Clinical Summaries

Abstract

HomeCirculationVol. 122, No. 13Clinical Summaries Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBClinical SummariesOriginal Research Put Into Perspective for the Practicing Clinician Originally published28 Sep 2010https://doi.org/10.1161/CIR.0b013e3181ed3402Circulation. 2010;122:1253–1254Long-Term Recording of Cardiac Arrhythmias With an Implantable Cardiac Monitor in Patients With Reduced Ejection Fraction After Acute Myocardial Infarction: The Cardiac Arrhythmias and Risk Stratification After Acute Myocardial Infarction (CARISMA) StudyCardiac Arrhythmias and Risk Stratification After Acute Myocardial Infarction (CARISMA) reports on long-term cardiac arrhythmias recorded by an implantable cardiac monitor in patients with left ventricular ≤40% after myocardial infarction. Clinically significant bradyarrhythmias and tachyarrhythmias were documented in a substantial proportion of patients, most of them asymptomatic. A large number of the documented arrhythmias would result in device therapy according to the current guidelines. The most significant arrhythmia was intermittent high-degree atrioventricular block, which was associated with a very high risk of cardiac death. However, the study was observational, and whether the use of implantable cardiac monitors in this population could improve clinical outcome should be tested in larger randomized trials. See p 1258.Long-Term Benefit of Primary Prevention With an Implantable Cardioverter-Defibrillator: An Extended 8-Year Follow-Up Study of the Multicenter Automatic Defibrillator Implantation Trial IICurrent guidelines for device-based therapy provide a recommendation for primary prevention with implantable cardioverter-defibrillator (ICD) therapy in patients with an ejection fraction of ≤35%. Presently, however, there are no data from clinical trials on the long-term benefit of ICD therapy. The present study is the first to assess the long-term survival benefit associated with primary prevention with an ICD in the low–ejection fraction population. We provide 8-year follow-up data for all participants in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II). The study shows that the life-saving benefit of the ICD was sustained during the extended follow-up period, providing a significant 34% reduction in the risk of death during 8 years of follow-up. The survival benefit of the ICD was evident during both the early (0 to 4 years) and late (5 to 8 years) phases of the extended follow-up period. Furthermore, we show enhanced long-term survival benefit from primary ICD therapy among patients who received backup pacing devices and among those who did not develop symptomatic heart failure after ICD implantation. Our findings on the continued life-prolonging benefit of the ICD during long-term follow-up provide support for a more widespread use of the ICD in a primary prevention setting. However, our data also suggest that more measures should be taken to improve long-term device efficacy in the low–ejection fraction population, including appropriate device programming as well as measures for prevention of heart failure progression after ICD implantation. See p 1265.Who Are the Long-QT Syndrome Patients Who Receive an Implantable Cardioverter-Defibrillator and What Happens to Them? Data From the European Long-QT Syndrome Implantable Cardioverter-Defibrillator (LQTS ICD) RegistryThe key therapies for long-QT syndrome (LQTS) are β-blockers, left cardiac sympathetic denervation (LCSD), and the implantable cardioverter-defibrillator (ICD). The ICD, despite concerns about complications in the young, is being used in a growing number of patients. There are no adequate data on the patient characteristics associated with ICD implantation in clinical practice and on their outcome. We initiated a largely European LQTS ICD Registry. Among the 233 patients enrolled and with a mean follow-up close to 5 years, there was an excess of female patients and of LQT3 patients. Unexpectedly, 9% of the patients were asymptomatic when they received an ICD. Appropriate shocks were received by 28% of patients; adverse events occurred in 25%. We developed a scoring system based on simple, easily available clinical variables to verify possible prediction of appropriate shocks. These were predicted by age <20 years at implantation, a QTc >500 milliseconds, prior cardiac arrest, and cardiac events despite therapy; within 7 years, appropriate shocks occurred in no patients without any of these variables and in 70% of those with all of them. Our data suggest how to identify logical candidates for ICD implantation and indicate that some specific programming features may decrease the rate of unnecessary shocks. The relatively high incidence of complications within 5 years in a relatively young population calls for a reassessment of the criteria for implanting ICDs in LQTS patients. The proposed risk scoring system may increase the probability of a rational decision, balancing safety with quality of life. See p 1272.Importance of Refractory Pain and Hypertension in Acute Type B Aortic Dissection: Insights From the International Registry of Acute Aortic Dissection (IRAD)Medical management is generally recommended for patients with uncomplicated acute type B aortic dissection (ABAD), whereas invasive treatment such as surgical or endovascular approaches is typically recommended for ABAD patients with complications such as malperfusion syndromes, extending dissection, or aortic rupture, who are defined as high risk. The optimal approach for uncomplicated ABAD patients who develop recurrent/refractory pain or refractory hypertension is still being debated. We used data from the International Registry of Acute Aortic Dissection to better define the importance of refractory pain and/or refractory hypertension in ABAD. We found that in uncomplicated ABAD patients, medical therapy was associated with excellent outcomes, whereas the in-hospital mortality was considerably increased in those ABAD patients with refractory pain and/or refractory hypertension, especially when these patients underwent medical management. These observations suggest that ABAD patients presenting with refractory hypertension and/or pain symptoms in the absence of other complications are at intermediate risk for an adverse in-hospital outcome but still have a better outcome than the high-risk group. More invasive treatment, such as an endovascular approach, may be indicated in this intermediate-risk group. See p 1283.Volume-Outcome Relationships and Abdominal Aortic Aneurysm RepairThere is a well-established literature relating procedure volume to outcomes of care, but incorporating such information into clinical decision making is problematic when there is >1 treatment option for a particular condition. In the case of abdominal aortic aneurysm repair, surgeons may choose traditional open or endovascular repair. Because the approach is decided by the surgeon after referral, it is not clear whether the referring physician should consider overall abdominal aortic aneurysm repair volume or specific volumes for open and endovascular repair in their referral decisions. In this study, we used comprehensive data from the Medicare program over the years 2001–2006 to investigate the relationship between institutional volume and outcomes of abdominal aortic aneurysm repair. We found that whereas there is a relatively constant relationship between open repair and perioperative mortality, for endovascular repair there is a significant improvement in mortality from the lowest quintile of volume to the second lowest, but improvements beyond that volume are small. Because virtually all high-volume open repair facilities have at least modest endovascular volume, referral decisions should be made on the basis of open repair volume rather than total or endovascular repair volume. Our data also suggest the possibility that as endovascular repair increasingly replaces open repair, fewer hospitals will have adequate open repair volume to maintain the experience needed to achieve optimal outcomes. See p 1290.In Vivo Measurement of Mitral Leaflet Surface Area and Subvalvular Geometry in Patients With Asymmetrical Septal Hypertrophy : Insights Into the Mechanism of Outflow Tract ObstructionDynamic left ventricular outflow tract obstruction (LVOTO) has long been recognized as a central feature of hypertrophic cardiomyopathy. Analyzing the determinants of systolic anterior motion of the mitral valve and consequent LVOTO in patients with asymmetrical septal hypertrophy requires a comprehensive 3-dimensional analysis of mitral leaflet area, papillary muscle (PM) geometry, and distribution of left ventricular hypertrophy. This study used real-time 3-dimensional echocardiography to demonstrate that patients with asymmetrical septal hypertrophy and LVOTO have larger mitral leaflet areas and shorter inter-PM distance. Determinants of minimal LVOT area during systole were end-systolic volume, indexed total mitral leaflet area, inter-PM distance, annular height, and LVOT hypertrophy index. These findings support the concept that myocardium is not the only tissue affected in patients with asymmetrical septal hypertrophy, and integrated PM–mitral valve geometry best explains the pathogenesis of LVOTO in patients with asymmetrical septal hypertrophy, with increased mitral leaflet area and annular height allowing greater leaflet slack, and PM position and LVOT hypertrophy positioning the slack leaflet into left ventricular outflow. Because each element of PM–mitral valve geometry can be thoroughly evaluated with the use of real-time 3-dimensional echocardiography, an individualized strategy can be applied accordingly, and primary changes of the mitral leaflet and subvalvular apparatus can be potential targets of new treatment options for effective relief of LVOTO. See p 1298.MicroRNA-494 Targeting Both Proapoptotic and Antiapoptotic Proteins Protects Against Ischemia/Reperfusion-Induced Cardiac InjuryMicroRNAs (miRs), a new class of non–protein-coding small RNAs, have emerged as regulators that control the expression of hundreds of proteins. As a consequence, they may widely influence the signaling networks leading to pathological or physiological responses such as myocardial ischemia/reperfusion-induced injury and ischemia preconditioning–elicited cardioprotection. Although miR expression has been profiled in infarcted hearts from animal models and human patients, the role of a specific miR in ischemic heart disease is just emerging. Uncovering miRs as important regulators not only for single genes but also for whole gene networks has enormous therapeutic implications. In the present study, we discovered that increased levels of mature miR-494 rendered cardioprotection against ischemia/reperfusion-induced injury, whereas knockdown of endogenous miR-494 by administration of antagomiR-494 sensitized hearts to ischemia/reperfusion injury. Importantly, we identified that miR-494–targeted PTEN, ROCK1, and CAMKIIδ in cardiomyocytes consequently activated the Akt signaling pathway. These data suggest that the downregulation of miR-494 observed in human failing hearts may be causally involved in the progression of heart failure, at least in part. Therefore, systemic or local administration of miR-494 may be the newest prospect for the management of ischemic heart disease. See p 1308.Transcatheter Aortic Valve Implantation : Durability of Clinical and Hemodynamic Outcomes Beyond 3 Years in a Large Patient CohortTranscatheter aortic valve implantation is rapidly gaining acceptance as a viable therapy for high-risk patients with severe symptomatic aortic stenosis. Thus far, short-term outcomes have been encouraging, with limited data beyond 1 year. The present study evaluated the medium- to long-term outcomes of an early cohort undergoing transcatheter aortic valve implantation, with all patients evaluated by follow-up at a minimum of 3 years from the procedure. The study demonstrated excellent durability, no evidence of structural valvular failure, and preserved hemodynamics. Small changes in valve area and transvalvular gradients were documented for the first time, which were generally similar to those in previously published surgical series that reported on bioprosthetic valves in the aortic position. Patients showed significant improvement in functional state, which appeared to be preserved over time. Postprocedural aortic regurgitation was generally mild and did not appear to worsen over time. Detailed computed tomographic imaging demonstrated no evidence of valve fracture, deformation, or valve migration. At a median of 3.7 years, patients surviving more than 30 days after a successful procedure had a survival rate of 57%. The bulk of late mortality in this high-risk cohort was due to significant comorbidities and was generally unrelated to aortic valve disease. Overall, when used in patients who are deemed to be poor surgical candidates, transcatheter aortic valve implantation appears to offer an adequate and lasting resolution of symptomatic aortic stenosis. See p 1319. 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