Circulation. 2005;111:829
(Circulation. 2005;111:829.)
© 2005 American Heart Association, Inc.
Issue Highlights
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QTc PROLONGATION BY GRAPEFRUIT JUICE AND ITS POTENTIAL PHARMACOLOGICAL BASIS: HERG CHANNEL BLOCKADE BY FLAVONOIDS, by Zitron et al.
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Select dietary flavonoids, found in fruits, vegetables, teas,
and wines, are known to have antioxidant properties and positively
influence vascular function. Consumption of foods rich in these
flavonoids has been associated with reduced cardiovascular disease.
The effect of these agents on cardiac electrophysiology, however,
has not been reported. In this issue of
Circulation, Zitron
and colleagues demonstrate that many of these flavonoids inhibit
cardiac potassium channels. Additionally, pink grapefruit juice,
given to normal subjects, prolonged QTc. This finding suggests
that select dietary flavonoid intake can influence cardiac electrophysiology.
Whether these effects are proarrhythmic or antiarrhythmic is
currently not known. See p
835.
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DISTINCT HERITABLE PATTERNS OF ANGIOGRAPHIC CORONARY ARTERY DISEASE IN FAMILIES WITH MYOCARDIAL INFARCTION, by Fischer et al.
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Although most clinicians are familiar with the established risk
factors for the development of coronary artery disease (CAD)
and myocardial infarction (MI), a common question that arises
is 'How much of a patient’s risk for CAD or MI is genetically
determined?’ To answer this question, Fischer and colleagues
performed a detailed analysis of 402 families in which the index
patient had an MI before the age of 60. Indeed, traditional
risk factors played a large role in the risk of developing CAD,
but after correction for such factors, evidence emerged that
certain angiographic patterns of CAD appeared to be under genetic
control. Specifically, left main disease and proximal stenoses
in the major epicardial coronary arteries displayed a high heritability
pattern. Future research will need to focus on incorporating
this new information in screening strategies in asymptomatic
relatives of patients with CAD and MI. See p
855.
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HIGH PREVALENCE OF CARDIAC PARVOVIRUS B19 INFECTION IN PATIENTS WITH ISOLATED LEFT VENTRICULAR DIASTOLIC DYSFUNCTION, by Tschöpe et al.
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Is diastolic dysfunction a viral cardiomyopathy? When a patient
presents with congestive heart failure and systolic ventricular
dysfunction, the possibility of viral myocarditis is clearly
in the differential diagnosis. But should we think of isolated
diastolic dysfunction as a postviral syndrome? This week in
Circulation, Tschöpe et al present their findings from
extensive evaluation in a series of patients with diastolic
dysfunction. They included endomycardial biopsies in their workup
and screened the samples for the presence of the genome of parvovirus
B19, the cause of fifth disease in children. Their findings
are intriguing and offer the possibility that unexplained diastolic
dysfunction might be a consequence of infection with this common
virus. See p
879.
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Images in Cardiovascular Medicine
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Sinus of Valsalva Rupture With Dissection Into the Interventricular
Septum: Diagnosis by Echocardiography and Magnetic Resonance
Imaging. See p
e101.
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