Genetic parameters for performance, feed efficiency, and carcass traits in Senepol heifers.

Improving feed efficiency is a key breeding goal in the beef cattle industry. In this study, we estimated the genetic parameters for feed efficiency and carcass traits in Senepol cattle raised in tropical regions. Various indicators of feed efficiency [gain to feed ratio (G:F), feed conversion ratio (FCR), residual weight gain (RG), residual intake and body weight gain (RIG), and residual feed intake (RFI)] as well as growth [final BW, average daily gain (ADG), and DM intake (DMI)], and carcass [rib-eye area (REA), backfat thickness (BF), intramuscular fat score, and carcass conformation score] traits were included in the study. After data editing, records from 1 393 heifers obtained between 2009 and 2018 were used for the analyses. We fitted an animal model that included contemporary group (animals from the same farm that were evaluated in the same test season) as the fixed effect, and a linear effect of animal age at the beginning of the test as a covariate; in addition to random direct additive genetic and residual effects. The (co)variance components were estimated by Bayesian inference in uni- and bivariate analyses. Our results showed that feed efficiency indicators derived from residual variables such as RG, RIG, and RFI can be improved through genetic selection (h2 = 0.14 ± 0.06, 0.13 ± 0.06, and 0.20 ± 0.08, respectively). Variables calculated as ratios such as G:F and FCR were more influenced by environmental factors (h2 = 0.08 ± 0.05 and 0.09 ± 0.05), and were, therefore, less suitable for use in breeding programs. The traits with the greatest and impact on genetic progress in feed efficiency were ADG, REA, and BF. The traits with the greatest and least impact on growth and carcass traits were RG and RFI, respectively. Selection for feed efficiency will result in distinct overall effects on the growth and carcass traits of Senepol heifers. Direct selection for lower RFI may reduce DMI and increase carcass fatness at the finishing stage, but it might also result in reduced growth and muscle deposition. Residual BW gain is associated with the highest weight gain and zero impact on REA and BF, however, it is linked to higher feed consumption. Thus, the most suitable feed efficiency indicator was RIG, as it promoted the greatest decrease in feed intake concomitant with faster growth, with a similar impact on carcass traits when compared to the other feed efficiency indicators.

Actualización del tratamiento de las arritmias en niños / Up-date of treatment of arrhythmias in children

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[Evaluation of biochemical markers of myocardial lesion after radiofrequency ablation. Value of troponin I]. / Evaluación de marcadores de lesión miocárdica tras la ablación con radiofrecuencia. Utilidad de la troponina I.

INTRODUCTION AND OBJECTIVES: Radiofrequency catheter ablation is the curative treatment of choice for many cardiac arrhythmias. After radiofrequency ablation there is always a localized endomyocardial necrosis, which is necessary to eliminate the arrhythmia. The volume of the necrosis may be evaluated by the rise of several biochemical markers, classically CK and CK-MB. However, the sensitivity and specificity of these markers are not optimal and are probably less than ideal for this purpose. Cardiac Troponin I (cTnI) is a newly available biochemical marker available, with a high cardiac specificity. We designed this study in order to determine the value of serum levels of several cardiac markers in patients who underwent radiofrequency catheter ablation and to establish the utility of cTnI. METHODS: We analyzed the data from 51 patients who underwent radiofrequency ablation and from 16 control patients. In respect to the ablation target, we included in the study 14 left accessory pathways, 7 right accessory pathways, 12 atrioventricular nodal reentry tachycardia, 5 ventricular tachycardia and 13 atrial flutter or fibrillation. The levels of CK, CK-MB, cTnI, and myoglobin were compared with clinical findings, ST-T wave abnormalities and the presence of arrhythmias after ablation. To evaluate the diagnostic capability for each biochemical marker we used the ROC curves. RESULTS: A pathological value of cTnI was found in 47 out of 51 (92%) patients in the ablation group. CK-MB had a lower sensitivity (63%). The sensitivity for the other biochemical markers ranged from 30% for CK to 67% for Myoglobin. The area under the ROC curve for cTnI was 0.9375, significantly superior to the other biochemical markers (0.86, 0.76, 0.75 for MB, Myoglobin, CK respectively) (p < 0.05). The lowest cTnI released was found in patients after nodal reentry tachycardia ablation and the highest after atrial flutter ablation. cTnI increased above normal values in 4 patients in the control group (patients who underwent an electrophysiological study without catheter ablation). We found a moderate level of correlation between the number of radiofrequency pulses and cardiac cTnI release (r = 0.69; p < 0.0001). The correlation was different in each target, ranging between r = 0.25 (p = NS, 0.43) for atrial flutter and fibrillation to r = 0.99 (p < 0.0001) for ventricular tachycardia. CONCLUSIONS: cTnI had the greatest sensitivity (92%) for detecting minor myocardial damage. Thus, we can conclude that the serum level of cTnI detects the minor myocardial damage produced by radiofrequency ablation.

[Psychiatric symptoms in acute myeloblastic leukemia: a clinical case]. / Síntomas psiquiátricos en leucemia mieloblástica aguda: un caso clínico.

The psychiatric manifestations of hematological diseases are interesting because of their diverse presentations, complex treatment, pharmacological interactions, and frequent infectious complications. A patient with acute myeloblastic leukemia (AML) presented psychiatric manifestations of sudden onset and psychotic characteristics. The absence of organic lesions in routine neuroimaging studies suggested an added schizophreniform disorder. Further neurological study using more sensitive methods disclosed herpetic encephalitis as the origin of delirium. This case illustrates how early diagnosis, although not always possible, is important if major sequelae are to be avoided. Likewise, it is important to make a through search for organic factors in psychotic pictures that appear in the context of systemic disease.

Heart rate variability and inappropriate sinus tachycardia after catheter ablation of supraventricular tachycardia.

Sinus tachycardia has been reported after radiofrequency catheter ablation of supraventricular tachycardia. Frequently, these patients require beta-blocking agents for symptomatic control. The purpose of this study was to evaluate prospectively the incidence of inappropriate sinus tachycardia and heart rate variability after ablation of atrioventricular nodal reentrant tachycardia and accessory pathways. Patients undergoing ablation had 24-h ambulatory monitoring ECG (Holter) performed before the procedure, on the day of the ablation, and 3 months afterwards. There were 170 patients, mean age 48 +/- 23 years; 93 were female. A complete study of the 24-h Holter with analysis of heart rate variability: SD, rMSSD, pNN50, high and low frequency was obtained. There was a low prevalence of inappropriate sinus tachycardia after the ablation procedure (10 of 170 patients: five with four atrioventricular nodal reentry, with posteroseptal accessory pathways and one of the latter following ablation of the left accessory pathway). There was no modification of time and frequency domain parameters of heart rate variability in the remaining patients who underwent radiofrequency ablation. Holter monitoring 3 months after ablation showed that parameters of heart rate and heart rate variability had normalized in patients who had developed inappropriate sinus tachycardia. Inappropriate sinus tachycardia may be initiated by both radiofrequency ablation of atrioventricular nodal reentrant tachycardia and radiofrequency ablation of posteroseptal accessory pathways. Specific damage to the posteroseptal region is responsible for these changes, which usually recover spontaneously after 3 months.

[The pectoral implant of an automatic defibrillator by cardiologists in an electrophysiology laboratory]. / Implante pectoral de desfibrilador automático por cardiólogos en un laboratorio de electrofisiología.

We have performed 2 implantations of transvenous automatic cardioverter defibrillator in a cardiac laboratory devoted to electrophysiology and pacemaker implantation. This is a preliminary experience with a novel implant strategy. Cardiologists were the primary operators. The automatic cardioverter defibrillator were placed in a subcutaneous pectoral region, with a non-thoracotomy lead system. The automatic cardioverter defibrillator were two Medtronic 7219D PCD Jewel, with a Transvene system. There were no perioperative complications. Acceptable defibrillation threshold were obtained in both patients, 12 and 20 J, respectively. Leads were inserted percutaneously through the left subclavian vein. After 8 months of follow-up the patients continue to tolerate the device satisfactorily. Implantation of automatic cardioverter defibrillator systems by trained cardiologists in an electrophysiology laboratory is safe and feasible. Moreover, its cost-effectiveness is superior, the saving includes the surgeons, and the reduction of stay in unit of intensive care and hospitalization.

[Usefulness of the RR variability in the diagnosis of neurogenic syncope]. / Utilidad de la variabilidad del RR para el diagnóstico del síncope neurogénico.

UNLABELLED: INTRODUCTION AND PURPOSES: Autonomic nervous system plays an important role in the pathogenesis of vasovagal/vasodepressor syncope and may also be assessed by the RR variability analysis. Head up tilt test (HUT) is a currently established tool to evaluate patients with neuromediated syncope. However, the relationship between heart rate variability and tilt induced syncope is not established. The purpose of this study was to assess the differences in heart rate variability among patients with syncope and negative or positive tilt test. METHODS: Fifty patients (mean age 33 +/- 17 years, 24 female, 26 male) with syncope underwent tilt test (20 min, 80 degrees tilt and 20 min more under isoproterenol infusion). Twenty-three patients have a negative tilt, the rest had a positive test. There were not significant differences in age or sex. Immediately after the HUT a 24-hour ambulatory electrocardiogram was performed (Marquette system 8000, 002A program). The parameters measured during Holter monitoring were: SDANN, SD, rMSSD, pNN50 and frequency analysis of heart rate spectrum (low frequency 0.04-0.15 Hz, high frequency 0.15-0.4 Hz and the relation low/high). No significant differences were detected in age and sex in patients with and without positive HUT. RESULTS: pNN50 and rMSSD were the best predictors of the results of tilt (p = 0.006). SDANN and SDNN were not useful parameter. The finding of a value of pNN50 > 25% (value significantly different between patients with HUT--and +) have a specificity for predicting a positive HUT of 82.6%, with a sensibility of 51.8%. Positive predictive value was 77%. As can be easily understood, if the cut value of pNN50 is lowered, its sensibility increased and the specificity. decreased. In the frequency analysis only the relation low/high (L/H) was significantly different between both populations. CONCLUSIONS: Heart rate variability is a useful tool in the evaluation of patients with vasovagal syncope, that may identify patients with chronically elevated vagal tone and thus may predict tilt test results.

[The efficacy and safety of intravenous propafenone in the acute treatment of spontaneous sustained ventricular tachycardia]. / Eficacia y seguridad de la propafenona intravenosa en el tratamiento agudo de la taquicardia ventricular sostenida espontánea.

UNLABELLED: INTRODUCTION AND PURPOSES: Propafenone is an antiarrhythmic drug with well known electrophysiological effects. We performed this prospective non comparative study, in order to evaluate its efficacy and safety to terminate spontaneous episodes of monomorphic sustained ventricular tachycardia. METHODS: Thirty-two episodes of sustained monomorphic ventricular tachycardia in 32 consecutive patients were treated with intravenous propafenone. Twenty-five were male and 7 female, mean age of 62 +/- 12 years; 23 suffered chronic ischemic heart disease, 2 dilated cardiomyopathy, 1 arrhythmogenic dysplasia of the right ventricle and 6 no organic heart disease. Patients with overt heart failure, acute myocardial infarction or a systolic blood pressure less than 90 mmHg were excluded. The ventricular origin of the tachycardia was assessed by clinical and electrocardiographic criteria and by the presence of AV dissociation in intraesophageal recording. The dose of propafenone was 0.2 mg/kg/min until interruption of ventricular tachycardia, or maximal dose of 2.5 mg/kg in 10 min. RESULTS: In 23 episodes (72%) sinus rhythm was restored in less than 10 minutes (mean time and dose, 398 +/- 97 s and 95 +/- 42 mg, respectively). Two patients developed proarrhythmia with acceleration of the ventricular tachycardia. A significant decrease in blood pressure was noted in 6 patients. Presence of organic heart disease, advanced age and poor functional class were the best predictors of inefficacy to convert to sinus rhythm and of the presence of acute adverse effects (p < 0.05). CONCLUSIONS: Propafenone is an effective drug for the acute conversion of spontaneous monomorphic sustained ventricular tachycardia, especially in patients without organic heart disease. Age, functional class and presence of organic heart disease could predict the response to propafenone and the incidence of complications.

Comparison of flecainide and procainamide in cardioversion of atrial fibrillation.

In this prospective, controlled and randomized cross-over study we tried to establish the efficiency and safety of flecainide vs procainamide for the treatment of acute atrial fibrillation. Eighty patients (30 females, 50 males, mean age: 55 +/- 14 years) were included. Patients entered into the study if they had atrial fibrillation of recent onset (< 24 h) with a ventricular rate > 100 beats.min-1 at rest and were < 75 years of age. Exclusion criteria were any sign of heart failure, conduction disturbances, sick sinus syndrome or acute ischaemic events. Randomly 40 patients received flecainide and 40 procainamide as the first treatment. There were no significant clinical difference between the two groups. Procainamide ws given at a dose of 1 g infused over 30 min, and followed by an infusion of 2 mg.min-1 over 1 h. Flecainide was given at a dose of 1.5 mg.kg-1 over 15 min followed by an infusion of 1.5 mg.kg-1 over 1 h. Drug infusion was continued until maximal dose, intolerance or reversion to sinus rhythm. After 1 h of wash out, patients remaining in atrial fibrillation were started on the second drug. Left atrial size was measured by echo. Serum levels of drug and atrial size did not differ between patients who returned to sinus rhythm and those who remained in atrial fibrillation. Conversion to sinus rhythm was achieved in 37 (92%) of the 40 patients treated with flecainide and 25 (65%) of those treated with procainamide (P < 0.001). The time required for reversion to sinus rhythm was similar between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[The nonpharmacological treatment of tachyarrhythmias in 23 children and adolescents]. / Tratamiento no farmacológico de las taquiarritmias en 23 pacientes en edad infantil y juvenil.

We comment the results with non pharmacological treatment in 23 patients (mean age 11 +/- 4 years) with multiple episodes of palpitations, most of them required intravenous drugs for interrupting it. Twenty-eight procedures were performed, 17 catheter ablation and 11 surgical interventions. The energy source employed for fulguration until 1990 was DC and since 1991 radiofrequency. The best results with catheter ablation were obtained with accessory pathways. Interruption was achieved in all patients after a mean of 1.2 sessions per patient, but it was definitive in only 72%. Most of the patients (81%) remained asymptomatic without antiarrhythmic drugs. Nine patients with accessory pathways underwent surgery interruption, it was achieved in all; only one patient had arrhythmia recurrence, due to a second pathway in a different localization. We could not ablate a ectopic atrial tachycardia, that underwent surgery. There was only one indication for surgery in a patient with ventricular tachycardia. Catheter ablation does not present technical problem in children and teenagers, different from adults. The presented results lead us to suppose that the indications for non pharmacological treatment in the young will become more common.

Atrial fibrillation in Wolff-Parkinson-White syndrome: reversal of isoproterenol effects by sotalol.

Sotalol has Class II and III antiarrhythmic effects. Its efficacy and safety as a treatment of atrial fibrillation in patients with the Wolff-Parkinson-White (WPW) syndrome is controversial. We evaluated the effects of isoproterenol and IV sotalol (1.5 mg/kg in 10 minutes) given together versus isoproterenol alone on anterograde conduction through the AV node and accessory pathway. Atrial fibrillation was induced in 22 patients with WPW (13 men, 9 women, 36 +/- 16 years old). AV node and accessory pathway conduction were both enhanced by isoproterenol, although the effect was greater on the AV node. The minimum interval between preexcited QRS complexes shortened in all patients. Conversely, sotalol caused a significant prolongation of the shortest preexcited QRS interval as well as of the shortest interval between narrow QRS complexes. In addition, sotalol reversed all the effects of isoproterenol during atrial fibrillation. The percent of preexcited QRS complexes was not significantly modified because variations in ventricular preexcitation results from a balance between the relative effects on refractoriness of the accessory pathway versus of the AV node and in the amount of respective anterograde and retrograde concealed conduction. There were no serious adverse effects. Reversion to sinus rhythm was documented in 12 patients (60%). These short-term observations suggest that sotalol may be safe and effective in the treatment of patients with WPW and atrial fibrillation.

Cardiac fulguration, a new alternative therapy for atrioventricular nodal reentrant tachycardia.

Ten patients underwent endocardial catheter ablation of the atrioventricular junction for atrioventricular nodal reentrant tachycardias. Unipolar cathodic discharges at the distal electrode were administered against an external plate. Bipolar His and atrial deflections showed a mean of 0.15 mv and 0.5 mv respectively. Mean total energy used per patient was 195 J (range: 50-750), with a mean number of ablating discharges of 2.0 per patient, (range: 1-5). Complete atrioventricular block was achieved, but conduction reappeared in all except one patient, after a mean interval of 19.9 min. Electrophysiological evaluation was assessed 3-8 days after ablation. Sustained atrioventricular nodal reentrant tachycardias were no longer inducible in any patient. Retrograde conduction was abolished in six, and was slow and decremental in four. First-degree atrioventricular block, with intranodal delay was diagnosed in six, with an AH interval that ranged from 240 to 130 ms. Mean cycle length for appearance of Wenckebach atrioventricular block was 390 ms after ablation. One patient developed complete atrioventricular block after two discharges of 50 J, another required a repeat ablation for recurrence of intranodal tachycardia and also developed complete anterograde block in a new session of ablation with a 150 J discharge. In these two patients permanent pacing was needed. Eight patients were cured after a mean follow-up of 20 months. Less energy and fewer discharges should be administered to abolish functional dissociation of the atrioventricular node, without complete interruption of anterograde conduction.

[The interruption of atrioventricular conduction by cardiac fulguration in patients with supraventricular tachycardias. The mid- and long-term results]. / Interrupción de la conducción auriculoventricular mediante fulguración cardíaca en pacientes con taquicardias supraventriculares. Resultados a medio y largo plazo.

Catheter ablation of the atrioventricular node is a therapeutic technique for the treatment of patients with drug-refractory supraventricular tachyarrhythmias. In our Arrhythmia Unit 25 patients (8 women, 17 men) aged (mean +/- DE) 56 +/- 10 years have undergone fulguration of the atrioventricular junction since 1986. The more frequent treated rhythm disturbance was atrial flutter or fibrillation, with uncontrolled rapid ventricular response. Absence of organic heart disease was diagnosed in 9 patients; the remainder had valvular heart disease (2), cor pulmonale (2), cardiomyopathy (7), hypertensive heart disease (2) and Wolff-Parkinson-White syndrome (3). Under general anesthesia 1.8 +/- 0.8 shocks/patients were delivered along 1.2 +/- 0.7 sessions/patient. In 23 of 25 patients (92%) complete atrioventricular block was achieved, and a pacemaker was implanted. There were no complications. The other 2 patients were referred to surgery for cryoablation of the atrioventricular junction. Patients were followed for an average of 21 +/- 12 months. Four patients have died: two due to congestive heart failure, which was present prior to the ablation procedure, the third because of a metastatic carcinoma, and the fourth had a sudden death 14 months after the procedure (he had dilated cardiomyopathy and Wolff-Parkinson-White syndrome). The remainder in chronic stable complete atrioventricular block are asymptomatic for arrhythmias and without antiarrhythmic medication.

Dose related efficacy of adenosine triphosphate in spontaneous supraventricular tachyarrhythmias.

Intravenous adenosine triphosphate has been proved to be useful for the treatment of supraventricular tachyarrhythmias. The optimal dose to be employed, however, has yet to be stated. Forty-two episodes of spontaneous paroxysmal supraventricular tachycardia, observed in 33 patients (16 men and 17 women, mean age 51 years) were treated with intravenous boluses. These were given in 10 mg increments at increasing doses from 10 to 50 mg at intervals of three minutes if the arrhythmia persisted despite the previous dose. When using a dose less than or equal to 40 mg, tachycardia was terminated in 37 of 42 episodes in less than 50 seconds. In four of the remaining five, atrial flutter and ectopic atrial tachycardia were diagnosed after administration of adenosine triphosphate. The other patient was subsequently found to have an atrioventricular reentrant tachycardia incorporating two accessory pathways. More than half of the treated episodes of supraventricular tachycardia terminated with the minimal dose of 10 mg and 7.1% required 40 mg. In five patients, arrhythmia ceased and reappeared despite the use of adenosine triphosphate. All the patients experienced an unpleasant feeling of dyspnoea or suffocation after injection of the drug. Sinus pauses and bradycardia following termination of the arrhythmia were directly correlated with the dose employed (P less than 0.05). We conclude that adenosine triphosphate is a useful, safe and effective drug at low dose in correctly diagnosed reentrant tachycardias involving the atrioventricular node. It is also useful as a diagnostic tool in patients with supraventricular tachyarrhythmias.

[Cardiac fulguration. A healing treatment for intranodal re-entry tachycardias refractory to medication]. / Fulguración cardíaca. Un tratamiento curativo para las taquicardias de reentrada intranodal refractarias a medicación.

Six patients underwent fulguration of the AV junction for typical paroxysmal intranodal reentry tachycardias, refractory to medical treatment. Unipolar cathodic discharges at distal electrode were administered against an external plate. Bipolar His and atrial deflections showed mean values of 0.16 and 0.54 mv, respectively. Mean energy used was 233 J (range 50-750), with a mean number of 1.6 (range 1-3) discharges per patient. Complete AV block was achieved, but conduction reappeared in all, within a mean of 30 minutes. Electrophysiologic evaluation was assessed 3-8 days after ablation. Intranodal reentry tachycardias could not be initiated in any patient. Retrograde conduction was abolished in 3 patients, and in three it was slow and decremental. First degree AV block, with intranodal delay was diagnosed in 4 with a mean AH interval of 237 msec (range 190-300). Mean rate for appearance of Wenckebach AV block was 154 b/m. None of the patients required permanent pacing. Mean follow-up of the patients was 6.8 months. One of the patients required a new ablation for reappearance of intranodal tachycardia and CAVB was achieved in the second ablation. The other five remain asymptomatic. Intranodal reentry tachycardias can be cured by fulguration. Less energy and less discharges should be administered to abolish functional dissociation of the AV node, without complete interruption of anterograde conduction.