Microvascular coronary flow comparison in acute myocardial infarction angioplasty treated with a mesh covered stent (MGUARD stent) versus bare metal stent: MICAMI-MGUARD.

Background: Distal embolization of thrombus/platelet aggregates decreases myocardial reperfusion during primary percutaneous coronary intervention (PCI), and is associated with worse immediate and long-term prognosis of patients with ST-elevation myocardial infarction (STEMI).

Objective: Assess the efficacy of a mesh covered stent (MGuard™ stent, MGS) in preventing distal embolization and microvascular reperfusion impairment during primary PCI, compared with a bare metal stent (BMS).

Methods: Forty patients with STEMI referred for primary PCI were randomized for stenting the culprit lesion with the MGS (n = 20) or a BMS (n = 20).

[Long term follow up of patients consulting in a Chest Pain Unit].

Background: chest pain (CT) constitutes an important cause of consultation and diagnostic dilemma in the emergency room, especially due to the possible presence of coronary disease. Its presentation, diagnosis and prognosis are different between men and women.

Aim: to report a follow-up of patients attended at a Chest Pain Unit (CPU), evaluating gender differences.

[Chest pain unit: first experience in Chile].

Background: In large series, nearly 60% of admissions for suspected acute coronary syndrome (ACS) had a non-coronary etiology of the pain. However, short term mortality of non recognized ACS patients, mistakenly discharged from the emergency room is at least twice greater than the expected if they would had been admitted. The concept of a chest pain unit (CPU) is a methodological approach developed to address these issues.

[Permanent pacemaker implantation in patients with persistent left superior vena cava and absent right superior vena cava. Report of three cases].

Persistent left superior vena cava and absent right superior vena cava is an uncommon anatomical association. This is a challenging situation for permanent pacemaker implantation. We report three patients with this anomaly and a permanent pacemaker successfully implanted through the left superior vena cava and coronary sinus, without acute or chronic complications.

[Radiofrequency ablation of ventricular tachycardia in a patient after surgery for Tetralogy of Fallot: case report].

Ventricular tachycardia is one of the most feared complications after surgical repair of Tetralogy of Fallot and it is associated with sudden death. We report a 26 years old female with a history of surgical repair of Tetralogy of Fallot at age of 4 year-old, who developed sustained ventricular tachycardia despite antiarrhythmic drugs. She was successfully treated with radiofrequency catheter ablation.

[Periodontal disease among patients with acute coronary syndrome].

Background: Epidemiological studies suggest an association between periodontal disease and coronary heart disease. It is possible that periodontal disease may contribute to plaque destabilization in patients with acute coronary syndrome.

Aim: To assess the association between severity of periodontal disease, the number of acute plaques and extension of coronary artery disease in patients with acute coronary syndrome.

Oral rapamycin to prevent human coronary stent restenosis: a pilot study.

Background: Recent human trials with rapamycin-eluting stents have shown very low restenosis rates. However, the high costs of these devices preclude their use in routine angioplasty, especially when considering multiple stenting. We evaluated whether orally administered rapamycin inhibits in-stent neointimal growth in patients with unstable angina.

[A 36 years experience with implantable pacemakers. A historical analysis].

Background: The implantation of pacemakers improves cardiac function and quality of life, in particular with dual chamber DDD and DDDR modes.

Aim: To evaluate our clinical experience and results on pacemaker implantation, from 1963 to 1998.

Material And Methods: Computerized data collected from 2,445 consecutive paced patients was reviewed.

[Refractory arterial hypertension and the use of anticonvulsant drugs. Case report].

Resistant arterial hypertension is uncommon when there is good compliance to antihypertensive therapy and secondary causes have been ruled out. We report a 41 years old male that suffered hypertensive encephalopathy and received prophylactic anticonvulsant therapy showing progressive raise of arterial pressure levels. Renovascular hypertension, aldosteronism and pheochromocytoma were discarded and, in spite of combined use of antihypertensive drugs, he did not achieve normal blood pressure.

[Reversible myocardial ischemia in hypothyroidism: Case report].

A silent, reversible myocardial ischemia with normal coronary angiography and reversible with thyroid hormone substitution, has been recently described in hypothyroid patients. We report a 49 years old male with an abnormal exercise electrocardiogram detected in a preventive medical examination. He had laboratory evidence of hypothyroidism and a history of two years of asthenia and progressive coarsening of the voice.

[The collagen of the restenosis post angioplasty with stent: Is its origin in intima or adventitia?].

Background: Restenosis post stenting is due to the deposit of extracellular matrix, mainly collagen in the neointima. Controversy exists regarding if collagen is generated locally or by immigration from the adventitia.

Aim: To study the fibrocellular response after stent implantation in rabbit iliac arteries.

[Treatment of advanced heart failure by heart transplantation].

Background: Heart transplantation currently provides the most effective treatment for advanced heart failure. However, medical therapy for this condition has also improved, heart donors are scarce and the cost of the procedure is high. Therefore the indications and management of these patients need reevaluation.

[Chronic atrial flutter: an infrequent manifestation of sick sinus syndrome. Clinical case].

We report a 41 years old female, previously operated of an atrial septal defect, presenting with a persisting atrial flutter. Sinus node dysfunction became evident during an electrophysiological study at the moment of interrupting the flutter with electrical stimulation. The patient was treated with his bundle ablation and implantation of a definitive pacemaker.

[D/D genotype of the gene for angiotensin converting enzyme as a risk factor for post-stent coronary restenosis].

Introduction: Although intracoronary stenting has decreased restenosis rate compared to percutaneous balloon angioplasty, still a high number of patients develop in-stent restenosis, which is an entity primarily due to tissue proliferation. Experimental studies have indicated that the renin-angiotensin system is involved in neointimal hyperplasia. Plasma and cellular levels of ACE are associated with an I/D polymorphism in the ACE gene.

[Use of dual-chamber pacemaker. Short and long-term results].

Background: Continuous improvement of dual chamber DDD pacemakers, electrode stability and programmed sequential stimulation changed the prognosis of patients implanted with these devices.

Aim: To report our experience with the use of dual chamber pacemakers.

Material And Methods: One hundred seventy six patients (116 male), aged 13 to 91 years old, who received a dual chamber pacemaker implant, are reported.

[Unstable angina: immediate and one-year results of transluminal coronary angioplasty treatment].

Background: Unstable angina is characterized by angina at rest, angina of recent onset or accelerating angina. It is caused by a fissure or ulceration of an atheromatous plaque leading to thrombi formation and coronary spasm.

Aim: To report the immediate and late results of coronary angioplasty in patients with unstable angina.

[Rotational atherectomy (Rotablator) for percutaneous transluminal coronary angioplasty].

Background: The use of Rotablator in percutaneous transluminal coronary angioplasty attempts to reduce the atheromatous plaque abrading it and fragmenting the parietal calcium of the artery.

Aim: To report our experience with the use of Rotablator.

Patients And Methods: Rotational atherectomy was performed in 189 patients aged 60.

[Cardiovascular effects of AV interval shortening with electrical stimulation in dilated cardiomyopathy].

Background: A temporal alteration between atrial and ventricular contraction, in which the last one would be abnormally retarded, could exist in patients with dilated cardiomyopathy. This alteration could have adverse hemodynamic effects.

Aim: To study the hemodynamic modifications caused by an artificial shortening of AV interval in patients with dilated cardiomyopathy.

[Radiofrequency catheter ablation in patients with common atrial flutter].

Background: Type 1 atrial flutter is produced by a reentry circuit located in the right atrium that can be interrupted applying radiofrequency in the inferior cava-tricuspid valve isthmus.

Aim: To report our experience in the treatment of atrial flutter with radiofrequency ablation.

Patients And Methods: Nine patients (eight male) whose ages ranged from 6 to 72 years old were studied.

[Noncardiogenic pulmonary edema associated with hydrochlorothiazide use].

A 54 years old female patient with a mitral valve prolapse and a rheumatoid arthritis treated with steroids was admitted with dyspnea and hypotension, that started 30 min after taking a pill containing enapril and hydrochlorothiazide. Hemodynamic monitoring with a Swan-Ganz catheter showed a pulmonary capillary pressure of 5 mm Hg, a systemic vascular resistance of 887 (dyn sec)/cm5 and a cardiac output of 10 l/min. The patient had a history of adverse reactions to thiazides and responded to volume replacement, dopamine and steroids.

[Radiofrequency fulguration for supraventricular tachycardia in pediatrics].

Supraventricular tachycardias (SVT) are the most frequent cause of tachycardia in children. Its pharmacological treatment has adverse effects, is not curative, and is not always effective. During the last few years radiofrequency ablation (RF-A) has changed the treatment.

[Fulguration with radiofrequency of the slow nodal pathway: experience in 30 consecutive cases].

Atrioventricular nodal reentry tachycardia (AVNRT) is one of the most frequent mechanisms of paroxysmal supraventricular tachycardia. In these patients tachycardia is maintained due to anterograde conduction through a slow pathway and retrograde conduction to the atrium via a fast pathway. We present herein our experience in ablation of the slow pathway.

[Junctional reciprocating tachycardia: clinical and electrophysiological characteristics, and the role of fulguration in 5 cases].

The permanent form is a variety of junctional reciprocating tachycardia that is refractory to medical treatment. The anterograde arm of the circuit is formed by the His Purkinje bundle and the retrograde conduction is through a slow conduction Accessory Atrioventricular Pathway. We report five patients with this type of arrhythmia, subjected to electrophysiological assessment.