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Biomedical subjects

A Olivares

Publications and source records attributed to A Olivares.

At least 19 recordsLinked to original sources

Differential effect of fetal, neonatal and treatment variables on neurodevelopment in infants with congenital hypothyroidism.

OBJECTIVES: To identify the influence of fetal, neonatal and treatment variables on neurodevelopment in children with congenital hypothyroidism. METHODS: A multiple regression analysis was performed in the neurodevelopmental scores of 26 children with CH who were assessed at 3, 6, 12 and 18 months for postural control, fine eye-hand coordination and language. The independent variables were: duration of fetal hypothyroidism, initial biochemical severity, days at starting treatment, initial dose, and efficiency of treatment. RESULTS: Postural control was predicted by duration of fetal hypothyroidism and language by the biochemical severity of the disease at birth. Fine eye-hand coordination was not predicted by any variable. CONCLUSION: This pattern of influences suggests that fetal and neonatal hypothyroidism have different effects on brain maturation sites during the first 2 years of life and that some subtle neurocognitive deficits are probably unavoidable.

Child Development↗

Left atrial function: bridge to central and hormonal determinants of exercise capacity in patients with chronic heart failure.

UNLABELLED: The stroke volume response to exercise is a critical determinant in meeting peripheral metabolic demands in patients with chronic hear failure. The Left atrium, by its position, is important in coupling right and left ventricles, to left preload reserve and to modulate sympathetic activity. We performed this study to investigate the relationship between exercise capacity and diastolic and systolic left atrium function in patients with chronic heart failure. METHODS: We considered 128 consecutive patients with severe chronic heart failure (EF < 35%) due to ischemic or idiopathic dilated cardiomyopathy. Cardiac output, right atrial pressure, pulmonary artery pressures and mean pulmonary wedge pressure (A, X, V, Y wedge pressures) were determined during right cardiac catheterization. By Echocardiography evaluation, we measured atrial pressures and volume during early and late left atrial systolic filling and we calculated left atrial chamber stiffness by this equation P = A*eKV1. (P = left atrial pressure; A = elastic constant (mmHg*ml); e = the base of the natural logarithm; V1 = left atrial volume (ml); K = left atrial chamber stiffness constant (ml-1) = ln (V/X)/(maximal--minimal left atrial volumes)). All patients performed cardiopulmonary exercise test with modified Noughton protocol. Plasma norepinephrine and Atrial natriuretic factor levels were determined. RESULTS: Maximal and minimal left atrial volumes were inversely related to oxygen consumption (r = -.44, p < .001; r = -.61, p < .001). At rest, no differences were found in plasma norepinephrine concentrations (309 +/- 152 pg/ml vs 309 +/- 394 pg/ml; p = ns) and systemic vascular resistance (1706 +/- 435 vs 1771 +/- 524 dynes/cm sec-5; p = ns) in patients with large or normal left atrial volumes. During exercise the chronotropic response increased less in patients with large atrial volumes (56 +/- 13 vs 45 +/- 14; p = .001). The left atrial chamber stiffness constant was inversely related to peak oxygen consumption and exercise time. Patients with different chamber stiffness showed statistical difference in peak VO2 (16 +/- 4 vs 11 +/- 3 ml/kg/min; p = .0001). Left atrial ejection fraction was directly related to peak oxygen consumption (r = 0.55), but the most strongly correlation was with atrial filling fraction (r = .67). CONCLUSIONS: This study demonstrates a strong relationship between left atrial function and exercise capacity in patients with chronic heart failure.

Chronic Disease↗

Changes in the biological:immunological ratio of basal and GnRH-releasable FSH during the follicular, pre-ovulatory and luteal phases of the human menstrual cycle.

BACKGROUND: Significant changes in charge isoform distribution of serum FSH occur throughout the human menstrual cycle. In the present study, we analysed the impact of the changing endocrine milieu characteristic of the menstrual cycle on the capability of basal and gonadotrophin-releasing hormone (GnRH)-releasable FSH to trigger intracellular signal transduction via the human FSH receptor. METHODS: Seven normal women underwent blood sampling every 10 min for 10 h during the early follicular phase (FP), pre-ovulatory phase (PO) and mid- to late luteal phase (LP) of the menstrual cycle. Serum from successive samples collected across 2 h intervals containing FSH released under baseline and exogenous GnRH-stimulated conditions was tested for bioactivity employing a homologous in-vitro assay. RESULTS: The biological to immunological (B:I) ratio of basal and GnRH-releasable FSH was significantly (P < 0.05 ) higher at LP (range, 0.83 +/- 0.07 to 1.35 +/- 0.30) than during the FP (0.43 +/- 0.02 to 0.65 +/- 0.04) and PO (0.49 +/- 0.05 to 0.62 +/- 0.06). In all phases, the B:I FSH ratio in baseline samples was similar to those exhibited by samples collected after 10 and 90 microg GnRH administration. CONCLUSIONS: The selective increase in the capability of the admixture of FSH isoforms circulating during the LP to activate the FSH receptor, apparently represents an additional mechanism through which the anterior pituitary may regulate the maturation of those follicles destined to ovulate during the coming cycle.

Adult↗

Prostaglandins and reproduction of the scallop argopecten purpuratus: II. relationship with gamete release.

Levels of prostaglandins E(2) and F(2alpha) were measured in male and female gonadal portions of the functional hermaphroditic scallop Argopecten purpuratus, at the time of spawning. For these measurements, mature scallops were stimulated to initiate their chain of spawning events, and prostaglandins (PGs) were analyzed in samples before stimulation, when animals appeared stimulated to release sperm, during the release of sperm, when animals appeared stimulated to release oocytes, when most of the oocytes had been released, and 24 hr after the end of spawning. The experiment was run twice, once in winter and once in spring. An additional in vitro experiment was carried out to analyze activity of the monoamines dopamine and serotonin on the levels of these prostaglandins. For this, minced tissue of the female portion of the gonad was incubated for different time periods with each of the amines at 10(-5) M. PGs were determined in the tissue samples by radioimmunoanalysis. The results showed that the amounts of the PGs increased significantly in both parts of the gonad during the global process of spawning and decreased when it had been completed. Incubation of minced gonad with the amines affected the time course of PGs variations, i.e., the effect of these compounds depended on the incubation time used. The results support a model for the regulation of spawning which assumes the occurrence of a stimulus which is detected by receptors, processed by nerve cells, and sent to the gonad where intermediation by amines (changing the time course of the process) induces liberation of gametes, in some way modulated by prostaglandins.

Animals↗

Reactivity of different LH and FSH standards and preparations in the world health organization matched reagents for enzyme-linked immunoassays of gonadotrophins.

The immunoreactivity of various LH and FSH calibration standards and recombinant preparations in the enzyme-linked immunoassay (EIA) systems for gonadotrophins developed for the Special Programme of Research in Human Reproduction of the World Health Organization (WHO) were compared. The preparations tested included three LH and two FSH pituitary standards (calibrated against LH 80/552 and 68/40 and FSH 78/549 respectively) provided with the EIA or radioimmunoassay WHO matched reagent kits, the pituitary preparation LER-907, and recombinant human LH (rhLH) and FSH (rhFSH). Simultaneous curve fitting of the EIA dose-response curves revealed no significant differences among the slopes generated by the WHO LH standards and LER-907; in contrast, no parallelism was found between the curves of rhLH and the pituitary-derived LH standards. No significant differences were found among the slopes of the curves elicited by the pituitary and recombinant FSH preparations. Each LH preparation exhibited a high degree of charge heterogeneity. Considerable variations in charge isoform distribution among the WHO LH standards, rhLH and LER-907 were also evident. In contrast, the FSH preparations were less heterogeneous and exhibited minor differences in charge distribution. Despite the existing differences in charge isoform distribution, all the pituitary-derived preparations as well as rhFSH seem appropriate for using as calibration standards in this particular EIA system.

Animals↗

A preponderance of circulating basic isoforms is associated with decreased plasma half-life and biological to immunological ratio of gonadotropin-releasing hormone-releasable luteinizing hormone in obese men.

Hormonal abnormalities of the reproductive axis have been described in obesity. In men, extreme obesity is associated with low serum testosterone (T) and high estrogen [estrone and estradiol (E(2))] levels. As changes in the sex steroid milieu may profoundly affect the carbohydrate heterogeneity and thus some of the biological and physicochemical properties of the LH molecule, we analyzed the relative distribution of LH isoforms circulating under baseline conditions (endogenous GnRH drive) as well as the forms discharged by exogenous GnRH stimulation from putative acutely releasable and reserve pituitary pools in overweight men. Secondarily, we determined the impact of the changes in LH terminal glycosylation on the in vitro bioactivity and endogenous half-life of the gonadotropin. Seven obese subjects with body mass indexes ranging from 35.7-45.5 kg/m(2) and seven normal men with body mass indexes from 22.5-24.2 kg/m(2) underwent blood sampling at 10-min intervals for a total of 10 h before and after the iv administration of 10 and 90 microg GnRH. Basally released and exogenous GnRH-stimulated serum LH isoforms were separated by preparative chromatofocusing and identified by RIA of eluent fractions. Serum pools of successive samples collected across 2-h intervals (five serum pools per subject) containing LH released under baseline and exogenous GnRH-stimulated conditions were tested for bioactivity employing a homologous in vitro bioassay. Mean serum T and E(2) levels were significantly lower and higher, respectively, in the obese men than in the control group [serum T, 13.5 +/- 2.4 vs. 19.4 +/- 1.4 nmol/L (mean +/- SEM; P: = 0.01); serum E(2), 0.184 +/- 0.01 vs. 0.153 +/- 0.01 nmol/L (P: < 0.05)]. Mean baseline serum LH levels were similar in obese subjects and normal controls (13.3 +/- 1.3 and 12.2 +/- 1.2 IU/L). Although multiple parameter deconvolution of the exogenous GnRH-induced LH pulses revealed that the magnitude of the pituitary response in terms of secretory burst mass, secretory amplitude, and half-duration of the LH pulses was similar in obese and control subjects, the apparent endogenous half-life of LH was significantly (P: < 0.05) shorter in the obese group (98 +/- 11 min) than in the normal controls (132 +/- 10 min). Under all conditions studied, the relative abundance of basic isoforms (those with pH >/=7.0) was significantly (P: < 0.05) increased in the obese subjects compared with the controls (percentages of LH immunoactivity recovered at pH >/=7.0: obese subjects, 34-57%; normal controls, 22-46%). The biological to immunological ratio of LH released in baseline and low dose (10 microg) GnRH-stimulated conditions were similar in obese subjects and normal controls, whereas LH released by obese subjects in response to the high (90 microg) GnRH dose exhibited significantly lower ratios than those detected in normal individuals (0.62 +/- 0.07 and 0.45 +/- 0.09 vs. 1.01 +/- 0.10 and 0.81 +/- 0.09 for LH released within 10-120 min and 130-240 min after GnRH administration in obese and controls, respectively; P: < 0.05). Collectively, these results indicate that the altered sex steroid hormone milieu characteristic of extreme obesity provokes a selective increase in the release of less acidic LH isoforms, which may potentially modify the intensity and duration of the blood LH signal delivered to the gonad. Altered glycosylation of LH may therefore represent an additional mechanism modulating the hypogonadal state prevailing in morbid obesity.

Adult↗

Receptor binding activity and in vitro biological activity of the human FSH charge isoforms as disclosed by heterologous and homologous assay systems: implications for the structure-function relationship of the FSH variants.

Follicle-stimulating hormone (FSH) is produced and secreted in multiple molecular forms. These isoforms differ in their oligosaccharide structures, which determine the particular behavior of a given variant in in vitro and in vivo systems. Employing heterologous cell assay systems, this and other laboratories have shown that highly sialylated human FSH variants exhibit lower receptor binding/immunoactivity as well as in vitro bioactivity/immunoactivity relationships than their less sialylated counterparts. It is not known, however, whether this characteristic behavior of the FSH isoforms is reproduced by homologous assay systems, in which unique variants of the receptor are presumptively expressed. To gain further insights into the structure-activity relationship of the various FSH isoforms, we analyzed the capacity of nine charge isoforms obtained after high-resolution chromatofocusing (pH window, 7.10 to <3.80) of anterior pituitary glycoprotein extracts to bind and activate their cognate receptor expressed by naturally occurring heterologous cell systems (rat granulosa cells and seminiferous tubule homogenates) as well as by human embryonic kidney-derived 293 (HEK-293) cells transfected with the human FSH (FSH-R) receptor cDNA. In both (heterologous and homologous) receptor assay systems, the isoforms displaced 125I-labeled FSH from the receptor in a dose-response manner; however, whereas in the heterologous systems, the receptor binding activity varied according to the elution pH value/sialic content of the isoforms, with the less acidic variants exhibiting higher receptor binding activity (r = 0.851 and 0.495 [p < 0.01 and p < 0.05] for the granulosa cell and testicular homogenate receptor assay systems, respectively) than the more acidic/sialylated analogs, in the homologous assay, this relationship was practically absent (r = 0.372, p N.S.). The capacity of the isoforms to induce androgen aromatization by rat granulosa cells followed the same trend shown by its corresponding receptor assay system (r = 0.864, p < 0.01). Interestingly and in contrast to the results observed in the homologous receptor binding assay, the ability of the isoforms to induce cAMP production by HEK-293 cells varied according to their elution pH value, with the more sialylated isoforms exhibiting lower potency than their less acidic counterparts (r = 0.852, p < 0.01). The results yielded by the heterologous assays suggest that the different potency of the isoforms to elicit a biological effect in a naturally occurring receptor system depends primarily on the particular affinity of the receptor molecule for each isoform. The existence of a clear dissociation between receptor binding and signal transduction in the homologous system indicate that this later function is rather related to the different ability of the FSH glycosylation variants to induce and/or stabilize distinct receptor conformations that may permit preferential or different degrees of activation/inhibition of a given signal transduction pathway. Thus, the human FSH receptor-transducer system apparently possesses sufficient versatility to respond in a different manner to glycosylation-dependent diverse FSH signals.

Animals↗

Dynamics of basal and gonadotropin-releasing hormone-releasable serum follicle-stimulating hormone charge isoform distribution throughout the human menstrual cycle.

In the present study we analyzed physiological changes in the relative distribution of FSH isoforms circulating under baseline conditions throughout the ovarian cycle as well as the forms discharged by GnRH stimulation from putative acutely releasable and reserve pituitary pools. Eight normally menstruating women underwent blood sampling on three occasions, once each during the presumptive early or midfollicular phase (FP), late follicular phase to midcycle (preovulatory phase; PO), and mid- to late luteal phase (LP) of the menstrual cycle. Blood samples were withdrawn at 10-min intervals for a total of 10 h before and after the iv administration of 10 and 90 micrograms GnRH. GnRH-stimulated FSH pulses were analyzed for secretory burst mass, secretory burst amplitude, integrated FSH concentrations, and endogenous FSH half-life by deconvolution. Serum FSH isoforms were separated by preparative chromatofocusing in 30 x 1-cm columns and identified by RIA of eluent fractions. The changes observed in serum FSH isoform distribution were then correlated with the corresponding secretory and clearance estimates of the released FSH molecules. In each phase of the menstrual cycle, a significant rise in serum FSH concentrations was observed after administration of the consecutive low and high dose GnRH pulses. The magnitude of the response in terms of secretory burst mass, secretory amplitude, and area of GnRH-induced FSH peaks was significantly higher during the PO. In all cycle phases, but particularly during the FP and PO, administration of the 90-micrograms GnRH dose elicited higher (1.4- to 1.7-fold) FSH secretory responses than the lower dose. Multiple parameter deconvolution of the GnRH-induced FSH pulses revealed that FSH molecules released in response to 10 micrograms GnRH at PO exhibited significantly (P < 0.01) shorter plasma half-lives (108 +/- 11 min) than those released during the follicular and luteal phases of the same menstrual cycles (apparent plasma half-life of FSH released at FP, 222 +/- 37 and 271 +/- 47 min for 10 and 90 micrograms GnRH-induced FSH pulses, respectively; LP, 244 +/- 41 and 198 +/- 40 min; P = NS, FP vs. LP) and in response to the high dose GnRH challenge at PO (276 +/- 40 min). Under all conditions studied, serum FSH charge isoforms were distributed along a pH range of 7.0 to less than 4.0.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

On the nature of the follicle-stimulating signal delivered to the ovary during exogenously controlled follicular maturation. A search into the immunological and biological attributes and the molecular composition of two preparations of urofollitropin.

In the present study, we analyzed the immunological and biological potencies as well as the molecular composition of urinary follicle-stimulating hormone (FSH) present in determined lots of regular and highly purified (HP) commercial preparations of urofollitropin in order to obtain additional insights on the particular type of gonadotropin signal received by the ovary during exogenously regulated ovarian stimulation. In both preparations, a high degree of FSH charge heterogeneity was detected as disclosed by chromatofocusing analysis (pH range 7.5 to < 4.0). Urinary FSH present in the HP compound was consistently more acidic and exhibited a longer survival in rat circulation than the regular formulation. Inter-batch variability for FSH heterogeneity and in vitro bioactivity was higher in the partially purified preparation than in the HP analog. In the regular preparation, the amount of immunoreactive and bioactive FSH per ampule was two times higher than that present in the HP preparation; the resultant in vitro B/I ratios were similar. Although both urinary FSH preparations showed detectable amounts of immunoreactive and bioactive luteinizing hormone and choriogonadotropin hormone material, the degree of activity present in the less purified formulation was considerably higher than that shown by the HP analog. When the capability of each urinary FSH preparation to induce ovarian tissue-type plasminogen activator enzyme activity in hypophysectomized rats was determined, both formulations exhibited similar potencies despite the existing differences in plasma clearance rate and charge distribution profile. The present study indicates that the isoform composition of urinary FSH in the two commercial preparations analyzed differs according to the degree of purity of the formulation. More FSH material is needed in the partially purified FSH preparation to induce biological effects similar in magnitude to those exhibited by the highly purified analog. The possible impact of these variations in the molecular composition of the FSH signal on other biological functions of the ovary during the course of exogenously controlled follicular growth and maturation still remains to be ascertained.

Animals↗

Considerations on the distribution of aflatoxigenic Aspergillus flavus in feeds.

The distribution of aflatoxin producing isolates of the Aspergillus flavus group in feeds was studied. Aflatoxin production was investigated by a sequential method previously reported (fluorescence in Coconut Agar Medium, rapid extraction from a wheat medium, and total extraction from the same wheat medium). Twenty-seven of 32 samples contained A. flavus, and 21 of them had at least one aflatoxicogenic isolate of A. flavus. Of the 115 isolates analysed, 65 produced aflatoxins, mainly B aflatoxins.

Aflatoxins↗

Micro-abscesses and presumptive inflammatory nodules of the brain.

Sixteen cases of micro-abscesses and presumptive inflammatory nodules of the brain are analyzed. The increasing frequency of cortico-subcortical small nodular lesions diagnosed by CT scan, as well as the number of cases successfully treated with antibiotics, are stressed. In the authors opinion, initial antibiotic treatment with a high possibility of a cure is indicated in patients with a presumptive inflammatory cortico-subcortical nodular lesions diagnosed by CT scan.

Adolescent↗

[Lofepramine: a comparative clinical study with amitriptyline].

Lofepramine, a new tricycle antidepressant, is compared with amitriptyline in a double-blind study. A brief pharmacological description of the drug is made emphasizing its low toxicity and anticholinergic peripheral effects, high plasmatic concentration levels and good tolerance and elimination in comparison with some other known tricycle antidepressants. Sixty depressive outpatients of a Mental Health Service in Lima, 5 male and 55 female, aging 16 to 65, 29 endogenous and 31 neurotic were studied with both drugs in a equimolar dosage. Through the chi square test, no statistical significance was found in maximal therapeutic response, Hamilton Depression Rating Scale scores, type of depression, and side-effects xerostomy which is lesser with lofepramine. A discussion of these results is made and it is concluded that in the present study lofepramine compared with amitriptyline has a similar therapeutic effect. Though not statistically significant, lofepramine seems to be better for neurotic depression and patients sensitive to anticholinergic side-effects.

Adjustment Disorders↗

Continuous spinal anesthesia: a comparative study of standard microcatheter and Spinocath.

BACKGROUND AND OBJECTIVES: This prospective, randomized study evaluated the advantages and disadvantages of a new subarachnoid catheter. METHODS: Sixty ASA I-IV patients aged 40-70 years, scheduled for total knee arthroplasty, were randomly distributed into group 1 (Spinocath; Braun Melsungen, Germany) and group 2 (Intralong; Pajunk, Germany). The study tabulated details of subarachnoid catheter insertion, dural puncture, time to free cerebrospinal fluid (CSF) flow, anesthesia onset time, surgery anesthesia time, the upper level of sensory block reached, the anesthesiologist-evaluated degree of difficulty with the technique, and the quality of analgesia obtained and complications. At the end of surgery, all the catheters were removed, and their patency was checked. RESULTS: Spinocath insertion required 6.3 +/- 3.2 minutes in group 1 versus 3.9 +/- 1.2 minutes in group 2 (P < .01) with similar difficulties with catheter introduction. Perception of dural puncture was better in group 1 (P < .05). There were significant intergroup differences in time to free flow of CSF through the catheter. In group 2, correct catheter positioning had to be confirmed by aspiration in 80% of cases (P < .05). At the end of surgery, the catheters were removed, and there were no significant differences between groups. The anesthetic blocks were similar with both systems. Patient opinion of the technique did not differ between groups, and regression analysis did not show any differences between groups or correlation to any incident during performance of the technique. Globally, the anesthesiologists participating in the study considered both systems to be easy to use and adequate for continuous spinal anesthesia. With respect to the advantage afforded by a directional needle in orientating the catheter within the spinal canal, the Spinocath system-with a longer technique performance time than the standard approach-involves a success rate and incidence of technical problems similar to that of the conventional technique.

Adult↗

Basal and gonadotropin-releasing hormone-releasable serum follicle-stimulating hormone charge isoform distribution and in vitro biological-to-immunological ratio in male puberty.

Follicle-stimulating hormone is synthesized and secreted as a mixture of heterogeneous isoforms that differ from each other in carbohydrate structure, biological potency, and plasma half-life. The relative abundance of the FSH isoforms will depend on the endocrine status of the donor at the time of sample collection. In the present study, we attempted to define the impact of the changing endocrine milieu characteristic of male puberty on the charge heterogeneity and plasma half-life of the serum FSH isoforms released under endogenous and exogenous GnRH drives, and examined whether such a varying hormone milieu modifies the capability of the circulating hormone to trigger intracellular signal transduction at the human FSH receptor level. Forty healthy male subjects at Tanner stages (Ts) 1 to 5 were sampled at 10 min intervals for 10 h. Serum from successive samples collected across 2-4 h intervals containing FSH released under basal, low-dose (10 microg), and high-dose (90 microg) exogenous GnRH-stimulated conditions was subjected to preparative chromatofocusing and tested for bioactivity employing a homologous cell in vitro bioassay system. Deconvolution analysis was applied to estimate the apparent endogenous FSH plasma half-life in samples obtained after administration of low-dose exogenous GnRH. Under all conditions studied, serum FSH charge isoforms were distributed along a pH range of 7.0 to less than 3.0. Comparisons across the different Tanner stages revealed a significant and selective increase in the ratio of FSH isoforms with elution pH values <4.50 relative to those with values >/=4.50 at Ts-2. At Ts-3, this ratio returned to that present at Ts-1, to decline thereafter during the ensuing pubertal stages. Serum bioactive FSH concentrations progressively increased (from 3.72 +/- 1.3 to 16.2 +/- 5.3 IU/L) throughout puberty, and in all conditions bioactive FSH concentrations exceeded those detected by a specific radioimmunoassay. The biological to immunological (B:I) FSH ratio at baseline was significantly (p < 0.05) lower at Ts-1 and Ts-2 (1.33 +/- 0.30 and 1.62 +/- 0.34, respectively) than at more advanced stages of pubertal development (2.28 +/- 0.20, 2.96 +/- 0.38, and 2.77 +/- 0.63 at Ts-3-, 4-, and -5, respectively) Similar differences were detected in samples containing FSH molecules released after low- and high-dose GnRH administration. The apparent endogenous FSH half-life of the deconvolved GnRH-induced FSH pulses was similar in the five study groups. These results demonstrate that the transition from infancy to sexual maturity in men is accompanied by qualitative changes in the circulating FSH isoform mixture. Although the changes in FSH glycosylation occurring throughout puberty are not of sufficient magnitude to alter the survival of the gonadotropin in circulation, they allow preferential secretion of bioactive FSH. The enrichment of the circulating mix of FSH isoforms with highly bioactive variants throughout spontaneous puberty may potentially favor the development of spermatogenesis and acquisition of reproductive competence.

Adolescent↗

[Arrhythmia in acute myocardial infarction with involvement of the right ventricle].

Arrhythmias and conduction disorders were studied in 110 patients with posteroinferior myocardial infarction with right ventricular involvement. All the patients were hospitalized in the coronary care unit, and were compared with another 110 patients with posteroinferior myocardial infarction without extension to the right ventricle. 99% of the patients with right ventricular infarction and 96.3% of the patients with isolated inferior infarction had some type of arrhythmia. The disorders of automatism were similar in both groups (90% vs 91%, respectively). The conduction disturbances were observed in 68% of the infarctions extended to the right ventricle and in 20% of the isolated left ventricular infarctions (p greater than 0.01). A-V block occurred in 52% of the infarctions with right ventricular involvement and only in 10.9% of the control group. Intraventricular conduction disorders also were more frequent in right ventricular infarction (24.5% vs 10.9%) (p less than 0.02), especially the RBBB (18.2% vs 6.4%). Ventricular fibrillation was observed in 5.5% and 0.9%, and polymorphic ventricular tachycardia (torsades de pointes) in 12.7% and 1.9% respectively. In 62 patients with right ventricular infarction it was necessary to implant a pacemaker as compared to 12 patients in the control group. Mortality was higher in the patients with inferior infarction extended to the right ventricle (23 patients vs 2 patients). None of the deaths were due to arrhythmias. It can be concluded that conduction disorders and the number of pacemaker implants are more common in the infarctions with right ventricular involvement due to more severe damage to the conduction system.

Arrhythmias, Cardiac↗