Long-term outcome of intraventricular conduction delays in the general population.

BACKGROUND: Previous population studies have presented conflicting results regarding the prognostic impact of intraventricular conduction delays (IVCD). METHODS: We studied long-term prognostic impact and the association with comorbidities of eight IVCDs in a random sample of 6,299 Finnish subjects (2,857 men and 3,442 women, mean age 52.8, SD 14.9 years) aged 30 or over who participated in the health examination including 12-lead ECG. For left bundle branch block (LBBB) and non-specific IVCD (NSIVCD), two different definitions were used. RESULTS: During 16.5 years' follow-up, 1,309 of the 6,299 subjects (20.8%) died and of these 655 (10.4%) were cardiovascular (CV) deaths. After controlling for known clinical risk factors, the hazard ratio for CV death, compared with individuals without IVCD, was 1.55 for the Minnesota definition of LBBB (95% confidence interval 1.04-2.31, p = .032) and 1.27 (95% confidence interval 0.80-2.02, p = .308) for the Strauss' definition of LBBB. Subjects with NSIVCD were associated with twofold to threefold increase in CV mortality depending on the definition. While right bundle branch block, left anterior fascicular block and incomplete bundle branch blocks were associated with seemingly higher mortality, this was no longer the case after adjustment for age and sex. The presence of R-R' pattern was not associated with any adverse outcome. CONCLUSIONS: In a population study with long-term follow-up, NSIVCD and Minnesota definition of LBBB were independently associated with CV mortality. Other IVCDs had no significant impact on prognosis. The prognostic impact of LBBB and NSIVCD was affected by the definition of the conduction disorder.

Evaluation of a real-time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia substrate assessment.

AIMS: Potential advantages of real-time magnetic resonance imaging (MRI)-guided electrophysiology (MR-EP) include contemporaneous three-dimensional substrate assessment at the time of intervention, improved procedural guidance, and ablation lesion assessment. We evaluated a novel real-time MR-EP system to perform endocardial voltage mapping and assessment of delayed conduction in a porcine ischaemia-reperfusion model. METHODS AND RESULTS: Sites of low voltage and slow conduction identified using the system were registered and compared to regions of late gadolinium enhancement (LGE) on MRI. The Sorensen-Dice similarity coefficient (DSC) between LGE scar maps and voltage maps was computed on a nodal basis. A total of 445 electrograms were recorded in sinus rhythm (range: 30-186) using the MR-EP system including 138 electrograms from LGE regions. Pacing captured at 103 sites; 47 (45.6%) sites had a stimulus-to-QRS (S-QRS) delay of ≥40 ms. Using conventional (0.5-1.5 mV) bipolar voltage thresholds, the sensitivity and specificity of voltage mapping using the MR-EP system to identify MR-derived LGE was 57% and 96%, respectively. Voltage mapping had a better predictive ability in detecting LGE compared to S-QRS measurements using this system (area under curve: 0.907 vs. 0.840). Using an electrical threshold of 1.5 mV to define abnormal myocardium, the total DSC, scar DSC, and normal myocardium DSC between voltage maps and LGE scar maps was 79.0 ± 6.0%, 35.0 ± 10.1%, and 90.4 ± 8.6%, respectively. CONCLUSION: Low-voltage zones and regions of delayed conduction determined using a real-time MR-EP system are moderately associated with LGE areas identified on MRI.

Distribution of Conduction Disorders in Patients With Congenital Heart Disease and Right Atrial Volume Overload.

OBJECTIVES: This study sought to quantify characteristics of atrial conduction disorders in patients with right atrial (RA) volume overload. BACKGROUND: Patients with an interatrial shunt are prone to developing atrial fibrillation (AF), which may be related to conduction disorders occurring due to atrial stretch. METHODS: Thirty-one patients undergoing surgery for an interatrial shunt (49 ± 14 years of age) underwent epicardial sinus rhythm mapping of the RA, Bachmann's bundle (BB), and left atrium (LA). Conduction delay (CD) was defined as interelectrode conduction time (CT) of 7 to 11 ms and conduction block (CB) as CT ≥12 ms. Prevalence of CD or CB (percentage of mapped region), length of lines, and severity of CB (75th percentile of CTs ≥12 ms) were analyzed. RESULTS: All patients had some degree of CD and CB. Prevalence of CD and CB was higher in the RA and BB than in the LA (p < 0.0083 after Bonferroni correction). The longest CB line within each patient was found in the RA in most patients (52%). Interindividual variation in prevalence and lengths of lines was considerable. CB was more severe in the RA than in the LA (p < 0.0083). Within the RA, conduction disorders were more prevalent and more severe in the intercaval region than in the RA free wall (p < 0.05). CONCLUSIONS: In patients with an interatrial shunt, conduction disorders during sinus rhythm are most pronounced in the RA-particularly the intercaval region-and BB. Knowledge of the conduction during sinus rhythm is essential to determine the relevance of conduction disorders for initiation and perpetuation of AF.

Late ventricular standstill following an elective TAVI.

Transcatheter aortic valve implantations (TAVIs) may be complicated by a need for permanent pacemaker implantation post procedure, usually due to local trauma or compression on the conduction system. There are some features that might help predict that a patient is high risk for developing conduction disease following TAVI, for example, underlying right bundle branch block or use of certain types of TAVI. It might also become apparent during the procedure, or before temporary wire removal post procedure. Higher risk patients may undergo rhythm monitoring for longer periods post TAVI. We present a case where a patient required an unexpected emergency pacemaker following a TAVI, despite low risk clinical features, a low risk baseline ECG, and the use of a low risk TAVI valve. In addition, this very significant conduction disease only became apparent over 72 hours following implantation, despite normal resting ECGs and telemetry up to that point.

Long term evaluation of electromechanical delay in patients with atrial septal defect after transcatheter closure.

Some studies have been showed that electromechanical delay, which may pose an increased tendency to atrial fibrillation, may prolong in patients with various clinical conditions. In addition, the electromechanical delay in patients with secundum type atrial septal defect (ASD) compared to healthy people have been reported previously. Therefore, in the present study, we prospectively evaluated the mid-term and long-term effects of the transcatheter closure of secundum type ASD on the lateral atrial conduction time (PA), septal PA, tricuspid PA, left and right intra-atrial electromechanical delay (ILeft-EMD and IRight-EMD, respectively) and inter-atrial electromechanical delay (IA-EMD) measured by means of Doppler echocardiography. Our prospective study included a total of 45 secundum type ASD patients who undergone percutaneous transcatheter closure from December 2012 to April 2015. All patients underwent transthoracic echocardiography (TTE) before the closure, at sixth and twelfth months after the closure. In comparison of the EMD sixth months after the device closure, there were statistically significant decrease in lateral PA, septal PA, tricuspid PA, ILeft-EMD, IRight-EMD and IA-EMD compared to pre-device closure values. Twelfth months after the device closure, we also observed statistically significant decrease in lateral PA, septal PA, tricuspid PA, ILeft-EMD, IRight-EMD and IA-EMD compared to 6-month post-device closure values. In the present study, we observed that the atrial EMD improves after device closure and continues to improve after twelfth month following post-device closure.

Assessment of Subclinical Cardiac Alterations and Atrial Electromechanical Delay by Tissue Doppler Echocardiography in Patients with Nonfunctioning Adrenal Incidentaloma.

BACKGROUND: Majority of the incidentally discovered adrenal masses, called adrenal incidentaloma (AI), are nonfunctioning adrenal adenomas. The appropriate management of AI is still a matter debate, so it is necessary to investigate their associated morbidity. However, data regarding morphological and functional cardiac alterations are limited in this group. OBJECTIVE: In this study, we aimed to assess cardiac structural and functional characteristics and atrial conduction properties in patients with nonfunctioning AI. METHODS: Thirty patients with nonfunctioning AI and 46 properly matched control subjects were included in the study. After hormonal and biochemical analysis, all participants underwent transthoracic echocardiography to obtain systolic and diastolic parameters of both ventricles, in addition to atrial conduction times by tissue Doppler echocardiography. Data were analyzed with Statistical Package for the Social Sciences (SPSS, Chicago, IL, United States) statistics, version 17.0 for Windows. P < 0.05 was considered statistically significant. RESULTS: Left ventricular (LV) mass index and LV myocardial performance index were significantly increased in AI group. Among atrial conduction times, both intra- and interatrial electromechanical delays were significantly prolonged in patients with nonfunctioning AI. Other laboratory and echocardiographic findings were similar between groups. CONCLUSION: Our study revealed that intra- and inter-atrial conduction times were prolonged, and LV mass index was increased in patients with nonfunctioning AI. These findings may be markers of subclinical cardiac involvement and tendency to cardiovascular complications. Close follow-up is necessary for individuals with nonfunctioning AI for their increased cardiovascular risk.

The effects of septal myectomy and alcohol septal ablation for hypertrophic cardiomyopathy on the cardiac conduction system.

AV conduction abnormalities are observed in 15-30% of patients with hypertrophic cardiomyopathy but are usually not severe enough to require permanent pacemaker implant. Both septal myectomy and alcohol septal ablation are effective options to relieve symptoms due to left ventricular outflow tract gradient in patients with hypertrophic cardiomyopathy but have procedure-specific effects on AV conduction and the His Purkinje system. Septal myectomy is associated with the development of LBBB in 50-100% of patients, while alcohol septal ablation is associated with RBBB in 37-70% of patients. Baseline abnormalities in the contralateral bundles and the presence of conduction disease have an important impact on the likelihood of the development of AV block for both of these therapies. AV block requiring permanent pacing occurs in approximately 2-3% of patients after septal myectomy and 10-15% of patients after alcohol septal ablation. Permanent pacemaker implant after alcohol septal ablation is more common in older patients (> 55 years old 13 vs. < 55 years old 5%; p = 0.06). Improved outcomes for septal myectomy and alcohol septal ablation are observed in experienced centers. Septal reduction therapies should be performed at medical centers with a dedicated hypertrophic cardiomyopathy program using a multidisciplinary approach.

Atrial fibrillation and conduction system disease: the roles of catheter ablation and permanent pacing.

Atrial fibrillation (AF) and diseases of the cardiac conduction system frequently co-exist, and interactions between these rhythm disturbances can adversely impact patient outcomes. Concurrent AF and sinus node disease often manifests as the tachy-brady syndrome wherein the underlying sinus node dysfunction can pose a challenge to AF management. Similarly, the combination of AF and left bundle branch block increases mortality in individuals with co-existent heart failure and hampers effective delivery of cardiac resynchronization therapy. A thorough understanding of the therapeutic interventions available for these conditions, including the role of catheter ablation and permanent pacemaker programming, is crucial for optimal management in affected patients.

Intra- and interatrial conduction abnormalities: hemodynamic and arrhythmic significance.

Alterations of normal intra- and interatrial conduction are a common outcome of multiple cardiovascular conditions. They arise most commonly in the context of advanced age, cardiovascular risk factors, organic heart disease, atrial fibrosis, and left atrial enlargement. Interatrial block (IAB), the most frequent and extensively studied atrial conduction disorder, affects up to 20% of the general primary care population. IAB can be partial (P wave duration ≥ 120 ms on any of the 12 ECG leads) or advanced (P wave ≥ 120 ms and biphasic morphology (positive-negative) in inferior leads). Advanced IAB is an independent risk factor for supraventricular tachyarrhythmias and embolic stroke in a variety of clinical settings. Advanced IAB is a cause of left atrial electromechanical dysfunction and left atrioventricular dyssynchrony and has been associated with left ventricular diastolic dysfunction. P wave duration is associated with cardiovascular and all-cause mortality in the general population. Atrial conduction abnormalities should be identified as markers of atrial remodeling, prognostic indicators, and, in the case of advanced IAB, a true arrhythmologic syndrome. IAB and other P wave abnormalities should prompt the search for associated conditions, the treatment of which may partially reverse atrial remodeling or prevent it if administered upstream. Future studies will help define the role of preventive therapeutic interventions in high-risk patients, including antiarrhythmic drug therapy and oral anticoagulation. Implications for the treatment of heart failure and for pacing should also be further investigated.

Assessment of Subclinical Cardiac Alterations and Atrial Electromechanical Delay by Tissue Doppler Echocardiography in Patients with Nonfunctioning Adrenal Incidentaloma / Avaliação de Alterações Cardíacas Subclínicas e Atraso Eletromecânico Atrial por Ecocardiografia com Doppler Tecidual em Pacientes com Incidentaloma Adrenal Não Funcionante

Abstract Background: Majority of the incidentally discovered adrenal masses, called adrenal incidentaloma (AI), are nonfunctioning adrenal adenomas. The appropriate management of AI is still a matter debate, so it is necessary to investigate their associated morbidity. However, data regarding morphological and functional cardiac alterations are limited in this group. Objective: In this study, we aimed to assess cardiac structural and functional characteristics and atrial conduction properties in patients with nonfunctioning AI. Methods: Thirty patients with nonfunctioning AI and 46 properly matched control subjects were included in the study. After hormonal and biochemical analysis, all participants underwent transthoracic echocardiography to obtain systolic and diastolic parameters of both ventricles, in addition to atrial conduction times by tissue Doppler echocardiography. Data were analyzed with Statistical Package for the Social Sciences (SPSS, Chicago, IL, United States) statistics, version 17.0 for Windows. P < 0.05 was considered statistically significant. Results: Left ventricular (LV) mass index and LV myocardial performance index were significantly increased in AI group. Among atrial conduction times, both intra- and interatrial electromechanical delays were significantly prolonged in patients with nonfunctioning AI. Other laboratory and echocardiographic findings were similar between groups. Conclusion: Our study revealed that intra- and inter-atrial conduction times were prolonged, and LV mass index was increased in patients with nonfunctioning AI. These findings may be markers of subclinical cardiac involvement and tendency to cardiovascular complications. Close follow-up is necessary for individuals with nonfunctioning AI for their increased cardiovascular risk.

Resumo Fundamento: A maioria das massas adrenais descobertas incidentalmente, denominadas incidentaloma adrenal (IA), são adenomas adrenais não funcionantes. O manejo adequado da IA ainda é um tema de debate, e por isso é necessário investigar suas morbidades associadas. Entretanto, dados referentes a alterações cardíacas morfológicas e funcionais são limitados nesse grupo. Objetivo: Neste estudo, objetivamos avaliar as características estruturais e funcionais cardíacas e as propriedades de condução atrial em pacientes com IA não funcionante. Métodos: Trinta pacientes com IA não funcionante e 46 controles adequadamente pareados foram incluídos no estudo. Após análise hormonal e bioquímica, todos os participantes foram submetidos a ecocardiograma transtorácico para obtenção de parâmetros sistólicos e diastólicos de ambos os ventrículos, além dos tempos de condução atrial pelo ecocardiograma com Doppler tecidual. Os dados foram analisados com o Statistical Package for the Social Sciences (SPSS, Chicago, IL, Estados Unidos), versão 17.0 para Windows. P < 0,05 foi considerado estatisticamente significativo. Resultados: O índice de massa do ventrículo esquerdo (VE) e o índice de desempenho miocárdico do VE foram significativamente aumentados no grupo IA. Entre os tempos de condução atrial, os atrasos eletromecânicos intra- e interatriais foram significativamente prolongados em pacientes com IA não funcionante. Outros achados laboratoriais e ecocardiográficos foram semelhantes entre os grupos. Conclusão: Nosso estudo revelou que os tempos de condução intra- e interatrial estavam prolongados e o índice de massa do VE estava aumentado em pacientes com IA não funcionante. Esses achados podem ser marcadores de envolvimento cardíaco subclínico e de tendência a complicações cardiovasculares. Um acompanhamento rigoroso é necessário para indivíduos com IA não funcionante, devido ao aumento do risco cardiovascular.