Isosorbide dinitrate sublingual therapy for inferior myocardial infarction: randomized trial to assess infarct size limitation.

To assess the potential of isosorbide dinitrate sublingual therapy for limiting myocardial infarct size, 41 patients with inferior acute myocardial infarction (AMI) were studied. Twenty patients were randomly assigned to the control group and 21 to the treatment group. Patients in the treatment group received 10 mg of isosorbide dinitrate every 2 hours for 72 hours. To estimate infarct size, QRS scoring, peak creatine kinase (CK) serum levels and CK curves were used. There were no significant differences between the 2 groups in maximal or cumulative activity of CK or QRS score (percent of left ventricle infarcted: 16% in the control group, 17% in the treatment group). In both groups the QRS score increased significantly by 13 hours after AMI, and the increase was highly significant by 19 to 23 hours. Thus, sublingual isosorbide dinitrate at the dosage given did not reduce infarct size in patients with inferior AMI.

[Study of heart rate variability in acute myocardial infarction and its relationship with ventricular function and other clinical variables]. / Estudio de la variabilidad de la frecuencia cardíaca en el infarto agudo de miocardio y su relación con la función ventricular y otras variables clínicas.

BACKGROUND: The influence of ventricular function (VF) on prognosis in acute myocardial infarction (AMI) is well known. Heart rate variability (HRV), as a neurohumoral parameter could predict VF after discharge in AMI patients. Our goal is to investigate the possible relation among HRV, VF and another clinical variables in AMI. PATIENTS AND METHODS: We studied 37 patients with AMI after hospital discharge. Age, AMI type, location, enzymes, treatment (thrombolysis versus no thrombolysis) were evaluated. The left ventricular ejection fraction (LVEF) was assessed by radionuclide ventriculography in 27 subjects. Twenty nine subjects without cardiopathy were the control group. Twenty four hour electrocardiographic recordings were obtained and a proper software was used to measure HRV. This was evaluated with time domain measures: RR interval, standard deviation of the mean RR interval (SDNN), standard deviation of the average of the RR intervals measured every 5 minutes during 24 hours (SDANN) and number of two consecutive RR intervals with a variability > 50 ms (pNN50). We considered a decreased variability if SDANN was less than 100 ms. Two groups were established: 1) low heart rate variability (LHRV) if SDANN was less than 100 ms, and 2) normal heart rate variability (NHRV) if SDANN was larger than 100 ms. Continuous variables were examined by the t-test, chi square for discrete ones and linear regression analysis was used to assess the relation among variables. A p < 0.05 was considered significant. RESULTS: The percentage of infarcted patients in the group of LHRV is 75%, whereas it is 14% in the control group (p < 0.05). SDANN, SDNN and pNN50 values are significantly lower (p < 0.05) in the AMI than in the control group. LHRV was more frequent in patients with complicated AMI with congestive heart failure. LVEF was significantly lower (35% vs 56%) in the LHRV than in the NHRV group. No significant differences were found among: site, type infarct, treatment or ventricular ectopy in the Holter before discharge. There is good correlation (r = 0.635; p < 0.05) between LVEF and HRV measures. No correlation was found between HRV and age, or the enzymatic size of infarction. CONCLUSIONS: 1) LHRV is frequent in the late phase of AMI, and 2) LHRV can be an indirect index of left ventricular failure.

[Permanent endocardial pacemaker. Review of 116 implantations (author's transl)]. / Marcapaso endocavitario permanente. A propósito de 116 implantaciones.

A retrospective study on the results of 116 permanent ventricular pacemaker implantations performed in the Service of Cardiology of the Hospital Clinico Universitario in Salamanca is reported. In the majority of cases the indication for a pacemaker was a complete atrioventricular block (53 cases). Sixteen cases had a "sick-sinus syndrome". An apparent cardiopathy was not found in 84 percent of the cases. In the group of patients with cardiopathy that of ischemic type was the most common. The technique of endocardiac catheter pacing was employed in all cases. An 18 percent of global complications occurred, but in no case an early electrode displacement was registered. Complications appeared at a later time included erosion of the pacemaker in ten cases, and displacement and/or deinsertion in seven. The mean life for 18 displaced generators was 41.3 months. A sudden equipment malfunction occurred in two cases, and an inhibition by potentials of the pectoralis major muscle in another. Morbidity rate was lower to that of other published series, may be due to the use of modern generators with a progressive reduction of its diameter and weight and more flexible electrodes which allow a better implantation. The mortality rate was zero.