Influence of atrial fibrillation on cardiac brain natriuretic peptide release during haemodynamic stress in heart failure

Relevance of short-term variation of B-type natriuretic peptide in patients with clinically stable heart failure

BACKGROUND

In patients with clinically stable chronic heart failure, circulating B-type natriuretic peptide (BNP) levels may exhibit considerable variation over a period of a few days. The aim of this study was to evaluate the clinical impact of this phenomenon.

METHODS

In 23 patients with clinically stable mild-to-moderate systolic heart failure [median (interquartile range) 72 (64-77) years, left ventricular ejection fraction 30 (27-40)%] and a history of previous hospitalization for heart failure, BNP was measured at two time points [T1 and T2, interval 5 (3-7) days] for calculation of the absolute change in BNP concentrations between T1 and T2 (DeltaBNP; irrespective of whether there was a decrease or increase). Follow-up for rehospitalization was 436 (407-458) days.

RESULTS

In the group overall, DeltaBNP was 26 (9-116) pg/ml [19 (10-28)% of the value at T1]. During follow-up, 8/23 (35%) patients were rehospitalized. BNP concentrations at T1 [340 (187-533) vs. 210 (108-606) pg/ml; P = 0.33] and T2 [328 (125-491) vs. 259 (89-536) pg/ml; P = 0.51] were similar in patients who were rehospitalized and those who were not; however, DeltaBNP was higher in patients requiring rehospitalization [98 (36-186) vs. 19 (6-93) pg/ml; P = 0.04]. Patients with DeltaBNP <26 pg/ml had a longer rehospitalization-free survival than those with DeltaBNP > or = 26 pg/ml (log rank P = 0.02). Sensitivity and specificity of DeltaBNP > or = 26 pg/ml for the prediction of rehospitalization were 88% and 67% respectively.

CONCLUSIONS

In this small study among patients with clinically stable heart failure, higher DeltaBNP over a period of a few days was associated with a higher likelihood of rehospitalization during follow-up.

Characterization of Cardiac Brain Natriuretic Peptide Release in Patients With Paroxysmal Atrial Fibrillation Undergoing Left Atrial Ablation

Background— Paroxysmal atrial fibrillation (PAF) is associated with elevated levels of brain natriuretic peptide (BNP). The exact cardiac source and implications of this are currently unknown, as are the effects of left atrial ablation on cardiac BNP release. We sought to investigate BNP levels at different cardiac sites in PAF patients before and after left atrial ablation and compare these with a non–atrial fibrillation control cohort.

Methods and Results— Twenty PAF patients (52�10 years, 70% men; left ventricular ejection fraction, 55�3%) undergoing ablation were studied, BNP levels were measured at different cardiac sites before and after ablation and compared with a control cohort undergoing ablation for left lateral accessory pathways (10 patients, 41�11 years; left ventricular ejection fraction, 55�4%). In both cohorts, the coronary sinus BNP levels were the greatest. The PAF cohort had significantly greater BNP levels than the control cohort at all sites before and after ablation. Ablation of the left atrium was associated with a significant decrease in coronary sinus BNP levels ( P =0.05) and transcardiac BNP gradient ( P =0.03). This was not observed in the control cohort.

Conclusions— BNP levels are elevated in PAF, with the highest levels in the coronary sinus. Ablation of the left atrium was associated with an immediate decrease of BNP levels, implicating this as the source.

Atrial fibrillation is associated with decreased cardiac sympathetic response to isometric exercise in CHF in comparison to sinus rhythm

BACKGROUND

The presence of atrial fibrillation (AF) in congestive heart failure (CHF) is accompanied by increased mortality, although the exact mechanism is unclear. In previous studies, we have demonstrated cardiac baroreceptor abnormalities in association with AF and CHF. In this study, we sought to examine the effect of cardiac rhythm on the cardiac sympathetic response to exercise in CHF.

METHODS

In 13 CHF patients (six AF, seven SR, left ventricular ejection fraction 31 +/- 2%, age 61 +/- 1 years), we measured the hemodynamic and cardiac sympathetic response isometric handgrip (IHG) exercise.

RESULTS

At baseline the groups were well matched. Baseline hemodynamics and cardiac sympathetic activity did not significantly differ between the cohorts. In response to IHG exercise, both groups demonstrated significant hemodynamic responses. In conjunction, the sinus rhythm (SR) group demonstrated a significant increase in cardiac sympathetic response to exercise (P = 0.04) while in contrast the AF group did not (P = 0.6).

CONCLUSION

In this study, we demonstrate for the first time that the combination of AF and CHF is accompanied by a marked attenuation of the cardiac sympathetic response to acute hemodynamic stress. This implies AF is associated with a further impairment of baroreceptor response in CHF compared to SR. These findings present possible insights to the associated increased mortality and pathogenesis of AF with CHF.

Sinus rhythm restoration after atrial fibrillation: the clinical value of N-terminal pro-BNP measurements

AIM

To examine the effects of sinus rhythm (SR) restoration on N-Terminal pro-BNP (NTP-BNP) in patients with atrial fibrillation (AF).

METHODS

Subjects with paroxysmal and persistent AF and absence of organic heart disease were prospectively studied. Chemical or electrical restoration of SR was attempted within 48 hours (n = 37) or >3 weeks (n = 73). Clinical and laboratory (NTP-BNP, 72-hour Holter monitor, and electrocardiogram) assessment were obtained at baseline and at 1, 30, and 180 days after SR restoration. Patients were divided into three predefined "outcome groups": (a) maintenance of SR for 1 month, (b) SR with recurrent paroxysmal AF (PaAF), and (c) early (<30 days) recurrence persistent AF (RAF).

RESULTS

Of the 110 patients enrolled, 89 had initial successful SR restoration. Baseline NTP-BNP was 936 pg/mL (interquartile range (IQR) 333-2,026); ratio between baseline and 30-day NTP-BNP was 10.2 (IQR 6.42-22.0) for SR group, 3.3 (IQR 2.45-7.34) for PaAF, and 1.07 (IQR 0.87-1.22) for RAF (P < 0.001). Patients with ratio </=3 were more likely to have PaAF (46% vs 3%, OR 30, P < 0.001).

CONCLUSION

With SR restoration, NTP-BNP decline is observed up to 1 month. NTP-BNP drop is partially or completely abolished by PaAF and RAF, respectively. NTP-BNP does not predict successful SR restoration.

Usefulness of bedside tissue Doppler echocardiography and B-type natriuretic peptide (BNP) in differentiating congestive heart failure from noncardiac cause of acute dyspnea in elderly patients with a normal left ventricular ejection fraction and permanent, nonvalvular atrial fibrillation: insights from a prospective, monocenter study

BACKGROUND

The incremental role of bedside tissue Doppler echocardiography and B-type natriuretic peptide (BNP) over the clinical judgment has been recently reported in the emergency diagnosis of congestive heart failure with a normal left ventricular ejection fraction (HFNEF). However, how well does this diagnostic strategy be applicable in the setting of atrial fibrillation is unknown.

OBJECTIVE

To investigate the usefulness of bedside tissue Doppler echocardiography and BNP in the emergency diagnosis of HFNEF in elderly patients with permanent, nonvalvular atrial fibrillation.

METHODS

Forty-one consecutive elderly patients with an ejection fraction > or =50% (mean age 84 years; 22 with HFNEF and 19 with noncardiac cause), hospitalized for acute dyspnea at rest, were prospectively enrolled; bedside septal E/Ea and BNP were obtained at admission.

RESULTS

By multivariable logistic regression analysis including the clinical judgment of heart failure, E/Ea and BNP, E/Ea (P = 0.014) and BNP (P = 0.018) provided independent diagnostic information. Optimal cutoffs were 13 for E/Ea (area under the ROC curve of 0.846, P < 0.0001; sensitivity 81.8%, specificity 89.5%) and 253 pg/ml for BNP (area under the ROC curve of 0.928, P < 0.0001; sensitivity 86.4%, specificity 89.5%). The concordance between the clinical judgment and BNP concentration at the cutoff of 253 pg/ml correctly classified 24 of 25 patients; E/Ea at the cutoff of 13 correctly classified 14 of the 16 patients with discrepancy.

CONCLUSION

Bedside tissue Doppler echocardiography and BNP provide useful additional diagnostic information over the clinical judgment for the emergency diagnosis of HFNEF in elderly patients with permanent, nonvalvular atrial fibrillation.