title: Force-interval relationship predicts mortality in survivors of myocardial infarction with atrial fibrillation.
abstract: BACKGROUND
  RR interval variations lead to beat-to-beat blood pressure differences through the myocardial force-interval relationship (FIR). In sinus rhythm, an altered FIR leads to post-extrasystolic potentiation (PESP) of systolic blood pressure, which has been shown to predict adverse outcome in survivors of acute myocardial infarction (MI). The purpose of this study was (1) to develop a parameter to assess the FIR in patients with atrial fibrillation (AF) and (2) to investigate its association with mortality in MI survivors suffering from AF.
  
  
  RESULTS
  Thirty-two patients with acute MI and AF underwent 30-min recordings of ECG and continuous blood pressure. Episodes of a short RR interval (<80% of mean interval, RRi) preceding a long interval (>140%, RRi+1) were identified. The systolic pressures of the pulse waves following RRi and RRi+1 were labeled Pi and Pi+1. PESPAfib was calculated as (Pi+1-Pi)/(RRi+1-RRi). During 5years of follow-up, 13 patients died. When PESPAfib was dichotomized at the median, mortality rates were 63% and 19% in patients with high and low PESPAfib. Hazard ratio for mortality was 4.88 for patients with high PESPAfib (1.33-17.84, p=0.004). The association of PESPAfib and mortality was independent from LVEF, age, diabetes mellitus or mean heart rate.
  
  
  CONCLUSIONS
  PESPAfib, a measure for the FIR in patients with AF, can be derived from simultaneous ECG and blood pressure recordings. The results of this pilot study indicate that PESPAfib may be useful to predict adverse outcome in survivors of myocardial infarction suffering from AF.
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sinnecker
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Barthel
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany.
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Huster
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Müller
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany.
authors.forename: Josef
authors.initials: J
authors.lastname: Gebhardt
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Dommasch
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Schneider
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Steger
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany; DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany.
authors.forename: Karl-Ludwig
authors.initials: KL
authors.lastname: Laugwitz
authors.affiliation: Saint Paul's Cardiac Electrophysiology, University of London and Imperial College, London, United Kingdom.
authors.forename: Marek
authors.initials: M
authors.lastname: Malik
authors.affiliation: 1. Medizinische Klinik und Deutsches Herzzentrum München der Technischen Universität München, Munich, Germany; DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany. Electronic address: gschmidt@tum.de.
authors.forename: Georg
authors.initials: G
authors.lastname: Schmidt
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D010865:Pilot Projects; D011237:Predictive Value of Tests; D012372:ROC Curve; D018570:Risk Assessment / Q000379:methods*; D015996:Survival Rate / Q000639:trends; D017741:Survivors / Q000706:statistics & numerical data*; D013997:Time Factors
keywords: Atrial fibrillation; Force–interval relationship; Interval–force relationship; PESP; Post-extrasystolic potentiation; Risk stratification