Blood pressure linked to sudden cardiac death in HF patients

29 March 2007

Blood pressure (BP) levels are inversely related to sudden cardiac death (SCD) in patients with ischemic left ventricular (LV) dysfunction, researchers report.

The team found that patients whose BP levels stayed above 130/80 mmHg had a reduced risk of SCD in comparison with those with lower BP levels.

Monitoring BP may therefore help identify subgroups within the low ejection fraction (EF) population who would benefit most from implantable cardioverter defibrillator (ICD) therapy, say Ilan Goldenberg (University of Rochester, New York) and team.

Previous data from the MADIT (Multicenter Automatic Defibrillator Implantation Trial)-II showed that only about one third of patients in whom an ICD is implanted need device therapy for ventricular tachyarrhythmias, the researchers explain in the Journal of the American College of Cardiology.

To see if the established inverse correlation between BP and risk of all-cause mortality relates to arrhythmic deathand provides a useful risk stratification parameter, Goldenberg and colleagues analyzed the contribution of SBP and DBP to outcomes of 1231 patients in MADIT-II.

Patients in MADIT-II had previous myocardial infarction with New York Heart Association class I or III heart failure (HF). They were assigned to receive a prophylactic ICD or conventional medical therapy in a 3:2 ratio and followed-up over 20 months.

Multivariate analysis of patients who received conventional therapy showed that their risk of cardiac mortality decreased by 14%, and the risk of SCD by 16%, with each 10-mmHg increase in SBP. Corresponding reductions of 18% and 20% were seen with each 10-mmHg increase in DBP.

Quartile analysis showed that the decline in risk of SCD with increasing BP levels was mainly confined to patients with upper-quartile SBP (59% reduction in risk) and DBP (67% reduction) values.

There was a significant 32% reduction in the relative risk of death in the overall population implanted with ICDs.

Among patients with SBP >130 mmHg and DBP ≥80 mmHg, there was no survival benefit, at hazard ratios of 1.04 and 1.05, respectively.

In contrast, the respective risk reductions among patients with SBP ≤130 mmHg and DBP <80 mmHg were 39% and 38% (both p=0.002).

"In patients with ischemic LV dysfunction, SBP and DBP levels show an inverse correlation with sudden cardiac mortality," the authors conclude.

"These non-invasive hemodynamic parameters may be useful for identifying lower-risk patients, in whom the benefit of primary defibrillator implantation is more limited."

J Am Coll Cardiol 2007; 49: 1427-1433