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Immune Modulation Therapy Reduces Morbidity, Mortality in Severe Chronic Heart Failure: Presented at AHA

By Peggy Peck

CHICAGO, IL -- November 19, 2002 -- Immune modulation therapy effectively reduces QT interval (QTc) duration in patients with severe chronic heart failure and this shortened interval is associated with decreased morbidity and mortality, according to research presented at the American Heart Association's 2002Scientific Sessions.

Bojan Vrtovec, MD, PhD, a transplant fellow at the Texas Heart Institute, Houston, Texas, United States, said other researchers have observed that myocardial inflammation appears to prolong QTc and increase temporal dispersion of QT intervals (QTd). "Thus we theorized that if we could stress the blood we could create this same effect, which could improve outcomes," Dr. Vrotovec explained in an interview.

In this study, Kaplan-Meier survival analysis showed reduction in the risk of the composite end point of all-cause mortality or any hospitalization treated with immune modulation therapy (IMT) compared to placebo (12 versus 22 events, p=0.005) and in the risk of death (1 versus 6 deaths, p=0.022).

Seventy-three patients with severe chronic heart failure (CHF) were enrolled in the study. Thirty-six patients were randomized to IMT and 37 patients to placebo. All underwent baseline evaluation with QTc and QTd measurements and were evaluated again at the end of the study. Dr. Vrotovec said that only 20 IMT patients and 15 placebo patients had "evaluable measurements at both time points".

QTc was determined from the 12-lead electrocardiogram by averaging the QT interval from three beats in leads II and V4 using Fridericia's formula. QTd was determined by averaging the QT interval from three consecutive beats in each electrocardiogram lead and calculating the difference between the shortest and longest mean value.

All patients had blood drawn but blood from the IMT patients was oxidatively stressed ex-vivo. The patients were then injected with 10mL of blood on days 1, 2 and 14, and then monthly for six months.

While the IMT and placebo groups were well matched at baseline (447 ± 53 versus 450 ± 51 msec, p=ns), at end of study there was a reduction in mean QTc interval in the IMT group (-18 msec) compared to an increase in the placebo group (+12 msec), resulting in a significant difference between the two groups (429 ± 45 versus. 463 ± 45 msec, p=0.035).

Likewise, QTd was well matched at baseline for the IMT (76 msec) and placebo (63 msec, p=ns) groups. However, QTd decreased in the IMT group by 16 msec during the study, while it increased by 19 msec in the placebo group (p=0.001).

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