Archivos del Instituto de Cardiologia de Mexico最新文献

Objective: To communicate our results with primary angioplasty (PA) and stenting de novo in acute myocardial infarction.

Material and methods: 163 patients (pts) had clinical diagnosis of MI with an average onset time of symptoms of 2.5 hours. They were divided in two groups: 100 pts with PA using only balloon (group I) and 63 pts with primary stenting (group II) (63 pts with 85 stents). A high pressure technique (14-16 atm) was used in group II and all pts were on salicylic acid and ticlopidine. Both groups were compared.

Results: Clinical characteristics, infarct location and infarct related-artery were similar, being left anterior descending the more frequently vessel involved. Clinical success rate was higher in group II (97% vs 87%) and complication rate was threefold higher in group I (9% vs 3%). A mean follow up of 57 months in group I showed a 21% clinical and/or angiographic restenosis rate, while the 12 months follow up in group II failed to show any case of restenosis at all.

Conclusions: The use of stents in PA improves the results achieved with balloon procedures. There is a greater success rate, less complications and better survival patients who had the procedure while being in cardiogenic shock.

From january 1980 to december 1992 a total of 400 valvulopathies were subjected to conservative mitral procedures: 364 had rheumatic heart disease, 33 were congenital abnormalities and 3 probably myxomatous. Functional class and the cardiomegaly, were in grade III and IV in most cases. Different procedures were done; the most common one was commisurotomy, also subvalvular apparatus opening, annuloplasty ring and a newly designed procedure called "Tension Stitch". The results were satisfactory, with a reoperation rate of 9.2%, mostly caused by fibrosis which in turn caused dysfunction. A second cause were technical problems. The mortality rate was 2%, and was not caused by the procedure itself but because of bad clinical status of the patients. The follow up period was 13 years and showed an actuarial survival curve of 98%, with 90.8% free of reoperation and a very good post-op quality of life. We present this analysis in a effort to bring this procedure to the attention of cardiac surgeons, considering it as an alternative to prosthesis placement.

Unlabelled: It has been demonstrated that coronary flow, through hemodynamic forces, stimulates ventricular contraction and atrio-ventricular transmission; however, the mechanisms involved in these effects remain unknown. A possibility to explain the transduction mechanism, from a mechanical stimulus into a physiological response, could be the stretch-activated ion channels. Additionally we explored the role of nitric oxide as mediator of these actions.

Methods: We used the isolated perfused guinea pig heart according to the method of Langendorff, perfused with Krebs solution. We recorded the ventricular contraction by development of left ventricular pressure and the atrio-ventricular transmission. We studied the effects of the stretch activated ion channel blocker; gadolinium. Synthesis of nitric oxide was inhibited by L-NAME and induced with L-arginine.

Results: Gadolinium inhibited the stimulating effect of flow on atrio-ventricular transmission and ventricular contraction. Verapamil, a specific blocker of calcium channels, had no effect in the stimulatory effect of flow indicating that this type of calcium channel, do not play significant role in the effects of flow. L-NAME and L-arginine did not have effects on the effects of flow.

Conclusion: The stimulating effect of coronary flow in these parameters is regulated by stretch-activated ionic channels. This effect is independent of nitric oxide.

Unlabelled: We studied 398 patients with diagnosis of acute myocardial infarction who arrived within the first six hours of symptom onset that were treated with thrombolysis or primary angioplasty, they were divided in two groups: Group 1 (n = 198), those treated with 1.5 million U of streptokinase over 60 min and Group 2 (n = 200), those treated with primary angioplasty. In Group 1 the "pain-door" time was 3.7 +/- 1.7 hs vs 3.8 +/- 2.4 hs in group 2 (p = NS). The "door-needle" time was 48 +/- 12 min. compared with the "door-balloon" time of 84 +/- 30 min (p < 0.001). In Group 1, 154 (77.6%) of the patients had clinical of reperfusion after thrombolysis, 58 of them underwent coronary angiography and had an infarct related artery (IRA) patency rate of 45.3%. In Group 2 the IRA patency rate was 85.5% (p < 0.005).

Conclusion: Thrombolysis was achieved in a lesser period of time but our findings showed that primary angioplasty was more effective obtaining a TIMI 3 flow.

An increasing body of experimental and clinical work suggesting that tumor necrosis factor alpha plays a pathogenic role in heart failure continues to accumulate. This cytokine is produced in failing but not in normal hearts and experimentally, it's expression is induced by hemodynamic conditions of pressure or volume overload. Specific receptors for this cytokine are present in the heart and dynamic regulation in tumor necrosis factor receptor expression occurs in failing myocardium. In addition, tumor necrosis factor alpha may exert major cardiac effects that contribute to the development of the failing phenotype: induces negative contractil dysfunction, promotes fibrosis, induces cardiomyopathy in experimental animals and it is a major mediator of apoptosis in vivo and in vitro. The knowledge gained from studying the role of tumor necrosis factor alpha in cardiac function draws attention to a series of molecules previously unrecognized as potential mediators in the pathogenesis of heart failure.

Objective: The aim of this work is to describe the different aspects of diagnosis and postoperative follow-up in four patients after surgery for aortic-left ventricular tunnel (ALVT). The surgical techniques and results have been published, in the literature but there are no reports about the progression of aortic regurgitation.

Method: We reviewed the clinical features of four patients operated with ALVT. The clinical information (electrocar-diograms, echocardiograms and catheterilution) was studied in the preoperative period. Surgical technique and postoperative evolution were analysed. The follow-up period ranged between 4.7 and 13 years.

Results: In a 14 years period, four children (2 boys and 2 girls), were operated for ALVT. The mean age at the time of diagnosis was 8.5 years (ranged between 1 month and 14 years). A continuous murmurs was present in all cases, associated to cardiac failure in the youngest patient (1 month old). The clinical diagnosis was ALVT in the four cases but only in two the echocardiographic study showed correctly the anatomic aspects of the malformation. The angiohemodynamic study was correct in three patients and the differential diagnosis was made in last one with rupture of aortic sinuses of Valsalva to the left ventricle. All cases were operated; with direct closure of the aortic orifice (two cases), or with dacron patch (two cases). In one case aortic valve replacement was also performed. There was not mortality and the mean age at the time of surgery was 9 years (1.5 months and 14 years). The mean follow-up was 8.5 years (ranged between 4.7 and 13 years), three patients showed clinically and in the echocardiogram study an aortic valvular regurgitation without ALVT deshiscence. All cases are asymptomatic. No patient was reoperated.

Conclusion: The surgical treatment of ALVT must be done as soon as the diagnosis is made to prevent left ventricular enlargement, ventriculo-aortic floor distortion and aortic valvular lesion. A precise echocardiographic study is necessary to avoid catheterization. This study provided a clear knowledge of anatomic structure of the ALVT for both clinician and surgeons. This information is important in order to obtain an optimal surgical success, particularly to prevent the valvar aortic regurgitation.

A patient with episodes of palpitation in whom the electrocardiogram showed a right bundle branch (RBBB) configuration and right axis deviation underwent electrophysiologic study and radiofrequency ablation. Left ventricular endocardial mapping during ventricular tachycardia (VT) identified the earliest ventricular activation in the anterolateral wall of the left ventricle. The fused Purkinje potential was recorded at that site, and preceded the QRS complex by 47 mseg, with pace mapping showing an optimal match between the paced rhythm and the clinical VT. The stimulus to QRS time was equal to the Purkinje potential-QRS time. Several radiofrequency lesions were applied in this region, one of them resulted with termination of the tachycardia. Following delivery of this lesion the ventricular tachycardia couldn't be induced either at baseline or during isoproterenol infusion. During VT, atrial fibrillation and atrial flutter were observed, cardioversion was performed reverting to sinus rhythm.

Beside the immediate success of surgery and of embolization of angiodysplasias, certain number of patients return to medical consultation, because recanalization of the arteriovenous fistulae after their resection or obturation. From the presentation of two clinical cases of thoracic angiodysplasia: one of them slender, and threatening the other, the authors point out the complications and recurrence after surgical resection or arterial embolization. The recurrence takes place even when only one artery remains permeable after resection or embolization of the fistula. There are cases where the affected limb has to be amputated. However, angiodysplasia shows itself in the stump of the amputee limb. Uncontrolled angio-genesis is the natural history or postoperatory evolution of angiodysplasias, probably originated by an erroneous genetic program, which persist in spite of resection of the vascular malformation, causing a therapeutic failure.