Determination of Continuity Index Values in Atrial Fibrillation Ablation with Proactive Esophageal Cooling.

Radiofrequency (RF) ablation to perform pulmonary vein isolation (PVI) for the treatment of atrial fibrillation involves some risk to collateral structures, including the esophagus. Proactive esophageal cooling using a dedicated device has been granted marketing authorization by the Food and Drug Administration (FDA) to reduce the risk of ablation-related esophageal injury due to RF cardiac ablation procedures, and more recent data also suggest that esophageal cooling may contribute to improved long-term efficacy of treatment. A mechanistic underpinning explaining these findings exists through the quantification of lesion placement contiguity defined as the Continuity Index (CI). Kautzner et al. quantified the CI by the order of lesion placement, such that whenever a lesion is placed non-adjacent to the prior lesion, the CI is incremented by the number of segments the catheter tip has moved over. To facilitate real-time calculation of the CI and encourage further adoption of this instrument, we propose a modification in which the placement of non-adjacent lesions increments the CI by only one unit, avoiding the need to count potentially nebulous markers of atrial segmentation. The objective of this protocol is to describe the methods of calculating the CI both prospectively during real-time PVI cases and retrospectively using recorded case data. A comparison of the results obtained between cases that utilized proactive esophageal cooling and cases that used luminal esophageal temperature (LET) monitoring is then provided.

Reduced Continuity Index with Proactive Esophageal Cooling Compared to Luminal Temperature Monitoring During Radiofrequency Ablation: Improved Lesion Continuity with Esophageal Cooling.

Background: Proactive esophageal cooling is FDA cleared to reduce the likelihood of esophageal injury during radiofrequency ablation for treatment of atrial fibrillation (AF). Long-term follow-up data have also shown improved freedom from arrhythmia with proactive esophageal cooling compared to luminal esophageal temperature (LET) monitoring during pulmonary vein isolation (PVI). One hypothesized mechanism is improved lesion contiguity (as measured by the Continuity Index) with the use of cooling. We aimed to compare the Continuity Index of PVI cases using proactive esophageal cooling to those using LET monitoring. Methods: Continuity Index was calculated for PVI cases at two different hospitals within the same health system using a slightly modified Continuity Index to facilitate both real-time calculation during observation of PVI cases and retrospective determination from recorded cases. The results were then compared between proactively cooled cases and those using LET monitoring. Results: Continuity Indices for a total of 101 cases were obtained; 77 cases using proactive esophageal cooling and 24 cases using traditional LET monitoring. With proactive esophageal cooling, the average Continuity Index was 2.7 (1.3 on the left pulmonary vein, and 1.5 on the right pulmonary vein). With LET monitoring, the average Continuity Index was 27.3 (14.3 on the left, and 12.9 on the right), for a difference of 24.6 (p < 0.001). Conclusion: Proactive esophageal cooling during PVI is associated with significantly improved lesion contiguity when compared to LET monitoring. This finding may offer a mechanism for the greater freedom from arrhythmia seen with proactive cooling in long-term follow-up.

Procedural time reduction associated with active esophageal cooling during pulmonary vein isolation.

BACKGROUND: Active esophageal cooling is increasingly utilized as an alternative to luminal esophageal temperature (LET) monitoring for protection against thermal injury during pulmonary vein isolation (PVI) when treating atrial fibrillation (AF). Published data demonstrate the efficacy of active cooling in reducing thermal injury, but impacts on procedural efficiency are not as well characterized. LET monitoring compels pauses in ablation due to heat stacking and temperature overheating alarms that in turn delay progress of the PVI procedure, whereas active esophageal cooling allows avoidance of this phenomenon. Our objective was to measure the change in PVI procedure duration after implementation of active esophageal cooling as a protective measure against esophageal injury. METHODS: We performed a retrospective review under IRB approval of patients with AF undergoing PVI between January 2018 and February 2020. For each patient, we recorded age, gender, and total procedure time. We then compared procedure times before and after the implementation of active esophageal cooling as a replacement for LET monitoring. RESULTS: A total of 373 patients received PVI over the study period. LET monitoring using a multi-sensor probe was performed in 198 patients, and active esophageal cooling using a dedicated device was performed in 175 patients. Patient characteristics did not significantly differ between groups (mean age of 67 years, and gender 37.4% female). Mean procedure time was 146 ± 51 min in the LET-monitored patients, and 110 ± 39 min in the actively cooled patients, representing a reduction of 36 min, or 24.7% of total procedure time (p < .001). Median procedure time was 141 [IQR 104 to 174] min in the LET-monitored patients and 100 [IQR 84 to 122] min in the actively cooled patients, for a reduction of 41 min, or 29.1% of total procedure time (p < .001). CONCLUSIONS: Implementation of active esophageal cooling for protection against esophageal injury during PVI was associated with a significantly large reduction in procedure duration.

A prospective multi-site registry of real-world experience of catheter ablation for treatment of symptomatic paroxysmal and persistent atrial fibrillation (Real-AF): design and objectives.

PURPOSE: Catheter ablation has become a mainstay therapy for atrial fibrillation (AF) with rapid innovation over the past decade. Variability in ablation techniques may impact efficiency, safety, and efficacy; and the ideal strategy is unknown. Real-world evidence assessing the impact of procedural variations across multiple operators may provide insight into these questions. The Real-world Experience of Catheter Ablation for the Treatment of Symptomatic Paroxysmal (PAF) and Persistent (PsAF) Atrial Fibrillation registry (Real-AF) is a multicenter prospective registry that will enroll patients at high volume centers, including academic institutions and private practices, with operators performing ablations primarily with low fluoroscopy when possible. The study will also evaluate the contribution of advent in technologies and workflows to real-world clinical outcomes. METHODS: Patients presenting at participating centers are screened for enrollment. Data are collected at the time of procedure, 10-12 weeks, and 12 months post procedure and include patient and detailed procedural characteristics, with short and long-term outcomes. Arrhythmia recurrences are monitored through standard of care practice which includes continuous rhythm monitoring at 6 and 12 months, event monitors as needed for routine care or symptoms suggestive of recurrence, EKG performed at every visit, and interrogation of implanted device or ILR when applicable. RESULTS: Enrollment began in January 2018 with a single site. Additional sites began enrollment in October 2019. Through May 2021, 1,243 patients underwent 1,269 procedures at 13 institutions. Our goal is to enroll 4000 patients. DISCUSSION: Real-AF's multiple data sources and detailed procedural information, emphasis on high volume operators, inclusion of low fluoroscopy operators, and use of rigorous standardized follow-up methodology allow systematic documentation of clinical outcomes associated with changes in ablation workflow and technologies over time. Timely data sharing may enable real-time quality improvements in patient care and delivery. Trial registration Clinicaltrials.gov: NCT04088071 (registration date: September 12, 2019).

Drug-Coated Balloon Venoplasty for In-Stent Restenosis in a Patient With Recurrent Pulmonary Vein Stenosis Post Ablation for Atrial Fibrillation: Initial Experience With a New Treatment Technique.

Pulmonary vein stenosis (PVS) is an uncommon but serious complication following radiofrequency ablation for atrial fibrillation. Occurrence of this complication has risen with increased rates of ablation procedures, with >50,000 AF ablation procedures performed per year, and can occur within weeks to months post procedure. Currently, the main therapies for PVS include percutaneous interventions with balloon angioplasty and stenting, but these treatments are complicated by a high rate of restenosis. The optimal treatment for recurrent pulmonary vein in-stent restenosis has not been determined. We describe the novel use of a paclitaxel drug-coated balloon for the treatment of in-stent restenosis of the pulmonary veins.

Medical specialty certification in the United States-a false idol?

PURPOSE: Recent changes to medical specialty certification in the USA have prompted the process to come under intense scrutiny. METHODS: We review the history of board certification and the changes made to the process. As part of this review, we examine both literature and public record to examine the motives behind the changes made. We then review the legal challenges and changes under way to modify the current ABMS board re-certification process. RESULTS: In 1917, the first board certification was a lifetime designation, voluntary, and managed by unpaid board members with a focus to enhance quality for patients. Corresponding to the implementation of time-limited certification, $55 million of physician testing fees were transferred from the American Board of Internal Medicine to its Foundation between 1989 and 1999. From 2000 through 2007, and additional $20.66 million were transferred from the ABIM to its Foundation culminating in the purchase of a $2.3 million luxury condominium in December 2007. CONCLUSIONS: Significant financial conflicts of interest for the implementation of time-limited specialty certification exited and continue to plague the medical profession. The specialty boards and the organizations that created them should remove all requirements for time-limited board certification and resort to conventional self-selected ACGME-approved CME programs for ongoing education.

A Case-Based Approach to Improve Strategies to Reduce Risk for SCA Post-PCI

Atividade de educação médica continuada onde Ted E. Feldman (moderador), Westby G. Fisher (palestrante) e Rena L. Silver (palestrante) discorrem sobre a redução de riscos da morte cardíaca súbita pós angioplastia coronária. Há a possibilidade de assistir ao vídeo, ler a transcrição das falas com slides e fazer o download dos slides ou do áudio. Também traz a possibilidade de realizar o teste de educação médica continuada da atividade e informação de como obter créditos pela mesma. Necessário estar cadastrado no site www.theheart.org para acesso ao material.

A Heart Rhythm Society Electrophysiology Workforce study: current survey analysis of physician workforce trends.

BACKGROUND: Recent economic trends influenced by healthcare reform, an aging population, changes in physician reimbursement, and increasing competition will have a significant impact on the electrophysiology workforce. Therefore, there is an important need to obtain information about the EP workforce to assess training of arrhythmic healthcare providers in order the meet the requisite societal need. This report summarizes the data collected by the HRS Workforce Study Task Force in relation to physician workforce issues. OBJECTIVE: The HRS Workforce Study Task Force was charged with conducting a comprehensive study to assess changes in the field of electrophysiology since the last workforce study conducted in 2001 and to identify the population and distribution of professionals who treat patients with heart rhythm disorders. METHODS: A series of comprehensive questionnaires were designed by the HRS Workforce Study Task Force to conduct online surveys with physicians, basic science researchers, and allied professionals. Data collected in the physician survey included: personal demographics and professional profile characteristics such as primary work setting and areas of affiliation; workload characteristics such as hours worked, time spent by activity, workload relative to capacity, competition for patients, volume by specific procedure, sources of referrals, income levels, personal mobility, and anticipated future changes in the respondent's practice. Survey responses were collated and analyzed by the Workforce Study Task Force. RESULTS: Work capacity is expected to increase to offset some of the economic drivers; however, recruitment of new EPs could be challenging and uncertain. Specifically, geographic mobility (>50 miles) appears to be minimal at present overall and unlikely to significantly change for the majority of physicians once they have established themselves in a given community following the completion of their training. Practice time is predominantly spent performing device implantations, device follow-ups and ablations. These activities are being tasked upon younger physicians, thereby suggesting a need for trained allied professionals to assume a greater role in device management. The perception of competition varied by respondent age and geographic location but, in general, was felt to be at least moderate by most respondents. Furthermore, there are concerns that increasing competition may dilute operator experience and potentially lower high quality outcomes if increasing competition leads to lower procedural volumes. CONCLUSION: Based on findings from this study, the task force identified specific workforce (supply) trends and the key drivers of current and future challenges. Although specific areas will require further analysis, overall, the current EP workforce is stable, with the exception of geographic dispersion. However, the workforce must adapt to the key economic drivers (demand) and address future recruitment challenges.

Manifestation of left atrial events and interatrial frequency gradients in the surface electrocardiogram during atrial fibrillation: contributions from posterior leads.

BACKGROUND: In most patients, atrial fibrillation (AF) is initiated and maintained by pulmonary vein foci, but the relationship between left atrial (LA) events and the surface electrocardiogram (ECG) is largely unknown. We investigated whether LA events are reflected in the surface ECG and whether additional information can be obtained from recording posterior leads in patients with AF. METHODS AND RESULTS: In 10 patients undergoing radiofrequency ablation of AF, we identified 103 5-second segments with a significant frequency gradient between right (RA) and left (LA) intraatrial electrograms, or with frequency changes from segment to segment in the same patient. QRS-T cancellation methods were used to isolate atrial activity in the surface ECG and peak frequencies were computed. Peak frequencies of different posterior leads were very similar (6.0 +/- 1.3 Hz for V10, 6.0 +/- 0.9 Hz for V9, 5.9 +/- 1.4 Hz for V8, 6.0 +/- 1.3 Hz for V7). We found a strong correlation between V1 and RA and between V9 and LA, 0.89 and 0.88, respectively, while the lowest correlation was found between lead V1 and LA, 0.62, P < 0.0001. Magnitude-squared coherence values were highest between V1 and RA and between V9 and LA. CONCLUSION: We have demonstrated that, by recording additional surface ECG leads from posterior locations, RA and LA electrical events and interatrial frequency gradients can be monitored noninvasively.

Cardiac resynchronization with sequential biventricular pacing for the treatment of moderate-to-severe heart failure.

OBJECTIVES: The InSync III study evaluated sequential cardiac resynchronization therapy (CRT) in patients with moderate-to-severe heart failure and prolonged QRS. BACKGROUND: Simultaneous CRT improves hemodynamic and clinical performance in patients with moderate-to-severe heart failure (HF) and a wide QRS. Recent evidence suggests that sequentially stimulating the ventricles might provide additional benefit. METHODS: This multicenter, prospective, nonrandomized, six-month trial enrolled a total of 422 patients to determine the effectiveness of sequential CRT in patients with New York Heart Association (NYHA) functional class III or IV HF and a prolonged QRS. The study evaluated: whether patients receiving sequential CRT for six months experienced improvement in 6-min hall walk (6MHW) distance, NYHA functional class, and quality of life (QoL) over control group patients from the reported Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial; whether sequential CRT increased stroke volume compared to simultaneous CRT; and whether an increase in stroke volume translated into greater clinical improvements compared to patients receiving simultaneous CRT. RESULTS: InSync III patients experienced greater improvement in 6MHW, NYHA functional class, and QoL at six months compared to control (all p < 0.0001). Optimization of the sequential pacing increased (median 7.3%) stroke volume in 77% of patients. No additional improvement in NYHA functional class or QoL was seen compared to the simultaneous CRT group; however, InSync III patients demonstrated greater exercise capacity. CONCLUSIONS: Sequential CRT provided most patients with a modest increase in stroke volume above that achieved during simultaneous CRT. Patients receiving sequential CRT had improved exercise capacity, but no change in functional status or QoL.

Safety of transvenous cardiac resynchronization system implantation in patients with chronic heart failure: combined results of over 2,000 patients from a multicenter study program.

OBJECTIVES: The purpose of this study was to evaluate the safety of implanting a cardiac resynchronization therapy (CRT) system. BACKGROUND: Clinicians and patients require data on the safety of the CRT implant procedure to estimate procedural risk. METHODS: We evaluated outcomes of transvenous CRT system implantation in 2,078 patients from the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) study, the MIRACLE Implantable Cardioverter-Defibrillator (ICD) study, and the InSync III study. We compared the MIRACLE study to the InSync III study and the MIRACLE ICD study randomized phase to its general phase to evaluate the effect of new technologies. RESULTS: The implant attempt succeeded in 1,903 of 2,078 (91.6%) patients. Implant time decreased from 2.7 h in the MIRACLE study to 2.3 h in the InSync III study (p < 0.001), and from 2.8 h in the MIRACLE ICD study randomized phase to 2.4 h in the general phase (p < 0.001). The implant procedure produced 62 perioperative complications in 53 (9.3%) MIRACLE trial patients; 159 in 135 (21.1%) MIRACLE ICD study randomized phase patients and 71 in 62 (13.9%) general phase patients (p < 0.05 vs. randomized); and 41 in 37 (8.8%) InSync III study patients (p = NS vs. the MIRACLE study). We observed 73 postoperative complications in 62 (11.7%) MIRACLE trial patients, 77 in 68 (11.9%) MIRACLE ICD study randomized phase patients and 56 in 45 (11.0%) general phase patients (p = NS), and 37 in 34 (8.6%) InSync III study patients (p = NS). A total of 8% of patients required reoperation to treat lead dislodgement, extracardiac stimulation, or infection during follow-up. CONCLUSIONS: Transvenous CRT system implantation appears safe, well-tolerated, has a high success rate, and improves with operator experience and the addition of new technologies.

Surface ECG vector characteristics of organized and disorganized atrial activity during atrial fibrillation.

BACKGROUND: The aim of this study was to examine atrial organization from vectorcardiograms (VCGs) derived from the surface ECG of atrial fibrillatory waves. METHODS: We retrieved ECGs recorded during ventricular asystole from 22 patients with AF undergoing ablation of the AV junction. The synthesized VCG of each f-wave cycle of each ECG and its plane of best fit, described by azimuth and elevation angles relative to the frontal plane, were computed. RESULTS: Fifteen of the 22 ECGs had at least 30% of the planes in a single 30-degree region of azimuth angles. Of these 15, 12 had the greatest percentage of planes with azimuth angles within 30 degrees of the sagittal plane; two were near the frontal plane; and one near the right anterior oblique plane. CONCLUSIONS: Varying degrees of organization were observed from VCGs of fibrillatory waves with the more organized examples having planes predominately near the sagittal plane.

Effect of cardiac resynchronization therapy on left ventricular size and function in chronic heart failure.

BACKGROUND: Cardiac resynchronization therapy (CRT) has recently emerged as an effective treatment for patients with moderate to severe systolic heart failure and ventricular dyssynchrony. The purpose of the present study was to determine whether improvements in left ventricular (LV) size and function were associated with CRT. METHODS AND RESULTS: Doppler echocardiograms were obtained at baseline and at 3 and 6 months after therapy in 323 patients enrolled in the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial. Of these, 172 patients were randomized to CRT on and 151 patients to CRT off. Measurements were made of LV end-diastolic and end-systolic volumes, ejection fraction, LV mass, severity of mitral regurgitation (MR), peak transmitral velocities during early (E-wave) and late (A-wave) diastolic filling, and the myocardial performance index. At 6 months, CRT was associated with reduced end-diastolic and end-systolic volumes (both P<0.001), reduced LV mass (P<0.01), increased ejection fraction (P<0.001), reduced MR (P<0.001), and improved myocardial performance index (P<0.001) compared with control. beta-Blocker treatment status did not influence the effect of CRT. Improvements with CRT were greater in patients with a nonischemic versus ischemic cause of heart failure. CONCLUSIONS: CRT in patients with moderate-to-severe heart failure who were treated with optimal medical therapy is associated with reverse LV remodeling, improved systolic and diastolic function, and decreased MR. LV remodeling likely contributes to the symptomatic benefits of CRT and may herald improved longer-term survival.

Atrial flutter vector loops derived from the surface ECG: does the plane of the loop correspond anatomically to the macroreentrant circuit?

We hypothesized that if the right atrial circuit during isthmus dependent atrial flutter provides the dominant contribution to the surface electrocardiogram (ECG), the three-dimensional vector loop of the flutter waves would primarily be in a plane approximately parallel to the tricuspid ring. Twenty vectorcardiograms of isthmus dependent atrial flutter derived from 12-lead ECGs of 19 patients recorded prior to radiofrequency ablation were analyzed. The plane of each loop, described by azimuth and elevation angles relative to the frontal plane, was estimated with two methods: 1) plane of maximum loop area and 2) plane of best fit. The plane of maximum loop of the loops had mean azimuth of -58 +/- 37 degrees. and elevation of 15 +/- 15 degrees. The plane of best fit of the loops had mean azimuth of -50 +/- 46 degrees and elevation of 15 +/- 14 degrees. Thus, clinical implications include the potential to predict atrial flutter mechanisms prior to intracardiac mapping.

Cardiac resynchronization in chronic heart failure.

BACKGROUND: Previous studies have suggested that cardiac resynchronization achieved through atrial-synchronized biventricular pacing produces clinical benefits in patients with heart failure who have an intraventricular conduction delay. We conducted a double-blind trial to evaluate this therapeutic approach. METHODS: Four hundred fifty-three patients with moderate-to-severe symptoms of heart failure associated with an ejection fraction of 35 percent or less and a QRS interval of 130 msec or more were randomly assigned to a cardiac-resynchronization group (228 patients) or to a control group (225 patients) for six months, while conventional therapy for heart failure was maintained. The primary end points were the New York Heart Association functional class, quality of life, and the distance walked in six minutes. RESULTS: As compared with the control group, patients assigned to cardiac resynchronization experienced an improvement in the distance walked in six minutes (+39 vs. +10 m, P=0.005), functional class (P<0.001), quality of life (-18.0 vs. -9.0 points, P= 0.001), time on the treadmill during exercise testing (+81 vs. +19 sec, P=0.001), and ejection fraction (+4.6 percent vs. -0.2 percent, P<0.001). In addition, fewer patients in the group assigned to cardiac resynchronization than control patients required hospitalization (8 percent vs. 15 percent) or intravenous medications (7 percent vs. 15 percent) for the treatment of heart failure (P<0.05 for both comparisons). Implantation of the device was unsuccessful in 8 percent of patients and was complicated by refractory hypotension, bradycardia, or asystole in four patients (two of whom died) and by perforation of the coronary sinus requiring pericardiocentesis in two others. CONCLUSIONS: Cardiac resynchronization results in significant clinical improvement in patients who have moderate-to-severe heart failure and an intraventricular conduction delay.