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1.
Handb Exp Pharmacol ; 2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38844580

ABSTRACT

ß-Adrenoceptors (ß-ARs) provide an important therapeutic target for the treatment of cardiovascular disease. Three ß-ARs, ß1-AR, ß2-AR, ß3-AR are localized to the human heart. Activation of ß1-AR and ß2-ARs increases heart rate, force of contraction (inotropy) and consequently cardiac output to meet physiological demand. However, in disease, chronic over-activation of ß1-AR is responsible for the progression of disease (e.g. heart failure) mediated by pathological hypertrophy, adverse remodelling and premature cell death. Furthermore, activation of ß1-AR is critical in the pathogenesis of cardiac arrhythmias while activation of ß2-AR directly influences blood pressure haemostasis. There is an increasing awareness of the contribution of ß2-AR in cardiovascular disease, particularly arrhythmia generation. All ß-blockers used therapeutically to treat cardiovascular disease block ß1-AR with variable blockade of ß2-AR depending on relative affinity for ß1-AR vs ß2-AR. Since the introduction of ß-blockers into clinical practice in 1965, ß-blockers with different properties have been trialled, used and evaluated, leading to better understanding of their therapeutic effects and tolerability in various cardiovascular conditions. ß-Blockers with the property of intrinsic sympathomimetic activity (ISA), i.e. ß-blockers that also activate the receptor, were used in the past for post-treatment of myocardial infarction and had limited use in heart failure. The ß-blocker carvedilol continues to intrigue due to numerous properties that differentiate it from other ß-blockers and is used successfully in the treatment of heart failure. The discovery of ß3-AR in human heart created interest in the role of ß3-AR in heart failure but has not resulted in therapeutics at this stage.

2.
Heart Lung Circ ; 33(1): 46-54, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38065830

ABSTRACT

BACKGROUND: Pulsed field ablation (PFA) is a newer ablation energy source with the potential to reduce complications and improve efficacy compared to conventional thermal atrial fibrillation (AF) ablation. This study aimed to present an initial single-centre Australian experience of PFA for AF ablation. METHODS: Initial consecutive patients undergoing PFA for paroxysmal or persistent AF at a single centre were included. Baseline patient characteristics, procedural data and clinical outcomes were collected prospectively at the time of the procedure. Patients were followed up at 3 months and 6-monthly thereafter. RESULTS: In total, 100 PFA procedures were performed in 97 patients under general anaesthesia. All pulmonary veins (403 of 403) were successfully isolated acutely. Median follow-up was 218 days (range, 16-343 days), and the Kaplan-Meier estimate for freedom from atrial arrhythmias at 180 days was 87% (95% confidence interval 79%-95%). Median procedure time was 74 minutes (range, 48-134 minutes). Median fluoroscopy dose-area product was 345 µGym2 (interquartile range, 169-685 µGym2). Two (2%) pseudoaneurysm vascular access complications occurred. There were no cases of thromboembolic complications, stroke, phrenic nerve palsy, pulmonary vein stenosis, atrio-oesophageal fistula, or pericardial tamponade. CONCLUSIONS: Pulsed field ablation can be performed safely and efficiently, with encouraging efficacy in early follow-up. Further data and clinical trials will be required to assess the comparative utility of PFA in contemporary AF ablation practice.


Subject(s)
Atrial Fibrillation , Catheter Ablation , Pulmonary Veins , Humans , Atrial Fibrillation/surgery , Australia/epidemiology , Pulmonary Veins/surgery , Catheter Ablation/methods , Treatment Outcome , Recurrence
3.
Heart Lung Circ ; 32(8): 993-999, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37236845

ABSTRACT

INTRODUCTION: Left-bundle branch area pacing (LBBAP) is a relatively new technique for conduction system pacing. Australian safety and efficacy data is currently lacking. We aim to evaluate the learning curve, medium-term safety, and lead performance in a high-volume Australian setting. METHODS: We performed a retrospective cohort study of 200 consecutive LBBAP procedures performed by a single operator at two centres between January 2019 and May 2020. Left bundle branch area pacing was performed predominantly via left subclavian access using a 69 cm Medtronic SelectSecure 3830 pacing lead and a preformed non-steerable C315-His sheath. Procedural success was defined as evidence of left septal or left bundle branch area capture as evidenced by a right bundle branch block-like paced morphology. Procedural characteristics, and follow-up (including lead performance) data were collected. Procedural efficiency over time, as well as safety data, were collected. RESULTS: Median age was 78.26 years (interquartile range [IQR] 71-85), 37% were female. Atrial fibrillation was present in 22%. The left ventricular ejection fraction <50% in 24%, atrioventricular (AV) block was present in 43.5%, left bundle branch block in 22.5% and right bundle branch block in 24.5%. Acute procedural success was 91.5%. Implant threshold was 0.6V @ 0.5 ms, and 0.75V @ 0.5 ms at 11.9 months of follow-up. The QRS was significant reduced (baseline 134 ms vs implant 114 ms, p<0.001) There was a reduction in procedural time and X-ray dose over the course of the study. There were no complications specific to LBBAP. CONCLUSION: LBBAP appears to be a safe and effective pacing strategy. The QRS duration was significantly reduced compared to baseline. There appears to be an early learning curve with LBBAP.


Subject(s)
Atrioventricular Block , Bundle-Branch Block , Female , Humans , Aged , Male , Bundle-Branch Block/epidemiology , Bundle-Branch Block/therapy , Retrospective Studies , Stroke Volume , Australia/epidemiology , Ventricular Function, Left , Electrocardiography , Cardiac Pacing, Artificial , Treatment Outcome
4.
Heart Lung Circ ; 32(2): 184-196, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36599791

ABSTRACT

IMPORTANCE: Randomised trials have shown that catheter ablation (CA) is superior to medical therapy for ventricular tachycardia (VT) largely in patients with ischaemic heart disease. Whether this translates to patients with all forms and stages of structural heart disease (SHD-e.g., non-ischaemic heart disease) is unclear. This trial will help clarify whether catheter ablation offers superior outcomes compared to medical therapy for VT in all patients with SHD. OBJECTIVE: To determine in patients with SHD and spontaneous or inducible VT, if catheter ablation is more efficacious than medical therapy in control of VT during follow-up. DESIGN: Randomised controlled trial including 162 patients, with an allocation ratio of 1:1, stratified by left ventricular ejection fraction (LVEF) and geographical region of site, with a median follow-up of 18-months and a minimum follow-up of 1 year. SETTING: Multicentre study performed in centres across Australia. PARTICIPANTS: Structural heart disease patients with sustained VT or inducible VT (n=162). INTERVENTION: Early treatment, within 30 days of randomisation, with catheter ablation (intervention) or initial treatment with antiarrhythmic drugs only (control). MAIN OUTCOMES, MEASURES, AND RESULTS: Primary endpoint will be a composite of recurrent VT, VT storm (≥3 VT episodes in 24 hrs or incessant VT), or death. Secondary outcomes will include each of the individual primary endpoints, VT burden (number of VT episodes in the 6 months preceding intervention compared to the 6 months after intervention), cardiovascular hospitalisation, mortality (including all-cause mortality, cardiac death, and non-cardiac death) and LVEF (assessed by transthoracic echocardiography from baseline to 6-, 12-, 24- and 36-months post intervention). CONCLUSIONS AND RELEVANCE: The Catheter Ablation versus Anti-arrhythmic Drugs for Ventricular Tachycardia (CAAD-VT) trial will help determine whether catheter ablation is superior to antiarrhythmic drug therapy alone, in patients with SHD-related VT. TRIAL REGISTRY: Australian New Zealand Clinical Trials Registry (ANZCTR) TRIAL REGISTRATION ID: ACTRN12620000045910 TRIAL REGISTRATION URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377617&isReview=true.


Subject(s)
Catheter Ablation , Myocardial Ischemia , Tachycardia, Ventricular , Humans , Anti-Arrhythmia Agents/therapeutic use , Stroke Volume , Prospective Studies , Treatment Outcome , Ventricular Function, Left , Australia/epidemiology , Tachycardia, Ventricular/surgery , Tachycardia, Ventricular/etiology , Myocardial Ischemia/surgery , Catheter Ablation/methods , Randomized Controlled Trials as Topic , Multicenter Studies as Topic
5.
Europace ; 24(5): 762-773, 2022 05 03.
Article in English | MEDLINE | ID: mdl-34662385

ABSTRACT

AIMS: The aim of this study is to provide a thorough, quantified assessment of the substernal space as the site of extravascular implantable cardioverter-defibrillator (ICD) lead placement using computed tomography (CT) scans and summarizing adverse events and defibrillation efficacy across anatomical findings. Subcutaneous ICDs are an alternative to transvenous defibrillators but have limitations related to ICD lead distance from the heart. An alternative extravascular system with substernal lead placement has the potential to provide defibrillation at lower energy and pacing therapies from a single device. METHODS AND RESULTS: A multi-centre, non-randomized, retrospective analysis of 45 patient CT scans quantitatively and qualitatively assessing bony, cardiac, vascular, and other organ structures from two human clinical studies with substernal lead placement. Univariate logistic regression was used to evaluate 15 anatomical parameters for impact on defibrillation outcome and adjusted for multiple comparisons. Adverse events were summarized. Substernal implantation was attempted or completed in 45 patients. Defibrillation testing was successful in 37 of 41 subjects (90%) using ≥10 J safety margin. There were two intra-procedural adverse events in one patient, including reaction to anaesthesia and an episode of transient atrial fibrillation during ventricular fibrillation induction. Anatomical factors associated with defibrillation failure included large rib cage width, myocardium extending very posteriorly, and a low heart position in the chest (P-values <0.05), though not significant adjusting for multiple comparisons. CONCLUSION: Retrospective analysis demonstrates the ability to implant within the substernal space with low intra-procedural adverse events and high defibrillation efficacy despite a wide range of anatomical variability.


Subject(s)
Defibrillators, Implantable , Arrhythmias, Cardiac/therapy , Defibrillators, Implantable/adverse effects , Humans , Retrospective Studies , Ventricular Fibrillation/etiology , Ventricular Fibrillation/therapy
6.
Europace ; 23(7): 1024-1032, 2021 07 18.
Article in English | MEDLINE | ID: mdl-33595063

ABSTRACT

AIMS: There are conflicting data as to the impact of procedural volume on outcomes with specific reference to the incidence of major complications after catheter ablation for atrial fibrillation. Questions regarding minimum volume requirements and whether these should be per centre or per operator remain unclear. Studies have reported divergent results. We performed a systematic review and meta-analysis of studies reporting the relationship between either operator or hospital atrial fibrillation (AF) ablation volumes and incidence of complications. METHODS AND RESULTS: Databases were searched for studies describing the relationship between operator or hospital AF ablation volumes and incidence of complications which were published prior to 12 June 2020. Of 1593 articles identified, 14 (315 120 patients) were included in the meta-analysis. Almost two-thirds of the procedures were performed in low-volume centres. Both hospital volume of ≥50 and ≥100 procedures/year were associated with a significantly lower incidence of complications compared to <50/year (4.2% vs. 5.5%, OR = 0.58, 95% CI 0.50-0.66, P < 0.001) or <100/year (5.5% vs. 6.2%, OR = 0.62, 95% CI 0.53-0.73, P < 0.001), respectively. Hospitals performing ≥50 procedures/year demonstrated significantly lower mortality compared with those performing <50 procedures/year (0.16% vs. 0.55%, OR = 0.33, 95% CI 0.26-0.43, P < 0.001). A similar relationship existed between proceduralist volume of <50/year and incidence of complications [3.75% vs. 12.73%, P < 0.001; OR = 0.27 (0.23-0.32)]. CONCLUSION: There is an inverse relationship between both hospital and proceduralist AF ablation volume and the incidence of complications. Implementation of minimum hospital and operator AF ablation volume standards should be considered in the context of a broader strategy to identify AF ablation Centers of Excellence.


Subject(s)
Atrial Fibrillation , Catheter Ablation , Atrial Fibrillation/diagnosis , Atrial Fibrillation/epidemiology , Atrial Fibrillation/surgery , Catheter Ablation/adverse effects , Databases, Factual , Humans , Incidence , Treatment Outcome
7.
Europace ; 22(3): 450-495, 2020 03 01.
Article in English | MEDLINE | ID: mdl-31995197

ABSTRACT

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.


Subject(s)
Catheter Ablation , Tachycardia, Ventricular , Ventricular Premature Complexes , Cardiac Electrophysiology , Consensus , Humans , Tachycardia, Ventricular/diagnosis , Tachycardia, Ventricular/surgery
8.
Heart Lung Circ ; 29(7): 988-999, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32063472

ABSTRACT

Ventricular ectopics, also known as ventricular extrasystoles, premature ventricular contractions or complexes (PVC) and ventricular premature depolarisations (VPD) are beats arising from within the ventricles. When they occur in groupings such as bigeminy, trigeminy, couplets and triplets they are referred to as ventricular ectopy. The electrocardiographic (ECG) footprints of a ventricular ectopic include a broad (>110 ms), premature, ventricular complex (QRS deflection); no evidence of pure atrioventricular (AV) conduction; a full, more than, or less than compensatory pause; and discordant QRS and T wave axis. Ventricular ectopy is a very common finding on Holter monitoring at all ages, but particularly in the elderly. In the otherwise normal heart, ventricular ectopy is generally infrequent and a benign finding, but in patients with heart disease, they may be a harbinger to more serious ventricular tachyarrhythmias. In this review, the range and manifestations of ventricular ectopy will be explored in detail with ECG examples.


Subject(s)
Electrocardiography, Ambulatory/methods , Heart Conduction System/physiopathology , Heart Rate/physiology , Heart Ventricles/physiopathology , Ventricular Premature Complexes/physiopathology , Humans , Ventricular Premature Complexes/diagnosis
9.
Heart Lung Circ ; 29(10): 1476-1483, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32327309

ABSTRACT

BACKGROUND: Patients with serious mental illness (SMI) have an increased risk of sudden death. Higher rates of signal-averaged electrocardiogram (SAECG) abnormal late potentials (LP), which may be a predictor of sudden death risk, have been shown in patients with schizophrenia. We aimed to assess the prevalence and predictors of electrocardiograph (ECG) and SAECG abnormalities in a mixed SMI population. METHODS: Consecutive consenting inpatients with SMI had 12-lead ECG and SAECG recorded in addition to demographics, diagnoses and medications. Standard criteria for abnormal SAECG were applied. Multivariate regression analysis was performed to determine predictors of SAECG abnormalities including diagnoses, body mass index, ECG parameters, psychotropic medication use, and medications associated with Long QT or Brugada syndromes. RESULTS: Eighty (80) patients, 49% male, mean age 39±17 years were included. SAECG criteria abnormality for 1, 2 or 3 criteria were seen in 19, 3 and 5 cases (34% in total) respectively. Early repolarisation pattern was seen in 19% of patients. SAECG abnormality was associated with male gender (OR 7.3; 95% CI 2.3-23.4), and schizophrenia/schizoaffective disorder diagnosis (OR 7.4; 95% CI 1.9-29.0), but not with medication type or dose. CONCLUSIONS: In the mixed SMI population studied, there was a high rate of SAECG-detected late potentials (34%) and early repolarisation pattern (19%). Schizophrenia/schizoaffective disorder diagnosis was the strongest multivariate predictor identified. Further studies are needed to define the mechanism and significance of these cardiac abnormalities in SMI patients.


Subject(s)
Arrhythmias, Cardiac/etiology , Death, Sudden, Cardiac/etiology , Electrocardiography/methods , Mental Disorders/complications , Risk Assessment/methods , Adult , Arrhythmias, Cardiac/physiopathology , Death, Sudden, Cardiac/epidemiology , Female , Humans , Incidence , Male , Predictive Value of Tests , Queensland/epidemiology , Survival Rate/trends
10.
Heart Lung Circ ; 29(6): e57-e68, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32451232

ABSTRACT

The COVID-19 pandemic poses a significant stress on health resources in Australia. The Heart Rhythm Council of the Cardiac Society of Australia and New Zealand aims to provide a framework for efficient resource utilisation balanced with competing risks when appropriately treating patients with cardiac arrhythmias. This document provides practical recommendations for the electrophysiology (EP) and cardiac implantable electronic devices (CIED) services in Australia. The document will be updated regularly as new evidence and knowledge is gained with time.


Subject(s)
Betacoronavirus , Coronavirus Infections , Defibrillators, Implantable , Electrophysiologic Techniques, Cardiac , Pandemics , Pneumonia, Viral , Australia/epidemiology , COVID-19 , Coronavirus Infections/epidemiology , Coronavirus Infections/physiopathology , Coronavirus Infections/therapy , Humans , Pneumonia, Viral/epidemiology , Pneumonia, Viral/physiopathology , Pneumonia, Viral/therapy , SARS-CoV-2
11.
Europace ; 21(8): 1143-1144, 2019 Aug 01.
Article in English | MEDLINE | ID: mdl-31075787

ABSTRACT

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.


Subject(s)
Cardiac Electrophysiology , Catheter Ablation , Electrophysiologic Techniques, Cardiac/methods , Tachycardia, Ventricular , Ventricular Premature Complexes , Cardiac Electrophysiology/organization & administration , Cardiac Electrophysiology/standards , Cardiac Electrophysiology/trends , Catheter Ablation/instrumentation , Catheter Ablation/methods , Catheter Ablation/standards , Consensus , Heart Conduction System/pathology , Heart Conduction System/physiopathology , Heart Conduction System/surgery , Heart Diseases/classification , Heart Diseases/complications , Humans , International Cooperation , Quality Improvement/organization & administration , Societies, Medical , Tachycardia, Ventricular/diagnosis , Tachycardia, Ventricular/etiology , Tachycardia, Ventricular/physiopathology , Tachycardia, Ventricular/surgery , Treatment Outcome , Ventricular Premature Complexes/diagnosis , Ventricular Premature Complexes/etiology , Ventricular Premature Complexes/physiopathology , Ventricular Premature Complexes/surgery
12.
Heart Lung Circ ; 28(3): 379-388, 2019 Mar.
Article in English | MEDLINE | ID: mdl-29482954

ABSTRACT

BACKGROUND: Ectopy-mediated cardiomyopathy (EMC) is a potentially reversible form of left ventricular systolic dysfunction. Various risk factors for the development of EMC have been proposed in the literature. We aim to assess medium term outcomes of focal ventricular arrhythmia (VA) ablation in the setting of cardiomyopathy (CMP) and to validate published risk factors for EMC. METHODS: Medium term recovery of left ventricular (LV) function and freedom from VA recurrence was assessed and compared between patients undergoing focal VA ablation in the setting of CMP and a control group with normal LV function. Univariate and multivariate analyses for CMP risk factors were performed and compared against prior published risk factors. RESULTS: Of 152 patients who underwent 170 focal VA ablation procedures, 54 (36%) had CMP and the remaining 98 patients had normal LV systolic function. At medium term follow-up, 85% of patients with CMP were free of VA recurrence and median left ventricular ejection fraction (LVEF) had improved from 40 to 52%. Age, male gender, premature ventricular complex (PVC) burden, non- right ventricular outflow tract (RVOT) sites of origin, PVC QRS duration and PVC minimum coupling interval were predictive of CMP on univariate analysis, but only gender persisted on multivariate analysis. CONCLUSIONS: Medium term outcome in patients undergoing focal VA in the setting of CMP are satisfactory with improvement in LV function achievable in most patients. Prior risk factors described in the literature are variable and inconsistent, likely reflecting heterogeneous study populations.


Subject(s)
Catheter Ablation/methods , Electrocardiography , Heart Conduction System/physiopathology , Heart Ventricles/physiopathology , Stroke Volume/physiology , Ventricular Dysfunction, Left/complications , Ventricular Premature Complexes/etiology , Echocardiography , Female , Follow-Up Studies , Heart Conduction System/surgery , Heart Ventricles/diagnostic imaging , Humans , Magnetic Resonance Imaging, Cine/methods , Male , Middle Aged , Retrospective Studies , Risk Factors , Systole , Treatment Outcome , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/physiopathology , Ventricular Premature Complexes/diagnosis , Ventricular Premature Complexes/surgery
13.
Heart Lung Circ ; 28(10): 1472-1483, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31018908

ABSTRACT

Corporeal and particularly extra-corporeal interference is a very common problem encountered with both resting electrocardiograph (ECG) tracings and ambulatory recordings. The interference may be either electrical or mechanical and if severe, may affect the interpretation of the tracings. The interference, seen as artefact, can be divided into obvious, subtle or complicated. Obvious artefact may result from poor electrode attachment or body motion, whereas electrical interference is predominantly 50 or 60 Hz alternating current or radiofrequency waves from power lines, electrical equipment, mobile phones, fluorescent lights and electrical diathermy. Careful attention to the application of electrodes and finding the best environment for performing a 12-lead ECG will eradicate most interference. When subtle, the artefact can mimic cardiac arrhythmias, leading to incorrect interpretation of the tracings. There is also a complicated interference group, usually due to implanted cardiac electronic pacing devices and neurostimulators. These create persistent artefact, which may result in repeated unsuccessful attempts at procuring an artefact free tracing. This manuscript will describe the genesis of interference, how an ECG machine or monitor deals with interference and will discuss the common causes of interference. The characteristic patterns will be described and clues provided on how to differentiate subtle artefact from cardiac arrhythmias.


Subject(s)
Arrhythmias, Cardiac/diagnosis , Artifacts , Electrocardiography/methods , Heart Conduction System/physiopathology , Heart Rate/physiology , Arrhythmias, Cardiac/physiopathology , Humans
14.
Heart Lung Circ ; 28(10): 1463-1471, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31076238

ABSTRACT

Atrial ectopics, also known as a premature atrial complexes (PAC) or atrial premature depolarisations (APD), are supraventricular beats arising from a focus other than the sinus node. Because the various foci provide an array of electrocardiographic (ECG) appearances, an extensive, but confusing nomenclature has developed. Atrial ectopics are a very common finding on Holter ECG monitoring at all ages, the incidence increasing in frequency with age. In the otherwise normal heart, they are generally infrequent and an innocent finding, but in patients with heart disease, they may be a harbinger to more serious atrial tachyarrhythmias. In this review, the ECG footprints of atrial ectopy will be defined. These footprints include prematurity and P wave morphology. The associated features of variable atrioventricular (AV) conduction, variable post-ectopic pauses and variable QRS morphology due to aberrancy will also be discussed. Each of these features will be explained in detail with ECG examples.


Subject(s)
Atrial Premature Complexes/diagnosis , Heart Atria/physiopathology , Heart Conduction System/physiopathology , Heart Rate/physiology , Atrial Premature Complexes/physiopathology , Electrocardiography , Humans
15.
Heart Lung Circ ; 28(1): 39-48, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30301671

ABSTRACT

The 12-lead electrocardiograph (ECG) is of critical importance both in the diagnosis of wide complex tachycardia and in the further classification, characterisation and management of ventricular arrhythmias. With its diligent application and interpretation, remarkable precision can be achieved in the localisation of the site of origin of ventricular arrhythmias and this may have major implications in the care of these patients. This review discusses the technical, anatomic and mechanistic basis of ECG interpretation in ventricular arrhythmias.


Subject(s)
Electrocardiography , Heart Ventricles/physiopathology , Tachycardia, Ventricular/physiopathology , Equipment Design , Humans , Tachycardia, Ventricular/diagnosis
16.
Heart Lung Circ ; 28(1): 178-190, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30322758

ABSTRACT

Frequent ventricular ectopy is a common clinical presentation in patients suffering idiopathic ventricular outflow tract arrhythmias. These are focal arrhythmias that generally occur in patients without structural heart disease and share a predilection for characteristic anatomic sites of origin. Mechanistically, they are generally due to cyclic adenosine monophosphate (cAMP)-mediated triggered activity. As a result, there is typically an exercise or catecholamine related mode of induction and often a sensitivity to suppression with adenosine. Treatment options include clinical surveillance, medical therapy with anti-arrhythmic agents or catheter ablation. Medical therapy may offer symptomatic benefit but may have side-effects and usually results in burden reduction rather than eradication of ectopy. Catheter ablation using contemporary mapping techniques, whilst associated with some inherent procedural risk, is a potentially curative and safe option in most patients. Although usually associated with a good prognosis, some patients may develop an ectopy-mediated cardiomyopathy or, rarely, ectopy-induced polymorphic ventricular arrhythmias; catheter ablation is the treatment of choice in those patients.


Subject(s)
Catheter Ablation , Electrocardiography , Heart Ventricles/physiopathology , Ventricular Premature Complexes , Global Health , Humans , Incidence , Ventricular Premature Complexes/epidemiology , Ventricular Premature Complexes/physiopathology , Ventricular Premature Complexes/surgery
17.
Heart Lung Circ ; 28(11): 1677-1682, 2019 Nov.
Article in English | MEDLINE | ID: mdl-30392985

ABSTRACT

BACKGROUND: To describe the performance and clinical outcomes of consecutive patients having a leadless pacemaker (LP) implanted at a single institution. METHODS: Clinical data and device parameters were prospectively collected on all patients undergoing LP implantation from November 2015 to April 2018. RESULTS: A total of 79 patients (52 male), median age of 78 years, was included. Leadless pacemaker implantation was successful in 76 patients (96%). Implantation failed in two patients due to excessive venous tortuosity and due to inadequate sensing in another. Seventy-three (73) patients (96%) had chronic atrial fibrillation and all had a Class I or II indication for pacing. Procedure time was 29minutes (IQR 21-43) and fluoroscopy time was 8minutes (IQR 5-13). The median R wave at implant was 11.2mV (IQR 6.9-15.0). The median capture threshold at 0.24ms was 0.5V (IQR 0.4-0.9) and impedance was 754Ω (IQR 680-880). Intraprocedural acute dislodgement occurred in one patient following cutting of the tether but successful snaring and reimplantation was performed. During a median follow-up of 355days (range 9-905), overall electrical performance has been excellent. No patients have been readmitted for device revision or complications. Five (5) patients (7%) died during follow-up from unrelated causes. CONCLUSIONS: Leadless pacemakers can be implanted safely and effectively in the majority of patients. Device electrical performance was excellent over a median follow-up of 12 months.


Subject(s)
Atrial Fibrillation/therapy , Cardiac Pacing, Artificial/methods , Pacemaker, Artificial , Aged , Aged, 80 and over , Atrial Fibrillation/physiopathology , Australia , Electrocardiography , Equipment Design , Female , Follow-Up Studies , Humans , Male , Prospective Studies , Treatment Outcome
18.
Heart Lung Circ ; 28(1): 164-177, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30446243

ABSTRACT

Arrhythmogenic cardiomyopathy (ACM) is now commonly used to describe any form of non-hypertrophic, progressive cardiomyopathy characterised by fibrofatty infiltration of the ventricular myocardium. Right ventricular (RV) involvement refers to the classical arrhythmogenic right ventricular cardiomyopathy, but left ventricular, or bi-ventricular involvement are now recognised. ACM is mostly hereditary and associated with mutations in genes encoding proteins of the intercalated disc. ACM classically manifests as ventricular arrhythmias, and sudden death may be the first presentation of the disease. Heart failure is seen with advanced stages of the disease. Diagnosis can be challenging due to variable expressivity and incomplete penetrance, and is guided by established Taskforce criteria that incorporate electrical features (12-lead electrocardiography (ECG), features of ventricular arrhythmias), structural features (on imaging via echo and cardiac magnetic resonance imaging [MRI]), tissue characteristics (via biopsy), and familial/genetic evaluation. Electrical abnormalities may precede structural alterations, which also make diagnosis challenging, especially in differentiating ACM from other conditions such as benign right ventricular arrhythmias, channelopathies such as Brugada, or the Athlete's Heart. Genetic testing is critical in identifying familial mutations and initiating cascade testing, but finds a pathogenic mutation in only ∼50% of patients. Some critical genotype-phenotype correlations do exist and may help guide risk stratification and give clues to disease progression. Therapeutic strategies include restriction from high endurance and competitive sports, ß-blockers, antiarrhythmic drugs, heart failure medications, implantable cardioverter-defibrillators and combined endocardial/epicardial catheter ablation. Ablation has emerged as the treatment of choice for recurrent ventricular arrhythmias in ACM. This state-of-the-art review outlines the pathogenesis, diagnosis and treatment of ACM in the contemporary era.


Subject(s)
Arrhythmogenic Right Ventricular Dysplasia , Disease Management , Heart Conduction System/physiopathology , Heart Ventricles/diagnostic imaging , Ventricular Dysfunction, Left , Arrhythmogenic Right Ventricular Dysplasia/diagnosis , Arrhythmogenic Right Ventricular Dysplasia/physiopathology , Arrhythmogenic Right Ventricular Dysplasia/therapy , Diagnosis, Differential , Electrocardiography , Heart Ventricles/physiopathology , Humans , Magnetic Resonance Imaging, Cine , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/physiopathology , Ventricular Dysfunction, Left/therapy
20.
Med J Aust ; 209(8): 356-362, 2018 10 15.
Article in English | MEDLINE | ID: mdl-30067936

ABSTRACT

INTRODUCTION: Atrial fibrillation (AF) is increasing in prevalence and is associated with significant morbidity and mortality. The optimal diagnostic and treatment strategies for AF are continually evolving and care for patients requires confidence in integrating these new developments into practice. These clinical practice guidelines will assist Australian practitioners in the diagnosis and management of adult patients with AF. Main recommendations: These guidelines provide advice on the standardised assessment and management of patients with atrial fibrillation regarding: screening, prevention and diagnostic work-up; acute and chronic arrhythmia management with antiarrhythmic therapy and percutaneous and surgical ablative therapies; stroke prevention and optimal use of anticoagulants; and integrated multidisciplinary care. Changes in management as a result of the guideline: Opportunistic screening in the clinic or community is recommended for patients over 65 years of age. The importance of deciding between a rate and rhythm control strategy at the time of diagnosis and periodically thereafter is highlighted. ß-Blockers or non-dihydropyridine calcium channel antagonists remain the first line choice for acute and chronic rate control. Cardioversion remains first line choice for acute rhythm control when clinically indicated. Flecainide is preferable to amiodarone for acute and chronic rhythm control. Failure of rate or rhythm control should prompt consideration of percutaneous or surgical ablation. The sexless CHA2DS2-VA score is recommended to assess stroke risk, which standardises thresholds across men and women; anticoagulation is not recommended for a score of 0, and is recommended for a score of ≥ 2. If anticoagulation is indicated, non-vitamin K oral anticoagulants are recommended in preference to warfarin. An integrated care approach should be adopted, delivered by multidisciplinary teams, including patient education and the use of eHealth tools and resources where available. Regular monitoring and feedback of risk factor control, treatment adherence and persistence should occur.


Subject(s)
Atrial Fibrillation , Atrial Fibrillation/diagnosis , Atrial Fibrillation/prevention & control , Atrial Fibrillation/therapy , Australia , Humans , New Zealand
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