INSIDE THIS ISSUE OF JACC
Inside This Issue of JACC
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State-of-the-Art Paper
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Leptin Resistance May Be the Link Between Obesity and CVD.
High levels of circulating leptin are common in the obese and have been associated with insulin resistance and cardiovascular disease (CVD). But low levels of leptin are associated with obesity and increased food intake in animals. Martin and colleagues propose a model where leptin resistance may be tissue selective: central leptin resistance lead to increased food intake and obesity, while elevated circulating leptin stimulates pathways in peripheral tissues that predispose to CVD. Leptin resistance may represent a new diagnostic and therapeutic target in obesity-related CVD. See page 1201.
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Viewpoint and Commentary
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Initiatives to Shorten Total Ischemic Time for STEMI.
In their Viewpoint paper, Terkelsen and colleagues proffer that the 2007 Updated ACC/AHA STEMI Guidelines unfairly penalize the transfer of patients to percutaneous coronary intervention (PCI)-capable hospitals. This is because the acceptable time delay for primary PCI begins with emergency medical services arrival, but for fibrinolysis the time delay begins with arrival to the hospital door. Antman responds in a Commentary that the goal of both the D2B (Door to Balloon) Alliance and the AHA Mission: Lifeline is to shorten total ischemic time by focusing on in-hospital processes and comprehensive national initiatives, respectively. See pages 1211 and
1216. See figure.
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Heart Rhythm Disorders
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Changes in Atrial APD May Initiate or Propagate AF.
Narayan and colleagues hypothesized that changes in the action potential duration (APD) of atrial cells near the pulmonary veins (PVs) may allow a single premature atrial contraction to initiate atrial fibrillation (AF). They measured changes in the APD caused by changes in the diastolic interval (DI) from the prior beat. In patients with paroxysmal AF, the APD shortened to a greater extent than the DI; in patients with permanent AF the relative APD lengthened. This study reveals that changes in the APD near PVs may explain both the initiation and propagation of AF. See page 1222. See figure.
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Heart Rhythm Disorders
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Increased Frequency of J-Point Elevation in Patients With a History of VF.
J-point elevation is usually an innocent finding in young individuals, but some reports suggest an association with idiopathic ventricular fibrillation (VF). Rosso and colleagues performed a case-control study of 45 patients with idiopathic VF and 2 matched control groups. The J-point elevation was 3 times more common in those with VF (42% vs. 13%), particularly for J-point elevation in the limb leads. The finding of J-point elevation in an asymptomatic subject should not provoke an extensive evaluation as the risk of having idiopathic VF is estimated to be approximately 1 in 10,000. While J-point elevation in the limb leads is associated with VF, the absolute risk of VF remains low. See page 1231. See figure.
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Cardiac Resynchronization Therapy
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Patients With AF Benefit From CRT.
Although one-third of advanced heart failure patients exhibit atrial fibrillation (AF), it is unclear if they benefit from cardiac resynchronization therapy (CRT). Upadhyay and colleagues performed a meta-analysis comparing the outcomes for patients in sinus rhythm (SR) and AF treated with CRT. Five studies with over 1,000 subjects were included. Both AF and SR patients benefited significantly from CRT, with improvements in ejection fraction and in indices of quality of life. CRT appears to be beneficial in patients with AF, widened QRS, and left ventricular dysfunction, with benefits similar to those seen for patients in SR. See pages 1239 and
1247.
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Cardiomyopathy
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Poor Prognosis for Patients With Lamin A/C Mutations.
Mutations in the lamin A/C (LMNA) gene have been associated with idiopathic dilated cardiomyopathy (DCM) plus atrioventricular block (AVB). Pasotti and colleagues followed patients from 27 families in which at least 1 person was diagnosed with DCM and had an LMNA mutation. Of the 164 family members, 94 were carriers of LMNA gene mutations and 64% were phenotypically affected with a DCM. During a median follow-up of 4.5 years, over 70% of the affected individuals experienced an adverse event, mostly ventricular arrhythmias. By multivariable analysis, New York Heart Association funcational class III to IV and a history of competing in vigorous sports activity for  10 years were independent predictors of total events. DCMs caused by the LMNA gene defects are highly penetrant, and result in adult-onset DCM with high rates of ventricular arrhythmias. See pages 1250 and
1261. See figure.
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Cardiac Imaging
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DE-CMRI Can Quantify the Extent of Left Atrial Scarring After PVAI.
McGann and colleagues describe a delayed enhancement cardiac magnetic resonance imaging (DE-CMRI) technique for detecting left atrial wall injury after pulmonary vein antrum isolation (PVAI) procedures for atrial fibrillation (AF). Comparing pre- and 3-month post-magnetic resonance imaging images revealed that all PVAI patients have some areas of the left atrium that display delayed enhancement. There was a strong relationship between the degree of left atrial enhancement and freedom from AF recurrence. DE-CMRI may be useful for quantifying the extent of injury following PVAI and for defining the optimal locations for ablation energy. See pages 1263 and
1272. See figure.
Related Articles
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Leptin Resistance: A Possible Interface of Inflammation and Metabolism in Obesity-Related Cardiovascular Disease
- Seth S. Martin, Atif Qasim, and Muredach P. Reilly
J. Am. Coll. Cardiol. 2008 52: 1201-1210.
[Abstract]
[Full Text]
[PDF]
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Is There Any Time Left for Primary Percutaneous Coronary Intervention According to the 2007 Updated American College of Cardiology/American Heart Association ST-Segment Elevation Myocardial Infarction Guidelines and the D2B Alliance?
- Christian J. Terkelsen, Jacob T. Sørensen, and Torsten T. Nielsen
J. Am. Coll. Cardiol. 2008 52: 1211-1215.
[Abstract]
[Full Text]
[PDF]
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Time Is Muscle: Translation Into Practice
- Elliott M. Antman
J. Am. Coll. Cardiol. 2008 52: 1216-1221.
[Abstract]
[Full Text]
[PDF]
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Repolarization and Activation Restitution Near Human Pulmonary Veins and Atrial Fibrillation Initiation: A Mechanism for the Initiation of Atrial Fibrillation by Premature Beats
- Sanjiv M. Narayan, Dhruv Kazi, David E. Krummen, and Wouter-Jan Rappel
J. Am. Coll. Cardiol. 2008 52: 1222-1230.
[Abstract]
[Full Text]
[PDF]
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J-Point Elevation in Survivors of Primary Ventricular Fibrillation and Matched Control Subjects: Incidence and Clinical Significance
- Raphael Rosso, Evgeni Kogan, Bernard Belhassen, Uri Rozovski, Melvin M. Scheinman, David Zeltser, Amir Halkin, Arie Steinvil, Karin Heller, Michael Glikson, Amos Katz, and Sami Viskin
J. Am. Coll. Cardiol. 2008 52: 1231-1238.
[Abstract]
[Full Text]
[PDF]
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Cardiac Resynchronization in Patients With Atrial Fibrillation: A Meta-Analysis of Prospective Cohort Studies
- Gaurav A. Upadhyay, Niteesh K. Choudhry, Angelo Auricchio, Jeremy Ruskin, and Jagmeet P. Singh
J. Am. Coll. Cardiol. 2008 52: 1239-1246.
[Abstract]
[Full Text]
[PDF]
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Cardiac Dyssynchrony in Congestive Heart Failure and Atrial Fibrillation: Integrating Regularization and Resynchronization
- Jozef Bartunek and Marc Vanderheyden
J. Am. Coll. Cardiol. 2008 52: 1247-1249.
[Full Text]
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Long-Term Outcome and Risk Stratification in Dilated Cardiolaminopathies
- Michele Pasotti, Catherine Klersy, Andrea Pilotto, Nicola Marziliano, Claudio Rapezzi, Alessandra Serio, Savina Mannarino, Fabiana Gambarin, Valentina Favalli, Maurizia Grasso, Manuela Agozzino, Carlo Campana, Antonello Gavazzi, Oreste Febo, Massimiliano Marini, Maurizio Landolina, Andrea Mortara, Giovanni Piccolo, Mario Viganò, Luigi Tavazzi, and Eloisa Arbustini
J. Am. Coll. Cardiol. 2008 52: 1250-1260.
[Abstract]
[Full Text]
[PDF]
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Lamin A/C Gene and the Heart: How Genetics May Impact Clinical Care
- Luisa Mestroni and Matthew R.G. Taylor
J. Am. Coll. Cardiol. 2008 52: 1261-1262.
[Full Text]
[PDF]
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New Magnetic Resonance Imaging-Based Method for Defining the Extent of Left Atrial Wall Injury After the Ablation of Atrial Fibrillation
- Christopher J. McGann, Eugene G. Kholmovski, Robert S. Oakes, Joshua J.E. Blauer, Marcos Daccarett, Nathan Segerson, Kelly J. Airey, Nazem Akoum, Eric Fish, Troy J. Badger, Edward V.R. DiBella, Dennis Parker, Rob S. MacLeod, and Nassir F. Marrouche
J. Am. Coll. Cardiol. 2008 52: 1263-1271.
[Abstract]
[Full Text]
[PDF]
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Damage Assessment After Ablation: Role of Cardiovascular Magnetic Resonance
- Henry R. Halperin and Saman Nazarian
J. Am. Coll. Cardiol. 2008 52: 1272-1273.
[Full Text]
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State-of-the-Art Paper
Viewpoint and Commentary
