Exercise oscillatory ventilation may predict sudden cardiac death in heart failure patients.
OBJECTIVE
The purpose of this study was to test the ability of cardiopulmonary exercise testing (CPET)-derived variables as sudden cardiac death (SCD) predictors.


BACKGROUND
The CPET variables, such as peak oxygen uptake (VO2), ventilatory requirement to carbon dioxide (CO2) production (VE/VCO2) slope, and exercise oscillatory breathing (EOB), are strong predictors of overall mortality in chronic heart failure (CHF) patients. Even though up to 50% of CHF patients die from SCD, it is unknown whether any of these variables predicts SCD.


METHODS
One hundred fifty-six CHF patients (mean age: 60.9 +/- 9.4 years; mean ejection fraction: 34.9 +/- 10.6%) underwent CPET. Subjects were tracked for sudden versus pump-failure cardiac mortality over 27.8 +/- 25.2 months.


RESULTS
Seventeen patients died from SCD, and 17 died from cardiac pump failure. Survivors showed significantly higher peak VO2 (16.8 +/- 4.5 ml x kg(-1) x min(-1)) and lower VE/VCO2 slope (32.8 +/- 6.4) and prevalence of EOB (20.3%), compared with subjects who experienced arrhythmic (13.5 +/- 3.2 ml x kg(-1) x min(-1); 41.5 +/- 11.4; 100%) or nonarrhythmic (14.1 +/- 4.7 ml x kg(-1) x min(-1); 38.1 +/- 7.3; 47.1%) deaths (p < 0.05). At Cox regression analysis, all variables were significant univariate predictors of both sudden and pump failure death (p < 0.01). Multivariate analysis, including left ventricular (LV) ejection fraction, LV end systolic volume, and LV mass selected EOB, was the strongest predictor of both overall mortality (chi-square: 38.7, p < 0.001) and SCD (chi-square: 44.7, p < 0.001), whereas VE/VCO2 slope was the strongest ventilatory predictor of pump failure death (chi-square: 11.8, p = 0.001).


CONCLUSIONS
Exercise oscillatory breathing is an independent predictor of SCD in patients with CHF and might help as an additional marker for prioritization of antiarrhythmic strategies.
Guazzi
Marco
M
Cardiopulmonary Unit, Cardiology Division, University of Milano, San Paolo Hospital, Milano, Italy. marco.guazzi@unimi.it
Raimondo
Rosa
R
Vicenzi
Marco
M
Arena
Ross
R
Proserpio
Chiara
C
Sarzi Braga
Simona
S
Pedretti
Roberto
R
D002245:Carbon Dioxide / Q000378:metabolism; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology*; D006334:Heart Function Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012372:ROC Curve; D015656:Respiratory Mechanics; D012307:Risk Factors
D002245:Carbon Dioxide