Teetering on the Edge: Second-Degree Atrioventricular Block Following Long-Acting Second-Generation Antipsychotic.

Our case report highlights the importance of understanding various mechanisms of an atrioventricular block (AVB) and recognizing potential iatrogenic culprits. Despite the prevalent use of second-generation antipsychotics and the growing popularity of long-acting formulations, it is not routinely recognized as a cause for AVB. Second-generation antipsychotics such as risperidone have a dose-dependent pro-arrhythmic effect and are known to cause first-degree AVB. Our case presents an opportunity to recognize an unappreciated cause for AVB and switch to safer alternatives. In the era of long-acting injectables, it is important to monitor for these effects prior to escalating doses and risking high-degree AVB.

Prognostic Value of Nonischemic Ringlike Left Ventricular Scar in Patients With Apparently Idiopathic Nonsustained Ventricular Arrhythmias.

BACKGROUND: Left ventricular (LV) scar on late gadolinium enhancement (LGE) cardiac magnetic resonance has been correlated with life-threatening arrhythmic events in patients with apparently idiopathic ventricular arrhythmias (VAs). We investigated the prognostic significance of a specific LV-LGE phenotype characterized by a ringlike pattern of fibrosis. METHODS: A total of 686 patients with apparently idiopathic nonsustained VA underwent contrast-enhanced cardiac magnetic resonance. A ringlike pattern of LV scar was defined as LV subepicardial/midmyocardial LGE involving at least 3 contiguous segments in the same short-axis slice. The end point of the study was time to the composite outcome of all-cause death, resuscitated cardiac arrest because of ventricular fibrillation or hemodynamically unstable ventricular tachycardia and appropriate implantable cardioverter defibrillator therapy. RESULTS: A total of 28 patients (4%) had a ringlike pattern of scar (group A), 78 (11%) had a non-ringlike pattern (group B), and 580 (85%) had normal cardiac magnetic resonance with no LGE (group C). Group A patients were younger compared with groups B and C (median age, 40 vs 52 vs 45 years; P<0.01), more frequently men (96% vs 82% vs 55%; P<0.01), with a higher prevalence of family history of sudden cardiac death or cardiomyopathy (39% vs 14% vs 6%; P<0.01) and more frequent history of unexplained syncope (18% vs 9% vs 3%; P<0.01). All patients in group A showed VA with a right bundle-branch block morphology versus 69% in group B and 21% in group C (P<0.01). Multifocal VAs were observed in 46% of group A patients compared with 26% of group B and 4% of group C (P<0.01). After a median follow-up of 61 months (range, 34-84 months), the composite outcome occurred in 14 patients (50.0%) in group A versus 15 (19.0%) in group B and 2 (0.3%) in group C (P<0.01). After multivariable adjustment, the presence of LGE with ringlike pattern remained independently associated with increased risk of the composite end point (hazard ratio, 68.98 [95% CI, 14.67-324.39], P<0.01). CONCLUSIONS: In patients with apparently idiopathic nonsustained VA, nonischemic LV scar with a ringlike pattern is associated with malignant arrhythmic events.

Risk Stratification of Patients With Apparently Idiopathic Premature Ventricular Contractions: A Multicenter International CMR Registry.

OBJECTIVES: This study investigated the prevalence and prognostic significance of concealed myocardial abnormalities identified by cardiac magnetic resonance (CMR) imaging in patients with apparently idiopathic premature ventricular contractions (PVCs). BACKGROUND: The role of CMR imaging in patients with frequent PVCs and otherwise negative diagnostic workup is uncertain. METHODS: This was a multicenter, international study that included 518 patients (age 44 ± 15 years; 57% men) with frequent (>1,000/24 h) PVCs and negative routine diagnostic workup. Patients underwent a comprehensive CMR protocol including late gadolinium enhancement imaging for detection of necrosis and/or fibrosis. The study endpoint was a composite of sudden cardiac death, resuscitated cardiac arrest, and nonfatal episodes of ventricular fibrillation or sustained ventricular tachycardia that required appropriate implantable cardioverter-defibrillator therapy. RESULTS: Myocardial abnormalities were found in 85 (16%) patients. Male gender (odds ratio [OR]: 4.28; 95% confidence interval [CI]: 2.06 to 8.93; p = 0.01), family history of sudden cardiac death and/or cardiomyopathy (OR: 3.61; 95% CI: 1.33 to 9.82; p = 0.01), multifocal PVCs (OR: 11.12; 95% CI: 4.35 to 28.46; p < 0.01), and non-left bundle branch block inferior axis morphology (OR: 14.11; 95% CI: 7.35 to 27.07; p < 0.01) were all significantly related to the presence of myocardial abnormalities. After a median follow-up of 67 months, the composite endpoint occurred in 26 (5%) patients. Subjects with myocardial abnormalities on CMR had a higher incidence of the composite outcome (n = 25; 29%) compared with those without abnormalities (n = 1; 0.2%; p < 0.01). CONCLUSIONS: CMR can identify concealed myocardial abnormalities in 16% of patients with apparently idiopathic frequent PVCs. Presence of myocardial abnormalities on CMR predict worse clinical outcomes.

Left atrial appendage as a vantage point for mapping and ablating premature ventricular contractions originating in the epicardial left ventricular summit.

Idiopathic ventricular tachycardia arising from the LV summit epicardial area can be successfully mapped and possibly ablated from the left atrial appendage.

Catheter Ablation in the Right Ventricular Outflow Tract Associated With Occlusion of Left Anterior Descending Coronary Artery.

Major vessel injury during right ventricular outflow tract ablation is not something widely recognized, and routine evaluation of the left anterior descending (LAD) artery location in relation to the septal right ventricle is not routinely performed. In the present article, we report a case of acute LAD occlusion after right ventricular outflow tract ablation and then illustrate the intimately close relationship of the LAD artery to the anterior septal site of the RVOT (approximately 2-3 cm under the pulmonic valve), using a combination of intracardiac echocardiography and 3-dimensional electroanatomical mapping recorded during a second case, in order to specifically point to the area at risk.

Congenital Chagas' disease transmission in the United States: Diagnosis in adulthood.

Two brothers with congenitally-acquired Chagas' disease (CD) diagnosed during adulthood are reported. The patients were born in the USA to a mother from Bolivia who on subsequent assessment was found to be serologically positive for Trypanosoma cruzi. Serologic screening of all pregnant women who migrated from countries with endemic CD is strongly recommended.

Percutaneous epicardial ablation of ventricular arrhythmias arising from the left ventricular summit: outcomes and electrocardiogram correlates of success.

BACKGROUND: Percutaneous epicardial ablation of ventricular arrhythmias arising from the left ventricular summit is limited by the presence of major coronary vessels and epicardial fat. We report the outcomes of percutaneous epicardial mapping and ablation of ventricular arrhythmias arising from the left ventricular summit and the ECG features associated with successful ablation. METHODS AND RESULTS: Between January 2003 and December 2012, a total of 23 consecutive patients (49 ± 14 years; 39% men) with ventricular arrhythmias arising from the left ventricular summit underwent percutaneous epicardial instrumentation for mapping and ablation because of unsuccessful ablation from the coronary venous system and multiple endocardial LV/right ventricular sites. Successful epicardial ablation was achieved in 5 (22%) patients. In the remaining 18 (78%) cases, ablation was aborted for either close proximity to major coronary arteries or poor energy delivery over epicardial fat. The Q-wave amplitude ratio in aVL/aVR was higher in the successful group, with a ratio of > 1.85 present in 4 (80%) patients in the successful group versus 2 (11%) in the unsuccessful group (P = 0.008). The ratio of R/S wave in V1 was greater in the successful group, with 4 (80%) patients in the successful group having a R/S ratio of > 2 in V1 versus 5 (28%) in the unsuccessful group (P = 0.056). None of the patients in the successful group had an initial q wave in lead V1, as opposed to 6 (33%) in the unsuccessful group. The presence of at least 2 of the 3 ECG criteria above predicted successful ablation with 100% sensitivity and 72% specificity. CONCLUSIONS: Epicardial instrumentation for mapping and ablation of ventricular arrhythmias arising from the left ventricular summit is successful only in a minority of patients because of close proximity to major coronary arteries and epicardial fat. A Q-wave ratio of > 1.85 in aVL/aVR, a R/S ratio of > 2 in V1, and absence of q waves in lead V1 help identify appropriate candidates for epicardial ablation.

Long-term arrhythmia follow-up of patients with myotonic dystrophy.

BACKGROUND: Myotonic dystrophy (MD) is the most common muscular dystrophy in adults and is associated with sudden death. Reported predictors of sudden death in this population include atrial tachyarrhythmias, a PR interval greater than 240 milliseconds, aberrant QRS conduction, and any degree of AV block. OBJECTIVE: We sought to report on the arrhythmic outcome of a cohort of patients with a new diagnosis of genetically proven MD. METHODS: We performed a retrospective review of 37 patients with genetically confirmed MD referred to our electrophysiology clinic for primary cardiac screening. RESULTS: There were 25 patients with MD type 1 (MD1) and 12 patients with MD type 2 (MD2). Eight patients with MD1 (32%) had atrial fibrillation, compared to only one patient with MD2 (8.3%). Patients with MD1 were more likely to have evidence of conduction disease abnormalities (40% vs. 8.3%, P = ns) and had a higher all-cause mortality (16% vs. 0%) than those with MD2. Criteria for recommending ICD implantation were based on sudden death risk factors suggested by published literature. Eleven patients were offered an ICD, 2 refused and died within the next year. Of the 9 patients who received an ICD, 8 had MD1. Three patients received appropriate shocks, 2 for monomorphic VT, and one for polymorphic VT. CONCLUSION: The presence of AV conduction disturbance in MD patients is associated with a greater risk for ventricular arrhythmias. MD1 was more likely to be associated with cardiac arrhythmias than MD2. The incidence of ventricular arrhythmias among those who received a primary prevention ICD was 33% over 22 months, with 2 patients experiencing monomorphic VT and one experiencing polymorphic VT.

Idiopathic ventricular arrhythmias originating from the moderator band: Electrocardiographic characteristics and treatment by catheter ablation.

BACKGROUND: The moderator band (MB) can be a source of premature ventricular contractions (PVCs), monomorphic ventricular tachycardia (VT), and idiopathic ventricular fibrillation (IVF). OBJECTIVE: The purpose of this study was to define the electrocardiographic (ECG) characteristics and procedural techniques to successfully identify and ablate MB PVCs/VT. METHODS: In 10 patients with left bundle branch block morphology PVCs/VT, electroanatomic mapping in conjunction with intracardiac echocardiography (ICE) localized the site of origin of the PVCs to the MB. Clinical characteristics of the patients, ECG features, and procedural data were collected and analyzed. RESULTS: Seven patients presented with IVF and 3 presented with monomorphic VT. In all patients, the ventricular arrhythmias (VAs) had a left bundle branch block QRS with a late precordial transition (>V4), a rapid downstroke of the QRS in the precordial leads, and a left superior frontal plane axis. Mean QRS duration was 152.7 ± 15.2 ms. Six patients required a repeat procedure. After mean follow-up of 21.5 ± 11.6 months, all patients were free of sustained VAs, with only 1 patient requiring antiarrhythmic drug therapy and 1 patient having isolated PVCs no longer inducing VF. There were no procedural complications. CONCLUSION: VAs originating from the MB have a distinctive morphology and often are associated with PVC-induced ventricular fibrillation. Catheter ablation can be safely performed and is facilitated by ICE imaging.

Development and validation of a novel algorithm based on the ECG magnet response for rapid identification of any unknown pacemaker.

BACKGROUND: Pacemaker (PM) interrogation requires correct manufacturer identification. However, an unidentified PM is a frequent occurrence, requiring time-consuming steps to identify the device. OBJECTIVE: The purpose of this study was to develop and validate a novel algorithm for PM manufacturer identification, using the ECG response to magnet application. METHODS: Data on the magnet responses of all recent PM models (≤15 years) from the 5 major manufacturers were collected. An algorithm based on the ECG response to magnet application to identify the PM manufacturer was subsequently developed. Patients undergoing ECG during magnet application in various clinical situations were prospectively recruited in 7 centers. The algorithm was applied in the analysis of every ECG by a cardiologist blinded to PM information. A second blinded cardiologist analyzed a sample of randomly selected ECGs in order to assess the reproducibility of the results. RESULTS: A total of 250 ECGs were analyzed during magnet application. The algorithm led to the correct single manufacturer choice in 242 ECGs (96.8%), whereas 7 (2.8%) could only be narrowed to either 1 of 2 manufacturer possibilities. Only 2 (0.4%) incorrect manufacturer identifications occurred. The algorithm identified Medtronic and Sorin Group PMs with 100% sensitivity and specificity, Biotronik PMs with 100% sensitivity and 99.5% specificity, and St. Jude and Boston Scientific PMs with 92% sensitivity and 100% specificity. The results were reproducible between the 2 blinded cardiologists with 92% concordant findings. CONCLUSION: Unknown PM manufacturers can be accurately identified by analyzing the ECG magnet response using this newly developed algorithm.

Impedancia transtorácica como herramienta para el manejo del paciente con insuficiencia cardíaca / Transthoracic impedance monitoring in patients with heart failure / ImpedÔncia transtorácica como instrumento para o manejo de pacientes com insuficiÛncia cardíaca

Los pacientes con insuficiencia cardíaca son frecuentemente hospitalizados a causa de congestión pulmonar. Como estrategia para prevenir esta complicación, los pacientes son sometidos a frecuentes visitas médicas y a mediciones del peso diario. La impedancia transtorácica, junto a otros datos que informan acerca de la función cardíaca, puede ser monitoreada en forma remota y su uso es de gran ayuda. Inclusive, puede medirse en pacientes con desfibriladores implantables y ha demostrado ser más sensible que la medición del peso para predecir episodios de descompensación por insuficiencia cardíaca. En el presente artículo se hace una revisión de la información existente en relación con esta tecnología y con su uso clínico.(AU)

Patients with congestive heart failure are frequently admitted to the hospital due to episodes of pulmonary congestion. As a strategy to prevent hospitalizations, the patients are closely followed in clinic and are asked to weigh themselves daily. The transthoracic impedance and other physiologic data can be monitored remotely and its use of great help in the management of these patients. The transthoracic impedance, which can be measured by an internal defibrillator, has been proven to be more sensitive than daily weights in predicting heart failure admissions.(AU)

Pacientes com insuficiÛncia cardíaca congestiva sÒo freq³entemente internados no hospital devido a episódios de congestÒo pulmonar. Como estratégia para evitar esta complicaþÒo, os pacientes passam por consultas médicas freq³entes e mediþ§es de peso diário. A impedÔncia transtorácica, juntamente com de outros dados reportados sobre funþÒo cardíaca, podem ser monitorados O distÔncia e seu uso pode ser de grande ajuda no manejo desses pacientes. Inclusive, pode ser medido em pacientes com desfibriladores implantáveis e demonstrou ser mais sensível que a mediþÒo de peso para prever episódios de descompensaþÒo da insuficiÛncia cardíaca. O presente artigo realiza uma revisÒo da informaþÒo existente em relaþÒo com esta tecnologia e seu uso clínico.(AU)

Impedancia transtorácica como herramienta para el manejo del paciente con insuficiencia cardíaca / Transthoracic impedance monitoring in patients with heart failure / Impedância transtorácica como instrumento para o manejo de pacientes com insuficiência cardíaca

Los pacientes con insuficiencia cardíaca son frecuentemente hospitalizados a causa de congestión pulmonar. Como estrategia para prevenir esta complicación, los pacientes son sometidos a frecuentes visitas médicas y a mediciones del peso diario. La impedancia transtorácica, junto a otros datos que informan acerca de la función cardíaca, puede ser monitoreada en forma remota y su uso es de gran ayuda. Inclusive, puede medirse en pacientes con desfibriladores implantables y ha demostrado ser más sensible que la medición del peso para predecir episodios de descompensación por insuficiencia cardíaca. En el presente artículo se hace una revisión de la información existente en relación con esta tecnología y con su uso clínico.

Patients with congestive heart failure are frequently admitted to the hospital due to episodes of pulmonary congestion. As a strategy to prevent hospitalizations, the patients are closely followed in clinic and are asked to weigh themselves daily. The transthoracic impedance and other physiologic data can be monitored remotely and its use of great help in the management of these patients. The transthoracic impedance, which can be measured by an internal defibrillator, has been proven to be more sensitive than daily weights in predicting heart failure admissions.

Pacientes com insuficiência cardíaca congestiva são freqüentemente internados no hospital devido a episódios de congestão pulmonar. Como estratégia para evitar esta complicação, os pacientes passam por consultas médicas freqüentes e medições de peso diário. A impedância transtorácica, juntamente com de outros dados reportados sobre função cardíaca, podem ser monitorados à distância e seu uso pode ser de grande ajuda no manejo desses pacientes. Inclusive, pode ser medido em pacientes com desfibriladores implantáveis e demonstrou ser mais sensível que a medição de peso para prever episódios de descompensação da insuficiência cardíaca. O presente artigo realiza uma revisão da informação existente em relação com esta tecnologia e seu uso clínico.

Ventricular premature depolarization QRS duration as a new marker of risk for the development of ventricular premature depolarization-induced cardiomyopathy.

BACKGROUND: Frequent ventricular premature depolarizations (VPDs) can cause cardiomyopathy (CMP). The mechanisms underlying its development remain unclear, with VPD burden being only a weak predictor of risk. OBJECTIVE: To determine whether VPD QRS duration at the time of initial presentation could predict risk for the subsequent development of CMP in patients with normal left ventricular ejection fraction (LVEF). METHODS: From consecutive patients referred for ablation between January 1, 2006, and April 2, 2013, with ≥10% VPDs on 24-hour Holter monitoring, we identified 45 patients with normal LVEF and an electrocardiogram of the targeted VPD, who were then followed for at least 6 months (median 14 months; interquartile range [IQR] 8-32 months) before intervention. We excluded patients with structural or genetic heart disease. RESULTS: Of the 45 patients, 28 (62%) maintained normal LVEF and 17(38%) developed VPD-induced CMP. VPD burden was similar (26.5% [IQR 19.3%-39.5%] vs 26.0% [IQR 16.4%-41.0%]; P = 0.4) between the 2 groups. Patients who developed VPD-induced CMP had significantly longer VPD QRS duration (159 ms vs 142 ms; P < .001) and a longer sinus QRS duration (97 ms vs 89 ms; P = .04). A VPD QRS duration of ≥153 ms best predicted development of VPD CMP (82% sensitivity and 75% specificity). Longer VPD QRS duration and a non-outflow tract site of VPD origin were independent risk factors for left ventricular dysfunction after multivariate analysis. CONCLUSION: VPD QRS duration longer than 153 ms and a non-outflow tract site of origin might be useful predictors of the subsequent development of VPD-induced CMP.