Atrioventricular block – ABC CARDIOL

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Original Article

Clinical Outcomes Following PM Implantation: A 3-Year Comparative Study of Sick Sinus Syndrome and Atrioventricular Block

Fuat Polat et al. Haşim Tüner Veysi Can Sait Terzi

Abstract

Background

Permanent pacemaker implantation is an established treatment for both sick sinus syndrome (SSS) and atrioventricular block (AVB), yet limited data exist comparing long-term clinical outcomes and cardiac remodeling patterns between these distinct bradyarrhythmic etiologies.

Objectives

To compare three-year clinical outcomes and cardiac structural changes between SSS and AVB patients following permanent pacemaker implantation.

Methods

This retrospective observational study enrolled 192 adult patients (65 SSS, 127 AVB) who underwent pacemaker implantation between January 2018 and December 2020. Demographic data, echocardiographic parameters, pacemaker-recorded data, and clinical outcomes were assessed at baseline, one month, six months, one year, and three years. Primary outcomes included changes in cardiac structure and function, symptomatic improvement, new-onset atrial fibrillation, rehospitalization, and all-cause mortality.

Results

Both groups demonstrated significant declines in left ventricular ejection fraction over three years (SSS: 57.2±6.0% to 54.3±8.3%, p<0.001; AVB: 55.5±7.0% to 53.0±6.8%, p<0.001). Despite similar ventricular dysfunction progression, distinct remodeling patterns emerged: SSS patients exhibited significant increases in left atrial diameter (31.3 to 38.8 mm, p=0.040), left ventricular end-diastolic diameter (45.2 to 51.0 mm, p90%). Symptomatic improvement was comparable (SSS: 85.6% vs. AVB: 83.5%, p=0.84), as were new-onset atrial fibrillation (41.5% vs. 37.0%, p=0.54), rehospitalization (50.8% vs. 58.3%, p=0.38), and all-cause mortality (13.8% vs. 11.8%, p=0.69). Mortality predictors differed: mitral regurgitation severity in SSS versus coronary artery disease, beta-blocker therapy, and left atrial volume in AVB patients.

Conclusions

Despite similar symptomatic benefits and clinical outcomes, SSS and AVB patients demonstrate distinct cardiac remodeling patterns and different mortality predictors, supporting the need for etiology-specific follow-up strategies in pacemaker recipients.

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Research Letter

Lyme Carditis: An Infectious Cause of Atrioventricular Block – A Case Report

Eduardo Dan Itaya et al. Danilo Hantschick Fernandes Monteiro Gabriela Coelho Itaya Nathan Kong Andre d’Avila

Introduction

Lyme disease (LD) is the most common tick-borne illness in the United States, caused by the spirochete Borrelia burgdorferi. The most common presentation is the erythema migrans skin rash, observed in over 90% of cases during the early localized stage.^, Weeks to months post-tick bite, the disease may progress to extracutaneous manifestations in the early disseminated phase, leading to cardiac, neurologic, and joint symptoms.^,

Lyme carditis (LC) is a rare complication of LD, occurring in 0.3% to 4% of untreated adults.^, The most prominent manifestations are conduction system disturbances involving the atrioventricular (AV) node, often presenting as high-degree AV block (AVB).

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Case Report

Tuberculosis and Atrioventricular Block in a Patient with Takotsubo Syndrome: A Case Report

Viviana Karina Sanchez Albarracin

Case Report

An 83-year-old female patient diagnosed with senile dementia and experiencing unintentional weight loss over the past few months was referred to a tertiary hospital due to complaints of typical chest pain. There is no previous history of cardiovascular diseases.

During transport, the patient developed bradycardia, with a heart rate (HR) of 32 beats per minute, and upon arrival at the emergency room, it was observed that she was suffering from complete atrioventricular block () with episodes of non-sustained ventricular tachycardia.

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Case Report

Smartwatch for Identification of Atrioventricular Block in Post-cardiac Surgery: Going Beyond Atrial Fibrillation Detection

Matheus S. Moitinho et al. Camila R. Moreno Rosangela Monteiro Guilherme C. M. Rabello … Bruna M. Mariano Pietro C. C. O. Martins Flávio Tarasoutchi Nelson Samesima Alexandre de M. Soeiro Fabio B. Jatene

Introduction

In postoperative cardiac care, early detection and management of complications are crucial for optimal outcomes. Third-degree atrioventricular (AV) block, also known as complete heart block (CHB), is a significant concern, leading to symptoms like fatigue, exertion intolerance, and life-threatening events such as syncope or heart failure, often necessitating cardiac pacemaker (CP) implantation for timely intervention. In the postoperative period of cardiac surgery, conduction issues stemming from metabolic or inflammatory changes are common, necessitating temporary or permanent CPs to stabilize patients or symptoms. Approximately 6% of valve surgery patients may require a permanent CP due to CHB, which can emerge post-surgery.

Medical technology, including smart devices and remote telemonitoring platforms, has revolutionized postoperative care, offering real-time insights for close monitoring and early anomaly detection.

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Original Article

Body Surface Potential Mapping during Ventricular Depolarization in Athletes with Prolonged PQ Interval after Exercise

Natalya I. Ivonina et al. Alexey G. Ivonin Irina M. Roshchevskaya

Abstract

Background:

Prolongation of the PQ interval, generally associated with an atrioventricular conduction delay, may be related to changes in intraventricular impulse spreading.

Objective:

To assess, using body surface potential mapping (BSPM), the process of ventricular depolarization in athletes with prolonged PQ intervals at rest and after exercise.

Methods:

The study included 7 cross-country skiers with a PQ interval of more than 200 ms (Prolonged-PQ group) and 7 with a PQ interval of less than 200 ms (Normal-PQ group). The BSPM from 64 unipolar torso leads was performed before (Pre-Ex) and after the bicycle exercise test (Post-Ex). Body surface equipotential maps were analyzed during ventricular depolarization. The significance level was 5%.

Results:

Compared to Normal-PQ athletes, the first and second periods of the stable position of cardiac potentials on the torso surface were longer, and the formation of the “saddle” potential distribution occurred later, at Pre-Ex, in Prolonged-PQ athletes. At Post-Ex, the Prolonged-PQ group showed a shortening of the first and second periods of stable potential distributions and a decrease in appearance time of the “saddle” phenomenon relative to Pre-Ex (to the values near to those of the Normal-PQ group). Additionally, at Post-Ex, the first inversion of potential distributions and the total duration of ventricular depolarization in Prolonged-PQ athletes decreased compared to Pre-Ex and with similar values in Normal-PQ athletes. Compared to Normal-PQ athletes, the second inversion was longer at Pre-Ex and Post-Ex in Prolonged-PQ athletes.

Conclusion:

Prolonged-PQ athletes had significant differences in the temporal characteristics of BSPM during ventricular depolarization both at rest and after exercise as compared to Normal-PQ athletes.

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Research Letter

An Unusual Presentation of Lyme Carditis and Adenosine-Sensitive Atrioventricular Block

André Alexandre et al. Diana Ribeiro Maria João Sousa Hipólito Reis … João Silveira Severo Torres

Introduction

Lyme carditis (LC) is a relatively rare manifestation of the early disseminated stage of LC. ^, The most frequent presentation of LC is atrioventricular (AV) block characterized by rapid fluctuations in the grade and that occurs in approximately 80-90% of patients. ^, Other possible clinical manifestations of LC are myocarditis, pericarditis, dilated cardiomyopathy, and heart failure. ^, The clinical course is usually mild, short-term, and in most cases completely reversible after adequate antibiotic treatment. Indeed, high-grade AV block associated with Lyme disease typically resolves within the first ten days of antibiotic therapy. The authors present a case of a young female diagnosed with early disseminated Lyme disease and cardiac manifestations, in whom AV conduction disturbances persisted after four weeks of appropriate antibiotic treatment and led to an alternative diagnosis.

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Beat-to-Beat Alternating Bundle-Branch Block

Margarida Temtem et al. Joel Ponte Monteiro Marco Gomes Serrão Drumond Freitas

A 67-year-old man was admitted to the primary healthcare emergency department due to dizziness. During the physical examination, an irregular heart rhythm was detected, prompting a request for a 12-lead electrocardiogram (ECG). The ECG () revealed a beat-to-beat alternating pattern of right and left bundle branch blocks (RBBB and LBBB) with Mobitz I second-degree atrioventricular (AV) block.

The patient was transferred to the hospital emergency department, where two consecutive ECGs were performed. One ECG () showed persistent LBBB with first-degree AV block (PR interval of 320ms), and the subsequent ECG () indicated persistent RBBB with left anterior fascicular block and fixed 2:1 second-degree AV block.

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Research Letter

Cardiac Hydatid Cyst: An Uncommon Cause of Complete Atrioventricular Block

Renata Pibernat de Moraes et al. Mathias Silvestre de Brida Rodrigo Moraes Reis Raphael Santos Silva Camila Bergonsi de Farias

Abstract

Hydatidosis is a zoonosis caused by Echinococcus granulosus, leading to the formation of cysts on involved organs. Cardiac involvement is rare and can cause a wide range of complications secondary to rupture, embolization, or compression. Its diagnosis is challenging, and is generally confirmed through data related to clinical manifestations, environmental exposure, and laboratory and imaging exams. Surgical removal is necessary in most cases, in which an association with antiparasite therapy is recommended. The present article describes a case of a cardiac hydatid cyst associated with a complete atrioventricular block (AVB) in a young adult patient, with the need for a pacemaker implant, an atypical presentation, and scarce reports in the literature.

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Editorial

PRKAG2 Cardiomyopathy

Eduardo Back Sternick

Magalhães et al. assessed atrial flutter’s clinical, electrocardiographic, and electrophysiologic characteristics in patients with and without PRKAG2 cardiomyopathy. Although genetic sequencing was not carried out in their control patients, the absence of clinical features of this pathology is acceptable evidence of a non-carrier state. In humans, mutations in the PRKAG2 gene result in a highly penetrant phenotype. It is dominated by the cardiac features of left ventricular hypertrophy, ventricular pre-excitation, atrial tachyarrhythmia, cardiac conduction disease, and myocardial glycogen storage. It would be very unlikely to find a patient with a positive genotype for PRKAG2 in the setting of a negative phenotype.

Our group pioneered the study of PRKAG2 cardiomyopathy in Brazil. The first patient was assessed in 1994, a 36-years old male, with mild hypertension, with recurrent episodes of common atrial flutter. The electrocardiogram showed ventricular pre-excitation, enlarged P waves, a significant increase in the QRS voltage, and sinus bradycardia. Of 8 brothers, six had very similar electrocardiographic findings. Their mother had had a pacemaker implanted at the age of 42. The echocardiogram showed a non-obstructive form of asymmetric left ventricular hypertrophy and mild left atrial enlargement. There were sufficient elements to allow a presumptive diagnosis of a phenocopy of hypertrophic cardiomyopathy! In 1994, however, we were not able to make the diagnosis. The mutations of the PRKAG2 gene had yet to be reported in 1994, but it would be 7 years later. Then, in 2004, we undertook genetic sequencing of the patients. We presented our experience during the NASPE Congress of 2005. Our research received the first prize in clinical arrhythmia during the Brazilian Congress of Cardiac Arrhythmias of 2004.

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Editorial

First-Degree Atrioventricular Block: A Finding Not Always Benign!

First-degree atrioventricular block (AVB) is characterized by sinus rhythm, AV conduction 1:1 and PR interval > 200ms. The prevalence varies according to age group, relatively rare in the population 60 years. The reported prevalence in the general population ranges from 2 to 14%. In most cases (75%), it is due to a proximal or nodal block that tends to improve conduction with a reduction in the PR interval with maneuvers that lead to an increase in adrenergic tone and/or atropine infusion.

Usually considered a benign finding, PR interval prolongation or first-degree AV block has its prognosis more recently questioned due to emerging evidence that it is the independent factor in the increased risk of atrial fibrillation (AF), cardiac pacemaker implantation and all-cause mortality. In the Framingham cohort, the presence of first-degree AV block is considered a risk factor for the development of AF, a fact confirmed in subsequent studies in other community-based cohort with the demonstration of the association between PR prolongation and heart failure and/or AF.

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Original Article

Atrial Flutter in PRKAG2 Syndrome: Clinical and Electrophysiological Characteristics

Eduardo Faria Soares de Magalhães et al. Luiz Pereira de Magalhães Jussara de Oliveira Pinheiro Alex Teixeira Guabiru Roque Aras

Abstract

Background

PRKAG2 syndrome is a rare autosomal dominant disease, a phenocopy of hypertrophic cardiomyopathy characterized by intracellular glycogen accumulation. Clinical manifestations include ventricular preexcitation, cardiac conduction disorder, ventricular hypertrophy, and atrial arrhythmias.

Objective

To compare the clinical and electrophysiological characteristics observed in patients with atrial flutter, with and without PRKAG2 syndrome.

Methods

An observational study comparing patients with atrial flutter: group A consisted of five patients with PRKAG2 syndrome from a family, and group B consisted of 25 patients without phenotype of PRKAG2 syndrome. The level of significance was 5%.

Results

All patients in group A had ventricular preexcitation and right branch block, and four had pacemakers (80%). Patients in group A were younger (39±5.4 vs 58.6±17.6 years, p=0.021), had greater interventricular septum (median=18 vs 10 mm; p<0.001) and posterior wall thickness (median=14 vs 10 mm; p=0.001). In group A, four patients were submitted to an electrophysiological study, showing a fasciculoventricular pathway, and atrial flutter ablation was performed in tree. All patients in group B were submitted to ablation of atrial flutter, with no evidence of accessory pathway. Group B had a higher prevalence of hypertension, diabetes mellitus, coronary artery disease and sleep apnea, with no statistically significant difference.

Conclusion

Patients with PRKAG2 syndrome presented atrial flutter at an earlier age and had fewer comorbidities when compared to patients with atrial flutter without mutation phenotype. The occurrence of atrial flutter in young individuals, especially in the presence of ventricular preexcitation and familial ventricular hypertrophy, should raise the suspicion of PRKAG2 syndrome.

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Research Letter

Long-Term Cardiac Complications of PRKAG2 Syndrome

Luiz Pereira de Magalhães et al. Eduardo Faria Soares de Magalhães Jussara de Oliveira Pinheiro Alex Teixeira Guabiru … Francisco José Farias Borges dos Reis Roque Aras

Introduction

The PRKAG2 syndrome is a rare autosomal dominant inherited disease caused by mutations in the gene encoding the γ regulatory subunit of AMP-activated protein kinase.^, It has been associated with abnormal glycogen accumulation in cardiomyocytes, predisposing to ventricular hypertrophy, arrhythmias, and sudden death. Gollob et al. were the first to describe the mutation in 2001, calling attention to the need for differential diagnosis with hypertrophic cardiomyopathy.^, Although the prevalence of PRKAG2 syndrome is not established, the number of reported cases may be increasing due to wider availability of genotyping. Despite that, possible prognostic factors have not yet been described in the literature. Given the possible severity of clinical presentations and the scarcity of data regarding the natural history, our objectives were to evaluate the clinical course of patients with PRKAG2 syndrome over time and analyze the incidence of long-term cardiac complications.

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ABCIC

Case Report

Myocardial Viability in a Patient with Systemic Lupus Erythematosus

Elisa Carla Hilgemberg et al. Ursula Cristina Barbosa de Almeida Daco Roessler Larissa Ticiane Machado dos Santos Alair Sarmet Damas Claúdio Tinoco Mesquita

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IJCS

Case Report

Commotio Cordis Secondary to Aggression

Luisa Gonçalves et al. Inês Pires João Santos Joana Laranjeira Correia … Davide Moreira Inês Almeida

Case report

A 35-year-old man was admitted following a recovered cardiorespiratory arrest. He was attacked by another man with multiples blunts by a wood stick in the chest and head. An eyewitness statement indicated that the victim had lost consciousness and collapsed after being hit in the chest. He was in cardiac arrest, and a nearby healthcare professional provided first aid with cardiopulmonary resuscitation. The first electrocardiogram (ECG) rhythm strip, fifteen minutes later, identified ventricular fibrillation (VF) (). Sixteen electrical shocks were delivered, always with VF, before restoration of sinus rhythm and circulation. A 12-lead-ECG revealed sinus rhythm without ST deviations and a corrected QT interval of 414 msec. On admission, he was under ventilatory support, with a heart rate of 80 beats per minute, blood pressure of 121/70mmHg, and no signs of shock. There was no previously known medical condition, besides being an active smoker and a binge drinker, and no family history of early coronary disease, cardiomyopathy, or sudden death. He was under the influence of alcohol, as was confirmed by blood tests (blood alcohol level of 1.31g/L), and had a discretely elevated cardiac troponin-T of 0.9ng/ml (normal range, 0 to 0.08 ng/ml). The remaining analyzes, cranial and cervical CT scan, chest X-ray, and abdominal eco FAST were normal. An initial echocardiogram in the emergency department demonstrated normal-sized chambers and global ventricular systolic dysfunction explained by a prolonged cardiac arrest. He was admitted to the intensive care unit for post-resuscitation care with therapeutic hypothermia and temporary ventilatory support. At 48 hours of admission, there was a normalization of systolic function with a normal ejection fraction by echocardiogram (). Coronary angiography excluded coronary disease (). Serial electrocardiograms were not suggestive of an arrhythmogenic substrate (). The sudden cardiac arrest was assumed secondary to a commotio cordis (CC), and for this reason, the patient was not proposed for an implantable cardioverter-defibrillator (ICD). The clinical outcome was favorable, and the patient was discharged. He remained asymptomatic during three years of follow-up, with normal ECG, echocardiogram with strain-rate imaging, exercise stress test, and 24-hour-Holter. During mid-term follow-up, a cardiac magnetic resonance imaging (MRI) showed normal-sized chambers, global and regional function, and no myocardial edema or myocardial scar by late focal hyperenhancement (-).

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ABCIC

Case Report

Cardiac Sarcoidosis as a Cause of Total Atrioventricular Block: Importance of Differential Diagnosis

Jorge Elias Neto et al. Márcio Augusto Silva Ricardo Ryoshim Kuniyoshi Guilherme Futuro … Erick Sessa Merçon Petherson Susano Grativvol Fátima Cristina Pedrotti

Introduction

Sarcoidosis is a systemic granulomatous disorder of unknown cause that can affect virtually any organ. The extracardiac forms are usually benign and subjected to spontaneous remission. However, the prognosis may be unfavorable in case of cardiac involvement.

Symptomatic cardiac sarcoidosis (CS) is diagnosed in approximately 5% of patients with sarcoidosis. However, based on some autopsy series, the prevalence of subclinical CS can reach 25–30%.

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Clinicoradiological Correlation

Case 5/2020 – Corrected Transposition of the Great Arteries, with Good Natural Evolution in a 65-Year-Old Woman

Edmar Atik et al. Renato Maluf Auge Alessandra Costa Barreto Maria Angélica Binotto

Clinical data

The patient evolved without symptoms, doing her usual activities of daily living, such as housekeeping and dressmaking, when total atrioventricular block was identified during a routine evaluation with a heart rate of 66 bpm. At this time, a diagnosis of corrected transposition of the great arteries was made through the echocardiogram, with mild left atrioventricular valve regurgitation. Due to insufficient chronotropism and binodal disease, an atrioventricular pacemaker was placed on the right when she was 59 years old. She remained asymptomatic using antihypertensive medication, amlodipine, enalapril and hydrochlorothiazide. She denied any symptoms such as palpitations, chest pain or fatigue.

Physical examination: good overall status, eupneic, acyanotic, normal pulses in the four limbs. Weight: 61 Kgs, Height: 147 cm, BP=118×70 mmHg: 118 x 70 mm Hg, HR: 72 bpm.

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Hypothermia-Induced Electrocardiographic Changes

Ana Marques et al. Daniel Caldeira Alexandra Briosa Isabel João Hélder Pereira

An elderly female patient was brought to the Emergency Department due to loss of consciousness. The past medical history was remarkable for hypercholesterolemia and essential hypertension. The patient was not treated with any negative chronotropic drug. At the admission, the patient’s blood pressure was 90/60 mmHg, she had bradycardia (42/minute), and hypothermia (33ºC). Electrocardiogram (ECG) showed sinus bradycardia, 1st grade atrioventricular block, long corrected QT interval, and Osborn waves at the end of QRS complexes ( , arrowheads). Accordingly, these positive notching deflections were best seen in lateral precordial leads and disappeared after warming the patient to 36ºC ( ). The bradycardia, atrioventricular block, and QT prolongation were also resolved ( ). During the inward stay, head computed tomography scan, 24-hour Holter, and laboratory analysis were unremarkable for pathological findings. Transthoracic echocardiogram only revealed degenerative aortic and mitral valve changes. This case is illustrative of hypothermia-induced electrocardiographic changes, namely prolongation of the PR, RR and QT intervals and particularly the presence of Osborn Waves.^,

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IJCS

Case Report

Complete Atrioventricular Block and Cardiopulmonary Involvement in Rapidly Progressive Systemic Sclerosis

Eduarda Cal Viegas et al. Diane Xavier de Ávila Eduardo Nani Silva Luís Otávio Cardoso Mocarzel Ronaldo Altenburg Gismondi

Abstract

The heart and lung are target organs in systemic sclerosis (SSc) and similar symptoms (dyspnea and cough) may make the differential diagnosis between the two lesions difficult. In addition, complete atrioventricular block (CAVB) is a rare complication of this disease. This case report is about a patient with SSc and pulmonary fibrosis who was admitted to the emergency room with CAVB, heart failure (HF) and progressive worsening of the underlying disease.

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Letter to the Editor

Prolonged PR Interval and Outcome in Cardiac Resynchronization Therapy

Jakrin Kewcharoen et al. Chanavuth Kanitsoraphan

Dear Editor

We read the article “Baseline Prolonged PR Interval and Outcome of Cardiac Resynchronization Therapy: A Systematic Review and Meta-analysis” by Rattanawong et al. with great interest. The authors investigated the effect of prolonged PR interval on composite outcome among patients who received cardio resynchronized therapy. The authors conclude that prolonged PR is associated with worse outcome in this population.

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IJCS

Original Article

Incidence of Conduction Disorders and Requirements for Permanent Pacemaker After Transcatheter Aortic Valve Implantation

Marcela Cedenilla dos Santos et al. Cristiane da Cruz Lamas Fabiula Schwartz de Azevedo Alexandre Siciliano Colafranceschi … Clara Weksler Leandro Cordeiro Dias Rodrigues Gustavo de Castro Lacerda

Abstract

Background:

Transcatheter aortic valve implantation (TAVI) has become a therapeutic option for high-risk or non-operable patients with severe symptomatic aortic stenosis. Atrioventricular conduction disturbances requiring permanent pacemaker (PPM) are a common and clinically important complication.

Objectives:

To evaluate the incidence of conduction disorders (CDs) after TAVI and the need for subsequent PPM implantation. To identify the predictors of postoperative PPM implantation.

Methods:

Retrospective study. All patients who underwent TAVI in a public hospital from December/2011 to June/2016 were included. Multivariate analysis was conducted to establish the predictor of permanent pacemaker implantation. Survival curves were constructed by the Kaplan-Meyer method. Statistically significant variables were those with p value < 0.05.

Results:

64 patients with AS underwent TAVI. Eleven patients were excluded. TAVI induced a new CD in 40 (77%) of the remaining 53 patients. The most common new CDs were 3rd degree AV block (32%) and left bundle branch block (30%). Sixteen patients (30,2%) underwent PPM implantation during the index hospitalization. On univariate analysis the risk factors for PPM implantation were CoreValve® use (OR: 1,76; P = 0,005), larger prosthesis implantation (P = 0,015), presence of a QRS ≥ 120 ms (OR: 5,62; P = 0,012), and 1st degree AV block (OR: 13; P = 0.008). On multivariate analysis the presence of 1st degree AV block predicted the need for PPM.

Conclusion:

TAVI induced CDs requiring PPM in 30% of the patients. The presence of 1st degree AV block predicted the need for PPM.

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Case Report

Improvement of Pacing-Induced Dyssynchrony by Right Ventricular Septal Stimulation in a Child with Tetralogy of Fallot

Alexander González Guillen et al. Michel Cabrera Ortega Francisco Díaz Ramírez Dunia Bárbara Benítez Ramos

Introduction

Complete atrioventricular block (CAVB) is not an uncommon complication after surgical correction of tetralogy of Fallot (TOF). The choice of the ventricular pacing site in patients requiring pacemaker therapy depends on factors such as age, weight, presence of a venous anomaly, and intracardiac short -circuit. The harmful effects of ventricular pacing are most pronounced during right ventricular (RV) stimulation. Even then, RV pacing sites have been determined to be optimal in some patients with and without congenital heart disease.

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Editorial

Cardiac Autonomic Modulation – The Search for an Ultimate Technique

Esteban Rivarola et al. Mauricio Scanavacca

Abnormal parasympathetic activity on the heart has been implicated in several forms of symptomatic bradycardia, especially in young and otherwise healthy individuals. Neurally mediated syncope, sinus arrest and advanced atrioventricular (AV) block have high risk of injury and serious implications on quality of life. Nonetheless, until recently, their clinical management, mainly based on behavioral measures and pacing, have often proved to be ineffective or inadequate. An alternative approach to treat this specific population, avoiding device implants and continuous drug therapy seemed to be required.

Ganglionated plexus (GP) ablation was first described in 2005, with the purpose of targeting the main parasympathetic ganglia and promoting a vagal attenuation. During the last decade, several authors^– presented their clinical results, with significant remission of symptoms and electrocardiographic improvement, and autonomic modulation became an established therapeutic modality.

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Original Article

Minimally Invasive Epicardial Pacemaker Implantation in Neonates with Congenital Heart Block

Roberto Costa et al. Katia Regina da Silva Martino Martinelli Filho Roger Carrillo

Abstract

Background:

Few studies have characterized the surgical outcomes following epicardial pacemaker implantation in neonates with congenital complete atrioventricular block (CCAVB).

Objective:

This study sought to assess the long-term outcomes of a minimally invasive epicardial approach using a subxiphoid access for pacemaker implantation in neonates.

Methods:

Between July 2002 and February 2015, 16 consecutive neonates underwent epicardial pacemaker implantation due to CCAVB. Among these, 12 (75.0%) had congenital heart defects associated with CCAVB. The patients had a mean age of 4.7 ± 5.3 days and nine (56.3%) were female. Bipolar steroid-eluting epicardial leads were implanted in all patients through a minimally invasive subxiphoid approach and fixed on the diaphragmatic ventricular surface. The pulse generator was placed in an epigastric submuscular position.

Results:

All procedures were successful, with no perioperative complications or early deaths. Mean operating time was 90.2 ± 16.8 minutes. None of the patients displayed pacing or sensing dysfunction, and all parameters remained stable throughout the follow-up period of 4.1 ± 3.9 years. Three children underwent pulse generator replacement due to normal battery depletion at 4.0, 7.2, and 9.0 years of age without the need of ventricular lead replacement. There were two deaths at 12 and 325 days after pacemaker implantation due to bleeding from thrombolytic use and progressive refractory heart failure, respectively.

Conclusion:

Epicardial pacemaker implantation through a subxiphoid approach in neonates with CCAVB is technically feasible and associated with excellent surgical outcomes and pacing lead longevity.

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Leadless Pacemaker: a New Concept in Cardiac Pacing

Nicodemus Lopes et al. Diogo Cavaco Pedro Carmo Maurício Ibrahim Scanavacca Pedro Adragão

67 year-old female patient, pacemaker user since 1983 due to complete atrioventricular block. Between 1991 and 2004, the patient underwent six surgeries. The first was to replace the batteries, and the others for electrode displacement, generator extrusion, and finally for endocarditis, when surgical extraction of the system and epicardial electrode implantation in the right ventricle (RV) were performed. In the last assessment, in 2015, the patient presented with a very high ventricular stimulation threshold and battery depletion. Due to previous technical problems, implantation of transvenous leadless pacemaker was considered (Micra-Medtronic). This new cardiac stimulation system has, as its main characteristics, reduced generator size (volume of 0.8 cm³) and the absence of electrodes, making it possible to perform the implantation of the system directly in the RV. Implantation was performed at Hospital Santa Cruz, Carnaxide, Portugal. After local anesthesia, a sheath (23F) was introduced through the right femoral vein to take the system to the RV. Once inside the ventricle, the delivery catheter was directed to the septal and apical portion and the capsule was released. Fixation of the system in the right ventricle trabeculae, through its flexible tines, was confirmed by mechanical fixation tests. After that, electronic assessment was performed yielding good parameters. After ensuring that parameters were adequate and the capsule was well fixated, the capsule was released and the delivery system was removed. The patient did not present any immediate complications, and after 45 days of follow-up, electronic parameters were stable.

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