Quantifying the paradoxical effect of higher systolic blood pressure on mortality in chronic heart failure.

BACKGROUND: Although higher blood pressures are generally recognised to be an adverse prognostic marker in risk assessment of cardiology patients, its relationship to risk in chronic heart failure (CHF) may be different. OBJECTIVE: To examine systematically published reports on the relationship between blood pressure and mortality in CHF. METHODS: Medline and Embase were used to identify studies that gave a hazard or relative risk ratio for systolic blood pressure in a stable population with CHF. Included studies were analysed to obtain a unified hazard ratio and quantify the degree of confidence. RESULTS: 10 studies met the inclusion criteria, giving a total population of 8088, with 29 222 person-years of follow-up. All studies showed that a higher systolic blood pressure (SBP) was a favourable prognostic marker in CHF, in contrast to the general population where it is an indicator of poorer prognosis. The decrease in mortality rates associated with a 10 mm Hg higher SBP was 13.0% (95% CI 10.6% to 15.4%) in the heart failure population. This was not related to aetiology, ACE inhibitor or beta blocker use. CONCLUSION: SBP is an easily measured, continuous variable that has a remarkably consistent relationship with mortality within the CHF population. The potential of this simple variable in outpatient assessment of patients with CHF should not be neglected. One possible application of this information is in the optimisation of cardiac resynchronisation devices.

Haemodynamic effects of changes in atrioventricular and interventricular delay in cardiac resynchronisation therapy show a consistent pattern: analysis of shape, magnitude and relative importance of atrioventricular and interventricular delay.

OBJECTIVE: To assess the haemodynamic effect of simultaneously adjusting atrioventricular (AV) and interventricular (VV) delays. METHOD: 35 different combinations of AV and VV delay were tested by using digital photoplethysmography (Finometer) with repeated alternations to measure relative change in systolic blood pressure (SBP(rel)) in 15 patients with cardiac resynchronisation devices for heart failure. RESULTS: Changing AV delay had a larger effect than changing VV delay (range of SBP(rel) 21 v 4.2 mm Hg, p < 0.001). Each had a curvilinear effect. The curve of response to AV delay fitted extremely closely to a parabola (average R2 = 0.99, average residual variance 0.8 mm Hg2). The response to VV delay was significantly less curved (quadratic coefficient 67 v 1194 mm Hg/s2, p = 0.003) and therefore, although the residual variance was equally small (0.8 mm Hg2), the R2 value was 0.7. Reproducibility at two months was good, with the SD of the difference between two measurements of SBP(rel) being 2.5 mm Hg for AV delay (2% of mean systolic blood pressure) and 1.5 mm Hg for VV delay (1% of mean systolic blood pressure). CONCLUSIONS: Changing AV and VV delays results in a curvilinear acute blood pressure response. This shape fits very closely to a parabola, which may be valuable information in developing a streamlined clinical protocol. VV delay adjustment provides an additional, albeit smaller, haemodynamic benefit to AV optimisation.

Echocardiographic methods for selecting patients suitable for biventricular pacing therapy.

The large outcome studies of biventricular pacing to date have selected patients using electrocardiogram criteria (prolonged QRS and left bundle branch block morphology). However, 20-30% of patients do not appear to respond clinically, and as a result there has been much interest in developing more specific methods of detecting mechanical dyssynchrony. A number of different echocardiographic techniques have been developed which appear to offer greater sensitivity and specificity than ECG in selecting these patients. This paper reviews the most promising of the echocardiographic techniques and gives guidance for the clinical use of echocardiography in selecting patients for biventricular pacing.