography or intravascular ultrasound guidance and without subsequent anticoagulation.

Intracoronary stent placement proximal to a myocardial bridge: immediate and long-term results.

The intracoronary stent placement in a lesion proximal to a myocardial bridge is of special importance and is considered to be a challenge for the interventional cardiologist. In this study 4 cases of stent implantation proximal to a coronary bridged segment are described. In all cases complications were observed after the procedure.

Successful management of right coronary air embolus after intracoronary administration of verapamil.

A case of a 50 year-old male with a coronary air embolism is described. The case was successfully treated with intracoronary administration of verapamil.

New method for placement of intracoronary stents in order to avoid their embolization in the intravascular space.

Stent dislodgment from the delivery catheter is a well-known complication of angioplasty with stent implantation. The aim of our study was to investigate the feasibility, effectiveness, and safety of a new technique of intracoronary stent implantation in order to avoid stent loss in the intravascular space. Fifty consecutive patients were candidates for angioplasty and stent placement.

Effects of Grazing Pressure on Succession Process and Productivity of Old Fields on Mediterranean Islands.

/ Five experimental sites, located on four islands of the Aegean archipelago, were selected in order to assess the grazing-mediated recovery of natural vegetation in old fields. Years after abandonment of cultivation ranged from 5 to 40. Grazing pressure was proved of considerable magnitude in all but the Santorini site, which recovers without mediation of intense grazing.

Stent implantation in patient with visible intracoronary thrombus and compromised left ventricular function, after local thrombolysis using the Dispatch catheter.

The case of a patient with unstable angina and angiographic findings of significant (approximately 90%) right coronary artery stenosis with an intracoronary thrombus next to the lesion, total left anterior descending and circumflex occlusion and an ejection fraction of approximately 22% is described. The case was treated with stent implantation after local thrombolysis with the use of the Dispatch infusion catheter.

Aneurysm of the mitral-aortic intervalvular fibrosa as a rare cause of angina pectoris: angiographic demonstration.

Aneurysms of the mitral-aortic interventricular fibrosa (MAIF) are exceptionally rare complications, commonly following aortic valve endocarditis. This report describes the angiographic findings of such an aneurysm, in a patient who developed an uncommon symptomatology of unstable angina pectoris, caused by the aneurysm's expansion against the coronary arteries. Surgical treatment is also discussed.

Transesophageal echocardiographic Doppler study of coronary flow in a patient with myocardial bridging--a case report.

A case report of myocardial bridging of the left anterior descending artery is described. Coronary flow proximal to the myocardial bridge was studied with transesophageal echo Doppler. The patient, a 62-year-old farmer who sustained an anterior myocardial infarction, underwent thrombolysis and was admitted.

Angioplasty followed by coronary stenting at the anastomotic site of saphenous vein bypass graft with the native vessel: a case that needs special procedural strategy.

In this report we describe a case in which a saphenous vein graft stenosis at the site of anastomosis with the left anterior descending artery (LAD) was dilated with a special Controlled Angioplasty Technology (CAT) balloon, and then stented. Balloon angioplasty and stenting at the site of anastomosis represents a technical problem because of diameter discrepancy and needs special attention in order to avoid minor or major complications.

Posterior right diagonal artery. An angiographic study.

The purpose of this prospectively performed study was the angiographic visualization of the posterior right diagonal artery (PRDA) and its differentiation from the epicardial branches of the right coronary artery (RCA), that is, the right marginal artery and the posterior descending artery (PDA). The authors prospectively studied the angiographic findings of 607 patients who underwent coronary angiography. The incidence of the angiographically demonstrated PRDA and its distinction from other epicardial branches arising from the distal third of the RCA was the main point of interest.

Angioplasty without the use of "Y connector": a new, easier, bloodless method.

The "Y connector" that is used in angioplasty has the following disadvantages: 1) it is not blood-tight; 2) we need to "screw and unscrew" every time we want to inject contrast material or measure the pressure; and 3) it does not allow the advancement of the guidewire or the balloon catheter during the injection of contrast material. We created a new type of connection composed of a cut sheath for the femoral artery, connected with a cut (at the "hub") guiding catheter. The aim of this study was to examine the feasibility, efficacy, and safety of the new method.

Short-term angiographic and long-term clinical follow-up of a patient with a malexpanded vein graft stent.

Optimal stent expansion is considered imperative today in order to prevent subacute stent thrombosis and allows us to minimize antithrombotic therapy. The short-term angiographic and long-term clinical follow-up of a patient with a suboptimally expanded vein graft balloon expandable stent is presented. Intensive antithrombotic treatment along with unimpeded blood flow were probably highly beneficial.

Communication between a nongrafted left internal mammary artery and left anterior descending coronary artery following saphenous vein bypass grafting.

A case is described in which a pericardial branch of a nongrafted left internal mammary artery communicated directly with the distal left anterior descending artery, following saphenous vein bypass grafting. This type of collateralization following coronary artery bypass surgery seems to be very rare, and perhaps could protect the myocardium from severe ischemia.

Angioplasty of a left anterior descending artery originating from the right sinus of Valsalva (discussion in decision making).

In this case report, we describe a successful percutaneous transluminal coronary angioplasty of an abnormally originating left anterior descending artery from the right sinus of Valsalva. We discuss about the decision making in this rare and challenging case, since there is more than one opinion as to which is the appropriate treatment in this group of patients.

Cortical blindness following coronary arteriography: a rare but self-cured complication. Two case reports.

The rare and self-cured complication of cortical blindness following coronary arteriography is presented in 2 patients who underwent cardiac catheterization. Both patients were submitted to an aortocoronary bypass grafting procedure a few years before and were under clinical investigation for a new onset of unstable angina pectoris.

Stress echocardiography in elderly patients with coronary artery disease: applicability, safety and prognostic value of dobutamine and adenosine echocardiography in elderly patients.

Objectives: Our aim was to determine the applicability, safety and prognostic value of adenosine and dobutamine stress echocardiography in patients > or = 70 years old.

Background: These tests are sometimes mandatory because of difficulties and inaccuracies in interpreting traditional electrocardiographic stress tests. Furthermore, if these tests could be used to avoid coronary arteriography and cardiac catheterization, they would become essential in the care of the elderly, whose numbers are increasing.

Coronary artery discrete aneurysms, ectasia, and occlusive disease ane extensive arteriomegaly. Correlation, constellation, or coincidence? A case report.

The case of a sixty-five-year-old man with discrete coronary aneurysms, associated with coronary artery ectasia, stenoses, and total occlusion of the left anterior descending artery, that resulted in an acute anterior myocardial infarction, is presented. Aortography and digital subtraction angiography revealed marked aortic and iliac elongation, tortuosity, and aneurysmal dilatation as well as dilatated femoral and popliteal arteries with aneurysmal dilatation in places. It is considered that the case reflects the broad spectrum of atherosclerosis manifestations.

Single coronary artery from the right sinus of Valsalva, associated with absence of left anterior descending and an ostium-secundum-type atrial septal defect: a rare combination. A case report.

A case of single coronary artery from the sinus of Valsalva, with an anomalous origin of the left circumflex coronary artery from the just proximal portion of the right coronary artery, absence of the left anterior descending, and an ostium-secundum-type atrial septal defect is presented. This combination seems to be very rare.

Analysis of left atrioventricular plane movement during diastole in ischemic heart disease.

The aim of the present study was to investigate the properties of diastolic left atrioventricular plane displacement (AVPD) in coronary artery disease (CAD) patients. In 125 patients (mean age 58.7 +/- 13.