May 14th, 2013
Study Questions Role of Dual-Chamber ICDs for Primary Prevention
Larry Husten, PHD
The majority of patients who receive an ICD for primary prevention without a pacing indication have a dual-chamber ICD implanted. Although there are a number of theoretical advantages with dual-chamber devices, they are more likely to cause complications than single-chamber devices. Although CMS requires providers to justify the medical necessity of dual-chamber devices, current guidelines from the AHA/ACC and HRS do not specify a single-chamber device.
In a new study published in JAMA, Pamela Peterson and colleagues analyzed data from 32,000 patients enrolled in the National Cardiovascular Data Registry (NCDR) who received an ICD for primary prevention without a pacing indication. Of these, 38% received a single-chamber device and 62% received a dual-chamber device. At 1 year there were no significant differences in mortality, all-cause hospitalization, or heart failure hospitalization between the two groups. However, patients in the dual-chamber group had a higher risk of complications, including a highly significant increase in the 90-day risk of mechanical complications requiring re-operation (1.43% in the single-chamber group versus 2.02% in the dual-chamber group, p<0.001). A very similar pattern emerged when the investigators performed an analysis that matched patients in the two groups with a propensity model. The analysis suggested “that the choice of a dual-chamber device is relatively random with respect to patient characteristics…”
In their discussion the authors noted that dual-chamber devices are more expensive than single-chamber devices and are also likely to increase costs through more complications and a greater risk of generator depletion. “Our study does not provide evidence that would support the more costly and more morbid device for patients receiving an ICD for primary prevention,” they wrote.
The authors concluded:
“Many patients receiving primary prevention ICDs receive dual-chamber devices. Dual-chamber devices do not appear to offer any clinical benefit over single-chamber devices with regard to death, all-cause readmission, or heart failure readmission in the year following implant. However, dual-chamber ICDs are associated with higher rates of complications. Therefore, among patients without clear pacing indications, the decision to implant a dual-chamber ICD for primary prevention should be considered carefully.”
May 13th, 2013
Selections from Richard Lehman’s Literature Review: May 13th
Richard Lehman, BM, BCh, MRCGP
CardioExchange is pleased to reprint selections from Dr. Richard Lehman’s weekly journal review blog at BMJ.com. Selected summaries are relevant to our audience, but we encourage members to engage with the entire blog.
JAMA 8 May 2013 Vol 309
Effect of Long-Detection Interval vs. Standard-Detection Interval for ICDs on Antitachycardia Pacing and Shock Delivery (pg. 1903): When an implanted cardioverter defibrillator goes off inside you, you are sure to feel deeply shocked: whereas, for others, watching you drop dead might be even more shocking. One needs to strike a balance. That was the purpose of the ADVANCE III (Avoid Delivering Therapies for Nonsustained Arrhythmias in ICD Patients III) trial. Essentially this was a gamble on how many ventricular tachycardia beats are allowed to happen before the device fired: with current devices it is usually 18-24, whereas in this trial half the patients got a newly programmed device which counts to 30-40. They stayed alive as much, didn’t have more syncopal episodes, and had a third fewer shocks in the first year.
NEJM 9 May 2013 Vol 368
n–3 Fatty Acids in Patients with Multiple CV Risk Factors (pg. 1800): They’re at it again! Crunching up thousands of tons of lovely oily fish and turning them into capsules of n-3 fatty acids. These were then fed to Italian “men and women with multiple cardiovascular risk factors or atherosclerotic vascular disease but not myocardial infarction. Patients were randomly assigned to n−3 fatty acids (1 g daily) or placebo (olive oil).” Maybe 1G of olive oil is just a placebo: certainly for an Italian. Anyway, there was no difference at 5 years. To derive any protection, you have to eat the fish as well as the oils. Turbot is the best fish for n-3 fatty acids, I’m told: excellent as steaks or fillets fried in butter and served with a sauce of reduced cream, white wine and morels (or since you probably lack morels, some fresh chopped sorrel at the last minute); or just a simple hollandaise. The point of all fish is the butter that goes with them. There are those who assert that the quantity of butter should equal the quantity of fish, but I think that this should be left to the conscience of the individual believer.
Ann Intern Med 7 May 2013 Vol 158
Management Strategies for Asymptomatic Carotid Stenosis (pg. 676): Courtesy of the Annals, you can read the whole of a big systematic review of management strategies for asymptomatic carotid stenosis. Golly, what a mess. “Studies defined asymptomatic status heterogeneously. Participants in RCTs did not receive best available medical therapy… Future RCTs of asymptomatic carotid artery stenosis should explore whether revascularization interventions provide benefit to patients treated by best-available medical therapy.” Correct me if I’m wrong, but doesn’t that prove that all the 47 studies analysed here were actually unethical, because they tell us nothing about how to manage asymptomatic carotid stenosis and did not give patients an adequate control intervention?
May 13th, 2013
Novel Leadless Pacemaker Makes Debut at HRS 2013
Larry Husten, PHD
First results in human patients of a novel leadless pacemaker were presented last week at the HRS meeting in Denver by Vivek Reddy. Pacemaker leads are the most common source of complications associated with pacemakers today. The self-contained device is delivered via catheter to the right ventricle, to which it is attached with a fixation mechanism. The device is manufactured by Nanostim, Inc., a small company which is being acquired by St. Jude Medical.
Reddy reported on a feasibility study of 33 patients with indications for a VVI(R) pacemaker but who were not pacemaker dependent. The pacemaker was successfully implanted in 32 patients. One patient had a cardiac perforation and tamponade during the procedure. Five days after an uncomplicated surgical repair he had a large right-sided stroke and died.
During the course of the trial the procedure time shortened. Overall, the mean procedure time was 28 minutes. At evaluations at 2 days, 2 weeks, 6 weeks, and 3 months, pacing threshold, R-wave amplitude, and impedance were all similar to conventional pacemakers.
The device is expected to be available in Europe later this year. The investigators hope to start a large multicenter trial in the U.S. next year.
“Leadless pacemakers are a promising new technology that could eliminate one of the biggest complication risks with these life-saving devices – the lead,” said Reddy in an HRS press release. “Our initial experience indicates that the procedure is faster and minimally invasive compared to traditional implantation surgery, which may dramatically improve recovery times for patients.”
May 13th, 2013
Things I found at HRS 2013: Education, Science, Friends, and Mentors
Sandeep K Goyal, MD
Several Cardiology Fellows who are attending the Heart Rhythm Society meeting in Denver this week are blogging for CardioExchange. The Fellows include Luis Garcia, Sandeep Goyal, and Amit Mehrotra. You can view the previous post
I was strolling near the Convention Center around 1 pm Sunday, and the area was empty. Until a few hours back, this same place was full of people in suits and ties, their HRS badges hanging across their chests. The Hyatt lobby bar, where getting a seat was hard for last few days, was empty. It was a sign — HRS has ended, and it’s time to go home!
The City of Denver served as an excellent host to this conference. On a personal level, I learned a lot, made quite a few new friends (or connections as we call them these days!), and saw lots of old friends.
During my cardiology fellowship interviews, I met a lot of people who provided useful insights in their home programs and eventually played a big role in my decision to rank the programs the way I did. I never had a chance to see most of these people again, never had a chance to thank them in person. This HRS meeting connected me to lot of them, and I could finally express my gratitude for their help and advice 4 years ago.
Dr. Brian Olshansky struck me as a serious academic, when I met him for an interview at University of Iowa. I got to see his witty and sarcastic side during his Hyde Park Session, “Obamacare: Our Salvation?” He poked fun at rising healthcare costs, loss of physician autonomy, and physician-patient relationships. He was anguished that all the effort was directed at the health of the healthcare system and not the health of the patient.
Dr. Anne Curtis took the grand concourse for another Hyde Park Session, “Is There a Future for Academic EPs?” This was a much more serious, but optimistic, outlook on the future of academic EP. She stressed that keeping academic EP alive is not only useful but also indispensable. Yes, public funding is decreasing, but on the other hand there is more philanthropy. She suggested that cardiology/EP chairs at academic institutions engage with community philanthropists and help fund endowed chairs. Her advice for young trainees like me: If you have curiosity and drive to innovate and to seek answers to problems that perplex others, you have a very bright future in academic medicine.
I am leaving Denver with more knowledge, more friends, and more optimism than when I arrived here. I am already looking forward to San Francisco for HRS 2014.
May 13th, 2013
Blogging at HRS 2013: From The FIT Lounge, Insights From Douglas Zipes About Publishing
Sandeep K Goyal, MD
Several Cardiology Fellows who are attending the Heart Rhythm Society meeting in Denver this week are blogging for CardioExchange. The Fellows include Luis Garcia, Sandeep Goyal, and Amit Mehrotra. You can view the previous post
When I was planning my trip to Denver, it seemed like it was a lot of time to spend at a conference. Truthfully, it has been a great conference and time has flown by.
I finally managed to walk to the Fellows in Training lounge, hoping to connect with some co-fellows. I did find lot of fellows, but to my surprise Dr. Zipes was there and ready to answer burning questions about getting published.
I had a brief chat with him and gained some useful insights which I am excited to share with you.
Me: What motivated a busy and successful clinician-scientist like yourself to get into journal editing?
Dr. Zipes : One of my passions is to see good work materialize in print. Being an editor allows me to critically review new ideas and also helps me bring a world class EP journal to a receptive audience.
Me: What are certain things that authors shouldn’t do, when submitting a paper?
Dr. Zipes: One of things that I absolutely dislike is a “funny, cutesy title”, which doesn’t capture the essence of your paper. HeartRhythm is a scientific journal and readers would want and expect people to communicate in a scientific way.
Me: Your journal is known for a very quick turnaround time. How do you manage to do that?
Dr. Zipes: I personally review every paper and do it everyday, 365 days a year. It usually takes me somewhere from 5 seconds to 20 minutes to make my initial decision and I take pride in the fact that, if the paper is rejected, authors are notified of the rejection sooner than later. On the same note, we expect our reviewers to have quick turnaround time. Time from submission to my decision is less than 10 days and we publish papers in an online platform in 3-5 days after acceptance.
Me: I know you announced that this is your last year as editor-in-chief. Why did you decide to step down, and who is taking over?
Dr. Zipes: I made a personal decision to set a precedent not to keep this job longer than 10 years and it was time for someone new to take over. Dr Peng Sheng Chen is the right person for the job.
Me: How did your wife get involved with the Journal?
Dr. Zipes: I was in between managing editors many years ago when I started JCE and she helped me during that time. I realized that she was very good and asked her if she would consider it as a full time job. She refused initially but then I made her “an offer she couldn’t refuse”. She was tired of cooking, so I told her she could close the kitchen. She took the job, and I haven’t had a home-cooked meal in over 20 years!! But it’s a small price to pay for having a great managing editor.
Dr. Zipes then had to go and chair another session and I was ready to go and get some more education.
May 12th, 2013
How Should Recent Trials Affect CRT Practice?
Sana M Al-Khatib, MD, MHS and John Ryan, MD
In recent weeks the cardiac resynchronization therapy (CRT) field has been absorbing the publication of the BLOCK HF trial in the New England Journal of Medicine and the publication of the NARROW-CRT trial in Circulation: Arrhythmia and Electrophysiology. These trials raised the possibility that CRT may improve clinical status in some patients with ischemic cardiomyopathy and narrow QRS. At the same time, however, news emerged that the EchoCRT trial, which was looking at CRT in HF patients with QRS <130 msec, had been stopped due to futility. CardioExchange’s John Ryan asked Duke’s Sana Al-Khatib to answer questions about these developments.
Ryan: Are the data from BLOCK HF sufficient to change your practice? In patients with AV block and decreased EF, are you going to be recommend CRT placement? Or have you been doing so already?
Al-Khatib: BLOCK-HF was a well-designed and conducted trial. In general, we require more than one good trial to change practice; however, given these data from BLOCK-HF and the convincing data on the potential deleterious effects of right ventricular pacing from different studies, I personally think it is best to implant a biventricular device in patients who meet the entry criteria of the BLOCK-HF trial. We have not been implanting a CRT device in such patients. I expect the results of BLOCK-HF to change practice.
Ryan: Why are there discrepant results in CRT on patients with narrow QRS? What is your opinion on the effects of CRT in HF patients with narrow QRS?
Al-Khatib: I have concerns about the NARROW-CRT trial that range from the relatively small sample size, to the integrity of blinding, to the methodology they used to determine dyssynchrony. When the EchoCRT trial was stopped due to futility, my understanding is that the trial had a much larger number of patients than the patients enrolled in NARROW-CRT (close to or more than 1000 patients in Echo CRT compared with only 111 patients in NARROW CRT). Although the results have not been published, and I cannot give my final assessment of EchoCRT until I see the data, I have to infer, based on the resources and expertise invested in EchoCRT, that CRT is not likely at all to be beneficial in patients with a narrow QRS. Therefore, we, as a medical community, should focus our efforts on other patient populations.
May 10th, 2013
Blogging at HRS 2013: Great Takeaways on Day 2
Luis Garcia, MD
Several Cardiology Fellows who are attending the Heart Rhythm Society meeting in Denver this week are blogging for CardioExchange. The Fellows include Luis Garcia, Sandeep Goyal, and Amit Mehrotra. You can view the previous post
Today was an amazing day of emerging data and great advice!
Sanjiv Narayan presented the results of a rotor-guided approach to AF ablation without PVI. The success rate was above 80%. These results have the potential to shift the AF ablation paradigm away from a pulmonary vein isolation approach. Llearning more about how the the mapping system finds the rotors is also of great interest. To treat AF without PVI isolation is a possibility that may be much closer than we think!
Eric Prystowsky’s noon session on how to build a successful career for the EP fellow was very insightful. At this intimate roundtable session, Dr. Prystowsky stressed the importance of his “Ps” (patience, punctuality, passion). He also highlighted his “Q” (quality of life) and not missing nonrepeatable events in life (for example, your child’s kindergarten graduation).
Overall, great takeaways!
May 10th, 2013
Encouraging 4-Year Results for Boston Scientific’s Watchman Device in AF Patients
Larry Husten, PHD
Encouraging long-term results from the PROTECT AF trial comparing the Watchman left atrial appendage closure device to warfarin in atrial fibrillation (AF) patients were presented yesterday at the Heart Rhythm Society meeting in Denver.
Previously the main results of the trial, published in the Lancet, demonstrated that the Watchman was noninferior to warfarin, but the total number of events in the trial was small. In addition, there were more safety problems, as might be expected, in the early days after implantation. The FDA required the company to perform a confirmatory trial. That trial, PREVAIL, has been the subject of considerable controversy. Now, long-term followup of PROTECT AF may help better understand the risks and benefits of the device.
Vivek Reddy presented 4-year followup results from PROTECT AF. The primary efficacy endpoint — the combined rate of all stroke, cardiovascular, or unexplained death and systemic embolism — occurred in 2.3% of the device group versus 3.8% of the warfarin group (RR 0.60, CI 0.41-1.05).
Death from any cause occurred in 3.2% of the device group versus 4.8% of the warfarin group (HR 0.66, CI 0.45-0.98, p=0.0379). The cardiovascular death rate was 1% in the Watchman group versus 2.4% in the warfarin group (HR 0.40, p=0.0045).
In the initial publication of the trial there was an increased number of events in the primary safety endpoint in the Watchman group. With longer followup that difference is no longer significant. There were 60 events per 1666.2 patients years in the Watchman group versus 27 events per 878.2 patient years in the warfarin group (RR 1.17, 0.78-1.95, p=0.196). Twenty-two Watchman patients had pericardial tamponade. Although these patients required extended hospitalization there were no deaths or long-term disabilities in this group. Reddy also reported that due to the greater experience of the operators, safety events were greatly reduced (from 6.3% to 3.7%) after the first half of the trial.
“This is a significant development because for the first time we were able to demonstrate that the WATCHMAN device was superior to warfarin for both primary efficacy and also mortality,” said Reddy, in a Boston Scientific press release. “This has tremendous upside potential for patients. In the PROTECT AF trial, LAA closure with the WATCHMAN device demonstrated the potential for a device-based approach to reduce the risk of stroke in AF patients. As clinicians, we often feel uncomfortable with life-long systemic anticoagulation therapy in patients because of an increased risk of falls and bleeding. The four-year data provide additional support for LAA closure as a potential viable long-term alternative to chronic warfarin therapy for patients to reduce the risk of stroke.”
Sanjay Kaul said that a claim of superiority should be regarded with caution: “While the total number of events (information size) has increased from 39 to 73, which explains the narrowing of the credible (confidence) intervals, caution is warranted before ENTHUSIASTICALLY claiming superiority.”
May 10th, 2013
Blogging from HRS 2013: Excitement at the Convention Center and Outside
Sandeep K Goyal, MD
Several Cardiology Fellows who are attending the Heart Rhythm Society meeting in Denver this week are blogging for CardioExchange. The Fellows include Luis Garcia, Sandeep Goyal, and Amit Mehrotra. You can view the initial post
Greetings from the Mile High City, where the HRS meeting is in full force. Denver is an exciting place to host this prominent meeting. The convention center is ideally located in lower downtown (fondly called LODO). With a variety of cool restaurants and bars in walking distance, Denver has enough to keep one busy when not learning EP. The opening highlight was President Clinton’s plenary address, which was well received. All the pioneers in cardiac electrophysiology are here in Denver. I had the pleasure of listening to Drs. Zipes and Josephson talk about their personal journey in field of EP and what motivated them to work so hard.
Riata lead failure was a major highlight of last year’s meeting and has a formidable presence in this year’s meeting. I started off the morning attending the debate about routine extraction of Riata leads with externalized conductors. Let’s just say emotions ran high on both sides. The late-breaking session was notable for the BRUISE CONTROL study showing low pocket hematoma rate with uninterrupted Coumadin use.
I wandered over to the exhibit hall and was astonished by amount of new technology that’s on display. Innovative projects like leadless pacemakers, fluoroless guidance in EP lab and the ever-shrinking size of pacemaker and ICD generators certainly make me excited about the future of EP.
Now, I am off to an off-campus seminar regarding strategies to reduce CIED infections.
May 9th, 2013
Bruise Control: Continued Warfarin Beats Heparin Bridging During Device Implantation
Larry Husten, PHD
Many patients receiving an ICD or a pacemaker are already receiving oral anticoagulants. Current guidelines recommend replacement of the oral anticoagulant with the temporary use of heparin as a bridging strategy. Now a new study, BRUISE CONTROL (Bridge or Continue Coumadin for Device Surgery Randomized Controlled Trial), offers convincing evidence that this strategy is not beneficial and, in fact, results in an increase in device-pocket hematoma. Results of the trial were presented today at the Heart Rhythm Society meeting in Denver and published simultaneously in the New England Journal of Medicine.
A group of mostly Canadian investigators randomized 681 patients undergoing ICD or pacemaker implantation with an annual risk for thromboembolic events greater than 5% to either heparin bridging or continued warfarin. The trial was terminated early after a prespecified interim analysis by the data and safety monitoring board. The primary outcome — clinically significant device-pocket hematoma, which the investigators defined as a hematoma that led to prolonged hospitalization, interruption of anticoagulation, or hematoma evacuation — was significantly reduced in the continued-warfarin group, as were all three components of the endpoint:
Primary outcome: 3.5% with continued warfarin versus 16% with heparin bridging (RR 0.19, CI 0.10-0.36, p<0.001).
- Hematoma prolonging hospitalization: 1.2% vs. 4.7% (RR 0.24, CI 0.08-0.72, p<0.006)
- Hematoma requiring interruption of anticoagulation: 3.2% vs. 14.2% (RR0.20, CI 0.10-0.39, p<0.001)
- Hematoma requiring evacuation: 0.6% vs. 2.7% (RR 0.21, CI 0.05-1.00, p=0.03)
There were no other statistically significant or clinically significant differences between the groups; continued warfarin therapy did not result in any major perioperative bleeding. The investigators caution that their results only apply to patients like those in the trial who have a high risk for thromboembolic events. In addition, they note, it is unknown whether their results apply to the new generation of oral anticoagulants (dabigatran, rivaroxaban, and apixaban).
“To many, the substantial reduction in pocket hematoma that we observed with continued warfarin may be counterintuitive,” says co-principal investigator Vidal Essebag, in an HRS press release. “One explanation that has been proposed is the concept of an ‘anticoagulant stress test.’ That is, if patients undergo surgery while fully anticoagulated, any excessive bleeding will be detectable and appropriately managed while the wound is still open. In contrast, when surgery is performed with heparin bridging, such bleeding may remain latent, and appear only when full anticoagulation is resumed postoperatively.”
“We hope that Bruise Control will change how we are treating patients around the world,” says lead author David Birnie, in the press release. “Our study conclusively shows that treating patients with a high risk of stroke with continued warfarin instead of heparin bridging will improve patient outcomes, decrease complications and reduce hospitalization.”
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