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Biomedical subjects

J Magriña

Publications and source records attributed to J Magriña.

17 recordsLinked to original sources
PubMed1998

[Anatomopathological bases of latent ventricular dysfunction in insulin-dependent diabetics].

INTRODUCTION AND OBJECTIVES: The natural history of diabetic cardiomyopathy remains unclear, mainly due to concurrent coronary disease or hypertension. Since the presence of confounding factors is less likely in youngsters, they constitute a suitable study model to analyze early stages of diabetic cardiomyopathy. PATIENTS AND METHODS: We screened 33 young normotensive asymptomatic patients with type I diabetes mellitus. Mean age was 28 +/- 8 y (range 18 to 46 y) and there were 14 men. RESULTS: 2-D Echo showed normal left ventricular size and wall motion in all patients but one. Radionuclide basal ejection fraction was 56.5 +/- 6.6% and increased to 63 +/- 7.4% (p < 0.02) on exercise. According to Rozansky criteria, 16 patients had an abnormal response. Abnormal stress sestamibi was detected in 18 patients and only 3 had reversible defects. Coronary angiography was performed in 11 patients with at least one abnormal non-invasive study response. Coronary angiography revealed normal vessels in all patients and left anterior descending blood flow velocity (Doppler) increased 4 fold after papaverine infusion. Left ventricular biopsies showed hypertrophy (either nuclear or cellular) in 11, myocytolysis in 6, interstitial fibrosis in 9 and lipid deposits in 4. Morphometric analysis of cardiac samples comparing the diabetic group and a control group showed that the volume fraction of fibrosis (0.19 +/- 0.06 vs 0.10 +/- 0.06; p < 0.01), fiber area -mu2- (1,062 +/- 547 vs 600 +/- 167; p < 0.02) and fiber diameter -mu- (24.2 +/- 3.3 vs 15.1 +/- 3.4; p < 0.001) were higher in the former; and volume fraction of the myocytes was higher in the latter (0.71 +/- 0.006 vs 0.89 +/- 0.07; p < 0.001). CONCLUSIONS: Left ventricular dysfunction, not related to coronary atherosclerosis or small vessel disease, is frequent in asymptomatic young diabetic patients. Abnormal pathologic findings are common in the type of cell hypertrophy, interstitial fibrosis, myocytolysis and lipid deposits.

Adolescent↗
PubMed1993

Evaluation of myocardial perfusion defects by means of "bull's eye" images.

The purpose of this study was to evaluate the usefulness of so-called "bull's eye" imaging as a simplified display of tomographic slices in the detection of coronary artery disease (CAD). A total of 64 patients were studied at stress and at rest, by single photon emission computed tomography (SPECT), either with thallium-201 (201Tl) or with technetium-99m methoxy-isobutyl-isonitril (Tc-MIBI). The myocardial perfusion defects detected by bull's eye image alone and in combination with visual analysis of tomographic images were evaluated in all cases, taking coronary arteriographic results as a gold standard. The overall sensitivity and specificity for detection of CAD were as follows: bull's eye imaging, 100% and 70.8%; tomographic imaging (SPECT), 90% and 91.6%. The results of bull's eye imaging and SPECT interpreted together were 96.6% and 83.3%. The regional sensitivity and specificity of bull's eye for individual coronary arteries were: right coronary artery (RCA), 100% and 73.7%; left anterior descending (LAD), 100% and 87.2%; left circumflex (LCx), 100% and 97.3%. For SPECT they were: RCA, 93.7% and 89.5%; LAD, 86.6% and 92.3%; LCx, 73.3% and 97.4%. For bull's eye with SPECT they were: RCA, 94.4% and 86.1%; LAD, 87.5% and 92.1%; LCx, 82.3% and 97.2%. We conclude that the bull's eye image display allows an easier and more objective assessment of myocardial perfusion defects and shows higher sensitivity. However, it has a relatively low specificity which can cause an overestimation of perfusion defects. Thus, visual analysis of bull's eye imaging is a useful diagnostic tool but must be evaluated in conjunction with tomographic imaging.

Adult↗
PubMed1986

Systolic compression of coronary artery in hypertrophic cardiomyopathy.

To determine the prevalence and significance of the systolic compression of the anterior descending coronary artery in hypertrophic cardiomyopathy, we studied 54 consecutive patients out of a catheterization laboratory population of 1619. This angiographic finding was found to be more prevalent (P less than 0.001) and severe in myopathic than in secondary hypertrophy. Complete systolic occlusion occurred in 5 of the 6 patients with nonobstructive cardiomyopathy showing the systolic narrowing. Severe septal squeezing was also present in these cases and the diastolic time lag to refill the distal branches reached 20-33% of the diastolic period. This subset of patients showed the least dynamic anterior wall contraction (P less than 0.001) and the highest incidence of thallium-201 perfusion defects (P less than 0.05) and of recurrent cardiac arrest (P less than 0.05). We conclude that severe systolic compression of the descending coronary artery in hypertrophic cardiomyopathy may be an angiographic marker of the myopathic hypertrophy extending to the anterior wall and might contribute to ischemia when the time to restore the distal perfusion is greatly delayed.

Adolescent↗
PubMed1983

Prevalence and prognosis after a first nontransmural myocardial infarction.

Prevalence, prognosis, and coronary anatomy associated with nontransmural myocardial infarction (MI) were prospectively assessed in 458 consecutive men admitted to our coronary care unit with a first MI. Cardiac catheterization was performed in 402 of the 436 survivors within 1 month of the acute event. Mean follow-up was 33 months (range 5 to 72). Nontransmural MI was diagnosed in 28 patients (6%). These patients were younger (46 +/- 10 versus 51 +/- 7 years, p less than 0.001) and had lower peak creatine kinase values (601 +/- 319 versus 1,141 +/- 923 U, p less than 0.01) and better ejection fraction (63 +/- 8 versus 46 +/- 14, p less than 0.001) than did their counterparts. Survivors of nontransmural MI also had fewer affected arteries (p less than 0.001) and a lower prevalence of total or subtotal occlusion (greater than 90%) in the involved artery (p less than 0.01). Mortality in the acute phase and long-term survival at 4 years (Kaplan-Meier) in patients with nontransmural MI (94%) were similar to those in patients with transmural MI (90%). The occurrence of new nonfatal coronary events was also similar in both groups of MI survivors. Thus, in the absence of symptoms, more aggressive management to improve survival does not seem warranted after nontransmural MI.

Adult↗
PubMed1982

Determinants of prognosis in survivors of myocardial infarction: a prospective clinical angiographic study.

To identify predictors of late mortality, 259 consecutive men (less than or equal to 60 years old) who survived acute myocardial infarctions were catheterized one month after admission and were then followed for a mean of 34 months. Nineteen patients (7 per cent) died during the observation period. Of 79 base-line descriptors, 17 proved to be univariate predictors of survival. Cox regression analysis demonstrated that the ejection fraction (P less than 0.001), the number of diseased vessels (P less than 0.005), and the occurrence of congestive heart failure in the coronary unit (P less than 0.01) were the only independent predictors of survival. Risk stratification showed that the probability of survival at four years was highest in patients with normal ejection fractions (96 to 100 per cent, depending on the number of diseased vessels) and lowest in those with ejection fractions below 20 per cent (3o to 75 per cent). The prognosis in patients with ejection fractions between 21 and 49 per cent was significantly worse (78 per cent) than in those with normal ejection fractions only in the group with three-vessel involvement (P less than 0.01). Since most survivors of myocardial infarction who are likely to have their lives prolonged by coronary-artery bypass surgery are in this group, it is reasonable to limit routine coronary angiography to the 56 per cent of survivors who have ejection fractions between 21 and 49 per cent.

Adult↗
PubMed1982

Angiographic findings 1 month after myocardial infarction: a prospective study of 259 survivors.

Coronary anatomy as it relates to left ventricular function was assessed prospectively in patients who survived acute myocardial infarction. The study population included 259 consecutive male patients age 60 years or younger who underwent catheterization 30 days after the acute event. Coronary artery obstructive lesions (greater than 50% reduction in luminal diameter) were found in 241 patients (93%), 118 (45%) of whom had total and 76 (29%) subtotal (greater than 90%) stenosis) occlusion of at least one coronary artery. Normal coronary vessels were seen in eight patients (3%) and nonobstructive lesions in 10 (4%). One-, two- and three-vessel disease were present in 89, 86 and 66 patients, respectively. Patients with normal coronary arteries or nonobstructive lesions had higher ejection fractions than those with obstructive lesions in one, two or three vessels (p less than 0.05). Ejection fraction was lower (p less than .001) and the percentage of akinetic segments higher (p less than 0.001) in patients with total or subtotal lesions and no collaterals. Adequate collaterals, seen in 29 patients (11%), significantly improved regional wall motion (p less than 0.05) and decreased the percentage of akinetic segments (p less than 0.001). Thus, in a substantial number of patients (32% in our series), the infarcted area is spontaneously reperfused by collaterals or through the involved artery. Both mechanisms ameliorate wall motion in corresponding areas.

Collateral Circulation↗
PubMed1981

Myocardial infarction with normal coronary arteries: a prospective clinical-angiographic study.

The association of myocardial infarction with normal coronary arteries was analyzed prospectively. A series of 259 consecutive men aged 60 years or less underwent selective coronary angiography 30 days after a definite infarct. Coronary arterial lesions were documented in 251 patients, normal coronary arteries in the remaining 8. The latter patients had a significantly lower (p less than 0.001) mean age than the former; no patient older than 50 years had patent coronary arteries, whereas 5 of the 11 patients under age 35 had normal arteries. The prevalence of risk factors was similar in both groups of patients. Although there were no group differences in infarct size or location, patients with normal coronary arteries had a higher ejection fraction (p less than 0.01) and a lower left ventricular end-diastolic pressure (p less than 0.05). A previous history of angina or infarction and the occurrence of new coronary events were confined to patients with coronary arterial lesions. The clinical course of patients presenting with normal angiograms was uneventful. Transient coronary occlusion, the most likely mechanism of infarction in this group of patients, could not be ascribed to either spasm or platelet hyperactivity.

Blood Platelets↗
PubMed1981

Disabling angina pectoris with normal coronary arteries in patients undergoing long-term hemodialysis.

Reports of patients undergoing long-term hemodialysis presenting with angina pectoris have usually shown severe coronary atherosclerosis. We studied a series of nine patients undergoing regular maintenance dialysis referred for incapacitating angina. Of them, four had strictly normal coronary angiograms. The patients with normal angiograms were all females who were significantly younger (p less than 0.05) and had more severe hypertension and higher left ventricular wall stress than patients showing coronary artery lesions. Anemia and increased myocardial oxygen consumption due to high blood pressure may explain the syndrome of angina pectoris in the presence of long-term dialysis in patients with normal coronary arteries. The prevalence of this association cannot be ascertained unless prospective studies are conducted. However, our data suggest that it might not be an uncommon finding.

Adult↗
PubMed1980

Relief of angina by periarterial muscle resection of myocardial bridges.

A 47-year-old man presented with exertional angina. Selective coronary arteriography showed complete systolic segmental occlusion of the left anterior descending coronary artery producing milking effect. Permanent relief of symptoms was achieved by surgical excision of myocardial bridges. Postoperative angiography performed 11 months later was normal. Periarterial muscle resection should be considered in symptomatic patients with this rare anomaly.

Angina Pectoris↗
PubMed1978

Isolated T wave alternans.

Two patients with isolated T wave alternans are reported, with their vectocardiograms, their response to carotid sinus stimulation, and the response to calcium infusion in one of them with documented severe hypocalcemia. Eleven cases of the literature are briefly reviewed. The alternans of the T wave appears with severe QT prolongation, QT alternans, and an increased tendency to ventricular fibrillation. The findings are consistent with the hypothesis that T wave alternans may be the electrocardiographic manifestation of the transmembrane action potential alternans and could be related in some cases to hypocalcemia.

Adolescent↗
PubMed1978

Isolated T wave alternans elicited by hypocalcemia in dogs.

Isolated T wave alternans (TWA) could be consistently induced in 13 dogs by infusion of an acid dextrose solution (ACD) and in nine with a 2% EDTA disodium solution. To study the factors concerned in evoking TWA, serial determinations of total and ionized serum calcium (ICa), Mg, K, pH, pCO2 and pO2 were performed. Arterial or LV pressures and LV dp/dt as well as a standard electrocardiographic lead were monitored. TWA appeared after the QT interval was significantly prolonged and was associated with a fall in LV pressure and with mechanical alternans. QT alternans could also be detected in 50% of the cases. ICa levels were significantly reduced at the moment of appearance of the TWA. Data obtained support the conclusion that TWA was the result of a reduction in the level of the ICa, probably interfering with the calcium transport mechanisms of the myocardial cell, although the possibility that the alternans may be due to other effects of the two agents employed unrelated to calcium lowering cannot be excluded.

Animals↗