ROLE OF IMPEDANCE CARDIOGRAPHY IN PREDICTING CLINICAL
NEAR-TERM OUTCOMES OF PATIENTS WITH CARDIAC
RESYNCHRONIZATION THERAPY
Martino Martinelli Filho - Heart Institute (InCor), University of Sao Paulo Medical School Brazil
Giselle de Lima Peixoto - Heart Institute (InCor), University of Sao Paulo Medical School Brazil
Sérgio Freitas de Siqueira - Heart Institute (InCor), University of Sao Paulo Medical School Brazil
Silvana Angelina D'Ório Nishioka - Heart Institute (InCor), University of Sao Paulo Medical School
Brazil Ricardo Alkmim Teixeira - Heart Institute (InCor), University of Sao Paulo Medical School
Brazil Mariana Moreira Lensi - Heart Institute (InCor), University of Sao Paulo Medical School
Brazil Raquel Helena Ladeira da Trindade - Heart Institute (InCor), University of Sao Paulo Medical
School Brazil Anísio Alexandre Andrade Pedrosa - Heart Institute (InCor), University of Sao Paulo
Medical School Brazil Roberto Costa - Heart Institute (InCor), University of Sao Paulo Medical
School Brazil
Introduction The noninvasive impedance cardiography (ICG) uses changes in thoracic electrical
impedance to measure hemodynamic variables that can be used to predict worsening in patients with
heart failure (HF). This study aimed to identify predictors for near-term clinical outcomes of patients
with HF and cardiac resynchronization therapy (CRT).
Methods We prospectively evaluated 152 consecutive patients with HF previously submitted to CRT.
The patients underwent clinical status evaluation (functional class of NYHA, Minnesota Living with
Heart Failure Questionnaire [MLWHFQ] and comorbidities assessment), functional assessment
(six-minute walk test [6MWT], brain natriuretic peptide [BNP] and echocardiographic [ECHO]) and
ICG.
Results During a mean follow-up of 10.2±4.3 months there were 25 events (17 deaths and 8 HF
hospitalizations). Univariate analysis identified 21 variables associated with events: MLWHFQ score,
6MWT, hemoglobin, creatinine, BNP, QRS duration, left atrial (LA) dimension, systolic and diastolic
left ventricular (LV) diameter, end-systolic and end-diastolic LV volumes, LV ejection fraction, systolic
mean arterial pressure, pulse pressure, proportional pulse pressure and ICG parameters of cardiac debit,
systolic volume, LV ejection time, thoracic fluid content (TFC) and TFC index (TFCi). Multivariate
analysis identified 4 predictors of events: MLWHFQ score (Hazard Ratio [HR] 1.040; 95% Confidence
Interval [CI] 1.016-1.065, P=0.001), creatinine (HR 6.152; 95%CI 2.010-18.835, P=0.001), LA
dimension (HR 1.109; 95%CI 1.040-1.182, P=0.002) and TFCi (HR 1.214; 95%CI 1.062-1.387,
P=0.004). A TFCi above 18.8 KOhms-1 yielded sensitivity, specificity, positive predictive value and
negative predictive value of 76.0%, 59.1%, 26.7% and 92.6%, respectively.
Conclusion These results suggest that TFCi measured by ICG can identify patients at increased
near-term risk of HF hospitalization or death.