Michael Finucan

Differential Response to Cardiac Resynchronization Therapy and Clinical Outcomes According to QRS Morphology and QRS Duration

OBJECTIVES The goal of this study was to examine the relative impact of QRS morphology and duration in echocardiographic responses to cardiac resynchronization therapy (CRT) and clinical outcomes. BACKGROUND At least one-third of all patients treated with CRT fail to derive benefit. Patients without left bundle branch block (LBBB) or patients with smaller QRS duration (QRSd) respond less or not at all to CRT. METHODS We retrospectively assessed baseline characteristics, clinical and echocardiographic response, and outcomes of all patients who received CRT at our institution between December 2003 and July 2007. Patients were stratified into 4 groups according to their baseline QRS morphology and QRSd. RESULTS A total of 496 patients were included in the study; 216 (43.5%) had LBBB and a QRSd ≥150 ms, 85 (17.1%) had LBBB and QRSd <150 ms, 92 (18.5%) had non-LBBB and a QRSd ≥150 ms, and 103 (20.8%) had non-LBBB and QRSd <150 ms. Echocardiographic response (change in ejection fraction) was better in patients with LBBB and QRSd ≥150 ms (12 ± 12%) than in those with LBBB and QRSd <150 ms (8 ± 10%), non-LBBB and QRSd ≥150 ms (5 ± 9%), and non-LBBB and QRSd <150 ms (3 ± 11%) (p < 0.0001). In a multivariate stepwise model with change in ejection fraction as the dependent variable, the presented classification was the most important independent variable (p = 0.0003). Long-term survival was better in LBBB patients with QRSd ≥150 ms (p = 0.02), but this difference was not significant after adjustment for other baseline characteristics (p = 0.15). CONCLUSIONS QRS morphology is a more important baseline electrocardiographic determinant of CRT response than QRSd.

Determinants of dynamic changes in serum creatinine in acute decompensated heart failure: the importance of blood pressure reduction during treatment

‘Worsening renal function’ (WRF) and ‘improvement in renal function’ (IRF) monitored by changes in serum creatinine are frequently encountered during treatment of acute decompensated heart failure (ADHF). We sought to establish the important haemodynamic determinants of alterations in serum creatinine.

Elevated Plasma Marinobufagenin, An Endogenous Cardiotonic Steroid, Is Associated With Right Ventricular Dysfunction and Nitrative Stress in Heart Failure

Background—Plasma levels of cardiotonic steroids are elevated in volume-expanded states, such as chronic kidney disease, but the role of these natriuretic hormones in subjects with heart failure (HF) is unclear. We sought to determine the prognostic role of the cardiotonic steroids marinobufagenin (MBG) in HF, particularly in relation to long-term outcomes. Methods and Results—We first measured plasma MBG levels and performed comprehensive clinical, laboratory, and echocardiographic assessment in 245 patients with HF. All-cause mortality, cardiac transplantation, and HF hospitalization were tracked for 5 years. In our study cohort, median (interquartile range) MBG was 583 (383–812) pM. Higher MBG was associated with higher myeloperoxidase (r=0.42, P<0.0001), B-type natriuretic peptide (r=0.25, P=0.001), and asymmetrical dimethylarginine (r=0.32, P<0.001). Elevated levels of MBG were associated with measures of worse right ventricular function (RV s′, r=−0.39, P<0.0001) and predicted increased risk of adverse clinical outcomes (MBG≥574 pmol/L: hazard ratio 1.58 [1.10–2.31], P=0.014) even after adjustment for age, sex, diabetes mellitus, and ischemic pathogenesis. In mice, a left anterior descending coronary artery ligation model of HF lead to increases in MBG, whereas infusion of MBG into mice for 4 weeks lead to significant increases in myeloperoxidase, asymmetrical dimethylarginine, and cardiac fibrosis. Conclusions—In the setting of HF, elevated plasma levels of MBG are associated with right ventricular dysfunction and predict worse long-term clinical outcomes in multivariable models adjusting for established clinical and biochemical risk factors. Infusion of MBG seems to directly contribute to increased nitrative stress and cardiac fibrosis.

Lack of Concordance in Defining Worsening Renal Function by Rise in Creatinine vs Rise in Cystatin C

Worsening renal function (WRF) during treatment of acute decompensated heart failure (ADHF) is generally associated with adverse outcomes. An increase ≥0.3 mg/dL in creatinine level is widely used as the definition of WRF. The authors sought to determine the level of agreement between WRF based on changes in creatinine and changes in cystatin C (CysC) by analyzing data from 121 ADHF patients with available admission and day 3 creatinine and CysC levels. Admission creatinine and CysC levels were 1.39 (0.98-2.11) mg/dL and 1.95 (1.42-2.69) mg/L, respectively, and correlated well (r=0.81). On average, creatinine (-0.04±0.40 mg/dL) and CysC (0.001±0.34 mg/L) changed minimally from admission to day 3. Although the correlation between both markers on day 3 was still good (r=0.79), the correlation between changes therein was only modest (r=0.43). From the 14 and 15 patients who had WRF based on a ≥0.3 mg/dL increase in creatinine and ≥0.3 mg/L increase in CysC, respectively, only four (about 30%) met both definitions. These observations, together with recent insights in the inconsistencies of creatinine-defined concept of worsening renal function and outcomes, raises the need to research more reliable measures of renal function during treatment of ADHF.

Response and tolerance to oral vasodilator up-titration after intravenous vasodilator therapy in advanced decompensated heart failure

The aim of this study was to assess the haemodynamic response and tolerance to aggressive oral hydralazine/isosorbide dinitrate (HYD/ISDN) up‐titration after intravenous vasodilator therapy in advanced decompensated heart failure (ADHF).