Pulmonary vein isolation plus adjunctive therapy for the treatment of atrial fibrillation: a systematic review and meta-analysis.

BACKGROUND: Pulmonary vein isolation (PVI) is the primary technique for ablation of atrial fibrillation (AF). It is unclear whether adjunctive therapies in addition to PVI can reduce atrial arrhythmia recurrence (AAR) compared to PVI alone in patients with AF. METHODS: A meta-analysis of randomized controlled trials comparing PVI plus an adjunctive therapy (autonomic modulation, linear ablation, non-pulmonary vein trigger ablation, epicardial PVI [hybrid ablation], or left atrial substrate modification) to PVI alone was conducted. The primary outcome was AAR. Cumulative odd's ratios (OR) and 95% confidence intervals (CI) were calculated for each treatment type. RESULTS: Forty-six trials were identified that included 8,500 participants. The mean age (± standard deviation) was 60.2 (±4.1) years, and 27.2% of all patients were female. The mean follow-up time was 14.6 months. PVI plus autonomic modulation and PVI plus hybrid ablation were associated with a relative 53.1% (OR 0.47; 95% CI 0.32 to 0.69; p < 0.001) and 59.1% (OR 0.41; 95% CI 0.23 to 0.75; p = 0.003) reduction in AAR, respectively, compared to PVI alone. All categories had at least moderate interstudy heterogeneity except for hybrid ablation. CONCLUSION: Adjunctive autonomic modulation and epicardial PVI may improve the effectiveness of PVI. Larger, multi-center randomized controlled trials are needed to evaluate the efficacy of these therapies.

Irregular ventricular tachycardia originating from the moderator band.

Ventricular tachycardias (VT) may initially show beat to beat oscillations but rapidly stabilize into a regular tachycardia with a stable cycle length. A persistently irregular ventricular tachycardia is a rare phenomenon. We report a rare case of an "irregular" ventricular tachycardia with so pronounced oscillations in cycle length that it was initially misdiagnosed as atrial fibrillation with aberrant conduction. This ventricular tachycardia was incessant and resulted in a tachycardia induced cardiomyopathy refractory to several antiarrhythmic drugs. Mapping of the right ventricle demonstrated that the tachycardia had a focal origin in the moderator band close to its insertion into the anterior papillary muscle. Radiofrequency ablation eliminated the tachycardia with eventual normalization of left ventricular function. The moderator band and anterior papillary muscle of the right ventricle are known to be the source of short-coupled ventricular premature beats and regular ventricular tachycardias. However, an "irregular" ventricular tachycardia has not been previously reported to arise from these structures.

Pulmonary vein isolation with adjunctive left atrial ganglionic plexus ablation for treatment of atrial fibrillation: a meta-analysis of randomized controlled trials.

BACKGROUND: Adjunctive ganglionic plexus (GP) ablation may increase the efficacy of pulmonary vein isolation (PVI) for treatment of atrial fibrillation (AF). Prior meta-analyses examining PVI with adjunctive GP ablation have included non-randomized trials and have included trials evaluating thorascopic epicardial ablation. The objective of this study is to perform a meta-analysis of randomized controlled trials (RCTs) comparing endocardial catheter-based PVI to PVI with adjunctive GP ablation. METHODS: Summary odds ratio (OR) and 95% confidence intervals (CIs) were calculated. Heterogeneity was assessed with I2 values. Sub-group analysis was performed comparing arrhythmia recurrence between patients with paroxysmal versus persistent AF at trial baseline. Meta-regressions were performed with mean left atrial diameter and left ventricular ejection fraction at trial baseline as the moderator variables. RESULTS: Five RCTs were identified including 814 patients: 406 PVI + GP ablation and 408 PVI alone. The mean age of participants was 56.5 years and 74.7% were male. Four of these trials evaluated catheter-based endocardial ablation for a total of 574 patients: 289 PVI + GP ablation and 285 PVI alone. The odds of arrhythmia recurrence in patients undergoing adjunctive GP ablation with PVI compared with PVI alone were a reduced: odds ratio (OR) 0.58, 95% confidence interval (CI) 0.41-0.82, I2 = 40.2%. In the subgroup analysis, the odds of arrhythmia recurrence with adjunctive GP ablation were reduced in those with paroxysmal AF (OR 0.396, 95% CI 0.23-0.69, I2 = 0%). A non-significant trend to reduced arrhythmia recurrence was also observed in those with persistent AF (OR 0.726, 95% CI 0.475-1.112, I2 = 0%). When performing the meta-regression, increased left atrial diameter was associated with decreased treatment effect of adjunctive GP ablation (R2 index = 1.0, I2 = 0%). CONCLUSIONS: The addition of GP ablation to PVI was associated with reduced arrhythmia recurrence. Adjunctive GP ablation was more effective in paroxysmal AF and in patients with smaller atria. Larger RCTs are needed to confirm the efficacy of GP + PVI ablation.

Wide complex tachycardia in a patient with non-ischemic cardiomyopathy: What is the diagnosis?

A 55-year-old male presented with acute heart failure and incessant wide complex tachycardia resembling an outflow tract ventricular tachycardia. Meticulous analysis of the electrocardiograms established the diagnosis of pre-excitation with prolonged atrio-ventricular (A-V) conduction over a decrementally conducting accessory A-V pathway. "Linking" between the accessory A-V pathway and normal A-V conduction system resulted in sustained maximal pre-excitation as well as periodic transition to normal A-V conduction without appreciable change in heart rate. Successful radiofrequency ablation of this unusual accessory A-V pathway was performed at the aortic-mitral junction. This ameliorated the mechanical dysynchrony, allowed discontinuation of hemodynamic/inotropic support, and resulted in sustained symptomatic improvement.

Cannabis use disorder and increased risk of arrhythmia-related hospitalization in young adults.

BACKGROUND AND OBJECTIVES: Recent observations indicate that cannabis use can result in cardiovascular complications including arrhythmias. We studied the relationship between cannabis use disorder (CUD) and arrhythmia hospitalization. METHODS: We conducted a retrospective analysis of the Nationwide Inpatient Sample (2010-2014). Patients (age 15-54) with a primary diagnosis for arrhythmia (N = 570,556) were compared with non-arrhythmia (N = 67,662,082) inpatients for odds ratio (OR) of CUD by the logistic regression model, adjusted for demographics and comorbid risk factors. RESULTS: The incidence of CUD in arrhythmia inpatients was 2.6%. Among cannabis users, the most prevalent arrhythmia was atrial fibrillation (42%), followed by other arrhythmias (24%) and atrial flutter (8%). Patients with CUD were younger (15-24 years, OR: 4.23), male (OR: 1.70), and African American (OR: 2.70). CUD was associated with higher odds of arrhythmia hospitalization in the young population, 1.28 times in 15-24 years (95% confidence interval [CI]: 1.229-1.346) and 1.52 times in 25-34 years (95% CI: 1.469-1.578). CONCLUSION AND SCIENTIFIC SIGNIFICANCE: With the growing legalization in the United States, there is an increased use of medicinal/recreational cannabis. This is the first national study to our knowledge that found that CUD is associated with a 47%-52% increased likelihood of arrhythmia hospitalization in the younger population and the risk of association was controlled for potential confounders including other substances. The fact that atrial fibrillation is the most prevalent arrhythmia is of special concern since it can result in stroke and other embolic events. Physicians need to familiarize themselves with cannabis abuse or dependence as a risk factor for arrhythmia.

Short coupled torsade de pointes: Critical timing of the ventricular premature beats.

In this case report, we describe a 73 year old female with structuraly normal heart that developed shortcoupled torsades de pointes (TdP) resulting in an electrical storm unresponsible to several antiarrhythmic drugs, but fully controlled with verapamil. The critical timing of the ventricular premature beats that initiated TdP corresponded to those that occurred at the peak of the previous T wave. This behavior differentiates this entity from other forms of malignant ventricular arrhythmias in patients with structurally normal heart. It is imperative that the clinical set-up and unique electrocardiographic fingerprint of this unusual malignant entity be assiduously recognized since verapamil can be life-saving in this condition.

Advanced management of ventricular arrhythmias in chronic Chagas cardiomyopathy.

Chagas cardiomyopathy is a parasitic infection caused by Trypanosoma cruzi. Structural and functional abnormalities are the result of direct myocardial damage by the parasite, immunological reactions, dysautonomia, and microvascular alterations. Chronic Chagas cardiomyopathy (CCC) is the most serious and important manifestation of the disease, affecting up to 30% of patients in the chronic phase. It results in heart failure, arrhythmias, thromboembolism, and sudden cardiac death. As in other cardiomyopathies, scar-related reentry frequently results in ventricular tachycardia (VT). The scars typically are located in the inferior and lateral aspects of the left ventricle close to the mitral annulus extending from endocardium to epicardium. The scars may be more prominent in the epicardium than in the endocardium, so epicardial mapping and ablation frequently are required. Identification of late potentials during sinus rhythm and mid-diastolic potentials during hemodynamically tolerated VT are the main targets for ablation. High-density mapping during sinus rhythm can identify late isochronal regions that are then targeted for ablation. Preablation cardiac magnetic resonance imaging with late enhancement can identify potentials areas of arrhythmogenesis. Therapeutic alternatives for VT management include antiarrhythmic drugs and modulation of the cardiac autonomic nervous system.

Long-term safety and effectiveness of paroxysmal atrial fibrillation ablation using a porous tip contact force-sensing catheter from the SMART SF trial.

PURPOSE: The prospective, multicenter SMART SF trial demonstrated the acute safety and effectiveness of the 56-hole porous tip irrigated contact force (CF) catheter for drug-refractory paroxysmal atrial fibrillation (PAF) ablation with a low primary adverse event rate (2.5%), leading to FDA approval of the catheter. Here, we are reporting the long-term effectiveness and safety results that have not yet been reported. METHODS: Ablations were performed using the 56-hole porous tip irrigated CF catheter guided by the 3D mapping system stability module. The primary effectiveness endpoint was freedom from atrial tachyarrhythmia (including atrial fibrillation, atrial tachycardia, and/or atrial flutter), based on electrocardiographic data at 12 months. Atrial tachyarrhythmia recurrence occurring 3 months post procedure, acute procedural failures such as lack of entrance block confirmation of all PVs, and undergoing repeat procedure for atrial fibrillation in the evaluation period (91 to 365 days post the initial ablation procedure) were considered to be effectiveness failures. RESULTS: Seventy-eight patients (age 64.8 ± 9.7 years; male 52.6%; Caucasian 96.2%) participated in the 12-month effectiveness evaluation. Mean follow-up time was 373.5 ± 45.4 days. The Kaplan-Meier estimate of freedom from 12-month atrial tachyarrhythmia was 74.9%. Two procedure-related pericardial effusion events were reported at 92 and 180 days post procedure. There were no pulmonary vein stenosis complications or deaths reported through the 12-month follow-up period. CONCLUSIONS: The SMART SF 12-month follow-up evaluation corroborates the early safety and effectiveness success previously reported for PAF ablation with STSF.

Left posterior fascicular ventricular tachycardia in a young infant with a structurally normal heart: Clinical course and caveats to electrocardiographic diagnosis.

In this illustrative case report, we describe a rare case of left posterior fascicular ventricular tachycardia (LPFVT) in a 2 month-old infant with emphasis on electrocardiographic caveats to diagnosis. The clinical course, treatment, and eventual resolution of the VT over a 2 year follow-up is comprehensively compared and contrasted to a modicum of individual such case reports of infants. The corpus of each such case of infantile LPVT is systematically reviewed and succinctly summarized in a tabular compendium. The collective knowledge compiled here should allow for a refined approach to diagnosis and management of this unusual arrhythmia.

Prominent Epsilon Waves in a Patient With Cardiac Sarcoidosis.

Epsilon waves are the surface manifestation of myocardial regions with delayed activation and are considered the hallmark of arrhythmogenic right ventricular cardiomyopathy. However, other conditions can also result in epsilon waves and simulate arrhythmogenic right ventricular cardiomyopathy. In this case, a patient presents with recurrent ventricular tachycardia and large epsilon waves due to cardiac sarcoidosis. (Level of Difficulty: Intermediate.).

[Alternating bundle branch block in a supraventricular tachycardia: Which is the mechanism ?] / Bloqueo de rama alternante en una taquicardia supraventricular ¿ Cuál es el mecanismo subyacente ?

Functional bundle branch block during a supraventricular tachycardia can be observed with shorter cycle lengths and represent a physiologic response by the specialized intraventricular conduction system to accelerated AV nodal conduction. The present case corresponds to a young patient with exercise induced orthodromic A-V reentrant tachycardia and alternating bundle branch block. This unusual response is explained by the finding obtained during the electrophysiology study. An accelerated AV nodal conduction made the depolarizing wave front reach the bundle branches during their refractory period. Once block in one bundle was stablished, block persisted due to the linking phenomenon that is repetitive retrograde concealed conduction from the contralateral bundle. After catheter ablation of a concealed left-sided accessory A-V pathway, rapid atrial pacing at the same cycle length of the tachycardia reproduced the same aberrancies observed during tachycardia. This response proved that functional bundle branch block is due to the short cycle length and not the presence of an accessory A-V pathway.

El bloqueo de rama funcional durante una taquicardia supraventricular puede ser observado con longitudes de ciclo cortas y representa una respuesta fisiológica del sistema de conducción intraventricular por la existencia de conducción nodal auriculo ventricular acelerada. Presentamos el caso de un paciente joven con taquicardia reentrante aurículo-ventricular ortodrómica y bloqueo de rama alternante. Esta respuesta infrecuente se explica por el hallazgo obtenido durante el estudio electrofisiológico. Una conducción nodal aurículo-ventricular acelerada produce un frente de onda que despolariza las ramas durante sus períodos refractarios. Una vez que ocurrió el bloqueo en una de las ramas, dicho bloqueo persistió debido al fenómeno de linking, que es por conducción oculta retrógrada repetitiva de la rama contralateral. Después de la ablación transcatéter de una vía accesoria oculta lateral izquierda, el marcapaseo auricular rápido a la misma longitud de ciclo de la taquicardia, reprodujo la misma aberrancia observada durante la taquicardia. Este procedimiento demostró que el bloqueo de rama funcional fue debido a la longitud de ciclo corto y no a la presencia de una vía accesoria aurículo-ventricular.

Left ventricular noncompaction and orthodromic atrioventricular tachycardia observed in a patient with neurofibromatosis type 1.

Isolated left ventricular noncompaction (LVNC) was described for the first time in 1984. It is a rare congenital disease, characterized by prominent trabecular meshwork pattern and deep intertrabecular recesses, communicated with the left ventricular chamber. Clinical presentation varies from asymptomatic patients, to those developing supraventricular and ventricular arrhythmias, thromboembolism, heart failure and sudden cardiac death. We present an unusual case, where the patient with Neurofibromatosis type 1 presented with a wide complex orthodromic atrioventricular reentrant tachycardia (AVRT) and a diagnosis of left posterior paraseptal accessory pathway in association with LVNC.

Sympathetic responses induced by radiofrequency catheter ablation of atrial fibrillation.

Radiofrequency catheter ablation (RFCA) is a frequently performed procedure in patients with atrial fibrillation. Prior studies have shown that the RFCA may directly stimulate vagal afferents during the procedure, whereas the vagal tone assessed by heart rate variability (HRV) is lowered weeks after the RFCA procedure. The effects of RFCA performed in the left atrium on sympathetic nerve activity have not been assessed. In the present study, we hypothesized that RFCA would lower muscle sympathetic nerve activity (MSNA) during ablation and would raise MSNA 1 day postablation. A total of 18 patients were studied. In protocol 1 ( n = 10), electrocardiogram, blood pressure, and MSNA in the peroneal nerve were recorded through the RFCA procedure performed in the electrophysiology laboratory. In protocol 2, eight patients were studied before the procedure and 1 day postablation. RFCA led to a decrease in MSNA immediately after the procedure (25.4 ± 3.2 to 17.2 ± 3.8 bursts/min, P < 0.05). Cardiac parasympathetic activity was determined using indexes of HRV and increased during the procedure. One day postablation, MSNA was above baseline values (21.3 ± 3.7 to 35.7 ± 2.6 bursts/min, P < 0.05). HRV indexes of cardiac parasympathetic activity fell, and the HRV index of sympathovagal balance was not significantly altered. The results show that RFCA raised cardiac parasympathetic activity and decreased MSNA during the procedure. One day postablation, MSNA rose and cardiac parasympathetic activity fell. In addition, RFCA evokes differentiated sympathetic responses directed to the heart and skeletal muscles. NEW & NOTEWORTHY The effects of radiofrequency catheter ablation performed in the left atrium on muscle sympathetic nerve activity (MSNA) have not been assessed. The results of this study show that radiofrequency catheter ablation raised cardiac parasympathetic activity and decreased MSNA during the procedure. One day postablation, MSNA rose and cardiac parasympathetic activity fell. We speculate that the partial autonomic afferent denervation induces these effects on autonomic activity.

Ibutilide for the control of refractory ventricular tachycardia and ventricular fibrillation in patients with myocardial ischemia and hemodynamic instability.

INTRODUCTION: Recurrent ventricular tachycardia (VT) and ventricular fibrillation (VF) in patients with myocardial ischemia requiring hemodynamic support can be refractory to available antiarrhythmic agents and even to cardioversion and defibrillation. The purpose of this study was to report the effect of intravenous ibutilide in patients with a VT and/or VF storm in the presence of incomplete revascularization requiring hemodynamic support. METHODS AND RESULTS: Standard continuous telemetry and frequent 12-lead electrocardiograms were obtained to determine the effect of intravenous Ibutilide in these patients. We studied six consecutive patients (age 60 ± 12 years; five males) with incomplete revascularization and mechanical support (extracorporeal membrane of oxygenation = 2; left ventricular assist device = 4) with VT/VF refractory to lidocaine and amiodarone. Intravenous ibutilide was given as a last resort for management of their ventricular arrhythmias. Intravenous ibutilide (1-2 mg) allowed restoration of sinus rhythm in three patients with persistent VF that were refractory to multiple defibrillation shocks. When the 24-hour period before and after ibutilide administration was compared, this drug markedly reduced the number of required cardioversions/defibrillations in all patients from 20 ± 9 to 0.7 ± 0.8 shocks ( P = 0.036). CONCLUSIONS: In patients with myocardial ischemia requiring hemodynamic support, intravenous Ibutilide demonstrates a potent antiarrhythmic effect and can facilitate defibrillation in patients with refractory VF.

Cardiac automaticity: basic concepts and clinical observations.

PURPOSE: The purpose of this report was to review the basic mechanisms underlying cardiac automaticity. Second, we describe our clinical observations related to the anatomical and functional characteristics of sinus automaticity. METHODS: We first reviewed the main discoveries regarding the mechanisms responsible for cardiac automaticity. We then analyzed our clinical experience regarding the location of sinus automaticity in two unique populations: those with inappropriate sinus tachycardia and those with a dominant pacemaker located outside the crista terminalis region. RESULTS: We studied 26 patients with inappropriate sinus tachycardia (age 34 ± 8 years; 21 females). Non-contact endocardial mapping (Ensite 3000, Endocardial Solutions) was performed in 19 patients and high-density contact mapping (Carto-3, Biosense Webster with PentaRay catheter) in 7 patients. The site of earliest atrial activation shifted after each RF application within and outside the crista terminalis region, indicating a wide distribution of atrial pacemaker sites. We also analyzed 11 patients with dominant pacemakers located outside the crista terminalis (age 27 ± 7 years; five females). In all patients, the rhythm was the dominant pacemaker both at rest and during exercise and located in the right atrial appendage in 6 patients, in the left atrial appendage in 4 patients, and in the mitral annulus in 1 patient. Following ablation, earliest atrial activation shifted to the region of the crista terminalis at a slower rate. CONCLUSIONS: Membrane and sub-membrane mechanisms interact to generate cardiac automaticity. The present observations in patients with inappropriate sinus tachycardia and dominant pacemakers are consistent with a wide distribution of pacemaker sites within and outside the boundaries of the crista terminalis.