Gender, Age, and Regional Disparities in the Incidence and Mortality Trends of Infective Endocarditis in the United States Between 1990 and 2019.

The incidence of infective endocarditis (IE) has increased globally in the past decades, including in the United States. However, little is known about the differences in trends across states, gender, and age groups within the United States. Using the Global Burden of Disease database, we analyzed the incidence and mortality trends of IE in the United States between 1990 and 2019 using Joinpoint regression analyses, and compared between states, gender, and age groups. The age-standardized incidence rate (ASIR) of IE in the United States increased from 10.2/100,000 population in 1990 to 14.4 in 2019. The increase in ASIR was greater among men than women (45.8% vs 34.1%). The incidence increase was driven by 55+ year-olds (112.7% increase), with rapid increases in the 1990s and early 2000s, followed by a plateau around the mid-2000s. In contrast, the incidence among 5-to-19-year-olds decreased by -36.6% over the 30-year period. The incidence increased among all age groups in the last 5 years of observation (2015 to 2019), with the largest increase in 5-to-19-year-olds (3.3% yearly). The 30-year increase in ASIR was greatest in Utah (66.2%) and smallest in California (30.2%). The overall age-standardized mortality attributable to IE increased in the United States by 126% between 1990 and 2019 versus 19.6% globally. In conclusion, although the overall incidence and mortality of IE increased over the past 30 years in the United States, there are significant differences between regions, gender, and age groups. These findings indicate unevenly distributed disease burden of IE across the nation.

Atrial fibrillation/atrial flutter related mortality trends in the US population 2010-2020: Regional, racial, sex variations.

BACKGROUND: There is an evolving need to evaluate atrial fibrillation/atrial flutter (AF/AFL) mortality trends across races, sexes, geographic regions and urbanization statuses to better understand management inequalities. METHODS: This observational study utilized the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) database. Mortality rates due to AF/AFL as underlying and contributing causes of death between 2010 and 2020 were investigated. Mortality trends due to AF/AFL as contributing causes of death for different races, sexes, census regions and urbanization statuses were analyzed using annual percentage change (APC), and Joinpoint regression analysis. RESULTS: Mortality from AF/AFL as the underlying cause was increasing across the US until 2016 (APC 4.8%), followed by a plateau 2016-2020 (APC 0.0 %). Conversely, the mortality rate due to AF/AFL as a contributing cause increases 2010-2020 (APC 3.3%). The mortality rate in both sexes significantly increased in almost all groups, with the largest increase seen in Non-Hispanic Black males. Rural areas had a higher mortality rate (36.9 and 22.9 per 100,000 for males and females in 2020, respectively) and higher slope of increase than urban areas in total US population. Non-Hispanic White people had greater mortality than Non-Hispanic Black people; however, Non-Hispanic Black mortality rates are increasing at a faster rate in urban areas. CONCLUSION: AF/AFL as the underlying cause of death has plateaued from 2016 across the US 2010-2020; whilst AF/AFL as contributing cause of death is increasing. Significant discrepancies in mortality rates are identified between races and urbanization status.

Cardiogenic shock related cardiovascular disease mortality trends in US population: Heart failure vs. acute myocardial infarction as contributing causes.

BACKGROUND: Observational and trial data have revealed significant improvement in cardiogenic shock (CS) mortality due to acute myocardial infarction (AMI) after introducing early coronary revascularization. Less is known about CS mortality due to heart failure (HF), which is increasingly recognized as a distinct entity from AMI-CS. METHODS AND RESULTS: In this nationwide observational study, the CDC WONDER database was used to identify national trends in age-adjusted mortality rates (AAMR) due to CS (HF vs. AMI related) per 100,000 people aged 35-84. AAMR from AMI-CS decreased significantly from 1999 to 2009 (AAPC: -6.9% [95%CI -7.7, -6.1]) then stabilized from 2009 to 2020. By contrast, HF-CS associated AAMR rose steadily from 2009 to 2020 (AAPC: 13.3% [95%CI 11.4,15.2]). The mortality rate was almost twice as high in males compared to females in both AMI-CS and HF-CS throughout the study period. HF-CS mortality in the non-Hispanic Black population is increasing more quickly than that of the non-Hispanic White population (AAMR in 2020: 4.40 vs. 1.97 in 100,000). The AMI-CS mortality rate has been consistently higher in rural than urban areas (30% higher in 1999 and 28% higher in 2020). CONCLUSIONS: These trends highlight the fact that HF-CS and AMI-CS represent distinct clinical entities. While mortality associated with AMI-CS has primarily declined over the last two decades, the mortality related to HF-CS has increased significantly, particularly over the last decade, and is increasing rapidly among individuals younger than 65. Accordingly, a dramatic change in the demographics of CS patients in modern intensive care units is expected.

Demographic and State-Level Trends in Mortality Due to Ischemic Heart Disease in the United States from 1999 to 2019.

Although there have been advances in ischemic heart disease (IHD) care, variation in IHD-related mortality trends across the United States has not been well described. We used the Centers for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research database to evaluate variation in IHD-related mortality for demographic groups in the United States between 1999 and 2019. Age-adjusted mortality rates (AAMRs) were stratified by gender, race, Hispanic ethnicity, and US state. Crude mortality rates were evaluated using 10-year age groups. IHD-related AAMRs decreased from 195 to 88 per 100,000 nationally, with slower a decrease from 2010 to 2019 (average annual percent change [AAPC] -2.6% [95% confidence interval -2.9% to -2.2%]) compared with 2002 to 2010 (AAPC -5.3% [95% confidence interval -5.6% to -4.9%]). All groups had decreases in AAMRs, although Black populations persistently had the highest AAMR, and women had greater relative decreases than men. AAPC was -3.7% for White men, -4.7% for White women, -3.9% for Black men, -4.9% for Black women, -4.1% for Hispanic men, and -5.1% for Hispanic women. Populations ≥65 years had greater relative mortality decreases than populations <65 years. The median AAMR (2019) and AAPC (1999 to 2019) across states was 86 (range 58 to 134) and -3.8% (range -1.7% to -4.8%), respectively. In conclusion, declines in IHD-related mortality have slowed in the United States, with a significant geographic variation. Black populations persistently had the highest AAMRs, and decreases were relatively greater for women and populations ≥65 years. The impact of demographics and geography on IHD should be further explored and addressed as part of public health measures.

What Is the Response Seen During Para-Hisian Pacing?

We present an interesting tracing of para-Hisian pacing in a 45-year-old man with an episode of narrow complex tachycardia and past recurrent palpitations.

Cardiac Resynchronization and Circulating Markers of Sarcoplasmic Reticulum Calcium Handling and Sudden Death Risk.

Cardiac resynchronization therapy (CRT) can improve heart function and decrease arrhythmic events. We tested whether CRT altered circulating markers of calcium handling and sudden death risk. Circulating cardiac sodium channel messenger RNA (mRNA) splicing variants indicate arrhythmic risk, and a reduction in sarco/endoplasmic reticulum calcium adenosine triphosphatase 2a (SERCA2a) is thought to diminish contractility in heart failure. CRT was associated with a decreased proportion of circulating, nonfunctional sodium channels and improved SERCA2a mRNA expression. Patients without CRT did not have improvement in the biomarkers. These changes might explain the lower arrhythmic risk and improved contractility associated with CRT.

Incidence and Mortality Trends of Atrial Fibrillation/Atrial Flutter in the United States 1990 to 2017.

Atrial fibrillation (AF) and flutter (AFL) are the most common clinically significant arrhythmias in older adults with an increasing disease burden due to an aging population. However, up-to-date trends in disease burden and regional variation remain unknown. In an observational study utilizing the Global Burden of Disease (GBD) database, age-standardized mortality and incidence rates for AF overall and for each state in the United States (US) from 1990 to 2017 were determined. All analyses were stratified by gender. The relative change in age-standardized incidence rate (ASIR) and age-standardized death rate (ASDR) over the observation period were determined. Trends were analyzed using Joinpoint regression analysis. The mean ASIR per 100,000 population for men was 92 (+/-8) and for women was 62 (+/-5) in the US in 2017. The mean ASDR per 100,000 population for men was 5.8 (+/-0.3) and for women was 4.4 (+/-0.4). There were progressive increases in ASIR and ASDR in all but 1 state. The states with the greatest percentage change in incidence were New Hampshire (+13.5%) and Idaho (+16.0%) for men and women, respectively. The greatest change regarding mortality was seen in Mississippi (+26.3%) for men and Oregon (+53.8%) for women. In conclusion these findings provide updated evidence of increasing AF and/or AFL incidence and mortality on a national and regional level in the US, with women experiencing greater increases in incidence and mortality rates. This study demonstrates that the public health burden related to AF in the United States is progressively worsening but disproportionately across states and among women.

Electroanatomic Correlates of Depolarization Abnormalities in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy.

BACKGROUND: Epsilon waves and other depolarization abnormalities in the right precordial leads are thought to represent delayed activation of the right ventricular outflow tract in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). However, no study has directly correlated cardiac electrical activation with the surface ECG findings in ARVD/C. METHODS AND RESULTS: Thirty ARVD/C patients (mean age 32.7 ± 11.2 years, 16 men) underwent endocardial and epicardial electroanatomical activation mapping in sinus rhythm. Twelve-lead ECGs were classified into 5 patterns: (1) normal QRS (11 patients); (2) terminal activation delay (TAD) (3 patients); (3) incomplete right bundle branch block (IRBBB) (5 patients); (4) epsilon wave (5 patients); (5) complete right bundle branch block (CRBBB) (6 patients). Timing of local ventricular activation and extent of scar was then correlated with surface QRS. Earliest endocardial and epicardial RV activation occurred on the mid anteroseptal wall in all patients despite the CRBBB pattern on ECG. Total RV activation times increased from normal QRS to prolonged TAD, IRBBB, epsilon wave, and CRBBB, respectively (103.9 ± 5.6, 116.3 ± 6.5, 117.8 ± 2.7, 146.4 ± 16.3, and 154.3 ± 6.3, respectively, P < 0.05). The total epicardial scar area (cm(2) ) was similar among the different ECG patterns. Median endocardial scar burden was significantly higher in patients with epsilon waves even compared with patients with CRBBB (34.3 vs. 11.3 cm(2) , P < 0.01). Timing of epsilon wave corresponded to activation of the subtricuspid region in all patients. CONCLUSION: We found that epsilon waves are often associated with severe conduction delay and extensive endocardial scarring in addition to epicardial disease. The timing of epsilon waves on surface ECG correlated with electrical activation of the sub-tricuspid region.

2015 update on the diagnosis and management of arrhythmogenic right ventricular cardiomyopathy.

PURPOSE OF REVIEW: This review will discuss the recent advances in the diagnosis and management of arrhythmogenic right ventricular cardiomyopathy (ARVC). RECENT FINDINGS: Since the first detailed clinical description of the disease in 1982, we have learned much about the genetics, pathophysiology, diagnosis, and management of ARVC. We now appreciate that pathogenic mutations in desmosomal genes are the most common genetic finding. Although the right ventricle is mostly affected, left ventricular involvement is being increasingly recognized. Electrical instability precipitating sudden cardiac death often presents before structural abnormalities, and therefore early accurate diagnosis is of utmost importance. The broad spectrum of phenotypic variation, age-related penetrance, and lack of a definitive diagnostic test make the clinical diagnosis challenging. The diagnosis is made by fulfilling the 2010 Task Force criteria. Today, genetic testing and cardiac MRI play an important role in the diagnosis. Implantable cardioverter defibrillator implantation is the only lifesaving therapy available today for a subset of patients. In patients with recurrent ventricular arrhythmias, epicardial catheter ablation has demonstrated improved outcomes compared with endocardial ablation. Exercise restriction may delay the progression of disease. SUMMARY: ARVC is predominantly associated with mutations in desmosomal genes with incomplete penetrance and variable expressivity. Ventricular electrical instability is the hallmark of ARVC, often occurring before structural abnormalities. Goals in the evaluation and management of ARVC are early diagnosis, risk stratification for sudden cardiac death, minimizing ventricular arrhythmias, and delaying the progression of disease.

The association of left atrial low-voltage regions on electroanatomic mapping with low attenuation regions on cardiac computed tomography perfusion imaging in patients with atrial fibrillation.

BACKGROUND: Previous studies have shown that contrast-enhanced multidetector computed tomography (CE-MDCT) could identify ventricular fibrosis after myocardial infarction. However, whether CE-MDCT can characterize atrial low-voltage regions remains unknown. OBJECTIVE: The purpose of this study was to examine the association of CE-MDCT image attenuation with left atrial (LA) low bipolar voltage regions in patients undergoing repeat ablation for atrial fibrillation recurrence. METHODS: We enrolled 20 patients undergoing repeat ablation for atrial fibrillation recurrence. All patients underwent preprocedural 3-dimensional CE-MDCT of the LA, followed by voltage mapping (>100 points) of the LA during the ablation procedure. Epicardial and endocardial contours were manually drawn around LA myocardium on multiplanar CE-MDCT axial images. Segmented 3-dimensional images of the LA myocardium were reconstructed. Electroanatomic map points were retrospectively registered to the corresponding CE-MDCT images. RESULTS: A total of 2028 electroanatomic map points obtained in sinus rhythm from the LA endocardium were registered to the segmented LA wall CE-MDCT images. In a linear mixed model, each unit increase in the local image attenuation ratio was associated with 25.2% increase in log bipolar voltage (P = .046) after adjusting for age, sex, body mass index, and LA volume, as well as clustering of data by patient and LA regions. CONCLUSION: We demonstrate that the image attenuation ratio derived from CE-MDCT is associated with LA bipolar voltage. The potential ability to image fibrosis via CE-MDCT may provide a useful alternative in patients with contraindications to magnetic resonance imaging.

Outcomes and ventricular tachycardia recurrence characteristics after epicardial ablation of ventricular tachycardia in arrhythmogenic right ventricular dysplasia/cardiomyopathy.

BACKGROUND: Variable success rates have been reported after epicardial radiofrequency catheter ablation (RFA) in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). The details of the electroanatomic substrate are limited to a few studies, and the characteristics of the recurrent ventricular tachycardia (VT) in ARVD/C remain largely unknown. OBJECTIVE: The purpose of this study was to report procedural strategy, safety, and efficacy of epicardial RFA at a tertiary single center with a focus on the characteristics of the substrate and recurrent VT. METHODS: We included 30 ARVD/C patients (mean age 33.1 ± 11.1 years, 53% male) who underwent endocardial/epicardial mapping and epicardial catheter ablation of VT at the Johns Hopkins Hospital. Implantable cardioverter-defibrillator interrogations were evaluated for VT recurrence. RESULTS: The majority of critical VT circuits (69%) were on the epicardial surface, mostly in the subtricuspid region. Eight patients (27%) experienced VT recurrence after epicardial RFA, and the VT-free survival was 83%, 76%, and 70% at 6,12, and 24, months respectively. A significant reduction of VT burden was observed (P <.001), even among those with VT recurrence. No complications occurred except for acute pericarditis in 1 patient. The majority of VT recurrences occurred during the first year after RFA, during exercise, had fast cycle lengths, and required implantable cardioverter-defibrillator shock for termination. CONCLUSION: The vast majority of critical VT circuits were epicardial, mostly in the subtricuspid region. Epicardial RFA of VT appears to be both safe and effective in achieving arrhythmia control in ARVD/C. The features of the recurrent VT suggest a possible catecholamine-mediated mechanism with an origin in a region not targeted for ablation.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy and cardiac sarcoidosis: distinguishing features when the diagnosis is unclear.

BACKGROUND: Cardiac sarcoidosis (CS) may show overlap in the clinical presentation with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). We sought to investigate patients with CS who were misdiagnosed with ARVD/C and identify clinical features to distinguish these 2 groups. METHODS AND RESULTS: Among patients enrolled in the Johns Hopkins ARVD/C registry, 15 patients with definite 2010 diagnostic criteria for ARVD/C were subsequently diagnosed with CS. Forty-two pathogenic desmosomal mutation carriers with definite ARVD/C based on the 2010 diagnostic criteria served as a control group. Patients with CS were older at the age of symptom onset, more likely to have comorbidities, and develop heart failure symptoms over time (P<0.05). Electrocardiographically, PR interval prolongation and high-grade atrioventricular block were exclusively associated with CS (P<0.05). HV interval prolongation and increased number of ventricular tachycardias induced were also associated with CS (P<0.05). Radiographically, significant left ventricular dysfunction, myocardial delayed enhancement of the septum, and mediastinal lymphadenopathy were more often see in those with CS (P<0.05). CONCLUSIONS: The 2010 diagnostic criteria for ARVD/C have limited discrimination in distinguishing between ARVD/C and CS. Despite the overlay in clinical presentation, older age of symptom onset, presence of cardiovascular comorbidities, nonfamilial pattern of disease, PR interval prolongation, high-grade atrioventricular block, significant left ventricular dysfunction, myocardial delayed enhancement of the septum, and mediastinal lymphadenopathy should raise the suspicion for CS.

Mutation-positive arrhythmogenic right ventricular dysplasia/cardiomyopathy: the triangle of dysplasia displaced.

INTRODUCTION: The traditional description of the Triangle of Dysplasia in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C) predates genetic testing and excludes biventricular phenotypes. METHODS AND RESULTS: We analyzed Cardiac Magnetic Resonance (CMR) studies of 74 mutation-positive ARVD/C patients for regional abnormalities on a 5-segment RV and 17-segment LV model. The location of electroanatomic endo- and epicardial scar and site of successful VT ablation was recorded in 11 ARVD/C subjects. Among 54/74 (73%) subjects with abnormal CMR, the RV was abnormal in almost all (96%), and 52% had biventricular involvement. Isolated LV abnormalities were uncommon (4%). Dyskinetic basal inferior wall (94%) was the most prevalent RV abnormality, followed by basal anterior wall (87%) dyskinesis. Subepicardial fat infiltration in the posterolateral LV (80%) was the most frequent LV abnormality. Similar to CMR data, voltage maps revealed scar (<0.5 mV) in the RV basal inferior wall (100%), followed by the RV basal anterior wall (64%) and LV posterolateral wall (45%). All 16 RV VTs originated from the basal inferior wall (50%) or basal anterior wall (50%). Of 3 LV VTs, 2 localized to the posterolateral wall. In both modalities, RV apical involvement never occurred in isolation. CONCLUSION: Mutation-positive ARVD/C exhibits a previously unrecognized characteristic pattern of disease involving the basal inferior and anterior RV, and the posterolateral LV. The RV apex is only involved in advanced ARVD/C, typically as a part of global RV involvement. These results displace the RV apex from the Triangle of Dysplasia, and provide insights into the pathophysiology of ARVD/C.

Phrenic nerve injury: An underrecognized and potentially preventable complication of pulmonary vein isolation using a wide-area circumferential ablation approach.

INTRODUCTION: Phrenic nerve injury (PNI) is a well-known, although uncommon, complication of pulmonary vein isolation (PVI) using radiofrequency energy. Currently, there is no consensus about how to avoid or minimize this injury. The purpose of this study was to determine how often the phrenic nerve, as identified using a high-output pacing, lies along the ablation trajectory of a wide-area circumferential lesion set. We also sought to determine if PVI can be achieved without phrenic nerve injury by modifying the ablation lesion set so as to avoid those areas where phrenic nerve capture (PNC) is observed. METHODS AND RESULTS: We prospectively enrolled 100 consecutive patients (age 61.7 ± 9.2 years old, 75 men) who underwent RF PVI using a wide-area circumferential ablation approach. A high-output (20 mA at 2 milliseconds) endocardial pacing protocol was performed around the right pulmonary veins and the carina where a usual ablation lesion set would be made. A total of 30% of patients had PNC and required modification of ablation lines. In the group of patients with PNC, the carina was the most common site of capture (85%) followed by anterior right superior pulmonary vein (RSPV) (70%) and anterior right inferior pulmonary vein (RIPV) (30%). A total of 25% of PNC group had capture in all 3 (RSPV, RIPV, and carina) regions. There was no difference in the clinical characteristics between the groups with and without PNC. RF PVI caused no PNI in either group. CONCLUSION: High output pacing around the right pulmonary veins and the carina reveals that the phrenic nerve lies along a wide-area circumferential ablation trajectory in 30% of patients. Modification of ablation lines to avoid these sites may prevent phrenic nerve injury during RF PVI.

Risk stratification in arrhythmogenic right ventricular dysplasia/cardiomyopathy-associated desmosomal mutation carriers.

BACKGROUND: We investigated the role of phenotypic characteristics in stratifying the risk of sustained ventricular arrhythmias in patients harboring arrhythmogenic right ventricular dysplasia/cardiomyopathy-associated mutations. METHODS AND RESULTS: Clinical, electrocardiographic, and arrhythmic outcome (composite measure of first occurrence of sustained ventricular tachycardia/resuscitated sudden cardiac death/sudden cardiac death/appropriate implantable cardioverter-defibrillator therapy) data were obtained for 215 patients (104 families; 85% PKP-2). During a mean follow-up of 7 years, 86 (40%) patients experienced the arrhythmic outcome. Event-free survival was significantly lower among probands (P<0.001) and symptomatic (P<0.001) patients. Integration of ECG repolarization and depolarization abnormalities allowed for differential risk categorization. Event-free survival at 5 years for the low-risk ECG group (0-1 T inversions or minor depolarization changes) was 97% versus 81% for the intermediate-risk ECG group (2 T inversions+minor depolarization changes) versus 33% for the high-risk ECG group (≥3 T inversions±major or minor depolarization changes; P<0.001). Incremental arrhythmic risk was seen in patients with increasing premature ventricular complex count on a Holter (P<0.001). Proband status (hazard ratio, 7.7; 95% confidence interval, 2.8-22.5; P<0.001), ≥3 T-wave inversions (hazard ratio, 4.2; 95% confidence interval, 1.2-14.5; P=0.035), and male sex (hazard ratio, 1.8; 95% confidence interval, 1.2-2.8; P=0.004) were independent predictors of the first arrhythmic event on multivariable analysis. CONCLUSIONS: Pedigree evaluation, an ECG, and a Holter examination provide for comprehensive arrhythmic risk stratification in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy-associated mutations. We propose an approach to risk stratification based on these variables.

High prevalence of catecholamine-facilitated focal ventricular tachycardia in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy.

BACKGROUND: Exercise-related ventricular tachycardia (VT) and high burden of premature ventricular contractions (PVCs) are common in arrhythmogenic right ventricular dysplasia/cardiomyopathy. We hypothesized that VT in arrhythmogenic right ventricular dysplasia/cardiomyopathy shows a high degree of association with the PVC at baseline. METHODS AND RESULTS: The study population included 16 consecutive arrhythmogenic right ventricular dysplasia/cardiomyopathy patients with recurrent VT who underwent catheter ablation. Median age of the patients was 27 years (range, 18-66) and 50% were men. All patients had frequent ectopy at baseline with a median PVC count of 7275 (range, 1353-19 084). During EP study, a total of 27 VTs were induced, of which 16 (59%) occurred during high-dose isoproterenol infusion. VT morphology was identical to the baseline PVCs in all the VTs induced during high-dose isoproterenol infusion. Focal ablation at the site of earliest activation and 12/12 pace map of the PVC eliminated the VT in all cases. Target site for focal ablation localized to scar border. Cumulative freedom from VT after ablation was 85.2% and 74.5% at 1 and 2 years, respectively, which was associated with a reduction in PVC count. CONCLUSIONS: We report a high degree of association between PVCs at baseline and the VTs induced during catecholamine infusion. These VTs originated from the border region of scar most commonly in the right ventricular outflow tract and right ventricle basal regions. These findings highlight the importance of catecholamine challenge and PVC mapping, which can in turn facilitate ablation of the VT in arrhythmogenic right ventricular dysplasia/cardiomyopathy.

Response to atrial extrastimulus during supraventricular tachycardia: what is the mechanism?

We describe a case illustrating the potential challenges in distinguishing AV nodal reentry tachycardia (AVNRT) from automatic junctional tachycardia (JT). While an early atrial extrastimulus advanced the next His and ventricular depolarization without tachycardia termination, suggesting JT, other features indicated the correct diagnosis of AVNRT. This teaching case demonstrates a novel exception to a recently reported diagnostic pacing maneuver and illustrates the importance of considering response to multiple maneuvers in reaching a diagnosis of SVT mechanism.

Outcomes of catheter ablation of ventricular tachycardia in arrhythmogenic right ventricular dysplasia/cardiomyopathy.

BACKGROUND: Prior studies evaluating the efficacy of catheter ablation of ventricular tachycardia (VT) among patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) have reported varied outcomes. More recently, studies have suggested that an epicardial ablation is necessary for improved outcomes after catheter ablation of VT. The overall objective of the present study was to assess the efficacy of radiofrequency catheter ablation (RFA) of VT in ARVD/C, with particular focus on newer ablation strategies, including epicardial catheter ablation. METHODS AND RESULTS: The study population included 87 patients with ARVD/C who underwent a total of 175 RFA procedures between 1992 and 2011 at 80 different electrophysiology centers. Recurrence of VT following RFA and effect of RFA on the burden of VT were assessed. The mean age of the cohort was 38±13 years. Over a mean follow-up of 88.3±66 months, the overall freedom from VT of the 175 procedures was 47%, 21%, and 15%, at 1, 5, and 10 years, respectively. The cumulative freedom from VT following epicardial RFA was 64% and 45% at 1 and 5 years, respectively, which was significantly longer than endocardial RFA (P=0.021). Survival free of VT among procedures with 3D electroanatomic mapping was significantly longer compared to those without (P=0.016). Burden of VT was reduced irrespective of the ablation strategy (P<0.001). CONCLUSIONS: Although VT recurrences are common, RFA results in a significant reduction in the burden of VT in patients with ARVD/C. Further, although the use of 3D electroanatomic mapping systems and epicardial ablation strategies are associated with longer survival free of VT, recurrence rates remain considerable.