Heart
rhythm abnormalities (arrhythmias) are a worrisome side effect of certain drugs,
and have led to the discontinuation of several investigational antiretroviral
agents.
In a
study reported in the July 31, 2007 issue of AIDS, researchers assessed
the heart rhythms of 75 HIV positive, treatment-experienced patients (two-thirds
men) receiving ritonavir-boosted or unboosted atazanavir
(Reyataz).
Heart
rhythm is assessed using electrocardiography, which records the electrical activity
of the heart. An electrocardiogram (ECG or EKG) produces graphs that show the
heartbeat represented as a series of waves. Each segment of the wave is identified
with letters from "P" through "U." Specific parts of the heartbeat
are described using these letters, for example, the "QRS" interval or
the "QT" interval.
Normal
heart rhythm
Results
•
The "QRS" interval increased during treatment with atazanavir in 56
of the 75 subjects (74.7%), by a median 5 ms (P < 0.0001).
•
The "PR"
and adjusted "QT" intervals did not change significantly.
•
New asymptomatic bundle
branch blocks (disruption of electrical activity transmitted to one of the heart's
ventricles) were observed in 4 patients.
•
1 subject with a baseline
first-degree atrioventricular block developed symptomatic bradyarrhythmia (abnormally
slow heart rate) while also receiving the beta-blocker drug atenolol.
Conclusion
Based
on these findings, the authors concluded, "The electrocardiographic monitoring
of patients treated with atazanavir seems advisable."
8/21/07
Reference N
Gianotti, M Guffanti, L Galli, and others. Electrocardiographic changes in HIV-infected,
drug-experienced patients being treated with atazanavir. AIDS 21(12): 1648-1651.
July 31, 2007.
