Efectos del tratamiento médico guiado en pacientes con miocardiopatía inducida por bloqueo de rama izquierda

Introduction and objectivesLeft bundle branch block (LBBB)-induced cardiomyopathy occurs in patients with long-standing LBBB. These patients characteristically exhibit hyperresponsiveness to cardiac resynchronization therapies (CRT). However, there is scarce information on their response to medical treatment. The aim of this study was to assess the change in left ventricular ejection fraction (LVEF) after a 3-month period following titration of guideline-directed medical therapy for heart failure.MethodsThis retrospective analysis included all patients assessed in the heart failure unit of a Spanish University Hospital between 2020 and 2021, who presented with de novo ventricular dysfunction (LVEF < 40%) and had a history of long-standing LBBB with no other possible causes of cardiomyopathy.ResultsA total of 1497 patients were analyzed, of which 21 were finally eligible. Mean time from first diagnosis of LBBB to first consultation was 4.05 ± 4.1 years. Mean LVEF from first consultation to end of titration improved from 29.5 ± 5.7% to 32.7 ± 8.6% (P = .172), but none had recovered ventricular function at the end of follow-up. New York Heart Association functional class improved from 1.91 ± 0.46 to 1.81 ± 0.53 (P = .542). After CRT device implantation in 8 patients, LVEF improved by 18.1 ± 6.4% (P = .003).ConclusionsGuideline-directed medical therapy seems to be ineffective in improving LVEF and functional class in patients with de novo heart failure and LBBB-induced cardiomyopathy. Based on a positive response to CRT on LVEF improvement, early CRT implantation could be a reasonable strategy for these patients.Full English text available from:www.revespcardiol.org/en     

Riesgo arrítmico en episodios únicos o recurrentes de síncope inexplicado con bloqueo completo de rama

Introduction and objectivesPatients with a single syncopal episode (SSE) and complete bundle branch block (cBBB) are frequently managed more conservatively than patients with recurrent episodes (RSE). The objective of this study was to analyze if there are differences between patients with single or recurrent unexplained syncope and cBBB in arrhythmic risk, the diagnostic yield of tests, and clinical outcomes.MethodsCohort study of consecutive patients with unexplained syncope and cBBB with a median follow-up time of 3 years. The patients were evaluated via a stepwise workup protocol based on electrophysiological study (EPS) and long-term follow-up with an implantable cardiac monitor.ResultsOf the 503 patients included in the study, 238 (47.3%) had had only 1 syncopal episode. The risk of an arrhythmic syncope was similar in both groups (58.8% in SSE vs 57.0% in RSE; P = .68), also after adjustment for possible confounding variables (HR, 1.06; 95%CI, 0.81-1.38; P = .674). No significant differences between the groups were found in the EPS results and implantable cardiac monitor diagnostic yield. A total of 141 (59.2%) patients with SSE and 154 (58.1%) patients with RSE required cardiac device implantation (P = .797). After appropriate treatment, 35 (7%) patients had recurrence of syncope. The recurrence rate and mortality were also similar in both groups.ConclusionsPatients with cBBB and unexplained syncope are at high risk of an arrhythmic etiology, even after the first syncopal episode. Patients with SSE and RSE have a similar arrhythmic risk and similar outcomes, and therefore there is no clinical justification for not managing them in the same manner.Full English text available from:www.revespcardiol.org/en     

Manejo de la insuficiencia cardiaca con estimulación hisiana en bloqueo de rama derecha: reporte de caso

Cardiac resynchronization therapy has proven to be an effective therapy in patients with left bundle branch block and heart failure. Male, 47 years old, heart failure with a left ventricle ejection fraction of 17%, idiopathic heart failure. ECG with sinus rhythm, 1^st degree AV block, PR 400 ms, complete right bundle branch block, anterior hemi-fascicle of the left bundle of His, and QRS duration 200 ms. We decided to perform a selective His bundle pacing. In patients with right bundle branch block the biventricular cardiac resynchronization is not indicated due to low treatment response. His bundle pacing allows recruiting the blocked branch and restoring conduction throughout it, therefore, in the absence of necrosis the biventricular synchrony is achieved. We presented a case of His bundle pacing with recruitment of the right bundle branch, which reestablish biventricular synchrony measured by speckle tracking, and with a significant increase of the left ventricle ejection fraction from 17 to 36.6%, with an absolute increase of 19.6%.Key words: Cardiac resynchronization, Right bundle branch block, His bundle pacing, Heart failure, México     

Impacto del bloqueo del sistema renina-angiotensina en el pronóstico del síndrome coronario agudo en función de la fracción de eyección

Introduction and objectivesFor patients with acute coronary syndrome (ACS) treated with percutaneous coronary intervention (PCI), it is unclear whether angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) are associated with reduced mortality, particularly with preserved left ventricular ejection fraction (LVEF). The goal of this study was to determine the association between ACEI/ARB and mortality in ACS patients undergoing PCI, with and without reduced LVEF.MethodsData from the BleeMACS registry were used. The endpoint was 1-year all-cause mortality. The prognostic value of ACEI/ARB was tested after weighting by survival-time inverse probability and after adjustment by Cox regression, propensity score, and instrumental variable analysis.ResultsAmong 15 401 ACS patients who underwent PCI, ACEI/ARB were prescribed in 75.2%. There were 569 deaths (3.7%) during the first year after hospital discharge. After multivariable adjustment, ACEI/ARB were associated with lower 1-year mortality, ≤ 40% (HR, 0.62; 95%CI, 0.43-0.90; P = .012). The relative risk reduction of ACEI/ARB in mortality was 46.1% in patients with LVEF ≤ 40%, and 15.7% in patients with LVEF > 40% (P value for treatment-by-LVEF interaction = .008). For patients with LVEF > 40%, ACEI/ARB was associated with lower mortality only in ST-segment elevation myocardial infarction (HR, 0.44; 95%CI, 0.21-0.93; P = .031).ConclusionThe benefit of ACEI/ARB in decreasing mortality after an ACS in patients undergoing PCI is concentrated in patients with LVEF ≤ 40%, and in those with LVEF > 40% and ST-segment elevation myocardial infarction. In non–ST-segment elevation-ACS patients with LVEF > 40%, further studies are needed to assess the prognostic impact of ACEI/ARB.     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.