The Kansas City Heart Rhythm Symposium (KCHRS) is on its way to becoming one of the nation’s premiere educational events for heart rhythm disorders. Dr. Dhanunjaya Lakkireddy, Professor of Medicine at the University of Kansas Hospital, began this program in 2008 with a vision of bringing quality education to greater Kansas City, and has successfully transformed the program into an international meeting. KCHRS 2015 was held August 15-16 at the Sheraton Kansas City Hotel at Crown Center. 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 hosted outlets to educate attendees on new innovations and cutting-edge tools.
Course Director Dr. Lakkireddy started the first day with opening statements, thanking the audience, speakers, and sponsors for attending the symposium, and applauding their contributions to the EP field.
Next, Dr. Thomas Deering spoke about advanced heart failure (HF) management, including the role of dynamic intracardiac pressure monitors and thoracic impedance in predicting outcome. He went over the epidemic of HF, its economic burden, and what can be done to utilize available technology to reduce readmission rates. Recent studies suggest an increase in intracardiac pressure is the earliest sign of HF decompensation, whereas weight changes are actually a late phenomenon. He also highlighted the CHAMPION trial, in which use of the CardioMEMS HF System (St. Jude Medical) showed significant improvement in all-cause mortality, length of stay, and quality of life.
Dr. Eduardo Saad spoke on how to improve the efficacy of cardiac resynchronization therapy (CRT) by means of quadripolar leads, AV timing intervals, and other methods, as well as discussed the determinants of CRT response. He stressed the importance of lead positioning, in that LV lead placement in regions with the latest site of contraction had the best response to CRT. He also discussed LV endocardial pacing as an alternative approach to CRT when CS pacing is not viable, and the use of electroanatomical mapping to guide endocardial LV lead implantation. Use of multipoint LV stimulation has shown a promising initial result, and can be considered the standard of care whenever possible.
Dr. Luigi Di Biase then discussed using ablation to improve CRT response by targeting cardiac arrhythmia. Continuous biventricular pacing is the key to improved survival in CRT. The absence of CRT response may be due to atrial or ventricular arrhythmia by losing biventricular pacing. A study by Lakkireddy et al showed that PVCs can significantly reduce the percentage of biventricular pacing and that PVC ablation may be used to enhance CRT efficacy in non-responders with significant PVC burden. He also described the role of AV nodal ablation in CRT patients with atrial fibrillation (AF); a meta-analysis by Ganesan et al showed that AV nodal ablation was associated with a substantial reduction in all-cause mortality and cardiovascular mortality, with improvements in New York Heart Association (NYHA) functional class compared with medical therapy in CRT patients with AF.
In the next presentation, Dr. Mark Kroll spoke on DFT testing in the current era. He reviewed various ways of optimizing DFTs. He reviewed the SIMPLE trial and its limitations. He noted that although data shows <5% of ICD patients die suddenly, we should not be satisfied with this result, as 32% of missed sudden deaths might still be preventable by improving ICD technology.
The keynote speaker and recipient of the prestigious KU Pioneer in Electrophysiology Award was Dr. Jeremy Ruskin, who gave an inspiring speech on the importance of mentorship in medical education. He encouraged everyone to seek a mentor, both professionally and personally, in every stage of life. He explained the difference between mentoring and precepting. Mentorship focuses on the mentee and his or her career development, whereas in preceptorship, the goal is focused on the institution or the preceptor. In addition to being the founder of the annual AF Symposium, Dr. Ruskin is well known in the EP field for his seminal contributions and illustrious academic career spanning four decades.
Following this session, Dr. Loren Berenbom spoke on predicting complications in lead extraction, including a long implant duration and if the patient has a poor health status. High-risk factors included active fixation mechanism, an experienced extractor, prior cardiac surgery, and older patients at the time of implant. An INR >1.2 is also one of the predictors of major complications or mortality. He stressed the importance of a multidisciplinary lead extraction program to help improve outcomes.
Dr. Lakkireddy then discussed the development of leadless pacemakers, as well as their safety and efficacy as shown in the LEADLESS trial. Advantages of leadless pacemakers include the elimination of surgical pockets, reduced infection rates and bleeding risk, and increased patient comfort. Limitations of leadless pacemakers include that they cannot be used in patients with high right ventricular pressure/pulmonary arterial pressure or severe tricuspid regurgitation, as this can lead to device migration. Other limitations include the inability to correct pacing-mediated cardiomyopathy, that it is not available for atrial and LV pacing and is not fit for an ICD platform, and potential interference with radiofrequency energy.
Dr. Rhea Pimentel next highlighted the various types of cardiac monitoring, including the most recent advances in implantable monitors. Newer devices have been developed for patient comfort and compliance, and a novel algorithm is also available to detect asymptomatic arrhythmia and transmit the results without patient involvement. Besides syncope, cardiac monitoring is increasingly used in the management of AF as well as cryptogenic stroke. The future of cardiac monitoring is mobile health application. The current FDA-approved mobile monitoring systems include: AliveCor Heart Monitor (AliveCor), ECG Check Monitor (Cardiac Designs), eMotion ECG Mobile (Mega Electronics Ltd), and CardioSecur ACTIVE (CardioSecur).
Dr. Venkat Tholakanahalli then discussed how current guidelines do not distinguish indications at initial device implantation vs subsequent ICD generator replacement. He challenged us to reassess whether ICD indications are still appropriate at the time of generator replacement. A retrospective study by Kini et al, evaluating the appropriateness of a primary prevention ICD implant at the time of generator replacement, showed that out of 231 patients, an ICD was indicated in 40% of patients, 26% not indicated, and 34% unclear. Assuming 26% do not need generator replacement, the savings are $178 million. He concluded that generator replacement indications and outcomes need further study.
Dr. Raghuveer Dendi raised concerns about the increasing rate of device infections exceeding implant rate, and the burden that this has on healthcare costs. The rate of device infection is significantly higher during generator replacement when compared to new implants. He discussed whether capsulectomy can decrease pocket infection, as fibrotic tissue surrounding the device is often a potential nidus of infection. Dr. Dendi summarized the MAKE IT CLEAN study done at the University of Kansas Hospital; results showed no benefit in performing empiric pocket revision, and an increased incidence of hematoma formation. He stressed the importance of a pocket infection control program in every EP lab.
In the following session, Dr. J. Kevin Donahue provided updates on gene therapy, cardiac arrhythmias, and cardiac pacing. The basics of gene therapy using vector (adenovirus), a delivery method using focal myocardial injection, and epicardial gene painting were presented. He also described a strategy to replace sinus node function by increasing the automaticity of target cells using transcription factor TBX18. In addition, he noted that any intervention that disrupts the reentry mechanism will prevent AF with IKr block or connexin overexpression.
Next was a featured debate between Dr. Harikrishna Tandri and Dr. Jared Bunch. Dr. Tandri proposed that devices not labeled for MRI use may be MRI compatible, and off-label use may be alright in the correct circumstance. He pointed out the study by Roguin et al, which used modern devices (manufactured after the year 2000) with appropriate precaution and monitoring. He concluded that the old devices are neither MRI safe nor MRI compatible by FDA strict definition. Patients with older devices should not get a MRI scan without proper understanding of the risks, and should be approached with caution. Dr. Bunch proposed that not all devices are created equal, and presented the benefits of the MRI-compatible device. He also mentioned its possible adverse effects from electromagnetic interference, heat effects, and the potential to induce arrhythmia.
Dr. Martin Emert then discussed the subcutaneous ICD (S-ICD) as an alternative to the transvenous (TV)-ICD. S-ICDs have a sophisticated algorithm performance comparable to the TV-ICD. Dr. Emert described implantation techniques, induction testing, and ideal device placement. In contrast to the TV-ICD, the anatomic limitations, implantation risk, and explanation risk are not an issue with the S-ICD. Patients are indicated for this ICD as long as they don’t need CRT, pacing, or ATP for SMVT indication. Advantages over the TV-ICD include minimal infection risk, preserved venous access, an avoided risk associated with endovascular lead extraction, and no required fluoroscopy.
The next session began with Dr. Moussa Mansour presenting on the key features of three left atrial appendage (LAA) closure devices (LARIAT Suture Delivery Device, SentreHEART, Inc.; WATCHMAN LAAC Device, Boston Scientific; and the AtriClip, AtriCure, Inc.), including their safety, efficacy, and ideal candidates. He summarized the indication for each procedure: the WATCHMAN for patients who can take short-term anticoagulation; the AtriClip for patients undergoing concomitant heart surgery; and the promising role of the LARIAT in patients with a contraindication to anticoagulation.
Dr. Daniel Singer spoke about the era of the novel oral anticoagulants (NOAC). Three global long-term research clinical trials show that NOACs are effective and adequately safe. The potential beneficial impact in NOACs include: attracting warfarin-reluctant patients, reducing intracranial hemorrhage, and convenience. He discussed the pharmacokinetics of NOACS, as well as their possible drug interactions and contraindications. He presented on the major trials on NOACs: dabigatran (RE-LY), rivaroxaban (ROCKET AF), apixaban (ARISTOTLE), and edoxaban (ENGAGE AF). NOACs show noninferiority or superiority in terms of stroke, less intracranial bleeding, and most have more GI bleeding. There are also reversal agents in late stages of development; dabigatran-specific antibody idarucizumab (Boehringer Ingelheim) and andexanet alfa (Portola Pharmaceuticals, Inc.) for factor XA inhibitors are almost close to release (pending FDA approval).
Dr. Douglas Packer then discussed the role of anticoagulation in decreasing periprocedural risk of thromboembolism in AF ablation. He described the phenomenon of asymptomatic cerebral embolism (ACE) lesion in post-ablation patients. He presented a summary of clinical trials involving NOACs vs warfarin for stroke prevention in non-valvular AF, as well as anticoagulation strategies before, during, and after AF ablation.
Next, Dr. Young Hoon Kim described how LAA exclusion should be performed not only in patients with high stroke/bleeding risk, but also for those with recurrent ischemic stroke while anticoagulated, a history of major intracranial or GI bleed, and low CHA2DS2-VASc score but with thrombogenic LAA anatomy. LAA is an under-recognized trigger site of AF that appears to be responsible for arrhythmia in 27% of patients presenting for repeat procedures. When periprocedural complications are minimized, more patients can be included in this procedure.
Dr. Vivek Reddy proposed that even though data shows promising results for LAA exclusion in decreasing stroke risk, it is still associated with complications early on, and therefore, this procedure is best performed in patients with a history of bleeding, elderly patients with bleeding, those with renal dysfunction or are intolerant to oral anticoagulants, and most importantly, patient preference.
Dr. Kalyanam Shivkumar then spoke about the role of imaging in EP procedures. He discussed intracardiac echocardiograms (ICE) and their ability to create 3D imaging for navigation during procedures, how ECG imaging can detect and map abnormal substrate, and the role of MRI in VT ablation. The majority of patients referred for VT ablation have an ICD, which obscures image integrity and the clinical utility of MRI. Wideband MRI has been shown to suppress image artifacts induced by the ICD in a lot of these patients.
Dr. Eric Buch discussed the controversial topic of whether rotors play a role in the maintenance of AF, and how they can be potential targets for substrate modification if they remain in a stable location. A study by Lee et al showed that persistent AF is characterized by heterogeneous and unstable patterns of activation including wavefronts, transient rotational circuits, and disorganized activity. The FIRM study hypothesized that rotor sites would exhibit features distinguishing them from other atrial sites by evidence of rotational activity on electromagnetic mapping and distinctive quantitative characteristics. Although results from that study are promising, recent studies show technical challenges in rotor identification and the potential lack of benefit of ablating the rotors. More studies need to be done before this can be used routinely in AF ablation strategies.
Dr. John Di Marco spoke about the evolution of RF ablation for SVTs including AVNRT. He presented a historical perspective on the ablation technique of fast pathway modification and its potential risk for AV block. He discussed the potential targeting of slow pathways and its advantages, such as lower risk of AV block. He also presented information on the use of the cryocatheter for AVNRT, pediatric EP, and as a backup in tough RF cases. Use of this catheter has shown less risk of AV block. He described anatomical variants in slow pathway ablation sites, and summarized a checklist one should complete when doing an SVT ablation. This list included making sure the ECG/EGM connection is correct, using a certain type of catheter for optimal recording, and understanding normal vs abnormal anatomy, the role of drugs, presence of multiple tachycardias, vital structures at risk, or whether advanced mapping is needed.
Dr. Lakkireddy then presented on the role of the LAA as a trigger and substrate for AF maintenance, as well as the neurohormonal role of the LAA. Ablation of the LAA is technically challenging, and LAA exclusion with the LARIAT can reduce stroke risk and decrease AF burden. Physiologically, the LAA has a neuroendocrine property and is the main source of atrial natriuretic peptide. He also presented data on how various electrolytes, glucose, fatty acids, weight, and blood pressure are affected following LAA exclusion by means of the LARIAT. The LAALA-AF registry, recently published in JACC: Clinical EP, showed a 25% plus incremental benefit of eliminating the LAA along with AF ablation in persistent cases. In addition, he noted that SentreHEART recently received approval for an Investigational Device Exemption (IDE) from the FDA to begin enrollment in the randomized, controlled AMAZE trial.
In the following session, Dr. Jason Mensch presented on the role of anesthesiologists in EP. He described the different sedation states, types of sedatives, and their electrophysiological effects. He showed that general anesthesia reduces the prevalence of pulmonary vein reconnection during repeat ablation when compared with conscious sedation. Procedure-related factors requiring anesthesia consultation for sedation include: patient cooperation, minimizing movement, assist with hemodynamic management, procedure complexity, and prior history of OSA.
Dr. Singer then spoke about AF burden and anticoagulation. He concluded that based on the AFFIRM, TRENDS, ASSERT, VA CareLink, and IMPACT studies, AF raises the risk of stroke via cardioembolic mechanism, and there is evidence for an acute rise in stroke risk starting with the onset of AF and tapering off after the end of an AF episode. It is unclear whether there is a residual increase in stroke risk after an AF episode, whether anticoagulation following multi-hour episodes for higher risk patients makes sense, and whether oral anticoagulants can be stopped safely 30 days post AF. These issues will be determined by conducting more randomized clinical trials.
Dr. Deering spoke about cardiac dysautonomia, the epidemiology of syncope, and its economic burden related to hospitalization. The present approach in syncope evaluation is inefficient; although postural vital signs have the lowest cost and the most impact in guiding management, they are used infrequently. He concluded that autonomic dysfunction syndromes such as neurogenic orthostatic hypotension, postural orthostatic tachycardia syndrome, and inappropriate sinus tachycardia are diverse disorders with multiple clinical, physiological and psychological manifestations; workup is often inconclusive with usually ineffective or incomplete treatment. Therefore, clinical judgment and realistic goal setting are important.
Next, Dr. George Van Hare presented on issues surrounding genetic testing for inherited arrhythmia syndromes. Privacy concerns and adverse consequences of genetic testing may result in discrimination in life insurance, disability insurance, and long-term care insurance not prohibited by law. He reviewed the HRS/EHRA Expert Consensus Statement on the State of Genetic Testing for the Channelopathies and Cardiomyopathies (including LQTS, Brugada Syndrome, and cathecholaminergic polymorphic VT. He also spoke on the source of uncertainty in class 2 mutations, which shows tests are not deterministic but probabilistic due to incomplete penetrance and possible false positives. Although the results of genetic testing can lead to changes in management, it is also an intrusion of privacy since it affects not just the individual being tested, but also their families. There is currently a national discussion of privacy issues in genomic medicine.
To end the first day’s sessions, Dr. Madhu Reddy and Dr. Sanjaya Gupta presented some interesting cases, with a good discussion that followed.
At the start of day 2, the Dr. Manohar Sai Gowda Young CV Researcher Awards were given out in his memory. This year’s winners were Uma Mahesh Avula, MD (1st Place), Alon Eisen, MD (2nd Place), and Andrew Landstrom, MD, PhD (3rd Place).
Dr. Shivkumar and Dr. Vivek Reddy then participated in a debate on the value of routinely using hemodynamic support in VT ablation. They discussed the pros and cons of using these lifesaving yet expensive devices. The consensus was that they are important tools that should be readily available for use in the right patient, including those with very poor EF and hemodynamically unstable VT.
Dr. Bunch spoke on focused vs substrate modification in VT ablation. In patients with VT, the success rate of substrate modification remains suboptimal; more extensive ablation, which targets every area showing diseased recordings, may be more successful in the long term. A prospective study by Di Biase et al demonstrates that ablation using endo-epicardial homogenization of the scar significantly increases freedom from VAs in patients with ischemic cardiomyopathy and electrical storm. Further randomized trials are needed to confirm the clinical relevance.
Next, Dr. Packer discussed strategies using ICE to increase the success rate in difficult anatomical locations. Intracardiac echocardiography can image the heart in real time and help identify structures and other obstacles, thus promoting better navigation. It can be used for early detection of complications such as effusion. ICE can also be used to assess epicardial substrate in non-ischemic cardiomyopathy and scars in ischemic cardiomyopathy.
Dr. Kim then described techniques and indications for epicardial ablation. This approach is necessary in certain arrhythmias and is safe since it protects adjacent vital structures. He discussed the role of epicardial mapping and ablation in patients with ventricular arrhythmia. The technique can be used in the treatment of VT, VF, and AF.
Dr. Sonny Jackman spoke about how the intrinsic cardiac autonomic system plays a significant role in acute electrical remodeling. The intrinsic cardiac autonomic nervous system (GP activation) plays a major role in acute electrical remodeling in the canine model. He summarized that low-level vagal stimulation inhibits activity and prevents acute electrical atrial remodeling during rapid atrial pacing in a canine model, low-level vagal stimulation may be achieved non-invasively by stimulating the tragus of the ear, and that preliminary experience suggests that low vagal stimulation (tragus) significantly shortens induced arrhythmia episodes in patients with paroxysmal AF.
In the next session, Dr. Di Biase presented on the role of non-PV triggers in AF. He explained the presence of scar as a predictor of failure in AF ablation. Important potential triggers include the coronary sinus, LAA, interatrial septum, SVC, RA, and the ligament of Marshall. The presence of non-sustained atrial arrhythmia other than AF during an isoproterenol test is enough to warrant ablation. Anesthetic agents and antiarrhythmic drugs such as amiodarone may mask non-PV triggers. He noted that 15-20% of paroxysmal AF patients have a non-PV trigger. He concluded that LAA and CS are the most relevant triggers in non-paroxysmal AF patients.
Dr. Mansour then described the importance of force sensing in RF ablation, how to achieve an optimal contact force, and how force sensing can be used to assess ablation lesion formation. Based on the TOCCASTAR and SMART-AF studies, he concluded that force sensing improves the efficacy of ablation. The use of a deflectable sheath improves the ability to achieve the desired contact force and efficacy of ablation. In addition, integration of force sensing with other ablation markers such as catheter location, power, and duration is likely to allow the assessment of lesion formation during ablation.
Dr. Tandri spoke on the current status of AF ablation, noting that the procedural success rate for persistent AF is approximately 60%. AF is associated with increased collagen deposition, and the time in continuous AF correlates with scar. He summarized that scar imaging provides a valuable addition of prognostic information, and late gadolinium imaging has a role in detecting possible sites of reconnection. The technique to differentiate edema from irreversible injury is evolving. Integration in routine clinical practice will require further multicenter studies.
Dr. Saad next presented on the role of AV nodal ablation for the treatment of AF. AV nodal ablation still has a role for symptomatic treatment, as it is a highly effective procedure and gives significant improvement in quality of life. AV nodal ablation should be offered to patients who: are refractory to antiarrhythmic drugs or to those with repeated ablation procedures, have heart failure with failed PVI, or as an alternative to high-risk PVI when pharmacologic rate control cannot be achieved. It also plays an important role in CRT patients with LV dysfunction.
Dr. David Wilber reviewed the mechanism leading to cardiac structural remodeling associated with AF, the role of MRI in predicting ablation outcomes, and whether fibrosis can be an ablation target. He presented data on epicardial fat and fibrosis, and showed only modest correlation between epicardial fat and the extent of LA fibrosis. LA volume was the only other independent predictor of LA fibrosis. Substrate remodeling and fibrosis occur early in AF and may not be attributable to high atrial rates alone. AF may be chronic and often a progressive disease, and early intervention to maintain sinus rhythm is prudent. Strategies beyond sinus rhythm maintenance, targeting inflammation, profibrotic signaling pathways, and autonomic activation may be required to improve long-term outcomes.
Dr. Ruskin then presented on the role of AF in mild cognitive impairment. A recent meta-analysis demonstrated that AF is associated with a 40% increase in the risk for cognitive impairment independent of a history of symptomatic stroke and other comorbidities. One such mechanism may be silent cerebral infarctions (SCIs). Dr. Ruskin presented a meta-analysis and systematic review from his team; the results of this study showed that AF is associated with a more than two-fold increase in the odds for SCI.
Lastly, Dr. Madhu Reddy discussed the association between caffeine, alcohol, energy drinks, and exercise. Based on recent studies, he summarized that low-dose caffeine was in fact protective and had no negative impact on higher doses of caffeine. Acute excessive alcohol consumption most likely increases the risk of AF, and moderate daily alcohol (>2 drinks/day) has shown to increase the risk of AF. The role of energy drinks is unknown, although there were isolated case reports of “triggered AF”. In terms of exercise endurance, athletes are at higher risk of AF when compared to non-athletes. Unlike non-athletes, the mechanism of AF in athletes is often vagally mediated. Females are less likely to develop exercise-induced AF, and younger males are more likely to develop exercise-induced AF.
To round out the last day, top brass from some of the main device companies presented their vision for the next decade and their goals for patient care.
Next year’s KCHRS conference will be held on August 20-21, 2016.
Videos of the conference will be posted on www.kchrs.com in the coming month!