- Email: [email protected]
Clinical implication of right bundle branch block in hospitalized patients with acute heart failure: Data from the Korean Heart Failure (KorHF) Registry
416
Letters to the Editor
Clinical implication of right bundle branch block in hospitalized patients with acute heart failure: Data from the Korean Heart Failure (KorHF) Registry Sung-Jin Hong a, Jaewon Oh a, Seok-Min Kang a,b,⁎, Jong Chan Youn a, Seongwoo Han c, Eun-Seok Jeon d, Myeong-Chan Cho e, Jae-Joong Kim f, Byung-Su Yoo g, Shung Chull Chae h, Byung-Hee Oh i, Dong-Ju Choi i, Myung-Mook Lee j, Kyu-Hyung Ryu k on behalf of the KorHF Registry a
Cardiology Division, Severance Cardiovascular Hospital and Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea c Division of Cardiology, Korea University Hospital, Seoul, Republic of Korea d Division of Cardiology, Sungkyunkwan University Samsung Medical Center, Seoul, Republic of Korea e Division of Cardiology, Chungbuk National University Hospital, Cheongju, Republic of Korea f Division of Cardiology, Ulsan University Asan Medical Center, Seoul, Republic of Korea g Division of Cardiology, Yonsei university Wonju Christian Hospital, Wonju, Republic of Korea h Division of Cardiology, Kyungpook National University Hospital, Daegu, Republic of Korea i Division of Cardiology, Seoul National University Hospital, Seoul, Republic of Korea j Division of Cardiology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea k Division of Cardiology, Konkuk University Medical Center, Seoul, Republic of Korea b
a r t i c l e
i n f o
Article history: Received 15 March 2012 Accepted 17 March 2012 Available online 11 April 2012
square test. Survival curves were constructed using the Kaplan– Meier method and compared with the log-rank test by the BBB patterns. Cox proportional hazard analysis was used to adjust clinical and laboratory variables identified from the previous studies as risk factors for mortality [4,5], and the hazard ratio (HR) and a 95% confidence interval (CI) were estimated. Subgroup
Keywords: Bundle branch block Acute heart failure Clinical outcome Table 1 Baseline characteristics of study patients at the time of index hospitalization.
Conflicting data exist regarding the predictive value of bundle branch block (BBB) patterns for mortality in hospitalized patients with acute heart failure (AHF) [1–4]. Thus, we aimed to demonstrate the relationship between the BBB patterns and clinical outcomes in hospitalized patients with AHF enrolled in the Korean Heart Failure (KorHF) Registry. In addition, we sought to identify the subgroups of patients for whom these BBB patterns have a stronger association with clinical outcomes. The KorHF Registry prospectively enrolled 3200 AHF patients from 24 hospitals between June 2004 and April 2009 [5]. From the initial recruits, 537 patients without electrocardiographic data and 34 patients with permanent pacemakers including biventricular pacemakers were excluded. After this exclusion, 427 patients with a wide QRS complex that did not meet right BBB (RBBB) or left BBB (LBBB) criteria were excluded. The final analysis included 2202 patients. Detailed data regarding patient characteristics, laboratory and echocardiographic findings including left ventricular ejection fraction (LVEF) and systolic pulmonary artery pressure (PAP), and discharge medications were retrospectively collected. The primary composite endpoint was all-cause mortality or rehospitalization. If a patient was rehospitalized and then died, he was counted for once. The follow-up events were collected until October 2009, and follow-up rate was 81%. The institutional review board at Severance Hospital approved study protocol. The authors have certified that they comply with the Principles of Ethical Publishing [6]. Continuous variables were compared using the analysis of variance and categorical variables were compared using the chi-
⁎ Corresponding author at: Cardiology Division, Department of Internal Medicine, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120752, Republic of Korea. Tel.: + 82 2 2228 8450; fax: +82 2 393 2041. E-mail address: [email protected] (S.-M. Kang).
Age (years) Women BMI (kg/m2) Emergency department admission Intensive care unit admission Previous medical history Heart failure Hypertension Diabetes mellitus Chronic renal disease Chronic pulmonary disease Underlying disease Ischemic heart disease Hypertension Cardiomyopathy Valvular heart disease NYHA functional class III or IV Clinical finding SBP (mm Hg) Hypotension (SBP b 90 mm Hg) Heart rate (per min) Laboratory finding Sodium (mM) Hemoglobin (g/dL) Creatinine (mg/dL) NT-proBNP (ng/L) Echocardiographic finding LVEF (%) Medication at discharge Beta-blocker ACE inhibitor or ARB Aldosterone antagonist
RBBB
LBBB
No BBB
(n = 118)
(n = 107)
(n = 1977)
p value
68 ± 15 49 (41.5%) 23.2 ± 3.6 96 (81.4%)
71 ± 12 63 (58.9%) 22.8 ± 3.6 90 (84.9%)
67 ± 15 992 (50.2%) 23.3 ± 4.1 1522 (79.9%)
0.018 0.034 0.543 0.455
38 (32.2%)
38 (35.5%)
601 (30.4%)
0.506
47 (39.8%) 50 (42.4%) 36 (30.5%) 11 (9.3%) 8 (6.8%)
38 (35.3%) 48 (44.9%) 31 (29.0%) 4 (3.7%) 6 (5.6%)
499 (25.3%) 943 (47.7%) 631 (31.9%) 176 (8.9%) 70 (3.5%)
b0.001 0.462 0.781 0.175 0.125
54 (47.4%) 20(16.9%) 29 (25.4%) 15 (13.2%) 84 (80.0%)
43 (42.6%) 21(19.6%) 32 (31.7%) 12 (11.9%) 76 (75.2%)
850 (44.4%) 443(22.4%) 270 (14.1%) 229 (12.0%) 1145 (69.1%)
0.764 0.317 b0.001 0.929 0.031
129 ± 33 5 (4.2%)
127 ± 25 7 (6.5%)
133 ± 31 67 (3.4%)
0.073 0.215
87 ± 27
94 ± 29
92 ± 25
0.098
138.0 ± 5.4 12.3 ± 2.2 1.52 ± 1.21 9067 ± 11236
138.4 ± 4.9 12.3 ± 2.2 1.34 ± 0.91 7647 ± 7987
138.2 ± 5.2 12.4 ± 2.4 1.47 ± 1.15 8626 ± 10045
0.812 0.774 0.470 0.653
39.3 ± 13.6
29.3 ± 12.1
40.0 ± 15.7
b0.001
43 (36.4%) 68 (57.6%) 38 (32.2%)
29 (27.4%) 66 (61.7%) 36 (34.0%)
785 (40.3%) 1177 (59.6%) 580 (29.6%)
0.023 0.826 0.549
Values are meant ± SD or number (%). BMI = body mass index, NYHA = New York Heart Association, SBP = systolic blood pressure, ACE = Angiotensin converting enzyme, ARB = angiotensin II receptor blocker.
Letters to the Editor
Fig. 1. Kaplan–Meier analysis of event rate of the composite endpoint according to BBB patterns.
analyses stratified by selected clinical characteristics were performed for the composite endpoint, each using a test for heterogeneity to assess for interactions between the BBB patterns and clinical characteristics. All analyses were conducted using SPSS version 18.0. A p-value b 0.05 was considered statistically significant. RBBB was present in 118 (5.4%), LBBB in 107 (4.9%), and no BBB in 1977 (89.7%) patients. The baseline characteristics are presented in Table 1. Regarding the composite endpoint, 61 patients (51.7%) with RBBB, 38 patients (35.5%) with LBBB and 722 patients (36.5%) with no BBB were rehospitalized or died during a median follow-up period of 572 days. Kaplan–Meier analysis revealed that the composite endpoint at 3 years was significantly higher in RBBB (65.1%) compared to LBBB (49.9%) and no BBB (49.3%) (p = 0.004, Fig. 1). RBBB was also an independent predictor of the composite endpoint when compared to LBBB (HR = 2.57, p = 0.001) and no BBB (HR = 1.91, p b 0.001) even after adjustment (Table 2). In contrast to RBBB, LBBB did not have prognostic value in univariate and multivariate analysis. Regarding rehospitalization analyses, 144 non-survivors at discharge were excluded. On multivariate analysis, RBBB was an independent predictor of rehospitalization when compared to LBBB (HR=3.09, p=0.001) and no BBB (HR=2.21, pb 0.001) (Table 2). In terms of all-cause mortality, the unadjusted HR for RBBB vs. LBBB was 1.51 without significance (p=0.158). However, there was a significant difference between RBBB and no BBB (unadjusted HR=1.56, p=0.019). Multivariate analysis
417
showed a marginal significance for increased risk of all-cause mortality in the RBBB compared to no BBB (HR=1.63, p=0.049). For subgroup analyses for composite endpoint, the HRs of the composite endpoint for RBBB vs. LBBB were significantly higher in the subgroups of age b 65 years, men, no prior diabetes, no prior hypertension, ischemic heart disease, and angiotensin converting enzyme inhibitor use, though the test for interaction was not significant (Fig. 2). However, we observed a significant interaction between the BBB patterns and LVEF for predicting the composite endpoint (p = 0.045 for interaction). For LVEF ≤ 40%, HR for RBBB vs. LBBB was pronounced from 1.61 to 2.28 (p = 0.001). By contrast, for LVEF N 40%, HR was 0.77 (p = 0.578). When we compared systolic PAP according to the BBB patterns, it was not different among groups (p = 0.356, Fig. 3). Interestingly, in the RBBB patients, systolic PAP was significantly elevated in LVEF ≤ 40% vs. LVEF N 40% (52.5 ± 17.5 mm Hg vs. 40.0 ± 12.4 mm Hg, p = 0.014). By contrast, in the LBBB and no BBB patients, systolic PAP was not significantly different between LVEF ≤ 40% and LVEF N 40%. The principal finding of this study is that RBBB but not LBBB is an independent predictor of all-cause mortality or rehospitalization in hospitalized patients with AHF and its association is pronounced with reduced LV systolic function. Although recent studies have highlighted the prognostic value of QRS morphology on mortality in AHF, they did not show consistent result [1–4]. These conflicting results may be attributed to the heterogeneous nature of AHF and the patients’ characteristics enrolled in each study [7]. A recently published article by Abdel-Qadir et al. showed that patients with LBBB had worse prognosis than those without BBB in heart failure [2]. Compared to their patients’ characteristics, the subjects enrolled in our study were relatively younger, had a lower proportion of male, ischemic heart disease, and had a lower systolic blood pressure on admission. RBBB may result from various disorders affecting the right heart, which indicates structural changes in the right ventricle (RV) with pulmonary hypertension or RV dysfunction, which complicate the clinical course of the primarily left heart disease resulting in AHF. RV dysfunction had an additive predictive value in patients with LV systolic dysfunction [8,9]. Patients with AHF can have advanced cardiac diseases involving the LV that is severe enough to cause AHF. In these settings, LBBB itself may not provide incremental prognostic information in the patients with severe LV dysfunction. Our result that RBBB had a more marked prognostic impact especially in the reduced LV systolic function supports these explanations. Also, elevated systolic PAP in RBBB patients with reduced LV systolic function may be one of the reasons why they are related to poor clinical outcomes. In conclusion, RBBB is associated with poor clinical outcomes in hospitalized patients with AHF and its significance is pronounced with reduced LV systolic function.
Table 2 Clinical outcomes according to bundle branch block patterns. Number of events/ number of patients All-cause mortality or rehospitalization RBBB vs. LBBB 61/118 vs. 38/107 RBBB vs. no BBB 61/118 vs. 722/1977 LBBB vs. no BBB 38/107 vs. 722/1977 Rehospitalization RBBB vs. LBBB 41/110 vs. 25/99 RBBB vs. no BBB 41/110 vs. 470/1849 LBBB vs. no BBB 25/99 vs. 470/1849 All-cause mortality RBBB vs. LBBB 31/118 vs. 19/107 RBBB vs. no BBB 31/118 vs. 340/1977 LBBB vs. no BBB 19/107 vs. 340/1977
Univariate analysis
Multivariate analysis
HR
95% CI
p value
HR
95% CI
p value
1.61 1.54 0.96
1.07–2.41 1.19–2.00 0.69–1.33
0.022 0.001 0.811
2.57 1.91 0.75
1.46–4.50 1.37–2.67 0.46–1.20
0.001 b 0.001 0.223
1.64 1.60 0.98
1.00–2.69 1.16–2.20 0.65–1.46
0.052 0.004 0.912
3.09 2.21 0.72
1.59–6.01 1.51–3.25 0.41–1.27
0.001 b 0.001 0.253
1.51 1.56 1.03
0.85–2.67 1.08–2.25 0.65–1.64
0.158 0.019 0.899
2.19 1.63 0.75
0.96–5.00 1.00–2.65 0.37–1.49
0.062 0.049 0.406
Adjusted for age, sex, history of heart failure, myocardial infarction, diabetes, chronic pulmonary disease, systolic blood pressure, admission creatinine, hemoglobin, sodium, NTproBNP, LVEF, beta-blocker, ACE inhibitor and angiotensin II receptor blocker medication at discharge.
418
Letters to the Editor
Fig. 2. Forest plot of subgroup analyses of the composite endpoint comparing RBBB with LBBB. The test for interaction was significant only within strata formed by LVEF.
Fig. 3. Comparison systolic PAP according to the BBB patterns and LVEF. In each box plot, the mean value is indicated and the error bars represent the 95% CI.
References [1] McCullough PA, Hassan SA, Pallekonda V, et al. Bundle branch block patterns, age, renal dysfunction, and heart failure mortality. Int J Cardiol 2005;102:303–8. [2] Abdel-Qadir HM, Tu JV, Austin PC, Wang JT, Lee DS. Bundle branch block patterns and long-term outcomes in heart failure. Int J Cardiol 2011;146:213–8. [3] Mueller C, Laule-Kilian K, Klima T, et al. Right bundle branch block and long-term mortality in patients with acute congestive heart failure. J Intern Med 2006;260:421–8. [4] Barsheshet A, Goldenberg I, Garty M, et al. Relation of bundle branch block to longterm (four-year) mortality in hospitalized patients with systolic heart failure. Am J Cardiol 2011;107:540–4. [5] Choi DJ, Han S, Jeon ES, et al. Characteristics, outcomes and predictors of long-term mortality for patients hospitalized for acute heart failure: a report From the Korean Heart Failure Registry. Korean Circ J 2011;41:363–71.
0167-5273/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2012.03.155
[6] Coats AJS, Shewan LG. Statement on authorship and publishing ethics in the International Journal of Cardiology. Int J Cardiol 2011;153:239–40. [7] Metra M, Felker GM, Zaca V, et al. Acute heart failure: multiple clinical profiles and mechanisms require tailored therapy. Int J Cardiol 2010;144:175–9. [8] Ghio S, Gavazzi A, Campana C, et al. Independent and additive prognostic value of right ventricular systolic function and pulmonary artery pressure in patients with chronic heart failure. J Am Coll Cardiol 2001;37:183–8. [9] Juilliere Y, Barbier G, Feldmann L, Grentzinger A, Danchin N, Cherrier F. Additional predictive value of both left and right ventricular ejection fractions on long-term survival in idiopathic dilated cardiomyopathy. Eur Heart J 1997;18:276–80.
Letters to the Editor
Clinical implication of right bundle branch block in hospitalized patients with acute heart failure: Data from the Korean Heart Failure (KorHF) Registry Sung-Jin Hong a, Jaewon Oh a, Seok-Min Kang a,b,⁎, Jong Chan Youn a, Seongwoo Han c, Eun-Seok Jeon d, Myeong-Chan Cho e, Jae-Joong Kim f, Byung-Su Yoo g, Shung Chull Chae h, Byung-Hee Oh i, Dong-Ju Choi i, Myung-Mook Lee j, Kyu-Hyung Ryu k on behalf of the KorHF Registry a
Cardiology Division, Severance Cardiovascular Hospital and Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea c Division of Cardiology, Korea University Hospital, Seoul, Republic of Korea d Division of Cardiology, Sungkyunkwan University Samsung Medical Center, Seoul, Republic of Korea e Division of Cardiology, Chungbuk National University Hospital, Cheongju, Republic of Korea f Division of Cardiology, Ulsan University Asan Medical Center, Seoul, Republic of Korea g Division of Cardiology, Yonsei university Wonju Christian Hospital, Wonju, Republic of Korea h Division of Cardiology, Kyungpook National University Hospital, Daegu, Republic of Korea i Division of Cardiology, Seoul National University Hospital, Seoul, Republic of Korea j Division of Cardiology, Dongguk University Ilsan Hospital, Goyang, Republic of Korea k Division of Cardiology, Konkuk University Medical Center, Seoul, Republic of Korea b
a r t i c l e
i n f o
Article history: Received 15 March 2012 Accepted 17 March 2012 Available online 11 April 2012
square test. Survival curves were constructed using the Kaplan– Meier method and compared with the log-rank test by the BBB patterns. Cox proportional hazard analysis was used to adjust clinical and laboratory variables identified from the previous studies as risk factors for mortality [4,5], and the hazard ratio (HR) and a 95% confidence interval (CI) were estimated. Subgroup
Keywords: Bundle branch block Acute heart failure Clinical outcome Table 1 Baseline characteristics of study patients at the time of index hospitalization.
Conflicting data exist regarding the predictive value of bundle branch block (BBB) patterns for mortality in hospitalized patients with acute heart failure (AHF) [1–4]. Thus, we aimed to demonstrate the relationship between the BBB patterns and clinical outcomes in hospitalized patients with AHF enrolled in the Korean Heart Failure (KorHF) Registry. In addition, we sought to identify the subgroups of patients for whom these BBB patterns have a stronger association with clinical outcomes. The KorHF Registry prospectively enrolled 3200 AHF patients from 24 hospitals between June 2004 and April 2009 [5]. From the initial recruits, 537 patients without electrocardiographic data and 34 patients with permanent pacemakers including biventricular pacemakers were excluded. After this exclusion, 427 patients with a wide QRS complex that did not meet right BBB (RBBB) or left BBB (LBBB) criteria were excluded. The final analysis included 2202 patients. Detailed data regarding patient characteristics, laboratory and echocardiographic findings including left ventricular ejection fraction (LVEF) and systolic pulmonary artery pressure (PAP), and discharge medications were retrospectively collected. The primary composite endpoint was all-cause mortality or rehospitalization. If a patient was rehospitalized and then died, he was counted for once. The follow-up events were collected until October 2009, and follow-up rate was 81%. The institutional review board at Severance Hospital approved study protocol. The authors have certified that they comply with the Principles of Ethical Publishing [6]. Continuous variables were compared using the analysis of variance and categorical variables were compared using the chi-
⁎ Corresponding author at: Cardiology Division, Department of Internal Medicine, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120752, Republic of Korea. Tel.: + 82 2 2228 8450; fax: +82 2 393 2041. E-mail address: [email protected] (S.-M. Kang).
Age (years) Women BMI (kg/m2) Emergency department admission Intensive care unit admission Previous medical history Heart failure Hypertension Diabetes mellitus Chronic renal disease Chronic pulmonary disease Underlying disease Ischemic heart disease Hypertension Cardiomyopathy Valvular heart disease NYHA functional class III or IV Clinical finding SBP (mm Hg) Hypotension (SBP b 90 mm Hg) Heart rate (per min) Laboratory finding Sodium (mM) Hemoglobin (g/dL) Creatinine (mg/dL) NT-proBNP (ng/L) Echocardiographic finding LVEF (%) Medication at discharge Beta-blocker ACE inhibitor or ARB Aldosterone antagonist
RBBB
LBBB
No BBB
(n = 118)
(n = 107)
(n = 1977)
p value
68 ± 15 49 (41.5%) 23.2 ± 3.6 96 (81.4%)
71 ± 12 63 (58.9%) 22.8 ± 3.6 90 (84.9%)
67 ± 15 992 (50.2%) 23.3 ± 4.1 1522 (79.9%)
0.018 0.034 0.543 0.455
38 (32.2%)
38 (35.5%)
601 (30.4%)
0.506
47 (39.8%) 50 (42.4%) 36 (30.5%) 11 (9.3%) 8 (6.8%)
38 (35.3%) 48 (44.9%) 31 (29.0%) 4 (3.7%) 6 (5.6%)
499 (25.3%) 943 (47.7%) 631 (31.9%) 176 (8.9%) 70 (3.5%)
b0.001 0.462 0.781 0.175 0.125
54 (47.4%) 20(16.9%) 29 (25.4%) 15 (13.2%) 84 (80.0%)
43 (42.6%) 21(19.6%) 32 (31.7%) 12 (11.9%) 76 (75.2%)
850 (44.4%) 443(22.4%) 270 (14.1%) 229 (12.0%) 1145 (69.1%)
0.764 0.317 b0.001 0.929 0.031
129 ± 33 5 (4.2%)
127 ± 25 7 (6.5%)
133 ± 31 67 (3.4%)
0.073 0.215
87 ± 27
94 ± 29
92 ± 25
0.098
138.0 ± 5.4 12.3 ± 2.2 1.52 ± 1.21 9067 ± 11236
138.4 ± 4.9 12.3 ± 2.2 1.34 ± 0.91 7647 ± 7987
138.2 ± 5.2 12.4 ± 2.4 1.47 ± 1.15 8626 ± 10045
0.812 0.774 0.470 0.653
39.3 ± 13.6
29.3 ± 12.1
40.0 ± 15.7
b0.001
43 (36.4%) 68 (57.6%) 38 (32.2%)
29 (27.4%) 66 (61.7%) 36 (34.0%)
785 (40.3%) 1177 (59.6%) 580 (29.6%)
0.023 0.826 0.549
Values are meant ± SD or number (%). BMI = body mass index, NYHA = New York Heart Association, SBP = systolic blood pressure, ACE = Angiotensin converting enzyme, ARB = angiotensin II receptor blocker.
Letters to the Editor
Fig. 1. Kaplan–Meier analysis of event rate of the composite endpoint according to BBB patterns.
analyses stratified by selected clinical characteristics were performed for the composite endpoint, each using a test for heterogeneity to assess for interactions between the BBB patterns and clinical characteristics. All analyses were conducted using SPSS version 18.0. A p-value b 0.05 was considered statistically significant. RBBB was present in 118 (5.4%), LBBB in 107 (4.9%), and no BBB in 1977 (89.7%) patients. The baseline characteristics are presented in Table 1. Regarding the composite endpoint, 61 patients (51.7%) with RBBB, 38 patients (35.5%) with LBBB and 722 patients (36.5%) with no BBB were rehospitalized or died during a median follow-up period of 572 days. Kaplan–Meier analysis revealed that the composite endpoint at 3 years was significantly higher in RBBB (65.1%) compared to LBBB (49.9%) and no BBB (49.3%) (p = 0.004, Fig. 1). RBBB was also an independent predictor of the composite endpoint when compared to LBBB (HR = 2.57, p = 0.001) and no BBB (HR = 1.91, p b 0.001) even after adjustment (Table 2). In contrast to RBBB, LBBB did not have prognostic value in univariate and multivariate analysis. Regarding rehospitalization analyses, 144 non-survivors at discharge were excluded. On multivariate analysis, RBBB was an independent predictor of rehospitalization when compared to LBBB (HR=3.09, p=0.001) and no BBB (HR=2.21, pb 0.001) (Table 2). In terms of all-cause mortality, the unadjusted HR for RBBB vs. LBBB was 1.51 without significance (p=0.158). However, there was a significant difference between RBBB and no BBB (unadjusted HR=1.56, p=0.019). Multivariate analysis
417
showed a marginal significance for increased risk of all-cause mortality in the RBBB compared to no BBB (HR=1.63, p=0.049). For subgroup analyses for composite endpoint, the HRs of the composite endpoint for RBBB vs. LBBB were significantly higher in the subgroups of age b 65 years, men, no prior diabetes, no prior hypertension, ischemic heart disease, and angiotensin converting enzyme inhibitor use, though the test for interaction was not significant (Fig. 2). However, we observed a significant interaction between the BBB patterns and LVEF for predicting the composite endpoint (p = 0.045 for interaction). For LVEF ≤ 40%, HR for RBBB vs. LBBB was pronounced from 1.61 to 2.28 (p = 0.001). By contrast, for LVEF N 40%, HR was 0.77 (p = 0.578). When we compared systolic PAP according to the BBB patterns, it was not different among groups (p = 0.356, Fig. 3). Interestingly, in the RBBB patients, systolic PAP was significantly elevated in LVEF ≤ 40% vs. LVEF N 40% (52.5 ± 17.5 mm Hg vs. 40.0 ± 12.4 mm Hg, p = 0.014). By contrast, in the LBBB and no BBB patients, systolic PAP was not significantly different between LVEF ≤ 40% and LVEF N 40%. The principal finding of this study is that RBBB but not LBBB is an independent predictor of all-cause mortality or rehospitalization in hospitalized patients with AHF and its association is pronounced with reduced LV systolic function. Although recent studies have highlighted the prognostic value of QRS morphology on mortality in AHF, they did not show consistent result [1–4]. These conflicting results may be attributed to the heterogeneous nature of AHF and the patients’ characteristics enrolled in each study [7]. A recently published article by Abdel-Qadir et al. showed that patients with LBBB had worse prognosis than those without BBB in heart failure [2]. Compared to their patients’ characteristics, the subjects enrolled in our study were relatively younger, had a lower proportion of male, ischemic heart disease, and had a lower systolic blood pressure on admission. RBBB may result from various disorders affecting the right heart, which indicates structural changes in the right ventricle (RV) with pulmonary hypertension or RV dysfunction, which complicate the clinical course of the primarily left heart disease resulting in AHF. RV dysfunction had an additive predictive value in patients with LV systolic dysfunction [8,9]. Patients with AHF can have advanced cardiac diseases involving the LV that is severe enough to cause AHF. In these settings, LBBB itself may not provide incremental prognostic information in the patients with severe LV dysfunction. Our result that RBBB had a more marked prognostic impact especially in the reduced LV systolic function supports these explanations. Also, elevated systolic PAP in RBBB patients with reduced LV systolic function may be one of the reasons why they are related to poor clinical outcomes. In conclusion, RBBB is associated with poor clinical outcomes in hospitalized patients with AHF and its significance is pronounced with reduced LV systolic function.
Table 2 Clinical outcomes according to bundle branch block patterns. Number of events/ number of patients All-cause mortality or rehospitalization RBBB vs. LBBB 61/118 vs. 38/107 RBBB vs. no BBB 61/118 vs. 722/1977 LBBB vs. no BBB 38/107 vs. 722/1977 Rehospitalization RBBB vs. LBBB 41/110 vs. 25/99 RBBB vs. no BBB 41/110 vs. 470/1849 LBBB vs. no BBB 25/99 vs. 470/1849 All-cause mortality RBBB vs. LBBB 31/118 vs. 19/107 RBBB vs. no BBB 31/118 vs. 340/1977 LBBB vs. no BBB 19/107 vs. 340/1977
Univariate analysis
Multivariate analysis
HR
95% CI
p value
HR
95% CI
p value
1.61 1.54 0.96
1.07–2.41 1.19–2.00 0.69–1.33
0.022 0.001 0.811
2.57 1.91 0.75
1.46–4.50 1.37–2.67 0.46–1.20
0.001 b 0.001 0.223
1.64 1.60 0.98
1.00–2.69 1.16–2.20 0.65–1.46
0.052 0.004 0.912
3.09 2.21 0.72
1.59–6.01 1.51–3.25 0.41–1.27
0.001 b 0.001 0.253
1.51 1.56 1.03
0.85–2.67 1.08–2.25 0.65–1.64
0.158 0.019 0.899
2.19 1.63 0.75
0.96–5.00 1.00–2.65 0.37–1.49
0.062 0.049 0.406
Adjusted for age, sex, history of heart failure, myocardial infarction, diabetes, chronic pulmonary disease, systolic blood pressure, admission creatinine, hemoglobin, sodium, NTproBNP, LVEF, beta-blocker, ACE inhibitor and angiotensin II receptor blocker medication at discharge.
418
Letters to the Editor
Fig. 2. Forest plot of subgroup analyses of the composite endpoint comparing RBBB with LBBB. The test for interaction was significant only within strata formed by LVEF.
Fig. 3. Comparison systolic PAP according to the BBB patterns and LVEF. In each box plot, the mean value is indicated and the error bars represent the 95% CI.
References [1] McCullough PA, Hassan SA, Pallekonda V, et al. Bundle branch block patterns, age, renal dysfunction, and heart failure mortality. Int J Cardiol 2005;102:303–8. [2] Abdel-Qadir HM, Tu JV, Austin PC, Wang JT, Lee DS. Bundle branch block patterns and long-term outcomes in heart failure. Int J Cardiol 2011;146:213–8. [3] Mueller C, Laule-Kilian K, Klima T, et al. Right bundle branch block and long-term mortality in patients with acute congestive heart failure. J Intern Med 2006;260:421–8. [4] Barsheshet A, Goldenberg I, Garty M, et al. Relation of bundle branch block to longterm (four-year) mortality in hospitalized patients with systolic heart failure. Am J Cardiol 2011;107:540–4. [5] Choi DJ, Han S, Jeon ES, et al. Characteristics, outcomes and predictors of long-term mortality for patients hospitalized for acute heart failure: a report From the Korean Heart Failure Registry. Korean Circ J 2011;41:363–71.
0167-5273/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2012.03.155
[6] Coats AJS, Shewan LG. Statement on authorship and publishing ethics in the International Journal of Cardiology. Int J Cardiol 2011;153:239–40. [7] Metra M, Felker GM, Zaca V, et al. Acute heart failure: multiple clinical profiles and mechanisms require tailored therapy. Int J Cardiol 2010;144:175–9. [8] Ghio S, Gavazzi A, Campana C, et al. Independent and additive prognostic value of right ventricular systolic function and pulmonary artery pressure in patients with chronic heart failure. J Am Coll Cardiol 2001;37:183–8. [9] Juilliere Y, Barbier G, Feldmann L, Grentzinger A, Danchin N, Cherrier F. Additional predictive value of both left and right ventricular ejection fractions on long-term survival in idiopathic dilated cardiomyopathy. Eur Heart J 1997;18:276–80.