Increased myocardial oxygen consumption rates are associated with maladaptive right ventricular remodeling and decreased event-free survival in heart failure patients.

BACKGROUND

Reduced left ventricular (LV) function is associated with increased myocardial oxygen consumption rate (MVO) and altered sympathetic activity, the role of which is not well described in right ventricular (RV) dysfunction.

METHODS AND RESULTS

33 patients with left heart failure were assessed for RV function/size using echocardiography. Positron emission tomography (PET) was used to measure C-acetate clearance rate (k), C-hydroxyephedrine (C-HED) standardized uptake value (SUV), and retention rate. RV MVO was estimated from k. C-HED SUV and retention indicated sympathetic neuronal function. A composite clinical endpoint was defined as unplanned cardiac hospitalization within 5 years. Patients with (n = 10) or without (n = 23) RV dysfunction were comparable in terms of sex (male: 70.0 vs 69.5%), LV ejection fraction (39.6 ± 9.0 vs 38.6 ± 9.4%), and systemic hypertension (70.0 vs 78.3%). RV dysfunction patients were older (70.9 ± 13.5 vs 59.4 ± 11.5 years; P = .03) and had a higher prevalence of pulmonary hypertension (60.0% vs 13.0%; P = .01). RV dysfunction was associated with increased RV MVO (.106 ± .042 vs .068 ± .031 mL/min/g; P = .02) and decreased C-HED SUV and retention (6.05 ± .53 vs 7.40 ± 1.39 g/mL (P < .001) and .08 ± .02 vs .11 ± .03 mL/min/g (P < .001), respectively). Patients with an RV MVO above the median had a shorter event-free survival (hazard ratio = 5.47; P = .01). Patients who died within the 5-year follow-up period showed a trend (not statistically significant) for higher RV MVO (.120 ± .026 vs .074 ± .038 mL/min/g; P = .05).

CONCLUSIONS

RV dysfunction is associated with increased oxygen consumption (also characterized by a higher risk for cardiac events) and impaired RV sympathetic function.