Nonsustained ventricular tachycardia, poor CHF prognosis. (Cardiac Pathology Risk Rises).
Patients with ischemic dilated cardiomyopathy and nonsustained ventricular tachycardia (NSVT) had a lower heart rate variability indicating increased risk of cardiac pathology including coronary vasoconstriction, decreased diastolic perfusion time, increased endothelial shear stress, increased platelet aggregation, and increased plaque instability, Dr. Dana Constantinescu reported at the Eighth World Congress on Heart Failure.
Patients with NSVT also had higher New York Heart Association functional classes, lower left ventricular ejection fractions, and increased left ventricle end-diastolic diameters, compared with patients with ischemic dilated cardiomyopathy but without NSVT.
Dr. Constantinescu, of Emergency Hospital in Bucharest, Romania, reported on a study by her colleague, Dr. Oana Istratescu-Wolkowski. The study group included 67 patients, aged 45-69 years, who were placed on 24-hour Holter monitoring to measure heart rate variability. All had ischemic dilated cardiomyopathy of more than year in duration, subsequent to a heart attack. The patients had a New York Heart Association functional class of II or III, a left ventricular ejection fraction of 39% or below, and were taking nitrates, digoxin, ACE inhibitors, diuretics, and anticoagulants.
Each patient was placed on a Holter monitor for 24-hour time domain monitoring and 34% were found to have NSVT. Heart rate variability was measured using standard deviation of the mean of all 5-minute segments of normal electrocardiographic R-R intervals (SDANN), standard deviation of normal-to-normal beats (SDNN), and percentage difference between adjacent normal R-R intervals greater than 50 milliseconds (pNN50).
The heart rate variability parameters of patients with NSVT were significantly worse. Patients without NSVT had slightly below-normal parameters for their NN intervals and pNN50 measurements but remained within normal limits on their SDNN and SDANN measurements.
On echocardiography those with NSVT had an average left ventricular ejection fraction of 24%, compared with 35% for those without-NSVT. Average left ventricle end-diastolic diameter was 70 mm in those with NSVT and 65 mm in those without NSVT.
Of the NSVT patients, 42% had New York Heart Association functional class III disease, compared with 19% of those without NSVT.
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|Title Annotation:||congestive heart failure|
|Author:||Sullivan, Michele G.|
|Publication:||Internal Medicine News|
|Date:||Sep 15, 2002|
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