Premature Ventricular Complexes: Benign versus Malignant - How to approach?

Premature Ventricular Complexes (PVCs) refer to electrical activity arising from ventricles resulting in ventricular contraction independent of the native rhythm. PVCs by themselves are common in the general population but based on the origin of the PVCs, either related to anatomical or electrical substrate, the disease process has a widely varied presentation and prognosis. The clinical presentation of symptoms may vary from being extremely benign, or very severe (malignant). Benign PVCs include those that are asymptomatic or induce very mild symptoms including palpitations, lightheadedness, chest discomfort, or the sensation of skipped beats. The middle range of PVCs present as heart failure or heart failure complicated by PVCs. The malignant variety may present as syncope, or sudden cardiac death. In this review we describe the multiple facets of PVC presentation and strategies of clinical management.

Ripple Frequency Determined via a Novel Algorithm Is Associated With Atrial Fibrillation Termination and Freedom From Atrial Fibrillation.

Background: Persistent atrial fibrillation (AF) is a complex arrhythmia, and attaining freedom from AF with ablation has been challenging. Objectives: This study evaluated a novel CARTO software algorithm based on the CARTO Ripple map for AF termination and 18-month freedom from AF. Methods: Consecutive patients who underwent first-time ablation for persistent AF were included. A high-density Ripple map was created using a Pentaray catheter. Following PVI, ablation was performed at locations with rapid Ripple activations, a protocol previously described by us. Patients were followed for 18 months to assess rhythm outcomes. A retrospective analysis was performed using the CARTO Ripple frequency software algorithm. The Ripple frequency algorithm quantifies amplitude changes in the bipolar electrogram. Results: A total of 115 AF maps were analyzed from 84 patients (mean age 65.9 years, 63.1% men). The top quartile of Ripple frequency corresponded to a visual reference with 96.7% sensitivity and 91.1% specificity. AF terminated during ablation in 88.1% of patients: pulmonary vein antrum alone (14.9%) or pulmonary vein plus nonantral sites (85.1%). The top quartile of Ripple frequency was present in nonantral areas associated with AF termination with 90.2% sensitivity and 86.5% specificity. After 14.0 ± 6.5 months and 1.2 ± 0.4 ablations, 78 (92.9%) of 84 patients were free of AF, and 79.8% were free of any atrial arrhythmia. Conclusion: A novel algorithm for automated analysis of CARTO Ripple frequency demonstrated good sensitivity and specificity for detecting atrial regions in persistent AF in which ablation is associated with frequent AF termination and freedom from AF during follow-up.

Catheter ablation of ventricular tachycardia in patients with prior cardiac surgery: An analysis from the International VT Ablation Center Collaborative Group.

INTRODUCTION: Patients with prior cardiac surgery may represent a subgroup of patients with ventricular tachycardia (VT) that may be more difficult to control with catheter ablation. METHODS: We evaluated 1901 patients with ischemic and nonischemic cardiomyopathy who underwent VT ablation at 12 centers. Clinical characteristics and VT radiofrequency ablation procedural outcomes were assessed and compared between those with and without prior cardiac surgery. Kaplan-Meier analysis was used to estimate freedom from recurrent VT and survival. RESULTS: There were 578 subjects (30.4%) with prior cardiac surgery identified in the cohort. Those with prior cardiac surgery were older (66.4 ± 11.0 years vs. 60.5 ± 13.9 years, p < .01), with lower left ventricular ejection fraction (30.2 ± 11.5% vs. 34.8 ± 13.6%, p < .01) and more ischemic heart disease (82.5% vs. 39.3%, p < .01) but less likely to undergo epicardial mapping or ablation (9.0% vs. 38.1%, p<.01) compared to those without prior surgery. When epicardial mapping was performed, a significantly greater proportion required surgical intervention for access (19/52 [36.5%] vs. 14/504 [2.8%]; p < .01). Procedural complications, including epicardial access-related complications, were lower (5.7% vs. 7.0%, p < .01) in patients with versus without prior cardiac surgery. VT-free survival (75.1% vs. 74.1%, p = .805) and survival (86.5% vs. 87.9%, p = .397) were not different between those with and without prior heart surgery, regardless of etiology of cardiomyopathy. VT recurrence was associated with increased mortality in patients with and without prior cardiac surgery. CONCLUSION: Despite different clinical characteristics and fewer epicardial procedures, the safety and efficacy of VT ablation in patients with prior cardiac surgery is similar to others in this cohort. The incremental yield of epicardial mapping in predominant ischemic cardiomyopathy population prior heart surgery may be low but appears safe in experienced centers.

Epicardial Ablation via Arterial and Venous Systems.

The intracoronary artery and venous routes provide unique roadmaps for mapping and interventions for ventricular arrhythmias and certain atrial arrhythmias. The unique anatomic location of these vessels on the epicardial surface enables mapping/interventions without the need to access the pericardial space. These anatomic routes also track deep into certain intramural regions, with interventions that are not accessible from either epicardial or endocardial routes. To map smaller vessels, multipolar catheters and wires are used to record local electrograms. Endocardial/epicardial ablation at adjacent sites is sometimes required to enhance successful outcomes. This article describes tools, techniques, and site-specific mapping and interventions.

QTc dispersion as a novel marker in identifying patients requiring an epicardial approach for ablation of scar mediated ventricular tachycardia.

INTRODUCTION: Epicardial exit sites of ventricular tachycardia (VT) are frequently encountered during VT ablation requiring an epicardial ablation approach for successful elimination of VT. We sought to assess the utility of repolarization markers in identifying individuals requiring an epicardial ablation approach in addition to an endocardial approach. METHODS: 32 patients who underwent successful ablation for scar mediated VT were included in the study. Fourteen patients who required a combined endocardial and epicardial VT ablation were defined as epicardial VT group (Epi) whereas 18 patients who were successfully ablated from the endocardium alone constituted the endocardial VT group (Endo). Repolarization markers during sinus rhythm were compared between the two groups. RESULTS: A higher QTc max and QTc dispersion were seen in the Epi group compared to Endo group (479 ± 34 vs 449 ± 20, p = 0.008 and 63 ± 13 vs 38 ± 8, p = 0.001, respectively). Ts-p and Ts-p/Tp-e were higher in the Epi group (166 ± 23 vs 143 ± 23, p = 0.008 and 1.55 ± 0.26 vs 1.3 ± 0.21, p < 0.005). On multivariate regression, QTc dispersion was an independent predictor of the need for an epicardial approach to ablation. A QTc dispersion more than 51.5 msec identified individuals requiring a combined epicardial and endocardial approach to ablation with a sensitivity of 92.9% and a specificity of 100%. CONCLUSIONS: Patients requiring an epicardial ablation have a higher QTc dispersion. A value greater than 51.5 msec reliably differentiates between the two groups with high sensitivity and specificity.

Atrial Fibrillation in the Elderly: The Role of Sub-Clinical Isolated Cardiac Amyloidosis.

Amyloid infiltration of the atrium is described in patients with valvular heart disease and is associated with an increased risk for atrial fibrillation(AF) while amyloid deposits in the ventricles is increasingly being diagnosed in patients with HFpEF. The role of amyloid deposits in patients with AF without valvular heart disease, which represents the most common form of AF globally, is undefined. In this study, we sought to assess the prevalence of sub-clinical isolated cardiac amyloidosis (ICA) at autopsy and the odds of AF in these patients. A total of 1083 patients were included in the study and 3.1% of patients were found to have asymptomatic ICA. Patients with ICA were older and had a higher odds of AF independent of age and CHA2DS2VASc score. Amongst patients with AF, those with ICA were more likely to have persistent forms of AF and had a lower sinus rhythm P-wave amplitude. Further studies are required to further define this entity, identify imaging modalities to aid in antemortem diagnosis of ICA and to establish the optimal management strategies in these patients.

Increased baseline ECG R-R dispersion predicts improvement in systolic function after atrial fibrillation ablation.

Background: Atrial fibrillation (AF) is associated with left ventricular (LV) systolic dysfunction which may improve after AF ablation. We hypothesised that increased ventricular irregularity, as measured by R-R dispersion on the baseline ECG, would predict improvement in the left ventricular ejection fraction (LVEF) after AF ablation. Methods: Patients with LVEF <50% at two US centres (2007-2016), having both a preablation and postablation echocardiogram or cardiac MRI, were included. LVEF improvement was defined as absolute increase in LVEF by >7.5%. Multivariable logistic regression (restricted to echocardiographic/ECG variables) was performed to evaluate predictors of LVEF improvement. Results: Fifty-two patients were included in this study. LVEF improved in 30 patients (58%) and was unchanged/worsened in 22 patients (42%). Those with versus without LVEF improvement had an increased baseline R-R dispersion (645±155 ms vs 537±154 ms, p=0.02, respectively). The average baseline heart rate in all patients was 93 beats per minute. After multivariable logistic regression, increased R-R dispersion (OR 1.59, 95% CI 1.00 to 2.55, p=0.03) predicted LVEF improvement. Conclusions: Increased R-R dispersion on ECG was independently associated with improved systolic function after AF ablation. This broadens the existing knowledge of arrhythmia-induced cardiomyopathy, demonstrating that irregular electrical activation (as measured by increased R-R dispersion on ECG) is associated with a cardiomyopathy capable of improving after AF ablation.

An unyielding valve leading to venous spasm during pacemaker implantation: a case report.

BACKGROUND: Subclavian venous spasm is an uncommon complication during permanent pacemaker implantation. The exact aetiology of subclavian venous spasm is not clear but has been suggested to be due to either mechanical irritation of the vein during needle puncture or due to chemical irritation from contrast injection. Here, we report a case of an unyielding subclavian vein valve that impeded guidewire advancement and the repeated guidewire manipulation led to venous spasm. CASE SUMMARY: A 45-year-old woman with a history of surgical repair of Tetrology of Fallot in childhood presented with symptomatic bifascicular block and underwent a permanent pacemaker implantation. A subclavian venogram done prior to the procedure showed a prominent valve in the distal portion of the vein. Following venous puncture, guidewire advancement was impeded by the prominent valve. The resulting guidewire manipulation led to subclavian venous spasm necessitating a medial subclavian venous puncture and access. DISCUSSION: Prolonged mechanical irritation of the vein during pacemaker implantation may lead to venous spasm impeding pacemaker implantation. Early identification of an impeding valve and obtaining access medial to the valve may help prevent this uncommon complication.

Outcomes of Catheter Ablation of Ventricular Tachycardia Based on Etiology in Nonischemic Heart Disease: An International Ventricular Tachycardia Ablation Center Collaborative Study.

OBJECTIVES: This study sought to characterize ventricular tachycardia (VT) ablation outcomes across nonischemic cardiomyopathy (NICM) etiologies and adjust these outcomes by patient-related comorbidities that could explain differences in arrhythmia recurrence rates. BACKGROUND: Outcomes of catheter ablation of VT in patients with NICM could be related to etiology of NICM. METHODS: Data from 2,075 patients with structural heart disease referred for catheter ablation of VT from 12 international centers was retrospectively analyzed. Patient characteristics and outcomes were noted for the 6 most common NICM etiologies. Multivariable Cox proportional hazards modeling was used to adjust for potential confounders. RESULTS: Of 780 NICM patients (57 ± 14 years of age, 18% women, left ventricular ejection fraction 37 ± 13%), underlying prevalence was 66% for dilated idiopathic cardiomyopathy (DICM), 13% for arrhythmogenic right ventricular cardiomyopathy (ARVC), 6% for valvular cardiomyopathy, 6% for myocarditis, 4% for hypertrophic cardiomyopathy, and 3% for sarcoidosis. One-year freedom from VT was 69%, and freedom from VT, heart transplantation, and death was 62%. On unadjusted competing risk analysis, VT ablation in ARVC demonstrated superior VT-free survival (82%) versus DICM (p ≤ 0.01). Valvular cardiomyopathy had the poorest unadjusted VT-free survival, at 47% (p < 0.01). After adjusting for comorbidities, including age, heart failure severity, ejection fraction, prior ablation, and antiarrhythmic medication use, myocarditis, ARVC, and DICM demonstrated similar outcomes, whereas hypertrophic cardiomyopathy, valvular cardiomyopathy, and sarcoidosis had the highest risk of VT recurrence. CONCLUSIONS: Catheter ablation of VT in NICM is effective. Etiology of NICM is a significant predictor of outcomes, with ARVC, myocarditis, and DICM having similar but superior outcomes to hypertrophic cardiomyopathy, valvular cardiomyopathy, and sarcoidosis, after adjusting for potential covariates.

Ventricular Tachycardia Ablation in the Elderly: An International Ventricular Tachycardia Center Collaborative Group Analysis.

BACKGROUND: Successful ventricular tachycardia (VT) ablation is associated with improved survival in patients with heart failure. However, the safety and efficacy of VT ablation in the elderly, a population with higher competing nonsudden death risk and comorbidities, have not been well defined. METHODS AND RESULTS: The International Ventricular Tachycardia Center Collaborative Study Group registry of 2061 patients who underwent VT ablation at 12 international centers was analyzed. Kaplan-Meier analysis was used to estimate survival of patients ≥70 years with and without VT recurrence. Of the 2049 patients who met inclusion criteria, 681 (33%) patients were ≥70 years of age (mean age, 75±4 years). Among these, 92% were men, 71% had ischemic VT, and 42% had VT storm at presentation. Mean (±SD) left ventricular ejection fraction was 30±11%. Compared with patients <70 years, patients ≥70 years had higher in-hospital (4.4% versus 2.3%; P=0.01) and 1-year mortality (15% versus 11%; P=0.002) but a similar incidence of VT recurrence at 1 year (26% versus 25%; P=0.74) and time to VT recurrence (280 versus 289 days; P=0.20). Absence of VT recurrence during follow-up was strongly associated with improved survival in patients ≥70 years. CONCLUSION: VT ablation in the elderly is feasible and reasonably safe with a modestly higher in-hospital and 1-year mortality, with similar rates of VT recurrence at 1 year compared with younger patients. Successful VT ablation, that is, lack of VT recurrence, is strongly associated with improved survival even in this elderly subgroup.

Outcomes after repeat ablation of ventricular tachycardia in structural heart disease: An analysis from the International VT Ablation Center Collaborative Group.

BACKGROUND: Data evaluating repeat radiofrequency ablation (>1RFA) of ventricular tachycardia (VT) are limited. OBJECTIVE: The purpose of this study was to determine the safety and outcomes of VT >1RFA in patients with structural heart disease. METHODS: Patients with structural heart disease undergoing VT RFA at 12 centers with data on prior RFA history were included. Characteristics and outcomes were compared between first-time (1RFA) and >1RFA patients. RESULTS: Of 1990 patients, 740 had >1RFA (mean 1.4 ± 0.9, range 1-10). >1RFA vs 1RFA patients did not differ with regard to age (62 ± 13 years vs 62 ± 13 years), left ventricular ejection fraction (33% ± 13% vs 34% ± 13%), or sex (88% vs 87% men), but they more often were nonischemic (53% vs 41%), had implantable cardioverter-defibrillator shocks (70% vs 63%) or VT storm (38% vs 33%), and had been treated with amiodarone (55% vs 48%) or ≥2 antiarrhythmic drugs (22% vs 14%). >1RFA procedures were longer (300 ± 122 minutes vs 266 ± 110 minutes), involved more epicardial access (41% vs 21%), induced VTs (2.4 ± 2.2 vs 1.9 ± 1.6) and only unmappable VTs (15% vs 9%), and VT was more often inducible after RFA (42% vs 33%, all P <.03). Total complications were higher for >1RFA vs 1RFA (8% vs 5%, P <.01), mostly related to pericardial effusion (2.4% vs 1.3%, P = .07) and venous thrombosis (0.8% vs 0.2%, P = .06). VT recurrence was higher for >1RFA vs 1RFA (29% vs 24%, P <.001). Survival was worse for >1RFA vs 1RFA if VT recurred (67% vs 78%, P = .003) but was equivalent if successful (93% vs 92%, P = .96). CONCLUSION: Patients requiring repeat VT ablation differ significantly from those undergoing first-time ablation. Despite more challenging ablation characteristics, VT-free survival after repeat ablations is encouraging. Mortality is comparable if VT does not recur after RFA at specialized centers.

Ventricular Tachycardia Ablation in Severe Heart Failure: An International Ventricular Tachycardia Ablation Center Collaboration Analysis.

BACKGROUND: Ventricular tachycardia (VT) radiofrequency ablation has been associated with reduced VT recurrence and mortality, although it is typically not considered among New York Heart Association class IV (NYHA IV) heart failure patients. We compared characteristics and VT radiofrequency ablation outcomes of those with and without NYHA IV in the International VT Ablation Center Collaboration. METHODS AND RESULTS: NYHA II-IV patients undergoing VT radiofrequency ablation at 12 international centers were included. Clinical variables, VT recurrence, and mortality were analyzed by NYHA IV status using Kaplan-Meier analysis and Cox proportional hazard models. There were significant differences between NYHA IV (n=111) and NYHA II and III (n=1254) patients: NYHA IV had lower left ventricular ejection fraction; more had diabetes mellitus, kidney disease, cardiac resynchronization implantable cardioverter-defibrillator, and VT storm despite greater antiarrhythmic drug use (P<0.01). NYHA IV subjects required more hemodynamic support, were inducible for more and slower VTs, and were less likely to undergo final programmed stimulation. There was no significant difference in acute complications. In-hospital deaths, recurrent VT, and 1-year mortality were higher in the NYHA IV group, in the context of greater baseline comorbidities. Importantly, NYHA IV patients without recurrent VT had similar survival compared with NYHA II and III patients with recurrent VT (68% versus 73%). Early VT recurrence (≤30 days) was significantly associated with mortality, especially in NYHA IV patients. CONCLUSIONS: Despite greater baseline comorbidities, VT radiofrequency ablation can be safely performed among NYHA IV patients. Early VT recurrence is significantly associated with subsequent mortality regardless of NYHA status. Elimination of recurrent VT in NYHA IV patients may reduce mortality to a level comparable to NYHA II and III with arrhythmia recurrence.

Post-Extrasystolic Potentiation as a Predictor of Recovery of Left Ventricular Dysfunction After Radiofrequency Catheter Ablation.

OBJECTIVES: This study hypothesizes that post-extrasystolic potentiation reflects left ventricle contractile reserve and therefore may predict an improvement of premature ventricular contraction (PVC)-induced cardiomyopathy after PVC ablation. BACKGROUND: Post-extrasystolic potentiation is a physiologic phenomenon of blood pressure accentuation after a PVC beat. METHODS: We performed a retrospective study of patients with a PVC burden of ≥10% PVC/24 h and left ventricular ejection fraction (LVEF) of <50% who underwent successful ablation between January 1, 2009, to June 30, 2015. Subjects were classified as having reversible (a final LVEF ≥50%) or irreversible (final LVEF <50%) LV dysfunction on a follow-up echocardiogram. A reference (control) group with ≥10% PVC but normal LV function was also identified. RESULTS: Sixty-one patients (age 68 ± 11 years, 98% male) were studied: 30 with preserved and 31 with reduced LVEF. During median follow-up of 9.4 months, the LVEF of 17 of 31 reduced EF patients improved (reversible) but 14 did not (irreversible). The post-PVC beat systolic blood pressure (SBP) (mm Hg) increase ranged from 12.1 in control subjects (LVEF >50%) to 11.5 in reversible patients to 5 in irreversible patients. In multivariate analysis, the independent predictors of reversible LV function were post-PVC SBP rise (odds ratio [OR]: 4.61; 95% confidence interval [CI]: 1.45 to 15.83 per 5-mm Hg increase; p < 0.001), post-PVC pulse pressure change (OR: 5.2; 95% CI: 2.3 to 18.6 per 5-mm Hg increase; p < 0.001), and PVC QRS duration (OR: 2.78; 95% CI: 1.63 to 10.94 per 10-ms increase; p < 0.001). CONCLUSIONS: In patients with LV dysfunction and frequent PVC, post-PVC SBP accentuation may be a marker for subsequent recovery of LVEF after ablation in presumed PVC-induced cardiomyopathy.

Intra-Atrial Right Coronary Artery and its Ablation Implications.

OBJECTIVES: The study examined the frequency in which a right coronary artery (RCA) anomaly resulting in intra-atrialization of the vessel might increase risk of RCA damage during routine radiofrequency ablation in the right atrium even with low power or temperature. BACKGROUND: Right coronary artery (RCA) injury with endocardial RF ablation of the right atrium is a rare complication. METHODS: This prospective observational study comprised an analysis of coronary artery anatomies in 331 patients who underwent autopsies at our institution from 2005 to 2014. The presence of intra-atrial RCA including the number and length of intra-atrial RCA segments with accompanying atherosclerosis and coronary anomalies were evaluated. RESULTS: The authors report a case series of 6 of 331 (1.8%) patients in whom autopsies showed evidence of an intra-atrial RCA. The patients were all men (average 69 ± 12 years of age). They observed 3 variations of the intra-atrial RCA course. In 2 similar variations, the RCA entered the anterolateral aspect of the right atrium, returning to its normal distribution to supply the distal RCA (case 4 of 6) and the atrioventricular nodal artery (case 1 of 6). In the sixth case, the atrialized artery was an anterior branch of the RCA, in which the artery similarly coursed across the pectinate muscles, extending to the region of the anterior crista terminalis, before diving into the muscle. CONCLUSIONS: The prevalence and variants of the intra-atrial RCA have not been reported before. In the presence of an intra-atrial artery, RCA damage may occur due to direct injury rather than collateral injury due to transmural extension of an ablation lesion.

Review of His-Purkinje System Abnormality with Case Studies.

A single beat arising as extra systole within the His-Purkinje system or from ventricle or even atrium based on conduction timing can invoke delayed conduction or block within intra-Hisian or infra-Hisian sites. This may be either manifested in the form of premature atrial or ventricular complexes or concealed as with His extra systoles. It appears commonly there is disease within the His-Purkinje system.

Sex and Catheter Ablation for Ventricular Tachycardia: An International Ventricular Tachycardia Ablation Center Collaborative Group Study.

Importance: Significant differences have been described between women and men regarding presentation, mechanism, and treatment outcome of certain arrhythmias. Previous studies of ventricular tachycardia (VT) ablation have not included sufficient women for meaningful comparison. Objective: To compare outcomes between women and men with structural heart disease undergoing VT ablation. Design, Setting, and Participants: Investigator-initiated, multicenter, observational study performed between 2002 and 2013, conducted by the International VT Ablation Center Collaborative Group, consisting of 12 high-volume ablation centers. Consecutive patients with structural heart disease undergoing VT ablation were studied. Structural heart disease was defined as left ventricular ejection fraction less than 55%, hypertrophic cardiomyopathy, or right ventricular cardiomyopathy, with scar confirmed during electroanatomic mapping. Exposures: Catheter ablation. Main Outcomes and Measures: Ventricular tachycardia-free survival and transplant-free survival were compared between women and men. Cox proportional hazard modeling was performed. Results: Of 2062 patients undergoing ablation, 266 (12.9%) were women. Mean (SD) age was 62.4 (13.3) years and 1095 (53.1%) had ischemic cardiomyopathy. Compared with men, women were younger, with higher left ventricular ejection fraction and less VT storm. Despite this, women had higher rates of 1-year VT recurrence following ablation (30.5% vs 25.3%; P = .03). This difference was only partially explained by higher prevalence of nonischemic cardiomyopathy among women and was actually most pronounced among those with ischemic cardiomyopathy. Conclusions and Relevance: In 12 high-volume ablation centers, women with structural heart disease have worse VT-free survival following ablation than men. Whether this is owing to differences in referral pattern, arrhythmia substrate, or undertreatment requires further study.