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HomeCirculationVol. 115, No. 4Issue Highlights Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIssue Highlights Originally published30 Jan 2007https://doi.org/10.1161/circ.115.4.427Circulation. 2007;115:427LOSS-OF-FUNCTION MUTATIONS IN THE CARDIAC CALCIUM CHANNEL UNDERLIE A NEW CLINICAL ENTITY CHARACTERIZED BY ST-SEGMENT ELEVATION, SHORT QT INTERVALS, AND SUDDEN CARDIAC DEATH, by Antzelevitch et al.There are multiple causes of inherited arrhythmia syndromes, many due to ion channelopathies. Mutations in ion channel encoding genes lead to clinical phenotypes of arrhythmias, conduction abnormalities, and vulnerability to sudden death. Recently, rather than typical long- or short-QT syndrome, Brugada syndrome, or conduction defects, reports of several overlapping clinical features bridge the spectrum of inherited arrhythmias. In this issue of Circulation, Antzelevitch and colleagues report finding mutations in L-type calcium channel encoding genes in 7/82 Brugada syndrome patients without SCN5A sodium channel or known long-QT syndrome mutations. Of these, 3 had an interesting clinical constellation of right precordial ST-segment elevation (resembling Brugada syndrome), short QT intervals (resembling short-QT syndrome), and sudden cardiac death. They characterize the clinical, genetic, and family histories and perform detailed in vitro biophysical functional analysis of the resultant calcium channel mutations, demonstrating loss of function deficits in this hybrid inherited arrhythmia disorder. See p 442.TRIGLYCERIDES AND THE RISK OF CORONARY HEART DISEASE: 10 158 INCIDENT CASES AMONG 262 525 PARTICIPANTS IN 29 WESTERN PROSPECTIVE STUDIES, by Sarwar et al.Although there have been many previous reports on the importance of serum triglyceride concentrations and the risk of coronary heart disease, the strength of the association and the existence of sex differences have remained controversial. Sarwar and colleagues report on case-control studies from Reykjavik and EPIC-Norfolk studies and present an updated meta-analysis in almost 300 000 participants in 29 Western prospective studies. They observed that the long-term stability of triglyceride measurements over time was similar to blood pressure and cholesterol values, and they account for regression dilution bias in their analysis. The authors observed that the top third of log-triglyceride values was associated with a 50% increased risk of coronary heart disease compared with the lower third. They also noted no major differences in risk by sex or in studies conducted among fasting versus nonfasting participants. The investigators note, however, that their data cannot resolve whether triglycerides per se are causally responsible for the excess coronary heart disease risk. See p 450.PROGNOSTIC VALUE OF HEART RATE INCREASE AT ONSET OF EXERCISE TESTING, by Leeper et al.Non–ST segment variables derived from the exercise ECG test have recently been shown to provide important prognostic information and, accordingly, have been the focus of much attention. Peak exercise capacity, the difference in heart rate from rest to peak exercise, and the fall in heart rate during early recovery can be easily measured during routine exercise testing and thus can be readily applied in clinical practice. In this issue, Leeper et al evaluate the prognostic value of heart rate responses at the start of exercise in 1959 patients referred for clinical treadmill testing and compare it to that provided by other variables derived from the same test. In an accompanying editorial, Bernard Chaitman offers important and practical insights regarding these interesting findings. See p 468 (editorial on p 430).Visit http://circ.ahajournals.org:Images in Cardiovascular MedicineCardiac Leiomyosarcoma. See p e47. Download figureDownload PowerPointKussmaul’s Sign in Right Ventricular Dysfunction. See p e49.Hemodynamic Consequences of Massive Coronary Air Embolism. See p e51.CorrespondenceSee p e54. Previous Back to top Next FiguresReferencesRelatedDetails January 30, 2007Vol 115, Issue 4 Advertisement Article InformationMetrics https://doi.org/10.1161/circ.115.4.427 Originally publishedJanuary 30, 2007 PDF download Advertisement