Asirvatham, Samuel J.

AbstractThe discrimination of ventricular tachycardia (VT) versus supraventricular wide complex tachycardia (SWCT) via 12‐lead electrocardiogram (ECG) is crucial for achieving appropriate, high‐quality, and cost‐effective care in patients presenting with wide QRS complex tachycardia (WCT). Decades of rigorous research have brought forth an expanding arsenal of applicable manual algorithm methods for differentiating WCTs. However, these algorithms are limited by their heavy reliance on the ECG interpreter for their proper execution. Herein, we introduce the Mayo Clinic ventricular tachycardia calculator (MC‐VTcalc) as a novel generalizable, accurate, and easy‐to‐use means to estimate VT probability independent of ECG interpreter competency. The MC‐VTcalc, through the use of web‐based and mobile device platforms, only requires the entry of computerized measurements (i.e., QRS duration, QRS axis, and T‐wave axis) that are routinely displayed on standard 12‐lead ECG recordings.

BACKGROUND: The outcomes of catheter ablation for atrial fibrillation in adults with congenital heart disease are not well described. METHODS: In a retrospective study of adult patients with congenital heart disease who underwent catheter ablation for atrial fibrillation between 2000 and 2020 at Mayo Clinic, procedural characteristics and outcomes were collected. The primary outcomes were atrial arrhythmia (AA) recurrence following a 3-month blanking period and repeat ablation. An arrhythmia clinical severity score was assessed pre- and post-ablation based on the duration of arrhythmia episodes, symptoms, cardioversion frequency, and antiarrhythmic drug use. RESULTS: One hundred forty-five patients (age, 57±12 years; 28% female; 63% paroxysmal atrial fibrillation) underwent 198 ablations with a median follow-up of 26 months (interquartile range, 14–69). One hundred ten, 26, and 9 patients had simple, moderate, and complex congenital heart disease, respectively. All patients underwent pulmonary vein isolation, and non–pulmonary vein targets were ablated in 79 (54%). AA recurrence at 12 months was 37% (95% CI, 29%–45%). On univariate analysis, increasing left atrial volume index was associated with higher odds of AA recurrence (odds ratio, 1.03 [1.00–1.06] per 1 mL/m 2 increment; P =0.05). Noninducibility of atrial flutter was predictive of decreased odds of AA recurrence (odds ratio, 0.43 [0.21–0.90]; P =0.03). A second ablation was performed in 43 patients after a median of 20 (interquartile range, 8–37) months. Arrhythmia clinical severity scores improved following ablation, reflecting a decrease in symptoms, cardioversions, and antiarrhythmic drugs. CONCLUSIONS: Catheter ablation of atrial fibrillation is feasible and effective in patients with adult congenital heart disease and reduces symptoms. Recurrence of AA frequently requires repeat ablation.

AbstractOutflow tract ventricular arrhythmias are the most common type of idiopathic ventricular arrhythmia. A systematic understanding of the outflow tract anatomy improves procedural efficacy and enables electrophysiologists to anticipate and prevent complications. This review emphasizes the three‐dimensional spatial relationships between the ventricular outflow tracts using seven anatomical principles. In turn, each principle is elaborated on from a clinical perspective relevant for the practicing electrophysiologist. The developmental anatomy of the outflow tracts is also discussed and reinforced with a clinical case.

Background: Long-term outcomes of lead management strategies of lead abandonment (LA) or transvenous lead extraction (TLE) during cardiac implantable electronic devices (CIED) procedures requiring lead addition or replacement remain unclear. Hypothesis: We hypothesized that there is no difference in long-term (10-year) outcomes of LA versus TLE during CIED procedures requiring lead addition. Methods: We performed a retrospective cohort study of a population residing in seven adjacent counties of southeastern Minnesota with follow-up at the Mayo Clinic and its health systems. Patients who underwent LA or TLE for sterile leads from January 1, 2000, to January 1, 2011, and had follow-up for at least 10-years or until their death were included. Outcomes were identified through a detailed chart review of the electronic health record from within the Mayo Clinic system. Results: A total of 172 patients were included in the study with 153 patients who underwent LA and 19 who underwent TLE for sterile leads. In long-term follow-up, indications for subsequent lead extraction arose in 9.1% (n=14) of patients with initial LA and 5.3% (n=1) in patients with initial TLE, after an average of 7-years. Moreover, out of 14 patients, who required secondary extraction in the LA cohort, 28.6% did not proceed with the extraction. Of the remaining 10 patients, 60% had clinical success and 40% had a clinical failure with the extraction. Subsequent device upgrades or revisions were performed in 18.3% of patients in the LA group and 31.6% in the TLE group, with no significant differences in procedural challenges such as requiring balloon venoplasty or serial dilation (5.2% vs. 5.3%, P=1.0). There was no difference in 10-year survival probability among LA group and TLE group (P=0.64). Conclusion: Indications for subsequent extraction arose in 9.1% of patients with the initial LA approach for sterile leads after an average of 7.3 years and 28.6% did not proceed with the extraction. Of the patients who underwent the subsequent extraction, 60% had clinical success and 40% had a clinical failure. There was no difference in 10-year survival probability between patients with the initial LA approach or TLE approach.

Background: Patients with ccTGA have a high incidence of atrial arrhythmias and premature failure of the systemic right ventricle. We sought to better define this risk. Methods: A retrospective review of all clinical data for patients with ccTGA followed at a large tertiary care institution was performed. The primary outcome was a composite of death and cardiac transplantation. Results: A cohort of 165 patients (age 41±16 years, 53% male) were followed for 11±8 years; 41 patients died, 7 underwent cardiac transplantation, and 4 underwent VAD placement. Male sex (HR 2.7, p=0.002), older age (HR 1.04, p<0.001), clinical heart failure symptoms (HR 7, p<0.001), heart failure hospitalization (HR 4.9, p<0.001), syncope (HR 1.8, p=0.04) and pulmonary hypertension (HR 2.77, p<0.001) were significant predictors of the primary outcome. Atrial fibrillation (HR 3.5, p=0.002), atrial flutter (HR 3.05, p=0.04), and prolonged QRS duration (HR 1.01, p=0.004) on the first ECG, as well as right and left atrial enlargement (HR 4, p<0.001 and 3.7, p<0.003) and severe systemic AV valve regurgitation (HR 3.8, p=0.03) on the first echocardiogram were associated with poor outcomes. Atrial arrhythmias occurred in 110(67%) patients: atrial fibrillation in 75(45%), atrial flutter in 50(30%), and supraventricular tachycardia in 16(9.7%) patients. Arrhythmias were largely asymptomatic in 109(66%) patients, while 25(14.5%) experienced palpitations, dizziness or presyncope, and 10(6%) presented with decompensated heart failure. Cardioversion and antiarrhythmic therapy were utilized in 53(32%) patients. Surgical pulmonary vein isolation or atrial MAZE were performed in 15(9%) patients, cryoablation of the CTI in 3 patients, and surgical ablation of an accessory pathway in 2 patients. One or more catheter ablation procedures were also performed in 18(11%) patients. Conclusions: Atrial fibrillation and flutter, heart failure, prolonged QRS duration, systemic AV valve regurgitation and pulmonary hypertension predict worse outcomes in ccTGA. Although asymptomatic in a majority of patients, atrial arrhythmias are associated with significant morbidity and mortality. Whether a rhythm control strategy even in asymptomatic patients may improve outcomes remains unknown.

BACKGROUND: Differentiation of wide QRS complex tachycardias (WCTs) into ventricular tachycardia (VT) and supraventricular wide QRS tachycardia (SWCT) through 12-lead electrocardiogram (ECG) interpretation is one of the most critical yet challenging tasks in clinical practice. Recent research highlights novel automated methods that successfully diagnose WCTs. We sought to directly compare the diagnostic efficacy of these novel automated WCT differentiation methods (i.e., WCT Formula, VT Prediction Model, and WCT Formula II) to traditional ECG interpretation approaches (i.e., Brugada and Vereckei aVR algorithms). METHODS: A collection of paired WCT and baselined ECGs were retrospectively analyzed. Next, an electrophysiologist blindly and prospectively applied the Brugada and Vereckei aVR algorithms. Separately, computerized measurements were used to apply the three automated WCT differentiation methods. The diagnostic performance of each method was then evaluated. RESULTS: 213 WCTs (111 VT and 102 SWCT) from 105 patients were analyzed. The WCT Formula demonstrated superior overall accuracy (84.7% vs. 64.8%), specificity (86.2% vs. 35.3%), positive predictive value (PPV) (85.7% vs. 60.7%), and positive (+) likelihood ratio (LR) (6.06 vs. 1.42) compared to Vereckei aVR algorithm. Similarly, the WCT Formula attained higher specificity (86.2% vs. 61.8%), PPV (85.7% vs. 71.9%), and (+) LR (6.06 vs. 2.36) than the Brugada algorithm. The WCT Formula II demonstrated superior overall accuracy (89.2% vs. 64.8%), specificity (84.3 % vs. 35.3%), PPV (86.7% vs. 60.7%), and positive (+) LR (5.97 vs.1.42) compared to Vereckei aVR algorithm as well as higher specificity (84.3 % vs. 61.8 %), PPV (86.7% vs. 71.9%), and (+) LR (5.97 vs. 2.36) than the Brugada algorithm. The VT prediction model yielded superior specificity (79.4% vs. 35.3%), PPV (79.8 vs. 60.7%) and (+) LR (3.63 vs.1.42) compared to the Vereckei aVR algorithm but did not demonstrate superior diagnostic performance to the Brugada algorithm. CONCLUSIONS: Novel automated WCT differentiation methods achieved similar or superior diagnostic performance metrics compared to traditional ECG interpretation approaches.

Introduction: Ebstein’s anomaly (EA) is a rare congenital anomaly of the tricuspid valve associated with heart failure and arrhythmias. Currently available imaging modalities like transthoracic echocardiography, cardiac magnetic resonance imaging (MRI), or computerized tomography (CT) are not viable for screening large asymptomatic populations. Hypothesis: A deep learning algorithm, implemented using a convolutional neural network (CNN) applied to the standard 12-lead ECG can be used as an accurate screening tool for EA in children and adults. Method: We identified 1,154 EA patients and 21,430 age- and sex-matched controls (1:20 ratio) between 1987 - 2020. A CNN was trained, validated and tested using digital 12-lead ECGs in 70%, 10% and 20% of the cohort respectively, divided by random shuffling. Results: The mean age was 26.68±19.23 years (41.8% aged < 18 years, 56.41% female) for the EA cohort and 28.36±18.65 years (37.2% aged <18 years, 55.67% female) for the control cohort. Following training and validation the area under the curve (AUC) for detecting EA in the testing cohort was 0.976 (95% CI 0.962 - 0.989) with prediction accuracy of 0.959. In subgroup analysis, the AUC was comparable in males (0.970, 95% CI 0.946-0.995) and females (0.979, 95% CI 0.964-0.994), those <18 (0.980, 95% CI 0.958-1.000) and ≥18 years old (0.972, 95% CI 0.954-0.989), as well as in those with right bundle branch block (RBBB) (0.969, 95% CI 0.950-0.989) and without RBBB (0.950, 95% CI 0.922-0.978) on ECG. Conclusion: Artificial intelligence enhanced ECG based detection of EA is possible with high diagnostic accuracy. Following further refinement and external validation, this algorithm can facilitate early detection of EA using ECGs, a widely available and inexpensive tool. Figure: Receiver operating characteristic (ROC) curve for the performance of the artificial intelligence CNN in detecting EA in the test cohort stratified by (A) age (< 18 and ≥ 18 years) and sex and (B) presence of RBBB.

Background: Recognition of the causes of early mortality after atrial fibrillation (AF) catheter ablation is essential for the improvement of patient safety. Objective: This study sought to determine the causes of early mortality (≤90-days) after AF ablation and to further understand the circumstances surrounding death after the procedure. Methods: We performed a retrospective analysis of AF ablation from January 1, 2013, to December 1, 2021 at the Mayo Clinic (Rochester, Phoenix, and Jacksonville). Causes of death were identified through a comprehensive chart review of the electronic health record from within the Mayo Clinic system and outside records when available. Results: A total of 6,723 patients were included in the study. The 30-day and 90-day all-cause mortality rates were 0.09% and 0.22%, respectively. Among all 90-day deaths, majority of the deaths (73.3%) did not have a direct relationship with the procedure. Sudden death was the most common cause of early death (20%), followed by peri-procedural stroke (13%), respiratory failure (13%), atrioesophageal fistula (13%), infection (7%), heart failure (7%), and traumatic brain injury (7%). The 90-day mortality rate directly due to AF ablation procedural complications was 0.06%. Most of the early deaths (93.3%) occurred after discharge from index hospitalization, among which 64.3% were readmitted before their death, 14% died at home, and 7% were discharged on comfort care and died in hospice. The main reason for readmission leading to death was respiratory failure (33%). Conclusion: Atrial fibrillation ablation procedure has a 90-day mortality of 0.22% and the most common cause of early mortality was sudden death. The majority (73.3%) of early mortality was not directly associated with a procedural complication, and the mortality rate due to complications associated with the AF ablation procedure was 0.06%.

Background: Recognition of the causes of early mortality after ventricular tachycardia (VT) ablation in patients with reduced left ventricular ejection fraction is an essential step toward improving post-procedural outcomes. Objective: This study sought to determine the causes of early mortality (≤30-days) after VT ablation in patients with reduced left ventricular ejection fraction and to understand further the circumstances surrounding death after the procedure. Methods: We performed a retrospective analysis of all patients undergoing VT ablation in patients with reduced left ventricular ejection fraction from January 1, 2013, to November 10, 2021, at the Mayo Clinic (Rochester, Phoenix, and Jacksonville). Causes of death were identified through a detailed chart review of the electronic health record within the Mayo Clinic system and outside records. Results: A total of 503 patients (mean age 63 ± 13 years, 11.2% female) with EF <50% were included in the study. The 30-day all-cause mortality rate was 5% (n=25), and the mortality rate due to a procedural complication was 0.4%. Among all 30-day deaths, recurrent VT was the most common primary cause of death (44%). This was followed by decompensated heart failure (28%), procedure-related death (8%), cerebrovascular accident (CVA) (4%), and infection (4%). Most patients (91%) who died from VT had the VT recurrence within three days of the ablation. 76% of patients with early mortality had delayed referral for VT ablation, and 72% opted for comfort care before death. Conclusions: The overall early mortality (≤30-days) rate after catheter ablation of VT in patients with reduced left ventricular ejection fraction was 5%, but the death rate directly due to a procedural complication was only 0.4%. The most common cause of death was recurrent VT, followed by heart failure. Further research into ablation strategies is vital to improving the safety, efficacy, and durability of VT ablation.

Background: Recognition of the infectious characteristics among the sepsis-related early mortality after transvenous lead removal (TLR) is an essential step to improving patient outcomes. Objective: This study sought to understand the infectious characteristic and circumstances among the sepsis-related early mortality after TLR. Methods: We performed a retrospective analysis of all patients undergoing TLR from January 1, 2001, to January 1, 2021 at the Mayo Clinic (Rochester, Phoenix, and Jacksonville). Patient details were identified through a detailed chart review of the electronic health record from within the Mayo Clinic system and outside records when available. Results: A total of 2,319 patients were included in the study. The overall 30-day sepsis-related mortality rate was 1.25% (n=29). Among the sepsis-related deaths, 24 patients (83%) had systemic cardiac implantable electronic device (CIED) infection, and 4 patients (14%) initially had isolated pocket infection. The average time from admission to TLR was 11 days. MSSA was the most common organism (n=8, 28%), and this was followed by MRSA (n=4, 14%) and Candida (n=3, 10%). Twenty of these patients (69%) had vegetation on the echocardiogram: vegetation on lead only in 9 patients, vegetation on both valve and lead in 8 patients, and vegetation on valve only in 3 patients. Among valvular vegetations, 5 patients had tricuspid valve vegetations, 3 patients had aortic valve vegetations, 2 patients had mitral valve vegetations, and 1 patient had both mitral and aortic valve vegetation. The average size of vegetation was 1.3±0.8 x 1.1±0.6 cm. Conclusions: The 30-day sepsis-related mortality rate was 1.25%. Among the sepsis-related early deaths, MSSA was the most common organism, and more than two-thirds (69%) of the patients had vegetations on cardiac imaging. This highlights the importance of further research to improve the infection outcome in TLR patients.