Dry suction water seal system for management of pericardial fluid during epicardial ablation.

INTRODUCTION: Epicardial ablation is an important approach in the management of patients with complex ventricular arrhythmias. Irrigated ablation catheters present a challenge in this potential space due to fluid accumulation that can cause hemodynamic compromise, requiring frequent manual fluid aspiration. In this series, we report our initial experience with the use of a dry suction water seal system for pericardial fluid management during epicardial ablation. METHODS: Consecutive patients undergoing epicardial ventricular tachycardia (VT) ablation at a single center were included. All patients underwent epicardial access via a subxiphoid approach with a single operator. A deflectable sheath was advanced into the pericardial space, and the side port was attached to a dry suction water seal system attached to wall suction at -20 mmHg. Procedural information including patient characteristics, outcomes, and adverse events. After a period of initial experience, pericardial fluid infusion and aspiration volumes were recorded. RESULTS: Eleven patients were included in this series. All patients underwent epicardial ablation with complete success achieved in 8 of the 11 patients and partial success in the remaining patients. Pericardial fluid intake ranging from 485 to 3050 mL with aspiration of 350-3050 mL using the dry suction water seal system. No adverse events occurred. CONCLUSION: Dry suction water seal drainage systems can provide a safe strategy for efficient pericardial fluid management during epicardial VT ablation, potentially shortening procedure duration.

Outcomes of transvenous lead extraction using the TightRail™ mechanical rotating dilator sheath and excimer laser sheath.

BACKGROUND: Transvenous lead extraction (TLE) is an important part of comprehensive lead management. The selection of tools available has expanded in recent years but data on their efficacy is limited. OBJECTIVE: To evaluate outcomes using the TightRail™ mechanical rotating mechanical dilator sheath in comparison to excimer laser sheaths and describe factors predictive of successful extraction. METHODS: Patients undergoing TLE at a single tertiary center (2013-2019) were included in a prospective registry. Leads targeted for extraction with either an SLS II/Glidelight™ or TightRail™ sheath were included. Outcomes were analyzed on a per-lead basis. Generalized estimating equation (GEE) models were used to assess differences in lead extraction success by extraction tool used while adjusting for nonindependence of multiple leads extracted from the same patient. Covariates included patient comorbidities, lead characteristics, and sheath size. RESULTS: A total of 575 leads extracted from 372 patients were included. Overall success rate was 97%. TightRail™ was the first tool used in 180 (31.3%) leads with success rate of 61.7%; laser sheaths were the first tool in 395 leads (68.7%) with success rate of 67.8%. Predictors of successful extraction included lead age, lead type, and sheath sizing. Extraction success did not differ based on whether a laser or TightRail™ sheath was used (adjusted odds ratio = 0.94; 95% confidence interval = 0.59-1.50). CONCLUSION: The TightRail™ sheath is an effective tool for TLE. Lead age, lead type, and sheath sizing were predictive of successful extraction but sheath type was not. These findings are hypothesis generating and warrant further investigation in a prospective, randomized study.

Ventricular Arrhythmias in Cardiac Sarcoidosis.

The diagnosis of cardiac sarcoidosis (CS), especially in cases where there is limited or no extracardiac involvement, is challenging. Patients with CS are at increased risk of ventricular arrhythmias and sudden cardiac death. Several techniques for risk stratification for sudden cardiac death have been proposed in this population, including advanced cardiac imaging and electrophysiology study. Clinical ventricular arrhythmias in patients with CS may be treated with immunosuppressant therapy, antiarrhythmic drugs, catheter ablation, or implantable cardioverter-defibrillator placement. This article will provide an update on techniques for diagnosing CS, risk stratifying patients with CS for sudden cardiac death, and treating patients with CS with ventricular arrhythmias, focusing on evidence that has become available since publication of the 2014 Heart Rhythm Society Expert Consensus Statement on the Diagnosis and Management of Arrhythmias Associated With Cardiac Sarcoidosis.

Current management and clinical outcomes for catheter ablation of atrioventricular nodal re-entrant tachycardia.

Aims: Historical studies of ablation of atrioventricular nodal re-entrant tachycardia (AVNRT) have shown high long-term success rates and low complication rates. The potential impact of several recent practice trends has not been described. This study aims to characterize recent clinical practice trends in AVNRT ablation and their associated success rates and complications. Methods and results: Patients undergoing initial ablation of AVNRT between 1 July 2005 and 30 June 2015 were included in this study. Patient demographics and procedural data were abstracted from procedure reports. Follow-up data, including AVNRT recurrence and complications, was evaluated through electronic medical record review. In total, 877 patients underwent catheter ablation for AVNRT. By the last recorded year, three-dimension (3D) electroanatomical mapping (EAM) was used in 36.2%, 43.2% included anaesthesia, and 23.1% utilized irrigated catheters. Long-term procedural success was 95.5%. The use of anaesthesia, 3D EAM, and irrigated ablation catheters were not associated with differences in success. The presence of an atrial 'echo' or 'AH' jump at the end of an acutely successful procedure was not associated with long-term recurrence (P = 0.18, P = 0.15, respectively). Complications, including AV block requiring a pacemaker (0.4%), were uncommon. Conclusion: In a large, contemporary cohort, catheter ablation for AVNRT remains highly successful with low complications rates. The increased use of anaesthesia as well as modern mapping and ablation tools were not associated with changes in clinical outcomes. Further prospective evaluation of such contemporary practices is warranted given the lack of evidence to support their escalating use.

Correlation of right ventricular multielectrode endocardial unipolar mapping and epicardial scar.

AIMS: Prior studies identified a relationship between epicardial bipolar and endocardial unipolar voltage. Whether the relationship is valid with smaller multielectrode mapping catheters has not been reported. We explored the association of right ventricular (RV) endocardial unipolar voltage mapping with epicardial bipolar voltage mapping using a multielectrode mapping catheter. METHODS: Electrograms from patients who underwent multielectrode endocardial and epicardial RV electroanatomical mapping during ablation procedures were analyzed. Each endocardial mapping point was matched to the corresponding nearest epicardial point. The correlation between unipolar endocardial voltage and epicardial bipolar voltage was determined. The optimal unipolar threshold to detect epicardial low voltage (< 1.0 mV) and dense scar (0.5 mV) was calculated. RESULTS: A total of 4,895 points were analyzed. There was a significant correlation between endocardial unipolar and epicardial bipolar voltage (Spearman rho  =  0.499, P  =  < 0.001). The extent of the correlation was inversely associated with wall thickness. The receiver operator characteristic analysis of endocardial unipolar voltage predicting epicardial bipolar voltage of < 1.0 mV and < 0.5 showed an area under the curve of 0.769 and 0.812, respectively. The endocardial unipolar voltage that had the highest sensitivity and specificity in detecting epicardial bipolar voltage of < 1.0 mV and < 0.5 mV was 3.3 mV (70.3% sensitivity, 70.3% specificity), and 2.8 mV (sensitivity 73.8%, specificity 73.3%), respectively. CONCLUSION: Epicardial low voltage of the RV can be assessed by unipolar endocardial voltage using small multielectrode catheters. The strength of the association was inversely correlated with the wall thickness.

Initial validation of a novel ECGI system for localization of premature ventricular contractions and ventricular tachycardia in structurally normal and abnormal hearts.

BACKGROUND: View into Ventricular Onset (VIVO) is a novel ECGI system that uses 3D body surface imaging, myocardial CT/MRI, and 12­lead ECG to localize earliest ventricular activation through analysis of simulated and clinical vector cardiograms. OBJECTIVE: To evaluate the accuracy of VIVO for the localization of ventricular arrhythmias (VA). METHODS: In twenty patients presenting for catheter ablation of VT [8] or PVC [12], VIVO was used to predict the site earliest activation using 12­lead ECG of the VA. Results were compared to invasive electroanatomic mapping (EAM). RESULTS: A total of 22 PVC/VT morphologies were analyzed using VIVO. VIVO accurately predicted the location of the VA in 11/13 PVC cases and 8/9 VT cases. VIVO correctly predicted right vs left ventricular foci in 20/22 cases. CONCLUSION: View into Ventricular Onset (VIVO) can accurately predict earliest activation of VA, which could aid in catheter ablation, and should be studied further.

Anterior pericardial access to facilitate electrophysiology study and catheter ablation of ventricular arrhythmias: A single tertiary center experience.

INTRODUCTION: Epicardial ablation is becoming an important part of management in patients with ventricular tachycardia (VT). Posterior epicardial access via the Sosa or needle-in-needle (NIN) approach for epicardial VT ablation is considered to be the method of choice for most electrophysiologists. Anterior epicardial access as an alternative technique has recently been proposed, but there are limited data about its safety, efficacy, and the rate of immediate complications. In this study, we report our experience with anterior epicardial access between 2009 and 2016. METHODS: Between 2009 and June 2016, 100 consecutive patients underwent epicardial VT ablation using an anterior approach. The success rate, epicardial bleeding, and other complications related to the epicardial access in these patients were compared to the previously reported rate of complications in patients whom epicardial access was performed using the NIN or Sosa techniques. RESULTS: Anterior epicardial access was obtained successfully in 100% of patients in the first attempt. The success rate of the anterior approach was comparable with the reported success rate of the NIN technique (100% vs. 100%, P value not significant) but better than the Sosa technique (100% vs. 94%, P = 0.012). None of the patients in the anterior approach series suffered from significant pericardial bleeding (defined as greater than 80 mL of blood loss), RV puncture/damage, or need for an emergent cardiac surgery. CONCLUSION: An anterior epicardial approach is feasible and appears to have an acceptable safety profile in comparison with other epicardial approaches.

Outcomes of an expedited same-day discharge protocol following cardiac implantable electronic device (CIED) implantation.

BACKGROUND: With increasing constraints on healthcare resources, greater attention is being focused on improved resource utilization. Prior studies have demonstrated safety of same-day discharge following CIED implantation but are limited by vague protocols with long observation periods. In this study, we evaluate the safety of an expedited 2 hour same-day discharge protocol following CIED implantation. METHODS: Patients undergoing CIED implantation at three centers between 2015 and 2021 were included. Procedural, demographic, and adverse event data were abstracted from the electronic health record. Patients were divided into same-day discharge (SDD) and delayed discharge (DD) cohorts. The primary outcome was complications including lead malfunction requiring revision, pneumothorax, hemothorax, lead dislodgement, lead perforation with tamponade, and mortality within 30 days of procedure. Outcomes were compared between the two cohorts using the χ2 test. RESULTS: A total of 4543 CIED implantation procedures were included with 1557 patients (34%) in the SDD cohort. SDD patients were comparatively younger, were more likely to be male, and had fewer comorbidities than DD patients. Among SDD patients, the mean time to post-operative chest X-ray was 2.6 h. SDD had lower rates of complications (1.3% vs 2.1%, p = 0.0487) and acute care utilization post-discharge (9.6% vs 14.0%, p < 0.0001). There was no difference in the 90-day infection rate between the cohorts. CONCLUSIONS: An expedited 2 hour same-day discharge protocol is safe and effective with low rates of complications, infection, and post-operative acute care utilization.

Outcomes of a Remote Cardiac Rehabilitation Program for Patients Undergoing Atrial Fibrillation Ablation: Pilot Study.

BACKGROUND: Risk factor modification, in particular exercise and weight loss, has been shown to improve outcomes for patients with atrial fibrillation (AF). However, access to structured supporting programs is limited. Barriers include the distance from appropriate facilities, insurance coverage, work or home responsibilities, and transportation. Digital health technology offers an opportunity to address this gap and offer scalable interventions for risk factor modification. OBJECTIVE: This study aims to assess the feasibility and effectiveness of a 12-week asynchronous remotely supervised exercise and patient education program, modeled on cardiac rehabilitation programs, in patients with AF. METHODS: A total of 12 patients undergoing catheter ablation of AF were enrolled in this pilot study. Participants met with an exercise physiologist for a supervised exercise session to generate a personalized exercise plan to be implemented over the subsequent 12-week program. Disease-specific education was also provided as well as instruction in areas such as blood pressure and weight measurement. A digital health toolkit for self-tracking was provided to facilitate monitoring of exercise time, blood pressure, weight, and cardiac rhythm. The exercise physiologist remotely monitored participants and completed weekly check-ins to titrate exercise targets and provide further education. The primary end point was program completion. Secondary end points included change in self-tracking adherence, weight, 6-minute walk test (6MWT), waist circumference, AF symptom score, and program satisfaction. RESULTS: The median participant age was 67.5 years, with a mean BMI of 33.8 kg/m2 and CHADs2VASC (Congestive Heart Failure, Hypertension, Age [≥75 years], Diabetes, Stroke/Transient Ischemic Attack, Vascular Disease, Age [65-74 years], Sex [Female]) of 1.5. A total of 11/12 (92%) participants completed the program, with 94% of expected check-ins completed and 2.9 exercise sessions per week. Adherence to electrocardiogram and blood pressure tracking was fair at 81% and 47%, respectively. Significant reductions in weight, waist circumference, and BMI were observed with improvements in 6MWT and AF symptom scores (P<.05) at the completion of the program. For program management, a mean of 2 hours per week or 0.5 hours per patient per week was required, inclusive of time for follow-up and intake visits. Participants rated the program highly (>8 on a 10-point Likert scale) in terms of the impact on health and wellness, educational value, and sustainability of the personal exercise program. CONCLUSIONS: An asynchronous remotely supervised exercise program augmented with AF-specific educational components for patients with AF was feasible and well received in this pilot study. While improvements in patient metrics like BMI and 6MWT are encouraging, they should be viewed as hypothesis generating. Based on insights gained, future program iterations will include particular attention to improved technology for data aggregation, adjustment of self-monitoring targets based on observed adherence, and protocol-driven exercise titration. The study design will need to incorporate strategies to facilitate the recruitment of a diverse and representative participant cohort.

Juvenile Heat Tolerance in Wheat for Attaining Higher Grain Yield by Shifting to Early Sowing in October in South Asia.

Farmers in northwestern and central India have been exploring to sow their wheat much earlier (October) than normal (November) to sustain productivity by escaping terminal heat stress and to utilize the available soil moisture after the harvesting of rice crop. However, current popular varieties are poorly adapted to early sowing due to the exposure of juvenile plants to the warmer temperatures in the month of October and early November. Therefore, a study was undertaken to identify wheat genotypes suited to October sowing under warmer temperatures in India. A diverse collection of 3322 bread wheat varieties and elite lines was prepared in CIMMYT, Mexico, and planted in the 3rd week of October during the crop season 2012-2013 in six locations (Ludhiana, Karnal, New Delhi, Indore, Pune and Dharwad) spread over northwestern plains zone (NWPZ) and central and Peninsular zone (CZ and PZ; designated as CPZ) of India. Agronomic traits data from the seedling stage to maturity were recorded. Results indicated substantial diversity for yield and yield-associated traits, with some lines showing indications of higher yields under October sowing. Based on agronomic performance and disease resistance, the top 48 lines (and two local checks) were identified and planted in the next crop season (2013-2014) in a replicated trial in all six locations under October sowing (third week). High yielding lines that could tolerate higher temperature in October sowing were identified for both zones; however, performance for grain yield was more promising in the NWPZ. Hence, a new trial of 30 lines was planted only in NWPZ under October sowing. Lines showing significantly superior yield over the best check and the most popular cultivars in the zone were identified. The study suggested that agronomically superior wheat varieties with early heat tolerance can be obtained that can provide yield up to 8 t/ha by planting in the third to fourth week of October.

Medical student engagement and leadership within a new learning community.

BACKGROUND: Many medical schools are establishing learning communities to foster cohesion among students and to strengthen relationships between students and faculty members. Emerging learning communities require nurturing and attention; this represents an opportunity wherein medical students can become involved as leaders. This study sought to understand issues related to active involvement among students who chose to become highly engaged in a newly developed learning community. METHODS: Between April and June 2008, 36 students who assumed leadership roles within the Colleges Program were queried electronically with open-ended questions about their engagement. Qualitative analysis of the written responses was independently performed by two investigators; coding was compared for agreement. Content analysis identified major themes. RESULTS: 35 students (97%) completed the questionnaire. Motives that emerged as reasons for getting involved included: endorsing the need for the program; excitement with the start-up; wanting to give back; commitment to institutional excellence; and collaboration with talented peers and faculty. Perceived benefits were grouped under the following domains: connecting with others; mentoring; learning new skills; and recognition. The most frequently identified drawbacks were the time commitment and the opportunity costs. Ideas for drawing medical students into new endeavors included: creating defined roles; offering a breadth of opportunities; empowering students with responsibility; and making them feel valued. CONCLUSIONS: Medical students were drawn to and took on leadership roles in a medical school curricular innovation. This example may prove helpful to others hoping to engage students as leaders in learning communities at their schools or those wishing to augment student involvement in other programs.

Utility of Cardiac Magnetic Resonance Imaging Versus Cardiac Positron Emission Tomography for Risk Stratification for Ventricular Arrhythmias in Patients With Cardiac Sarcoidosis.

Abnormalities on cardiac magnetic resonance imaging (CMR) and positron emission tomography (PET) predict ventricular arrhythmias (VA) in patients with cardiac sarcoidosis (CS). Little is known whether concurrent abnormalities on CMR and PET increases the risk of developing VA. Our aim was to compare the additive utility of CMR and PET in predicting VA in patients with CS. We included all patients treated at our institution from 2000 to 2018 who (1) had probable or definite CS and (2) had undergone both CMR and PET. The primary endpoint was VA at follow up, which was defined as sustained ventricular tachycardia, sudden cardiac death, or any appropriate device tachytherapy. Fifty patients were included, 88% of whom had a left ventricular ejection fraction >35%. During a mean follow-up 4.1 years, 7/50 (14%) patients had VA. The negative predictive value of LGE for VA was 100% and the negative predictive value of FDG for VA was 79%. Among groups, VA occurred in 4/21 (19%) subjects in the LGE+/FDG+ group, 3/14 (21%) in the LGE+/FDG- group, and 0/15 (0%) in the FDG+/LGE- group. There were no LGE-/FDG- patients. In conclusion, CMR may be the preferred initial clinical risk stratification tool in patients with CS. FDG uptake without LGE on initial imaging may not add additional prognostic information regarding VA risk.

Effect of sling application on efficacy of phototherapy in healthy term neonates with nonhemolytic jaundice: a randomized conrolled trial.

OBJECTIVE: To evaluate the efficacy of white reflecting material (slings) hung from the sides of compact fluorescent lamp (CFL) phototherapy equipment in reducing the duration of phototherapy in healthy term neonates with non-hemolytic jaundice. DESIGN: Randomized controlled trial. SETTING: Postnatal ward of a tertiary level neonatal unit. PARTICIPANTS AND INTERVENTION: Healthy term neonates with non-hemolytic jaundice between 24 hours and 10 days of age were randomly assigned to receive single surface phototherapy with (n=42) or without slings (n=42). OUTCOME MEASURE: Duration of phototherapy in hours (h) and the requirement of exchange transfusion. RESULTS: Birthweight (2790+/-352 vs. 2923+/-330 g), gestation (38+/-1.3 vs. 37+/-1.0 wk) and initial serum total bilirubin (STB) (16.6+/-2.4 vs. 16.1+/-2.2 mg/dL) were comparable between the two groups. There was no significant difference in the duration of phototherapy (mean+/-SD) between the Sling (23.3+/-12.9 h) and No sling (24.9+/-15.4 h) groups (P=0.6). The irradiance of photo-therapy equipment (microwatt/cm2, mean+/-SD) was higher in Sling group compared to No sling group (195.8+/-24.2 versus 179.7+/-27.7, P=0.01). There was a trend towards a higher rate of fall of serum total bilirubin (mg/dL, mean +/-SD) in the Sling group (0.23+/-0.49) compared to No sling group (0.03+/-0.47) (P=0.06). CONCLUSION: Though hanging of white reflective sling on sides of CFL phototherapy equipment resulted in marginal increase in irradiance, it did not decrease the duration of phototherapy.

Electrophysiology study for risk stratification in patients with cardiac sarcoidosis and abnormal cardiac imaging.

BACKGROUND: Abnormalities on cardiac imaging (cardiac magnetic resonance imaging [CMR] or positron emission tomography [PET]), left ventricular ejection fraction (LVEF), and electrophysiology study (EPS) all predict ventricular arrhythmias (VA) in patients with cardiac sarcoidosis (CS). We sought to assess the utility of EPS in patients with CS and abnormal cardiac imaging, focusing on those with LVEF >35%. METHODS: We identified all patients treated at our institution from 2000 to 2017 who: 1.) had probable or definite CS; 2.) had either late gadolinium enhancement (LGE) on CMR or abnormal 18-flourodeoxyglucose (FDG) uptake on PET, and 3.) had undergone EPS. The primary endpoint was VA during follow up. RESULTS: Twenty five patients were included, of whom 10 (40%) had positive EPS. During a mean follow-up of 4.8 +/- 3.4 years, 11 (44%) patients had VA. The positive predictive value (PPV) of EPS for VA was 100% and the negative predictive value (NPV) of EPS for VA was 93%. Among 12 patients with LVEF >35% and no prior VA, the PPV of EPS for VA was 100% and the NPV of EPS for VA was 90%. CONCLUSION: EPS may help with risk stratification in patients with CS and abnormal imaging, especially those without conventional indications for ICD placement. Among patients with LVEF >35% and no history of prior VA, a negative EPS has good positive and negative predictive value for future VA events.

Minimally invasive transtracheal cardiac plexus block for sympathetic neuromodulation.

BACKGROUND: Bilateral thoracoscopic stellectomy has antiarrhythmic effects, but the procedure is invasive with associated morbidity. Sympathetic nerves from both stellate ganglia form the deep cardiac plexus (CP) in the aortopulmonary window, anterior to the trachea. OBJECTIVE: The purpose of this study was to demonstrate a novel and minimally invasive transtracheal approach to block the CP in porcine models. METHODS: In 12 Yorkshire pigs, right (RSG) and left (LSG) stellate ganglia were electrically stimulated and sympathetic baseline response recorded (hemodynamic parameters and T-wave pattern). Aortopulmonary window was accessed transtracheally with endobronchial ultrasound guidance, and local stimulation of CP confirmed the location. Injection of 1% lidocaine (n = 10) or saline solution (n = 2) was performed, and RSG and LSG responses were re-evaluated and compared with baseline. RESULTS: Transtracheal lidocaine injection into the CP successfully blocked bilateral sympathetic induced changes (%) in T-wave amplitude (282.8% ± 152.2% vs 20.1% ± 16.5%; P <.001 [LSG]; 338.9% ± 189.8% vs 28% ± 18.3%; P <.001 [RSG]), Tp-Te interval (87.9% ± 37.2% vs 6.9% ± 6.7%; P <.001 [LSG]; 32.6% ± 27.4% vs 6.9% ± 4.7%; P <.035 [RSG]), and left ventricular dP/dTmax (148.3% ± 108.5% vs 16.5% ± 13.4%; P <.001 [LSG]; 243.1% ± 105.2% vs 19.0% ± 12.4%; P <.001 [RSG]). RSG-induced elevations of systemic, left ventricular, and pulmonary arterial pressures were blocked by lidocaine injection into CP (P <.005 for all comparisons). Stellate ganglia response was not affected in sham studies. No complications were observed during the procedures. CONCLUSION: Minimally invasive transtracheal injection of lidocaine into the CP blocked the sympathetic response of either RSG and LSG. Transtracheal assessment of CP may allow for minimally invasive and selective ablation of cardiac innervation, extending the cardiac sympathectomy denervation benefits to those not suitable for surgery.

Regional Strain by Cardiac Magnetic Resonance Imaging Improves Detection of Right Ventricular Scar Compared With Late Gadolinium Enhancement on a Multimodality Scar Evaluation in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy is an inherited cardiomyopathy characterized by fibrofatty replacement of right ventricular myocardium resulting in reentrant ventricular tachycardia (VT). Cardiac magnetic resonance imaging (CMR) can noninvasively measure regional abnormalities using tissue-tracking strain as well as late gadolinium enhancement (LGE). In this study, we examine arrhythmogenic substrate using regional CMR strain, LGE, and electroanatomic mapping (EAM) in arrhythmogenic right ventricular cardiomyopathy patients presenting for VT ablation. METHODS AND RESULTS: Twenty-one patients underwent right ventricular endocardial EAM, whereas 17 underwent epicardial EAM, to detect dense scar (<0.5 mV) as well as CMR study within 12 months. Quantitative regional strain analysis was performed in all 21 patients, although the presence of LGE was visually examined in 17 patients. Strain was lower in segments with dense scar on endocardial and epicardial EAM (-9.7±4.1 versus -7.3±4.0, and -9.8±2.8 versus -7.6±3.8; P<0.05), in segments with LGE scar (-9.9±4.4 versus -6.0±3.6; P=0.001), and at VT culprit sites (-7.4±3.7 versus -10.1±4.1; P<0.001), compared with the rest of right ventricular. On patient-clustered analysis, a unit increase in strain was associated with 21% and 18% decreased odds of scar on endocardial and epicardial EAM, respectively, 17% decreased odds of colocalizing VT culprit site, and 43% decreased odds of scar on LGE-CMR ( P<0.05 for all). LGE and EAM demonstrated poor agreement with κ=0.18 (endocardial, n=17) and κ=0.06 (epicardial, n=13). Only 8 (15%) VT termination sites exhibited LGE. CONCLUSIONS: Regional myocardial strain on cine CMR improves detection of arrhythmogenic VT substrate compared with LGE. This may enhance diagnostic accuracy of CMR in arrhythmogenic right ventricular cardiomyopathy without the need for invasive procedures and facilitate the planning of VT ablation procedures.

Field of view of mapping catheters quantified by electrogram associations with radius of myocardial attenuation on contrast-enhanced cardiac computed tomography.

BACKGROUND: Contrast-enhanced cardiac computed tomography (CE-CT) provides useful substrate characterization in patients with ventricular tachycardia (VT). OBJECTIVE: The purpose of this study was to describe the association between endocardial electrogram measurements and myocardial characteristics on CE-CT, in particular the field of view of electrogram features. METHODS: Fifteen patients with postinfarct VT who underwent catheter ablation with preprocedural CE-CT were included. Electroanatomic maps were registered to CE-CT, and myocardial attenuation surrounding each endocardial point was measured at a radius of 5, 10, and 15 mm. The association between endocardial voltage and attenuation was assessed using a multilevel random effects linear regression model, clustered by patient, with best model fit defined by highest log likelihood. RESULTS: A total of 4698 points were included. There was a significant association of bipolar and unipolar voltage with myocardial attenuation at all radii. For unipolar voltage, the best model fit was at an analysis radius of 15 mm regardless of the mapping catheter used. For bipolar voltage, the best model fit was at an analysis radius of 15 mm for points acquired with a conventional ablation catheter. In contrast, the best model fit for points acquired with a multipolar mapping catheter was at an analysis radius of 5 mm. CONCLUSION: Myocardial attenuation on CE-CT indicates a smaller myocardial field of view of bipolar electrograms using multipolar catheters with smaller electrodes in comparison to standard ablation catheters despite similar interelectrode spacing. Smaller electrodes may provide improved spatial resolution for the definition of myocardial substrate for VT ablation.