[The differential characteristics of early ventricular arrhythmias following a myocardial infarct in patients with and without ventricular fibrillation]. / Características diferenciales de las arritmias ventriculares precoces tras un infarto de miocardio en pacientes con y sin fibrilación ventricular.

OBJECTIVE: To evaluate the characteristics of early ventricular arrhythmias in acute myocardial infarction and their predictive value of ventricular fibrillation. PATIENTS AND METHODS: We retrospectively compared 85 patients who presented ventricular fibrillation with a control group of 187 consecutively acute myocardial infarction patients recorded within the first 12 hours after onset of acute myocardial infarction symptoms. Patients in Killip class III-IV were excluded. RESULTS: In the ventricular fibrillation group we observed a high prevalence of inferior site of infarction (69 vs 56%; p < 0.05), sum of ST in 3 leads (ST-3 leads) with maximal elevation (13 +/- 17 vs 8 +/- 7 mm; p < 0.005), basic heart rate (97 +/- 23 vs 88 +/- 18 bpm; p < 0.01), R-on-T phenomenon (16 vs 2%; p < 0.001). In 22 patients in whom the ventricular fibrillation episode was registered, the basic heart rate preceding the ventricular fibrillation was fast (113 +/- 54 bpm), and the prematurity index (coupling interval/QT) shorter than in the other ventricular arrhythmias (0.9 +/- 0.2 vs 1.2 +/- 0.3 s respectively; p < 0.005). The prematurity index of ventricular arrhythmias in the ventricular fibrillation group was shorter than in the control group (1.2 +/- 0.3 vs 1.5 +/- 0.3 s respectively; p < 0.0001) and the heart rate during runs was faster (172 +/- 54 vs 126 +/- 40 bpm; p < 0.01). The logistic regression analysis showed that R-on-T phenomenon (odds ratio [OR] = 2.8), inferior site of infarct (OR = 3.65), sum of ST-3 leads > 10 mm (OR = 5.82), and basic heart rate > 100 bpm (OR = 2.33) were independent risk factors for ventricular fibrillation. CONCLUSION: Characteristic ventricular arrhythmias were found to precede ventricular fibrillation episodes: R-on-T phenomenon or short prematurity index and fast runs of ventricular tachycardia, with other parameters such a inferior site of infarct, sum of ST-3 leads > 10 mm and basic heart rate > 100 bpm.

[Pulmonary volume and cardiopulmonary function in acute myocardial infarction (author's transl)]. / Volúmenes pulmonares y función cardiopulmonar en el infarto agudo de miocardio.

In order to evaluate alterations in lung mechanisms detected in patients with acute myocardial infarction (MI), changes in arterial oxygenation and pulmonary volume in relation to the hemodynamic status were measured in 19 patients with acute MI. Pulmonary volume was determined with spirometry and helium dilution closed technic at 24 and 72 hours and two months after acute MI. The first finding was decreased arterial PO2: 328 +/- 29 mm/Hg (mean +/- SE) which had significantly risen by the third day: 423 +/- 20 mm/Hg (p less than 0.02). This disturbance was accompanied by an increased pulmonary shunt (Qs/Qt) and VD/VT relation, which improved with time but did not return to normal. A manifest relationship was not found between the degree of hypoxemia and diminished functional residual capacity (FRC). During the acute phase lung volume was normal while patients were seated but upon assuming a supine position, vital capacity (VC), total lung capacity (TLC) and RV/TLC were altered considerably. The VC and RV/TLC alterations were significantly altered in patients with left ventricular dysfunction. No significant changes were found in pulmonary values during the acute phase and VC and TV/TLC had improved considerably two months later. It is probable that increased interstitial pulmonary edema bears the main responsibility for these alterations, including in uncomplicated acute MI.

[Pulmonary function differences in healthy subjects according to postural changes (author's transl)]. / Diferencias en la función pulmonar de sujetos sanos secundarias al cambio postural

The total lung capacity (TLC) and its subdivisions along with the forced spirometric values (FEF25-75 and FEV1) were determined in a group of 44 healthy subjects, composed of 29 women and 15 men. The determinations were carried out in a sitting position and in supine position, breathing air. All the pulmonary volumes diminished when the subject lay down, but the functional residual capacity (FRC) was that which underwent a greater reduction. The residual volume decrease was the only one which did not reach statistically significant levels. Women always showed smaller pulmonary volumes than men. It has been demonstrated that FRC can be exactly measured by means of the closed helium technique. The regression figures of FRC in supine position were determinted for both sexes, with a r = 0,33 (p less than 0,1) in women and r = 0,95 (p less than 0.001) in men. The forced spirometric tests did not undergo any important changes although the reduction of the FEV1 was significant in both sexes. The results obtained were compared with those published by other authors.

[Correlation between the Morris' index and pulmonary capillary pressure in patients with acute myocardial infarction]. / Correlación entre índice de Morris y presión capilar pulmonar en pacientes con infarto agudo de miocardio.

The authors study the usefulness of the measurement of the negative area of P in V1 (Morris' index) in patients with acute myocardial infarction. The study was carried out prospectively in 70 patients, 31 of them having a Swan-Ganz catheter inserted permitting simultaneous hemodynamic and electrocardiographic measurements. No overall correlation was found between pulmonary capillary pressure (PCP) and Morris' index (Mlx), but a correlation existed in the subgroup of patients that showed evident variations of Mlx values during the study. On admission a relationship between PCP and Mlx was evident in 68% of the cases, without statistical significance. No PCP-Mlx correlation was found in the patients in whom the Mlx was always normal or abnormal during the study, nor in those with a prior history of arterial hypertension or left heart failure. An intraatrial conduction defect was found in 13% of the cases, no PCP-Mlx correlation being present in those. The fact that the PCP-Mlx correlation is best in patients with changing Mlx values in successive measurements that in patients with a prior history of hypertension or left ventricular failure suggests that Mlx values may vary with changes of left atrial pressure. The measurement of the Mlx to estimate left atrial pressure has little value in patients with conditions that may cause left atrial enlargement and intraatrial conduction defects.

[Acute myocardial infarction of the right ventricle: hemodynamic and electrocardiographic correlation (author's transl)]. / Infarto agudo de miocardio de ventrículo derecho. Correlación electrocardiográfica-hemodinámica.

The electrocardiogram as a diagnostic aid in acute myocardial infarction of the right ventricle (AMI-RV) was studied prospectively in a group of 66 patients in our coronary unit. Diagnosis was AMI in all cases, divided into 29 (44%) with posterior-descending and 35 (53%) with anterior location. Electrocardiography was practiced with standard and special modes: CRnR, CR and VR. Thirty-nine patients were hemodynamically monitored. In 13 patients with posterior-descending location (19.6%) the hemodynamic pattern disclosed AMI. Right ventricular dysfunction was found in 17%, left ventricular dysfunction in 9% and biventricular dysfunction in 20%. In 30 patients (45.5%) ST increased to greater than 1 mm CR3R-CR6R of which 77% were false positive and 46% false negative. No improvement in these proportions was observed with the use of special mode, special in infarctions with anterior location. The correlation between hemodynamics-site of necrosis was better than that between hemodynamics-increase in ST in CRnR. The authors draw the conclusion that special modes as an aid to diagnosis are of limited value, sensitivity is 54% and specificity is 23%, which rises to 50% in posterior-descending infarctions. At present hemodynamics are the choice diagnostic procedure for AMI-RV which must be suspected if serial studies disclose PVC of more than 9 mm Hg.

[Usefulness of creatine phosphokinase isoenzyme, CK-MB, in the diagnosis of myocardial necrosis (author's transl)]. / Utilidad de la isoenzima de la creatinfosfocinasa, CK-MB, en el diagnóstico de la necrosis miocárdica.

With the objective of evaluating the clinical usefulness of a new immunologic method (Merck-1-Test CK-MB), in the determination of the CK-MB activity, 48 patients admitted to the Coronary Unit for angina pectoris were studied. Samples of blood were gathered upon admission and every 4 hours for 48-72 hours, determining in each one of them the total CPK, SGOT, LDH, and CK-MB; electrocardiograms (ECG) were taken and all possible causes for the increase in the enzymatic activity were recorded. Results were analyzed in order to study the following aspects: in the patients in which an acute myocardial infarction was diagnosed the CK-MB activity was studied, also the relation of CK-MB to the remaining parameters, each parameter's sensitivity and specificity and the relationship of the CK-MB to the prognosis of the patients. The usefulness of CF-MB in the differential diagnosis of myocardial necrosis and variations in the total CKP curve in the clinical course of acute myocardial infarction unrelated to myocardial necrosis were evaluated too. The following conclusions were drawn from the analysis of the data. The immunological method has the advantages of its sensitivity and easily and quickly performance (15 minutes), but it has the disadvantage that it detects CK-BB (elevated in cebrovascular disorders). Twenty-four hours after the onset of symptoms, the negativity of CK-MB does not exclude the diagnosis of a myocardial necrosis. CK-MB is more sensitive than total CPK in diagnosing the extent of the area of necrosis. CK-MB is very specific for myocardial necrosis but less sensitive than other parameters. A positive CK-MB upon the patient's admission confirmed the diagnosis of necrosis in 60 percent of the cases, but in 18 percent error was induced because of false positives. CK-MB permitted confirmations of the diagnosis of myocardial infarction in 33 percent of cases in which there was only a suggestion of necrosis by the ECG. The variation in the curve of total CPK in the course of an acute myocardial infarction is subjected to such a great number of factors intercurrent with time, that caution should be exercised in trying to relate a specific elevation of total CPK to an unsuccessful maneuver or to a possible extension of the area of necrosis.

Acute myocarditis and left ventricular "hypertrophy".

Echocardiographic abnormalities of myocarditis are polymorphous and nonspecific. The presence of increased ventricular wall thickness, typically transient, is an infrequent finding in myocarditis that can correspond to an improvement in the clinical status of the patient and the ejection fraction. We report the case of a patient with acute myocarditis and the echocardiographic abnormalities observed during the course of his myocarditis: transient left ventricular "hypertrophy" associated with improvement of the left ventricular function.