American Heart Association and American College of Cardiology Issue Joint Statement
DALLAS -- Hospital care providers need to be more aware
that cardiac arrest from a medication-induced heart rhythm problem is a rare
but potentially catastrophic event in patients, according to a joint scientific
statement from the American Heart Association and American College of
Cardiology.
The
statement, published online in Circulation: Journal of the American Heart
Association and Journal
of the American College of Cardiology, is endorsed by the American Association of Critical-Care
Nurses.
The
rhythm disturbance, called Torsade de Pointes (TdP), has a characteristic
electrocardiogram (ECG) pattern described as a "twisting" of points
on the read-out. The abnormal rhythm is associated with a drop in blood
pressure, which can lead to fainting. TdP may also lead to a more serious
rhythm disturbance called ventricular fibrillation, which may cause sudden
cardiac arrest. TdP is a special concern for patients in intensive care
units (ICU).
Medicines
that prolong the heart's Q-T interval increase the risk for TdP. The Q-T
interval is a measurement on an ECG that represents the time for electrical
activation and inactivation of the ventricles, the lower chambers of the heart.
"This
scientific statement is particularly important for healthcare professionals who
administer QT-prolonging drugs in hospital units where patients have continuous
ECG monitoring such as in ICUs," said Barbara J. Drew, R.N., Ph.D., chair
of the statement writing committee. "If the ECG warning signs of TdP
are recognized on the patient's cardiac monitor, then TdP and subsequent
cardiac arrest should be avoidable."
Patients
who require continuous ECG monitoring frequently have multiple risks for TdP
such as electrolyte imbalances and kidney problems, and are more likely to
receive medications intravenously, added Drew, who is a professor of nursing
and cardiology at the University of California in San Francisco.
The
tell-tale signs of TdP often occur an hour or so before ventricular
fibrillation and can be corrected with quick action, thus avoiding full cardiac
arrest.
Risk
factors for TdP include:
- Heart
rhythm abnormalities such as long Q-T syndrome (diagnosed by ECG) - Use
of medicines that cause long Q-T syndrome, especially those given intravenously
(most commonly: antibiotics, antipsychotics, antiarrhythmia drugs) - Heart
disease - Advanced
age - Female
gender - Low
blood levels of calcium, potassium or magnesium - Diuretic
use - Kidney
problems
The
statement suggests continuous ECG monitoring for at-risk patients, lists the
drugs and drug combinations most likely to cause TdP, and provides guidance for
managing drug-induced long Q-T syndrome and immediate treatment for TdP.
Co-authors
are Barbara J. Drew, R.N., Ph.D., (Chair); Michael J. Ackerman, M.D., Ph.D.;
Marjorie Funk, R.N., Ph.D.; Brian Gibler, M.D.; Paul D. Kligfield, M.D.;
Venugopal Menon, M.D.; George Philippides, M.D.; Dan M. Roden, M.D.; and
Wojciech Zareba, M.D., Ph.D.
SOURCE
American Heart Association