title: Single-beat estimation of the left ventricular end-diastolic pressure-volume relationship in patients with heart failure.
abstract: OBJECTIVE
  To test a method to predict the end-diastolic pressure-volume relationship (EDPVR) from a single beat in patients with heart failure.
  
  
  RESULTS
  Patients (New York Heart Association class III-IV) scheduled for mitral annuloplasty (n=9) or ventricular restoration (n=10) and patients with normal left ventricular function undergoing coronary artery bypass grafting (n=12) were instrumented with pressure-conductance catheters to measure pressure-volume loops before and after surgery. Data obtained during vena cava occlusion provided directly measured EDPVRs. Baseline end-diastolic pressure (P(m)) and volume (V(m)) were used for single-beat prediction of EDPVRs. Root-mean-squared error (RMSE) between measured and predicted EDPVRs, was 2.79+/-0.21 mm Hg. Measured versus predicted end-diastolic volumes at pressure levels 5, 10, 15 and 20 mm Hg showed tight correlations (R(2)=0.69-0.97). Bland-Altman analyses indicated overestimation at 5 mm Hg (bias: pre-surgery 44 ml (95% CI 29 to 58 ml); post-surgery 35 ml (23 to 47 ml)) and underestimation at 20 mm Hg (bias: pre-surgery -57 ml (-80 to -34 ml); post-surgery -13 ml (-20 to -7.0 ml)). End-diastolic volumes were significantly different between groups and between conditions, but these differences were not dependent on the method (ie, measured versus predicted). RMSEs were not different between groups or conditions, nor dependent on V(m) or P(m), indicating that EDPVR prediction was equally accurate over a wide volume range.
  
  
  CONCLUSIONS
  Single-beat EDPVRs obtained from hearts spanning a wide range of sizes and conditions accurately predicted directly measured EDPVRs with low RMSE. Single-beat EDPVR indices correlated well with directly measured values, but systematic biases were present at low and high pressures. The single-beat method facilitates less invasive EDPVR estimation, particularly when coupled with emerging non-invasive techniques to measure pressures and volumes.
authors.affiliation: Department of Cardiology, Leiden University Medical Centre, PO Box 9600, 2300RC, Leiden, The Netherlands.
authors.forename: Ellen A
authors.initials: EA
authors.lastname: Ten Brinke
authors.forename: Daniel
authors.initials: D
authors.lastname: Burkhoff
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Klautz
authors.forename: Carsten
authors.initials: C
authors.lastname: Tschöpe
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Schalij
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Bax
authors.forename: Ernst E
authors.initials: EE
authors.lastname: van der Wall
authors.forename: Robert A
authors.initials: RA
authors.lastname: Dion
authors.forename: Paul
authors.initials: P
authors.lastname: Steendijk
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000502:physiology*; D013479:Superior Vena Cava Syndrome / Q000503:physiopathology; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology