Quantification of ventricular resynchronization reserve by radionuclide phase analysis in heart failure patients: a prospective long-term study.
BACKGROUND
Phase analysis, developed to assess dyssynchrony from ECG-gated radionuclide ventriculography, has shown promising results. We hypothesized that quantifying the cardiac resynchronization reserve, that is, the extent of response to cardiac resynchronization therapy (CRT), by radionuclide imaging could potentially identify patients who are best suited for CRT.


RESULTS
Seventy-four patients ages 64.8±10.1 years were prospectively studied from July 2004 to July 2006, of whom 62.2% and 37.8%, respectively, were in New York Heart Association class 3 and 4. Mean QRS width was 173±25 ms. ECG-gated radionuclide ventriculography to quantify interventricular and intraventricular dyssynchrony was performed at baseline with and without CRT and at the 3-month follow-up visit. Amino-terminal-pro-brain natriuretic peptide (NT-pro-BNP) levels were also determined at baseline and at 3 months. During a mean follow-up of 10.1±7.6 months, there were 37 (50%) clinical events that defined the nonresponder group, including cardiac death or readmission for worsening heart failure. In multivariate Cox model analysis, higher NT-pro-BNP blood levels were associated with a significant increase in the risk for event (hazard ratio=1.085 for a 100 pg/L increase in NT-pro-BNP; 95% confidence interval, 1.014 to 1.161). Each 10° elevation in intraventricular dyssynchrony was associated with a decrease in the risk of events (hazard ratio=0.456, 95% confidence interval, 0.304 to 0.683). Receiver operating characteristic curve analysis demonstrated that an interventricular dyssynchrony cutoff value of 25.5° for intraventricular synchrony yielded 91.4% sensitivity and 84.4% specificity for predicting a good response to CRT.


CONCLUSIONS
The quantification of interventricular dyssynchrony with radionuclide phase analysis suggests that early postimplantation interventricular dyssynchrony may provide identification of CRT responders.
Hôpital cardiologique Louis Pradel, Hospices Civils de Lyon, Hospices Civils de Lyon, Bron cedex, France.
Raphael
R
Dauphin
Emilie
E
Nonin
Laurence
L
Bontemps
Madeleine
M
Vincent
Alain
A
Pinel
Serge
S
Bonijoly
Denis
D
Barborier
Arnaud
A
Ribier
Christine Mestre
CM
Fernandes
Patrick
P
Bert-Marcaz
Roland
R
Itti
Philippe
P
Chevalier
D000368:Aged; D015415:Biomarkers / Q000097:blood; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects; D016009:Chi-Square Distribution; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D005602:France; D006333:Heart Failure / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D018579:Patient Selection; D010446:Peptide Fragments / Q000097:blood; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D015635:Radionuclide Ventriculography; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left
D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain