Bloqueo aurículo-ventricular de tercer grado: atención y manejo en Atención Primaria / Third-degree atrioventricular block: care and management in Primary Care

El bloqueo auriculoventricular de tercer grado o completo se puede manifestar clínicamente de múltiples formas, como mareo, disnea o angina. Es una emergencia médica que el médico de familia debe ser capaz de identificar precozmente y tratar urgentemente. Presentamos el caso clínico de un paciente con bloqueo auriculoventricular completo y nuestro manejo en un Punto de Atención Continuada

Third-degree or complete atrioventricular block may manifest clinically in multiple ways, such as dizziness, dyspnea, or angina. It is a medical emergency that the family doctor should be able to identify early and treat urgently. We present the clinical case of a patient with complete atrioventricular block and its management in an emergency Primary Care unit

Benefits of fetal echocardiographic surveillance in pregnancies at risk of congenital heart block: single-center study of 212 anti-Ro52-positive pregnancies.

OBJECTIVES: Assuming that autoimmune congenital heart block (CHB) is a progressive disease amenable to therapeutic modulation, we introduced a surveillance program for at-risk pregnancies with the dual aim of investigating if fetal atrioventricular block (AVB) could be detected and treated before becoming complete and irreversible, and to establish the incidence of AVB I, II and III in a large prospective cohort. METHODS: This was a prospective study of 212 anti-Ro52 antibody-exposed pregnancies at risk of fetal AVB that were followed weekly between 18 and 24 weeks' gestation at our tertiary fetal cardiology center from 2000 to 2015. A 12-lead electrocardiogram (ECG) was recorded within 1 week after birth. Fetal Doppler atrioventricular (AV) intervals were converted to Z-scores using reference standard values derived from normal pregnancies. Each fetus was represented by the average value of the two recordings, obtained at two consecutive visits, which resulted in the longest AV interval. AV interval values were classified into normal AV conduction (Z-score ≤ 2.0) and three levels of delayed AV conduction: Z-score > 2.0 and ≤ 3.0, Z-score > 3.0 and ≤ 4.0, and Z-score > 4.0. RESULTS: AVB II or III developed in 6/204 (2.9%) pregnancies without a CHB history and 1/8 (12.5%) of those with a CHB history. AV intervals > 2 and ≤ 3, > 3 and ≤ 4, and > 4 were detected in 16.0%, 7.5% and 2.8% of cases, respectively, and were related to the PR interval on 185 available ECGs. Three of the five cases with AVB III and one of two cases with 2:1 AVB II developed within 1 week of AV interval Z-score of 1.0, 1.9, 2.8 and 1.9, respectively. Transplacental treatment with betamethasone was associated with restoration of 1:1 AV conduction in the two fetuses with AVB II, with a better long-term result (normal ECG vs AVB I or II) observed in the case in which treatment was started within 1 week after AVB developed. Betamethasone treatment did not reverse AVB III, although a temporary effect on AV conduction was observed in 1/5 cases. Notably, the three cases in which treatment was started within 1 week after AVB III development responded with a higher ventricular rate than the other two cases and did not require pacemaker implantation until a later age (2-5 years vs 1.5-2 months). CONCLUSION: Fetal AV interval is a poor predictor of CHB progression, but CHB surveillance still allows detection of fetuses with AVB II or III shortly after its development, allowing for timely treatment initiation and potentially better outcome. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Mobitz type I and II atrioventricular blocks during fingolimod therapy.

We investigated patients who showed a second-degree atrioventricular block (S-AVB) after the first fingolimod administration. We observed six patients with S-AVB, three Mobitz type I, and three type II. Monitoring continued on the second day for all patients. Three patients showed persistence of the S-AVB, with resolution on the second or third day. One patient had a persistent S-AVB up to the fourth day when fingolimod was discontinued. We conclude that Mobitz type II S-AVB is possible during fingolimod therapy. Patients with S-AVB could be monitored until resolution of the S-AVBs, as these may persist several days after the first fingolimod administration.

Diagnostic and Prognostic Implications of Surface Recordings from Patients with Atrioventricular Block.

The atrioventricular (AV) bridge is vulnerable to many circumstances that depress conduction. Abnormal impulse transmission may be caused by drugs, autonomic effects, or destructive processes. Type 1 (Wenckebach) AV block is owing to depressed AV nodal conduction and is recognized by a prolonging PR interval ending in a "dropped beat." Type II (Mobitz) AV block is owing to abnormal infranodal conduction, and is usually accompanied by bundle branch block. Second-degree AV block with 2:1 conduction can be a difficult problem. Third-degree (complete) AV block is a diagnosis too often rendered and too often incorrect.

Predictors of advanced His-Purkinje conduction disturbances in patients with unexplained syncope and bundle branch block.

BACKGROUND: For patients presenting with syncope and bundle branch block (BBB), results during electrophysiological studies (EPS) might depend on the electrocardiographic pattern of conduction disturbances. We sought to identify predictors of advanced His-Purkinje conduction disturbances (HPCDs) in these patients. METHODS: In this retrospective multicentre study, patients were included who: (1) presented with unexplained syncope; (2) had BBB (QRS duration ≥ 120 ms); and (3) were investigated with EPS. HPCD was diagnosed if the baseline His-ventricular interval was ≥ 70 ms or if second- or third-degree His-Purkinje block was observed during atrial pacing or pharmacological challenge. RESULTS: Of the 171 patients studied (72 ± 13 years, 64% male sex, mean left ventricular ejection fraction 57 ± 9%), advanced HPCD was found in 73 patients (43%). The following electrocardiographic features were associated with HPCD (P = 0.01): isolated right BBB (34.4%), right BBB with left anterior fascicular block (36.4%), left BBB (46.2%), and right BBB with left posterior fascicular block (LPFB, 78.6%). Multivariate analysis identified first-degree atrioventricular block (odds ratio, 2.4; 95% confidence interval, 1.2-4.7; P = 0.01) and LPFB (odds ratio, 4.8; 95% confidence interval, 1.3-18.5; P = 0.02) as the only 2 independent predictors of advanced HPCD. CONCLUSIONS: For patients presenting with syncope and BBB, first-degree atrioventricular block and LPFB increased the likelihood of finding HPCDs during EPS. However, no single electrocardiographic feature could consistently predict the outcome of EPS, so this investigation is still necessary in assessing the need for pacemaker implantation, irrespective of the precise appearance of abnormalities on ECG.

[The role of alfa-2-beta-adrenoreceptor in development of ventricular conduction disturbance].

BACKGROUND: The purpose of this study was to investigate association between the genetic polymorphism I/D of gene α2ß-adrenoreceptor (ADRA2B) and hereditary disorders of ventricular conduction. PATIENTS AND METHODS: In this study, 102 people with complete left bundle branch block (45.71 ± 1.852 years)--46 females and 56 males, and 86 people with complete right bundle branch block (34.59 ± 1.86 years)--41 females and 45 males. The study was approved by Ethic Committee of the KrasSMU. All participants were included in the study after written informed consent form. Cardiological examination included clinical examination, electrocardiography, echocardiography, Holter monitoring, stress-test, koronaroangiografy and radionuclide method of a myocardium and molecular and genetic researches. RESULTS: Statistically, significant prevalence of a homozygous genotype of DD on rare allele gene ADRA2B in both groups in comparison with group of control is established. The reliable dominance of the homozygous rare genotypes (D allele) of gene ADRA2B were detected in all groups. CONCLUSION: Polymorphism DD of a gene ADRA2B is a genetic predictor of predisposition to the blockade of the right and left bundle branch block.

Second-degree atrioventricular block revisited.

Type I second-degree atrioventricular (AV) block describes visible, differing, and generally decremental AV conduction. The literature contains numerous differing definitions of second-degree AV block, especially Mobitz type II second-degree AV block. The widespread use of numerous disparate definitions of type II block appears primarily responsible for many of the diagnostic problems surrounding second-degree AV block. Adherence to the correct definitions provides a logical and simple framework for clinical evaluation. Type II second-degree AV block describes what appears to be an all-or-none conduction without visible changes in the AV conduction time before and after the blocked impulse. Although the diagnosis of type II block requires a stable sinus rate, absence of sinus slowing is an important criterion of type II block because a vagal surge (generally a benign condition) can cause simultaneous sinus slowing and AV nodal block, which can superficially resemble type II block. Furthermore, type II block has not yet been reported in inferior myocardial infarction (MI) and in young athletes where type I block may be misinterpreted as type II block. The diagnosis of type II block cannot be established if the first postblock P wave is followed by a shortened PR interval or the P wave is not discernible. A narrow QRS type I block is almost always AV nodal, whereas a type I block with bundle branch block barring acute MI is infranodal in 60-70 % of cases. A 2:1 AV block cannot be classified in terms of type I or type II block, but it can be nodal or infranodal. A pattern resembling a narrow QRS type II block in association with an obvious type I structure in the same recording (e.g., Holter) effectively rules out type II block because the coexistence of both types of narrow QRS block is exceedingly rare. Concealed (nonpropagated) His bundle or ventricular extrasystoles may mimic both type I and/or type II block (pseudo AV block). All correctly defined type II blocks are infranodal. Infranodal block presenting with either type I or II manifestations requires pacing regardless of QRS duration or symptoms.

Diagnosing foetal atrioventricular heart blocks.

Foetal echocardiographic ultrasound techniques still remain the dominating modality for diagnosing foetal atrioventricular block (AVB). Foetal electrocardiography might become a valuable tool to measure time intervals, but magnetocardiography is unlikely to get a place in clinical practice. Assuming that AVB is a gradually progressing and preventable disease, starting during a critical period in mid-gestation with a less abnormal atrioventricular conduction before progressing to a complete irreversible AVB (CAVB), echocardiographic methods to detect first-degree AVB have been developed. The time intervals obtained with these techniques are all based on the identification of mechanical or hemodynamic events as markers of atrial (A) and ventricular (V) depolarizations and will accordingly include both electrical and mechanical components. Prospective observational studies have demonstrated a transient prolongation of AV time intervals in anti-Ro/SSA antibody-exposed foetuses, but it has not succeeded to identify a degree of AV time prolongation predicting irreversible cardiac damage and progression to CAVB. Causes of sustained bradycardia include CAVB, 2:1 AVB, sinus bradycardia and blocked atrial bigeminy (BAB). Using foetal echocardiographic techniques and a systematic approach, a correct diagnosis can be made in almost every case. Sinus bradycardia and CAVB are usually easy to diagnose, but BAB has a tendency to be sustained and shows a high degree of resemblance with 2:1 AVB when diagnosed during mid-gestational. As BAB resolves without treatment and 2:1 AVB may respond to treatment with fluorinated steroids, a correct diagnosis becomes an issue of major importance to avoid unnecessary treatment of harmless and spontaneously reversing conditions.

Atrioventricular block with 4:2 conduction pattern: what is the mechanism?

We present the case of a 72-year-old man who was admitted because of acute ST-segment elevation myocardial infarction and presented with second-degree atrioventricular block with 4:2 conduction. We propose 3 alternative explanations for such an unusual conduction pattern: (1) supernormal conduction, (2) 2-level block with 4:1 conduction ratio in the upper level and 3:2 conduction ratio in the lower level, and (3) presence of 2 populations of Purkinje cells in the remaining, critically injured fascicle, one with the phase-3 block and the other with slow diastolic depolarization, leading, during a pause after the first nonconducted P, to phase-4 block.

Second degree atrioventricular block Mobitz type I after administration of benzathine penicillin: case report.

BACKGROUND AND OBJECTIVES: Second degree atrioventricular block Mobitz type I is seen as a transitory change in the presence of inferior wall myocardial infarction or drug intoxication. The objective of this report was to present a case of second degree atrioventricular block Mobitz type I after administration of benzathine penicillin. CASE REPORT: The patient had a syncopal episode and sudoresis after administration of benzathine penicillin. On physical exam, he presented diaphoresis, bradycardia, and irregular heart rate. The electrocardiogram (ECG) showed second degree atrioventricular block Mobitz type I. Intravenous atropine, 0.5 mg, was administered. An ECG done one hour later was normal. The patient remained asymptomatic and, and after six hours he was discharged. CONCLUSIONS: The patient developed second degree atrioventricular block Mobitz type I after the administration of benzathine penicillin.

Bloqueio atrioventricular de 2° grau do tipo I Mobitz após aplicação de penicilina benzatina: relato de caso / Second degree atrioventricular block Mobitz type I after administration of benzathine penicillin: case report / Bloqueo atrioventricular de 2º grado tipo Mobitz I después de la aplicación de penicilina benzatina: relato de caso

JUSTIFICATIVA E OBJETIVOS: O bloqueio atrioventricular de 2º grau do tipo I de Mobitz é observado como alteração transitória na presença de infarto de parede inferior ou de intoxicação medicamentosa. O objetivo desse relato foi apresentar caso de bloqueio atrioventricular de 2º grau tipo I de Mobitz após aplicação de penicilina benzatina. RELATO DO CASO: Paciente apresentou síncope e sudorese após aplicação de penicilina benzatina. Ao exame físico apresentava-se sudoreico, bradicárdico e com ritmo irregular. Foi realizado eletrocardiograma (ECG) que mostrava bloqueio atrioventricular de 2º grau do tipo I de Mobitz. Administrou-se atropina 0,5 mg por via venosa. Após uma hora foi repetido o ECG que apresentava traçado normal. Paciente permaneceu seis horas assintomático e então recebeu alta. CONCLUSÕES: O bloqueio atrioventricular de 2º grau do tipo I de Mobitz surgiu após aplicação de penicilina benzatina.

BACKGROUND AND OBJECTIVES: Second degree atrioventricular block Mobitz type I is seen as a transitory change in the presence of inferior wall myocardial infarction or drug intoxication. The objective of this report was to present a case of second degree atrioventricular block Mobitz type I after administration of benzathine penicillin. CASE REPORT: The patient had a syncopal episode and sudoresis after administration of benzathine penicillin. On physical exam, he presented diaphoresis, bradycardia, and irregular heart rate. The electrocardiogram (ECG) showed second degree atrioventricular block Mobitz type I. Intravenous atropine, 0.5 mg, was administered. An ECG done one hour later was normal. The patient remained asymptomatic and, and after six hours he was discharged. CONCLUSIONS: The patient developed second degree atrioventricular block Mobitz type I after the administration of benzathine penicillin.

JUSTIFICATIVA Y OBJETIVOS: El bloqueo atrioventricular de 2º grado del tipo I de Mobitz es observado como una alteración transitoria en la presencia de infarto de la pared inferior o de intoxicación medicamentosa. El objetivo de este relato fue presentar un caso de bloqueo atrioventricular de 2º grado tipo I de Mobitz después de la aplicación de penicilina benzatina. RELATO DEL CASO: Paciente que presentó síncope y sudoración después de la aplicación de penicilina benzatina. En el examen físico sudaba, estaba bradicárdico y con ritmo irregular. Fue realizado el electrocardiograma (ECG) que mostraba un bloqueo atrioventricular de 2º del tipo I de Mobitz. Se le administró atropina 0,5 mg por vía venosa. Después de una hora, fue repetido el ECG que presentaba un trazado normal. El paciente permaneció seis horas asintomático y entonces recibió el alta. CONCLUSIONES: El bloqueo atrioventricular de 2º grado del tipo I de Mobitz surgió después de la aplicación de la penicilina benzatina.