Heart failure patients with heart block benefit significantly
from cardiac resynchronization therapy (CRT), according to the
results of an eight-year national clinical trial led by principal
investigator Anne
B. Curtis, MD.
Curtis, the Charles and Mary Bauer Professor and Chair of Medicine,
presented findings from the multicenter, randomized BLOCK HF trial
Nov. 6, during the American
Heart Association’s Scientific Sessions 2012 meeting in
Los Angeles.
According to Curtis, the trial confirms what clinicians and
researchers have long hypothesized:
Heart failure patients with heart block fare better when both
sides of their heart are resynchronized.
This procedure, known as biventricular pacing, involves
implanting a CRT device.
“The results of BLOCK HF may lead to a reassessment
of treatment guidelines for heart failure patients with heart
block,” Curtis says.
During the trial, sponsored by Medtronic, 342 patients
underwent conventional right ventricular pacing and 349 underwent
biventricular pacing with a CRT device.
Patients in the second group had a 26 percent reduction in the
combined endpoint of mortality, heart-failure related urgent care
and deterioration in heart function detected by echocardiography,
Curtis notes.
The trial also showed a 27 percent relative risk reduction in
the composite endpoint of heart failure urgent care and all-cause
mortality.
The BLOCK HF trial, which enrolled more than 900 patients, was
designed to address the best way to treat atrioventricular block, a
partial or complete block in the main “trunk” of the
heart’s electrical conduction system that affects more than
800,000 Americans and more than a million people worldwide.
“AV block prevents electrical impulses from reaching
the bottom chambers of the heart, which then beat very slowly or
not at all,” explains Curtis.
To treat it, many patients are implanted with a standard
pacemaker with leads or pacing wires in the heart’s right
atrium and right ventricle.
“But that fix can lead to other problems,” Curtis
says, “such as creating less synchrony between the left and
right ventricles of the heart, making their heart failure symptoms
even worse.”
Biventricular pacing with a CRT device, however, is more
complicated than implanting a standard pacemaker, making it a
procedure “clinicians don’t want to put patients
through without clear evidence of a benefit,” Curtis
explains.
“Today,” she adds, “we are showing that Block
HF does show that benefit.”
One of the world's leading clinical cardiac electrophysiologists
and an expert in cardiac arrhythmias, Curtis has significantly
advanced knowledge of human cardiac electrophysiology and heart
rhythm abnormalities.
Her research interests include clinical trials in implantable
device therapy for prevention of sudden cardiac death and
management of heart failure as well as clinical trials in atrial
fibrillation.
She has been principal investigator, co-investigator, sponsor or
steering committee member on 85 research studies and clinical
trials, and she has written more than 250 peer-reviewed
manuscripts, book chapters, reviews and editorials.
She also authored a book on cardiac pacing.
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