Kansas City Heart Rhythm Symposium 2014: Setting New Trends in Heart Rhythm Education

The Kansas City Heart Rhythm Symposium (KCHRS) is trending in a big way to become one of the nation’s premiere educational events for heart rhythm disorders. It fills a great void that existed in quality education in the greater Midwest for clinical electrophysiology. This program has been in place since 2008, and every year it has gained momentum and better reach, establishing itself as a standard feature on the national events calendar in the heart rhythm field. Dr. Dhanunjaya Lakkireddy, Professor of Medicine at the University of Kansas Hospital, started this program with a vision of bringing quality education to greater Kansas City, and has successfully transformed it into an international meeting. KCHRS 2014 took place August 16-17 at the Sheraton Kansas City at Crown Center hotel in Kansas City. The conference included world-renowned EP experts, clinicians, and scientists who discussed their innovative ideas, outcomes of their research, and expertise with the next generation of EP professionals. Leading companies in the field of medical technologies and devices also hosted outlets to educate the attendees regarding new innovations and cutting-edge technologies. 

Day 1

Highlights of the first day included opening statements by course director Dr. Lakkireddy, who thanked the audience, speakers, and sponsors for attending the symposium, and applauded their contributions to the field of electrophysiology. 

The first speaker, Dr. Detlef Wencker, spoke on new approaches in the management of advanced heart failure (HF). He stressed the growing burden of HF and its revolving door of readmission, and presented solutions to contain or decrease this readmission rate. He highlighted the importance of device therapy in improving cardiac function. He briefly outlined the results of the RELAX-HF trial, which showed improved survival over six months but no effect on rehospitalization. He outlined various strategies including the reemergence of outpatient infusion Rx as a potent adjunct to the mainstream in keeping patients out of hospitals. This strategy showed that the rate of readmissions decreased from 30% to 7%, and mortality decreased from 27% to 5% in patients who underwent outpatient diuretic therapy compared to controls who did not receive any therapy. However, the renal function did not change. Dr. Wencker concluded by saying that HF management has changed from a low output state to a hypervolemic state, setting the tone for a new paradigm shift in treating these patients. 

Dr. Paul Wang then spoke on novel diagnostic and therapeutic tools in the management of drug-resistant congestive HF. He focused on device-based therapies in modulating the autonomic nervous system at various levels to better manage HF, the interplay of sympathetic and parasympathetic systems, and different types of neurostimulatory approaches we can intercept. Dr. Wang focused on three different stimulation techniques. Studies such as Defeat-HF, comparing spinal cord stimulation vs spinal cord stimulation and medical therapy to a control group, showed significant improvement in clinical HF parameters, improved left ventricular ejection fraction (LVEF), significant reversal of left ventricular dilation, and a decrease in B-type natriuretic peptide and norepinephrine levels. Vagal nerve stimulation (VNS) is another mechanism that can minimize the deleterious effect of increased heart rate and incidence of ventricular arrhythmias. VNS concurrent with beta blockers increased LV ejection fraction. Baroreflex stimulation at the carotid sinus using a pacer device may in theory reverse LV remodeling and improve ejection fraction. All studies testing the above hypothesis are currently ongoing. Dr. Wang concluded by saying these new technologies will demonstrate the efficacy of neuromodulation in HF in a selected group of patients in the next few years. 

This talk was followed by a presentation on CRT. Dr. Jie Cheng explained the role of ventricular dyssynchrony (interventricular, intraventricular, or atrioventricular) and improvement in cardiac function by resynchronization. He highlighted the predictors of response, as well as the factors that lead to lack of response: inability to pace at preferred site, presence of RBBB, complex RV physiology, and intraventricular LV dyssynchrony. He closed the presentation by raising the possibility of futuristic therapies involving LV endocardial pacing and leadless pacing. 

At this year’s meeting, the prestigious KU Pioneers in Cardiovascular Electrophysiology Award was presented to Dr. Michel Haïssaguerre by Dr. Robert Simari, executive dean of the University of Kansas School of Medicine. Dr. Haïssaguerre is a Professor of Cardiology at the University of Bordeaux and heads the Department of Cardiology-Electrophysiology at the Hôpital Cardiologique du Haut-Lévêque. His scientific and clinical work focuses on cardiovascular electrophysiology, particularly on cardiac fibrillation. He is best known for his remarkable contributions in the area of atrial fibrillation (AF), introducing interventional ablation. He was the first to describe the importance of pulmonary vein triggers and drivers in the genesis of AF. In addition, he was first to propose the technique of pulmonary vein isolation, which subsequently paved the way for catheter-based therapies for AF. His team has also demonstrated the role of Purkinje cells in being triggers for human ventricular fibrillation, with or without heart disease. Headed by Professor Haïssaguerre along with cardiology teams from the University Hospital of Bordeaux, the Electrophysiology and Heart Modeling Institute (L’Institut de RYthmologie et Modélisation Cardiaque, or LIRYC) is one of six French university hospital institutions created in 2011 as part of the investments in the future program. LIRYC is a basic research, clinical, and teaching center focused on the understanding, care, and treatment of cardiac electrical diseases that lead to HF and sudden death. In addition, Dr. Haïssaguerre has published more than 500 articles in leading peer-reviewed cardiology journals. He enjoys an outstanding national and international scientific reputation, receiving numerous honors and awards.

Dr. Haïssaguerre presented on “The Fibrillating Heart — Triggers and Substrates,” with a focus on the past, present, and future of targeted therapy. He said multiple chaotic wavelets vs rotors are the focal triggers for the origin of paroxysmal AF, and pulmonary veins are the origin of these wavelets in 70% of patients. He noted we still need to find the cells with specific histology in pulmonary veins that are emitting these multiple wavelets, and also the mechanism behind atrial fibrosis and its prevention. He stressed that we need to ablate persistent AF as early as possible in order to improve procedural efficacy, both in the short and long term. He discussed mapping techniques to define the focal triggers by using body surface and phase mapping along with different EGM presentations. His focus then moved to ventricular fibrillation (VF). He reiterated that the main triggers in idiopathic VF are the Purkinje fibers of the conducting system. He discussed different clinical scenarios and the best ablation strategies to treat VF, summarizing, “if we can find the triggers of VF with body surface mapping, the patient’s life can be saved by targeted ablation and by preventing the SCD.” 

Next, Dr. Rhea Pimentel presented on advances in subcutaneous heart rhythm monitors and their relevance to arrhythmia therapy and stroke prevention. She discussed the types of strokes and incidence of strokes in different arrhythmic conditions. Dr. Pimentel described AF and its causative role in cryptogenic stroke — 36% of stroke survivors are classified as cryptogenic and these patients may need to be anticoagulated if AF is the diagnosis. She highlighted the importance of outpatient cardiac monitors in diagnosing AF, as one-third of AF patients are not aware of asymptomatic AF. She outlined the major trials that shed light on AF and stroke, mostly the TRENDS and ASSERT studies. The median duration between onset of AF and occurrence of stroke was 105 days in these trials. She concluded by saying that the duration of arrhythmia predicts the risk of stroke, and outpatient monitoring systems such as implantable loop recorders, which can monitor with longer duration, will help in the diagnosis. 

Dr. Gerhard Hindricks then presented ways to reduce radiation exposure and the use of fluoroscopy, which includes operator awareness/skills/technique, use of established mapping techniques, remote catheter navigation, and innovative concepts for catheter tracking and visualization, mainly electromagnetic technologies such as MRI. AF ablation and CRT implantation are the two procedures with the highest radiation exposure. He highly recommended reading the European guidelines on reducing radiation exposure. He also focused on the benefits of MediGuide and NavX mapping for pulmonary vein isolation and VT ablation. He concluded by saying, “fluoroscopy is the backbone of imaging during EP procedures; however, the new electromagnetic technologies will help to reduce radiation exposure.” 

Dr. Suneet Mittal presented on the use of antiarrhythmics (AAD) and their role in symptomatic patients compared to catheter ablation as done in the RAAFT-2 trial. Antiarrhythmics can be used to achieve rhythm control. He showed that catheter ablation is superior to a second AAD, especially in patients with paroxysmal or AF who fail the first AAD. Suppressive AADs are commonly employed during the first one to three months after ablation. 

Later, Dr. Lakkireddy spoke on the evolution of pacemakers, and noted that it took more than four decades for the idea of the leadless pacemaker to become a clinical reality. With current lead technology, complications are much higher, including device protrusion, lead fractures, venous/arterial punctures, extensive fibrosis/stenosis at the vessels, and device infections. These complications could potentially be avoided with the leadless pacemaker; leadless pacers can be implanted safely with greater efficacy. They are currently limited to single-chamber pacing devices. The future holds exciting possibilities for dual-chamber pacing, defibrillator platforms, and CRT. Limitations include how to place these leads in different chambers of the heart and achieve stability and communicability with the other. Overall, leadless pacemaker technology offers improved efficacy, reduced procedural time, and decreased complications in properly selected patients. 

Following this talk, Dr. Paul Friedman presented on genetic testing for electrical and structural cardiomyopathies. He explained the importance of genetic testing in diagnosing the disease, identifying family members once the causative gene in a proband is identified, and formulating the gene therapy. He also focused his talk on penetrance and variable expressivity in phenotypic presentation. He presented examples of long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and hypertrophic cardiomyopathy (HCM). He briefly mentioned the types of mutations and genes involved in LQTS, the ECG pattern, and who needs testing. He closed his presentation by saying that due to the complex nature of genetic testing, a genetic counselor and geneticist are needed, and indiscriminate use is ill advised. Clinically genetic testing is most useful in family ID with genotype-positive proband, and in patients with LQTS, CPVT, and HCM. 

Dr. George Van Hare presented on management of arrhythmias in congenital heart disease (CHD). He touched on the causes, etiology, and incidence of arrhythmias in adult CHD, which include Wolff-Parkinson-White syndrome (WPW), sinus node dysfunction (SND), supraventricular tachycardia (SVT), AF, atrial tachycardia (AT), and ventricular arrhythmias. Dr. Van Hare discussed the Mustard and Fontan surgical procedures, and the approach to arrhythmia treatment in these patients. He then focused on ICD indications in adult CHD patients; so far there is no clear indication for primary prevention. He noted that the tetralogy risk stratification can be done by using LV dysfunction, QRS length >180 sec, pulmonary insufficiency, positive EPS study for VT or VF, and older age at repair. He concluded by saying that since adult CHD disease patients are now being seen by adult cardiologists, we need to have a good understanding of the pathophysiology and the treatments available. 

There was an excellent debate between Dr. Martin Emert and Dr. Michael Gold, who discussed whether patients undergoing ICD implantation for primary prevention should have DFT testing performed. Dr. Emert was supportive of DFT testing; Dr. Gold strongly opposed it. DFT refers to the minimum shock strength that defibrillates. Dr. Emert said all ICD primary prevention trials did DFT testing and as per the LESS study, one conversion of VF is adequate for ICD implant. He added that DFT testing is safe and not associated with increased risk for HF, death, or future VT/VF episodes. He also focused on the SIMPLE trial, and outlined why DFT testing is needed, including to check for system integrity as partial insulation defects may not be identified, assure the device is working, and avoid liability issues. Dr. Gold stated that current ICDs do not need DFT testing, as biphasic waveforms were used, which are more effective than monophasic waveforms used before. Pectoral implantation is more effective in defibrillating than the abdominal implantation that was previously used, and defibrillation safety margins are 2-3 folds larger with contemporary devices. He said that with current ICDs, the sensitivity for detection of VT/VF is 100%, and device failure is extremely low. Dr. Gold added that with modern ICDs, undersensing of spontaneous VF is extremely low and not reproducible in the EP lab. 

Following the debate, Dr. Laurence Kotobi spoke on the challenges of providing care for non-native speakers, and how to improve physician communication. She presented studies on patient satisfaction and understanding based on physicians’ usage of medical jargon vs common language, and found that patients had better understanding and higher satisfaction when physicians used common language. Patients’ understanding of the disease process is critical, and every attempt should be made to achieve it. 

This speaker was followed by Dr. Bradley Knight, who spoke on the advantages of the new oral anticoagulants (NOACs) over warfarin, and presented scenarios in which warfarin is still an option. For example, warfarin is a better option for patients with valvular AF as shown in the RE-ALIGN study, for patients who cannot afford NOACs, patients with concerns about a lack of reversal agents, patients with gastrointestinal bleeding on NOACs, and elderly patients. He concluded by saying NOACs should be prescribed on a case-by-case basis.

Dr. Madhu Reddy then described appropriate selection of NOACs. He said most ischemic strokes occur in patients who are suboptimally anticoagulated. Fear of bleeding is a major concern for not prescribing vitamin K antagonists. In prescribing anticoagulants, we need to consider patient comorbidities, once daily vs BID dosing, and patient preferences. He discussed why we need to prescribe NOACs, and compared different NOACs and their indications in different groups of patient populations, mainly in patients with chronic renal insufficiency, GI bleeding, coronary artery disease, a high risk for ischemic stroke, and patients undergoing AF ablation. 

Dr. Andrea Natale later presented on bleeding risks as well as the reversal of warfarin and NOACs. He described the factors that should be considered in managing thromboembolism prophylaxis in patients undergoing EP procedures, such as type of AF and medications that reduced the incidence of minor and major bleeding. The embolus can form immediately after the transeptal puncture in some patients. He mentioned that in a 2007 study, which compared uninterrupted warfarin vs a traditional approach in which warfarin was stopped and started on Lovenox, there was no difference in minor or major bleeding. He also said the incidence of silent thromboembolism is up to 40%. In a study comparing patients undergoing EP studies off warfarin vs on warfarin with therapeutic INR vs on warfarin with subtherapeutic INR, the risk of thromboembolic episodes in patients on warfarin with therapeutic INR was only 2% — much lower than the two other groups. He stated that uninterrupted rivaroxaban is as safe as warfarin. In a study done comparing uninterrupted rivaroxaban vs rivaroxaban stopped 24-48 hours before the procedure, the rates of silent thrombi were 0% vs 29%, respectively. He concluded by saying that NOACs are comparable to warfarin in preventing thromboembolic episodes. 

This was followed by a presentation from Dr. Moussa Mansour, who spoke on left atrial appendage (LAA) occluders and ligators. He explained the different types of devices available including the PLAATO, WATCHMAN, AMPLATZER Cardiac Plug, and the LARIAT Suture Delivery Device. He said the WATCHMAN is the only device compared in randomized prospective trials and commercially available outside the U.S. He then focused on how these devices are deployed. He also explained the PROTECT AF study, Continuous Access Protocol, and PREVAIL study. For patients in whom oral anticoagulants are contraindicated, LAA closure devices have proven benefit in decreasing the risk of stroke compared to expected incidence of stroke in these populations. He explained the causes leading to incomplete closure and the measures that need to be taken for complete closure. However, the degree of LAA closure leaks did not translate into higher incidences of stroke. 

Next, Dr. Lakkireddy spoke on the impact of LAA exclusion on cardiac arrhythmias. He explained the functions of the LAA, mainly the thromboembolic properties, arrhythmogenic potential, cardiac reservoir function, and neurohormonal regulation. He said LAA is the main source of arrhythmogenic potential in 47% of paroxysmal AF. Exclusion of the LAA leads to electrical isolation and resolution of arrhythmias or decrease in the burden of arrhythmias. In the LAALA-AF study, exclusion of LAA using the Lariat device along with pulmonary vein isolation showed higher success rates in arrhythmogenic recurrence compared to PVI alone (35% vs 63%). He mentioned that LAA occlusion compared to LAA exclusion does not result in complete electrical isolation, as the LAA is still active. He stated that post Lariat, ANP levels go down compared to no change in epinephrine or norepinephrine. However, patients had better blood pressure and glycemic control. LAA exclusion has a significant positive effect on overall cardiac function. More data is yet to come. 

Following this talk, Dr. Kenneth Kreisler spoke on managing anesthesia during EP cases. The EP lab has a different environment compared to other locations such as operating rooms, which means the anesthesiologist is out of their comfort zone during ablation procedures. The success of ablation is higher when patients are under general anesthesia compared to conscious sedation. He focused on different types of anesthetic medications and their effectiveness during EP procedures, and said that communication between the electrophysiologist and anesthesiologist is the key to success. 

Dr. Srinivas Dukkipati spoke on wearable external defibrillators and their role in clinical practice. He explained the role of ICDs in the primary prevention of arrhythmias in the post-MI period, along with major studies that lead to their indication. All these studies excluded patients during the immediate post-MI period. He stated that one month following post MI, LVEF improves considerably compared to later months. The DINAMIT study did not show any benefit of ICD implantation in patients immediately post MI. He stated that wearable external defibrillators are an effective option for those at risk for sudden cardiac arrest who are not candidates for an ICD, particularly during the waiting period early after MI or revascularization or early after diagnosis of cardiomyopathy. However, which patients would benefit most during this waiting period and how to risk stratify those patients remains largely unknown. 

Dr. Loren Berenbom then discussed some of the advantages of subcutaneous ICDs, including a single electrode connection, 80 J biphasic shock, no leads in the heart (leaving the central vasculature untouched), preserved venous access, avoiding risks associated with endovascular extraction, and a reduced need for fluoroscopy at implant. He explained the properties and mechanisms of subcutaneous ICD function. S-ICDs need preoperative screening to identify patients whose S-ICD signals are challenging for detection and discrimination, QRS amplitudes, QRS to T wave amplitude ratio, QRS width and morphology using multiple postures. The EFFORTLESS S-ICD Registry is ongoing to evaluate efficacy. He also explained the incidence of inappropriate therapies, and outlined the best candidates for S-ICD placement. 

Dr. Mohan Viswanathan next presented on how EP practices can survive low reimbursements and high costs. He covered current issues as well as those we will face in the future with changes in the economy. He stated that healthcare costs increased to 17.9% of the GDP in 2013, and that retiring baby boomers will inundate the Medicare system. With an increase in device therapies for HF and an increase in the number of patients with AF, EP is expected to see a rise in total costs due to increased demand for these services. Are we are willing to pay for this increased cost? He also focused on the Affordable Care Act, and how it is affecting payment methods and physician reimbursement. He concluded that we have to know and follow the guidelines as ACOs, provide clear justification in gray areas before we manage anything, increase efficiency in the EP lab and outpatient clinics for growing needs, and take advantages of automated report generation (BARD). 

Dr. Mohamed Hamdan then spoke on orthostatic intolerance, focusing his talk on three disorders: neurocardiogenic syncope, postural orthostatic tachycardia syndrome, and autonomic dysfunction. He explained the pathophysiology, causes, and treatments for these disorders with a focus on guidelines. He also highlighted the studies that lead to different treatments for neurocardiogenic syncope. The VPS I, VPS II, and ISSUE III studies concluded that dual-chamber permanent pacing is effective in reducing the recurrence of syncope in patients above age 40 with asystolic neutrally mediated syncope. He stated that as per the ESC guidelines, cardiac pacing should be limited as a last resort of choice to a highly selected, small proportion of patients affected by severe reflex syncope. 

This was followed by Dr. J. David Burkhardt, who presented on periprocedural cardiac imaging. Dr. Burkhardt focused on the utility of intraprocedural use of intracardiac echocardiography (ICE) and pre-procedural use of CT and MRI. He also focused on the advantages and disadvantages of balloon technology. Based on the number of clinical trials, atrial fibrosis as defined by delayed enhancement MRI is associated with slower and more organized electrical activity, but with lower voltage than healthy atrial areas. MRI resolution for fibrosis detection is limited, and 90 percent of continuous CFAE sites occur at non-DE and patchy delayed enhancement LA sites. Fibrotic areas usually have stable potentials unlike CFAEs. He then discussed the findings of the DECAAF study, which are important when choosing the ablation strategy in persistent AF. He also focused on coronary sinus ablation. He concluded by saying cardiac CT/MRI may identify PV stenosis and other anatomic variations prior to ablation. Atrial scar is associated with non-PV triggers, which need to be addressed for acceptable success rates. Delayed enhancement MRI may identify scar but may not be particularly useful in assisting with the procedure. 

Dr. Kalyanam Shivkumar then presented on MRI-compatible pacemakers and defibrillators. He elaborated on the effect of MRI on implantable cardiac devices, physical and physiological effects of MRI, and his recommendations. Dr. Shivkumar stated that the effects of MRI include: heating, induction of VF, rapid atrial pacing, pacing at multiples of the RF pulse, reed switch malfunction, asynchronous pacing, inhibition of pacing output, and alteration of programming with potential damage to the pacemaker circuitry or movement of the device. He concluded that MRI can be safely performed with most of the currently available cardiac implantable devices with close monitoring during the procedure, with very few exceptions. 

The last presentation of the day was by Dr. David Singh, who discussed interesting EP cases and shared his opinions with the panel on how to manage patients in different clinical scenarios. Following this, Dr. John Seger discussed the chemical properties, pharmacokinetics, pharmacodynamics, uses, and contraindications of rivaroxaban.  

Day 2 

Day 2 started with the Manohar Gowda CV Research Awards presentation to the young investigators who have contributed and excelled in the field of cardiovascular research. Winners were unanimously selected by the expert panel and announced by Dr. James Vacek. This year, the winner of the first prize was Dr. Uma Avula for his research on mechanistic comparison of early missed vs on target rotor ablation. He concluded by saying on target ablation will decrease the burden of AF or resolve, but the nearly missed ablation targeting the border zone will push the rotors to unusual locations such as the pulmonary veins or posterior wall. The second prize was awarded to Dr. Arun Kanmanthareddy for his research on the risk of heart block and pacemaker implantation after TAVR-transaortic valve replacement vs SAVR-surgical aortic valve replacement. Dr. Kanmanthareddy compared the incidence of atrioventricular block and consequent pacemaker implantation between TAVR and SAVR, and also between the Edwards SAPIEN valve and CoreValve. He concluded that TAVR is associated with an increased number of atrioventricular block than SAVR, and CoreValve is associated with an increased number of atrioventricular block compared to the Edwards SAPIEN valve. The third prize was awarded to Dr. Arun Sridhar for his research work on trends in the incidence of stroke. Dr. Sridhar’s findings include increases in the incidence of strokes and in the incidence of stroke in patients with AF; however, despite the increase in comorbidities associated with AF, they don’t fully account for the increase in the incidence of stroke. 

Following these events, Dr. Raghuveer Dendi and Dr. Hindricks debated on whether balloon-based technologies are superior to single-tipped RF ablation catheters. Dr. Dendi said the advantages of balloon-based technology and cryoablation over RF catheter ablation are improved contact and stability, thus minimizing the amount of fluoro used, preserving the extracellular matrix and endothelial integrity, decreasing the risk of thrombus formation, and demonstrating well-demarcated lesions. He focused on clinical trials that compared cryoablation with RF ablation, and concluded that cryo technology is faster than RF and had a higher success rate. However, there is a learning curve with cryo, resulting in minimal complications, and point-by-point ablation is still needed to achieve pulmonary vein isolation in some patients. Also, multicenter trials are needed to confirm the superiority of cryoablation. Dr. Hindricks argued that RF ablation has been in place for the last 30 years and cryo is less effective — it does not decrease fluoroscopy time, and offers no benefit to patients and physicians. He said cryoablation cannot reach the ostia of pulmonary veins, and cryoablation has never been shown to be superior to RF ablation in randomized trials. The safety of cryoablation still needs to be figured out and the data is still coming; however, complications are not lower than expected. Dr. Hindricks believes RF ablation is the preferred choice of technique over cryoablation in most patients and in different types of arrhythmias. However, both said more data is needed to prove whether cryoablation is superior to RF ablation. 

Following the debate, Dr. Friedman presented on pulmonary vein isolation. He discussed sites of failure during ablation and methods to identify them, maneuvers to confirm the isolation, and techniques to maintain normal sinus rhythm outside the lab post procedure with a clinical scenario. He stated that low contact force, thick fibrous tissue, and not being able to ablate the substrate can lead to failure of ablation. Optimal force may also depend on the site. He discussed the EFFICAS I study findings, which focused on recurrent reconnection. He discussed how to differentiate between the PV potential vs pseudo PV potential. He then noted that a durable lesion requires sufficient contact force (10-20 g), confirmation of the elimination of PVPs, postoperative risk factor modification, and the timing ablation in the natural history of disease where it is better to ablate earlier than to wait. 

The next presentation was by Dr. Haïssaguerre, who spoke on ablation of persistent AF and the role of adjunctive strategies. He stated that in persistent AF, PVI is enough for AF resolution in 20% of patients; however, in 80% of patients, other strategies need to be identified such as CFAE and ganglionic plexi ablation. CFAEs are slow potentials originated from the atrial fibers. The presence of 2-3 different potentials means there are 2-3 different fibrous strands giving CFAEs. There are multiple causes for the origin of CFAEs. MRI can identify the fibrosis in certain groups of patients, and different mapping techniques can be used such as contact mapping, noninvasive mapping, and optical and phase mapping. He explained the different types of ablations and techniques that increase the success of AF ablation. 

Following this talk, Dr. Mittal presented on oral anticoagulation after successful AF ablation. His talk was focused on the assessment of stroke risk, what rate of stroke is acceptable, and the rate of subsequent TIA/strokes after successful ablation. He stated that given the inherent risk of bleeding with anticoagulants, it is imperative that we define an unacceptable risk of stroke. Current acceptance of the CHA2DS2-VASc risk stratification algorithm suggests a >2% annual risk to be high. To date, in patients undergoing catheter ablation, the nonprocedural TIA/stroke rate is well under 2%, even in patients with a CHA2DS2-VASc of 2 or more. Initial data suggests a relationship between successful ablation and low risk of thromboembolism. He concluded that very late recurrences of AF limit our understanding of truly successful AF ablation, and the utility of novel monitoring tools such as implantable loop recorders as a way to guide anticoagulation in post-ablation patients merit further investigation. 

The next presentation was by Dr. Dukkipati on whether advances in energy sources and contact feedback are equal to better ablation outcomes. Why does AF ablation fail? He reiterated the effects of pulmonary vein reconnections and non-PV sources of arrhythmia. He briefed on the new technologies and techniques that may offer durable PVI and improve clinical efficacy. Cryoballoon ablation, visually guided laser balloon, hot balloon, multielectrode irrigated ablation, and contact force catheters may help operators improve the durability of PV isolation and decrease the risk of recurrence. He highlighted different clinical trials and initial data on these new technologies and ablation techniques, and said these advances in energy sources, contact feedback, and other bells and whistles possibly provide better ablation outcomes. 

Dr. Mansour then gave a talk on preventing collateral damage during AF ablation. He explained complications from ablation, mainly esophageal injury, PV stenosis, and phrenic nerve injury, as well as the incidence, pathophysiology, and techniques that can identify these complications. He said the multisensory esophageal probes do not offer any more benefit over single-sensor probes, and the limitation for this technology is they measure the luminal temperature rather than intramural temperature. However, this technique remains the preferred choice to decrease esophageal injury. He concluded by saying the best way to prevent phrenic nerve injury is to delineate the area of overlap between the RA and LA, and ablating proximal to it. 

Dr. Natale presented techniques in VT ablation. He outlined the basics of myocardial scar and VT origin. He explained how endo-epicardial scar homogenization is performed, showed the results from the multicenter studies, and stated that endo-epicardial ablation of all abnormal potentials in patients with scar-related cardiomyopathy and ventricular arrhythmias increases the freedom from ventricular arrhythmias at follow-up. Epicardial ablation is performed in a higher percentage of cases in all patients with arrhythmogenic right ventricular cardiomyopathy, with significantly improved outcomes. The elimination of epicardial potentials with endocardial ablation in post-MI patients highlights the presence of mid-myocardial channels or connections between the endocardial and epicardial recordings. However, in NICM and scar-related VT, the benefit of an endocardial-only approach appears to be inferior compared to those with ischemic substrates. Fundamental differences in the distribution of the scar in patients with ischemic and nonischemic cardiomyopathies may partly explain these results. 

The next presentation was by Dr. Shivkumar, who spoke on autonomic modulation for the treatment of atrial and ventricular arrhythmias. He explained the role of autonomic nervous systems in modulating heart rate (chronotropy), repolarization and depolarization (dromotropy), contractility (inotropy), relaxation (lusitropy), and their interplay in the origin and maintenance of various arrhythmias, their physiology, neural response to cardiac injury, and neuraxial therapeutic strategies. He presented a case of a patient with resistant electrical storm that was successfully treated with epidural anesthesia. He stated that in patients with AF, pulmonary vein firings can be induced by autonomic stimulation. However, there are large gaps in our understanding of the pathophysiology of cardiac autonomic regulation that need to be urgently addressed. Finally, he recommended that meditation and yoga are the best ways to control the autonomic nervous system, and these areas need more research. 

Following this presentation, Dr. Viswanathan spoke on difficult VTs and PVCs. Outflow tract arrhythmias, proximity to the His bundle, septal VTs, papillary muscle foci, epicardial origin, and unstable arrhythmias are the difficult-to-ablate VTs and PVCs. He stressed the value of understanding history, types of substrate, epicardial scar by imaging, 12-lead EKGs, unipolar EGMs, late or focal endocardial or epicardial activation, and repeated late termination while chasing a difficult case. He focused on different treatment strategies for difficult-to-ablate VTs, including sympathectomy and renal denervation techniques, with questionable efficacy. 

Dr. Reddy then presented on the role of left ventricular assist devices and hemodynamic monitoring in VT ablation. He stated that 50-60% of patients have hemodynamically unstable VT. There are several systems that offer hemodynamic support, including the intra-aortic balloon pump (IABP), TandemHeart, and Impella. He compared the advantages and disadvantages of each tool. He stated that the criteria for patient selection for the use of these devices are not clear; however, some scenarios in which hemodynamic support could be of use will be: LVEF ≤40%, NICM, clinical VT with syncope, induced VT with hypotension, chronic kidney disease, and ablation done under general anesthesia. He focused on different studies that have evaluated the effectiveness of these different devices. He concluded that the issues with these devices include cost, extra time spent in managing these devices, complications that arise from these devices, and weaning off these devices after the ablation is done. 

Later, Dr. Wang lectured on the history, basic principles involved in body surface mapping, and the obstacles for development of this technology. He focused on the Rudy lab multielectrode vest, a multichannel mapping system for ECG signal acquisition and an anatomical imaging modality to determine heart-torso geometry. He discussed this technology in identification of AF and left atrial tachycardia. He summarized that body surface mapping with the addition of anatomical information is important for mapping arrhythmias. Advances in imaging may provide more data about fiber orientation and scar. 

The final talk of the symposium was by Dr. Srijoy Mahapatra, who spoke on physician and industry partnership. He compared the similarities between practicing physicians and industry physicians, and discussed how industry physicians can turn an idea into a reality to help patients get healthier. He discussed some of the new research tools being invented. He also discussed the roles and responsibilities of a medical director of a company in transitioning an idea into a reality. 

We’d like to thank everyone involved in making this symposium a grand success! We recognize the core team who worked hard to make this symposium a great learning experience to all our participants. Next year’s KCHRS conference will be held on August 15-16, 2015.