Right ventricular dysfunction is a predictor of non-response and clinical outcome following cardiac resynchronization therapy
© Alpendurada et al; licensee BioMed Central Ltd. 2011
Received: 6 July 2011
Accepted: 31 October 2011
Published: 31 October 2011
Cardiac resynchronization therapy (CRT) is an established treatment in advanced heart failure (HF). However, an important subset does not derive a significant benefit. Despite an established predictive role in HF, the significance of right ventricular (RV) dysfunction in predicting clinical benefit from CRT remains unclear. We investigated the role of RV function, assessed by cardiovascular magnetic resonance (CMR), in predicting response to and major adverse clinical events in HF patients undergoing CRT.
Sixty consecutive patients were evaluated with CMR prior to CRT implantation in a tertiary cardiac centre. The primary end-point was a composite of death from any cause or unplanned hospitalization for a major cardiovascular event. The secondary end-point was response to therapy, defined as improvement in left ventricular ejection fraction ≥ 5% on echocardiography at one year.
Eighteen patients (30%) met the primary end-point over a median follow-up period of 26 months, and 27 out of 56 patients (48%) were considered responders to CRT. On time-to-event analysis, only atrial fibrillation (HR 2.6, 95% CI 1.02-6.84, p = 0.047) and RV dysfunction, either by a reduced right ventricular ejection fraction-RVEF (HR 0.96, 95% CI 0.94-0.99, p = 0.006) or tricuspid annular plane systolic excursion-TAPSE (HR 0.88, 95% CI, 0.80-0.96, p = 0.006), were significant predictors of adverse events. On logistic regression analysis, preserved RVEF (OR 1.05, 95% CI 1.01-1.09, p = 0.01) and myocardial scar burden (OR 0.90, 95% CI 0.83-0.96, p = 0.004) were the sole independent predictors of response to CRT. Patients with marked RV dysfunction (RVEF < 30%) had a particularly low response rate (18.2%) to CRT.
Right ventricular function is an important predictor of both response to CRT and long-term clinical outcome. Routine assessment of the right ventricle should be considered in the evaluation of patients for CRT.
Keywordsheart failure cardiac resynchronization therapy right ventricular function cardiovascular magnetic resonance
Cardiac resynchronisation therapy (CRT) is an established therapeutic option for selected patients with symptomatic heart failure (HF). Amongst its benefits are reduced mortality, improved exercise tolerance and quality of life [1, 2]. However, a proportion of patients do not gain any significant benefit, the reasons for which are unclear. Thus a number of devices are being implanted with no discernible clinical benefit, which has important healthcare costs implications, as well as exposing patients to unnecessary risks. Our current strategy for assessing benefit with CRT is mainly focused on assessing symptomatic or functional response, but it is increasingly clear that this does not necessarily translate into improved clinical outcomes. It is therefore important to refine the selection criteria for device implantation to better identify those who would benefit-both in terms of response and improved clinical outcomes.
Whilst much attention has focused on remodelling of the left ventricle (LV), the role of the right ventricle (RV) in the appropriate selection of patients for CRT remains unclear . Previous studies assessing RV function have utilised echocardiography and radionuclide imaging [4–7]. However, accuracy of RV volumes and function by these techniques may be inaccurate due to the anatomical location and complex geometric structure. Cardiovascular magnetic resonance (CMR) offers superior three dimensional representation of the RV, leading to a more accurate and reproducible assessment of RV function . We therefore sought to assess the impact of RV function on outcomes in HF patients undergoing CRT implantation using CMR.
We studied 60 consecutive patients attending the Royal Brompton Hospital heart failure pacing clinic between January 2005 and March 2010 who fulfilled the following criteria: 1. New York Heart Association (NYHA) class III/IV at the time of CRT implantation; 2. QRS width ≥ 120 ms; 3. LVEF ≤ 35% by echocardiography, and; 4. CMR study within 3 months before CRT implantation.
These patients were evaluated for clinical (aetiology of heart failure, symptom status and medication, heart rate, blood pressure) and electrocardiographic (rhythm and QRS width) parameters at the time of device implantation. As this study involved review of local patient medical records, individual consent was not required by our Ethics Committee who approved the study.
Cardiovascular magnetic resonance studies were performed in 1.5T Sonata or Avanto scanners (Siemens, Erlangen, Germany). A short-axis stack from atrio-ventricular level to the apex was acquired using a steady-state free-precession cine sequence (echo time 1.6 ms, repetition time 3.2 ms, flip angle 60°, slice thickness 7 mm with a 3 mm gap, acquisition time of 8-12 cardiac cycles) to quantify left and right ventricular volumes. Long-axis cines were also acquired to define the valve plane throughout the cardiac cycle. An inversion recovery gradient echo sequence was used 10 minutes after gadolinium injection (Magnevist® or Gadovist® , 0.1 mmol/kg) to assess myocardial scar. Inversion times were set to null the normal myocardium with images repeated in two stacks of identical short-axis planes but separate phase-encoding directions to exclude artefact.
Valvular regurgitation was graded as mild (n = 1), moderate (n = 2) or severe (n = 3) by blinded observers, based on the echocardiographic and CMR findings. LVEF was also calculated by echocardiography before and 1 year after device implantation using the Simpson's method from the 2-chamber and 4-chamber views. Pulmonary artery systolic pressure was determined by echocardiography using standard methodology.
Contrast imaging with gadolinium was performed to assess the aetiology of the heart failure. Assessment of late gadolinium enhancement (LGE) in the left or right ventricle was interpreted by blinded observers. When present, the amount of LGE was quantified in a 16-segment model based on the "full width at half maximum" technique by customized analysis software (MRI-MASS, Medis, Leiden, the Netherlands) .
All patients were followed-up in a heart failure clinic and standard medications were adjusted and optimized at these appointments. Data was collected from local hospital records, nation-wide summary case records and the Office of National Statistics. The primary end-point was a composite of all-cause mortality or an unplanned hospitalization for a major cardiovascular event; only the first event in each patient was included in this analysis . The secondary end-point was echocardiographic response to CRT, defined as an improvement in LVEF by more than 5% by echocardiography 12 months after CRT implantation [12, 13].
Categorical variables are presented as frequency and percentage. Continuous variables are presented as mean ± standard deviation (SD) if normally distributed, or as median plus inter-quartile range (IQR) as appropriate. Continuous variables were compared with Student's t-test or the Mann-Whitney for non-parametric data. Correlation was assessed with Pearson's or Spearman's methods as appropriate.
Time to first event analysis was performed using Cox's proportional hazard models. Log-rank test was used to compare Kaplan-Meier cumulative event curves. Logistic regression was used to assess response to CRT at 12 months. Multivariate logistic regression analysis using a forward stepwise approach was performed on parameters that were significant on univariate analysis.
A two-tailed value of p-value < 0.05 was considered significant. All statistical analysis was performed using SPSS 19.0 (IBM, Chicago, Illinois, USA).
Baseline characteristics of the patients
65.3 ± 12.5
Heart failure, aetiology
QRS width (ms)
156 ± 21
Beats per minute (bpm)
76 ± 15
120 ± 20
72 ± 13
169 ± 62
124 ± 55
27 ± 8
113 ± 30
13.5 ± 5.6
Peak wall thickness (mm)
3.6 ± 0.9
Pulmonary artery pressure (mmHg)
38.7 ± 8.7
Late gadolinium enhancement
Subendocardial + mid-wall
Both mean left ventricular indexed end-diastolic and end-systolic volumes were high (169 ± 62 and 124 ± 55 mL/m2, respectively). The indexed left ventricular end-diastolic volume was increased in 93% of the patients, while the indexed left ventricular end-systolic volume was increased in 99% of the patients compared to normal reference values . The mean LVEF was 27 ± 8%, and the mean mass index was increased at 113 ± 30 g/m2.
Mitral regurgitation was seen in 90% of the patients, and was significant in 25% of patients (18% moderate, 7% severe). Aortic regurgitation was seen in 25% of patients, and was moderate in only one patient.
Right ventricular indexed volumes and ejection fraction were non-normally distributed, and hence presented as median plus inter-quartile ranges. The median end-diastolic and end-systolic volumes were 82 (65-123) mL/m2 and 38 (27-76) mL/m2, respectively. Right ventricular indexed end-diastolic volume was increased in 38% of patients, while the indexed end-systolic volume was increased in 53% of patients . The median RVEF was 52% (IQR 37-62%), with 53% of patients having a RVEF ≥ 50%.
The mean TAPSE was 13.5 ± 5.6 mm, with 40% of patients having values within normal limits when the standard echocardiographic cut-off value of 15 mm was considered. The mean peak RV wall thickness was 3.6 ± 0.9 mm.
In the 52 patients (87%) in whom it could be measured, the mean PASP was 38.7 ± 8.7 mmHg, with 37% of patients having a PAP > 40 mmHg. Tricuspid regurgitation was seen in 57% of the patients, and was significant in 14% of patients (12% moderate, 2% severe). No significant pulmonary regurgitation was identified in any patient.
There was a moderately strong correlation between RVEF with TAPSE (r = 0.58, p < 0.01), and a moderate correlation between RVEF and LVEF (r = 0.41, p < 0.01). Severity of mitral regurgitation was associated with a higher PAP (p = 0.01) and a lower RVEF (p < 0.01). Modest inverse correlations were observed between RVEF and pulmonary artery pressure (r = -0.37, p < 0.01), RV wall thickness (r = -0.28, p = 0.03) and severity of tricuspid regurgitation (p = 0.03). TAPSE was inversely related with RV wall thickness (r = -0.29, p = 0.03), but not with pulmonary artery pressure (r = -0.15, p = 0.28) or LVEF (r = 0.09, p = 0.48).
RVEF was similar in patients with an ischaemic and non-ischaemic aetiology (46.9 ± 14.8% vs. 49.5 ± 18.9, p = 0.56), and in patients with AF compared to those in sinus rhythm (45.4 ± 14.9% vs. 49.2 ± 17.8%, p = 0.48).
Left ventricular LGE was present in two-thirds of the patients: 19 patients (31.7%) had sub-endocardial enhancement suggesting myocardial infarction, 15 patients (25.0%) had a mid-wall enhancement pattern indicating fibrosis, and the remaining 6 patients (10.0%) had a mixed pattern of myocardial infarction and mid-wall fibrosis. Myocardial infarction was therefore present in 25 patients (41.7%): the septal wall was affected in 11 patients; the inferolateral wall was involved in 15 patients. The median percentage of scar in the myocardium was 4% (IQR 0-18%).
Right ventricular LGE was present in 5 patients (8.3%). All these patients had coronary artery disease with inferior myocardial infarctions of the LV extending to the inferior free wall of the RV.
Univariate analysis: Primary end-point (time to death from any cause or an unplanned hospitalization for a major cardiovascular event).
Events (n = 18)
No Events (n = 42)
69.6 ± 11.9
63.3 ± 12.3
Heart rate (bpm)
79.2 ± 19.4
74.1 ± 12.5
124 ± 22
118 ± 19
QRS width (ms)
151 ± 25
158 ± 21
EDV index (mL/m2)
159 ± 54
173 ± 64
ESV index (mL/m2)
120 ± 52
126 ± 56
26.9 ± 9.5
28.9 ± 7.6
Mass index (g/m2)
106 ± 25
115 ± 32
1.3 ± 0.6
1.2 ± 0.8
EDV index (mL/m2)
ESV index (mL/m2)
11.0 ± 4.4
14.5 ± 5.9
Wall thickness (mm)
3.9 ± 1.0
3.5 ± 0.9
42.5 ± 8.3
37.5 ± 8.5
After documenting AF as a predictor of outcomes, we performed a post-hoc analysis on delivery rate, defined as the percentage of paced left ventricular beats. Data was collected from routine pacing clinic visits during the first year of implantation. Unlike AF, delivery rate was not associated with the primary end-point (HR 0.97, 95% CI 0.88-1.08, p = 0.56).
Response to therapy
Univariate analysis: Response to cardiac resynchronization therapy (improvement of LVEF ≥ 5% at one year).
Response (n = 27)
No Response (n = 29)
64.0 ± 12.2
65.8 ± 12.2
Heart rate (bpm)
76 ± 15
76 ± 16
120 ± 20
119 ± 19
QRS width (ms)
161 ± 21
150 ± 22
EDV index (mL/m2)
156 ± 46
177 ± 71
ESV index (mL/m2)
111 ± 40
133 ± 63
30.5 ± 8.5
26.5 ± 7.2
Mass index (g/m2)
108 ± 26
118 ± 34
1.1 ± 0.6
1.3 ± 0.8
EDV index (mL/m2)
ESV index (mL/m2)
15.3 ± 5.8
11.8 ± 4.2
Wall thickness (mm)
3.3 ± 0.7
4.0 ± 1.0
36.9 ± 8.5
40.5 ± 9.0
Multivariate analysis: Response to cardiac resynchronization therapy (improvement of LVEF ≥ 5% at one year).
Response (n = 27)
No Response (n = 29)
This study shows that RV dysfunction is associated with non-response and adverse outcomes in patients on CRT. Despite meeting the standard criteria for CRT implantation, there was a heterogeneous distribution of RV function in our study population. Since LVEF was narrowly distributed by accepted indications for CRT, the wide RVEF distribution observed may indeed explain why RV function was an independent discriminator in this population with advanced HF. A lower RVEF was associated with a lower LVEF, more significant mitral regurgitation, and a higher PAP. This suggests that the RV dysfunction may derive from two fundamental mechanisms, the importance of which may vary from patient to patient: 1) an impairment of global biventricular intrinsic contractility; 2) pulmonary hypertension secondary to elevated LV filling pressures and mitral regurgitation.
Adverse RV function may reflect more extensive and severe cardiac disease, to which improving myocardial synchrony has little impact. Of note, the response rate of the subgroup of patients with RVEF < 0.3 was less than 20%. Thus, patients with poor RV function were unlikely to benefit from CRT. This may have implications in stratifying patients for device therapy.
Few studies have investigated RV function and dyssynchrony. Previous work has shown that anything up to 20-40% of RV systolic pressure and volume load may originate from contraction from the LV . Conversely, left bundle branch block (LBBB) may interfere with ventricular activation and induce mechanical dyssynchrony. Hence LBBB not only affects LV function but may impair RV function as well.
RV functional indices have been previously evaluated in CRT populations. Initial work by Field et al assessed RV function on adverse outcomes in a population of 77 patients undergoing CRT. This study showed that RV dysfunction measured by the Doppler-derived Tei index was a predictor of the composite end-point of death, transplantation and the implantation of left ventricular assist devices . More recent work focused on RV function and response to CRT. In a study of 44 patients undergoing CRT, echocardiographic indices of RV function (TAPSE and RV fractional area change) were significantly worse in non-responders versus responders to CRT . The value of TAPSE in predicting reverse remodelling was further validated in the CARE-HF population . A further radionuclide imaging study in 44 patients undergoing CRT showed that those with a low baseline RVEF were less likely to improve in NYHA class, and tended to improve less in functional capacity and LVEF .
The results of our study are in line with the above publications. However, we used CMR as the gold-standard technique for assessment of the RV, and RVEF as the reference marker of RV performance. Along with myocardial infarction, RVEF was an independent predictor of response to CRT. Among an array of established prognostic markers in HF, RVEF and TAPSE emerged as the strongest predictors of events. Our findings correlated response with outcomes over a clinically relevant timeframe, thus supporting the potential of RV function as a predictor of short-term response as well as longer-term outcome following CRT.
Tricuspid annular plane systolic excursion
Although available to all imaging modalities, and despite its validated prognostic value amongst cardiac and pulmonary conditions, RVEF estimation can be challenging as the right ventricle is a complex structure which cannot be modelled with simple geometric assumptions. Therefore, there is some interest in finding simpler ways for assessing RV performance. Of these, tricuspid annular plane systolic excursion (TAPSE) is the most described alternative to RVEF in the literature . This marker of RV longitudinal function is reproducible and easy to obtain, and has shown to be a predictor of adverse outcomes in heart failure, irrespective of NYHA status and LV function [16, 17]. In this study, TAPSE not only identified which patients would respond to CRT, but also the patients more likely to have major adverse events. Thus, TAPSE may be used by CMR as an alternative to RVEF for assessing RV function pre CRT when the latter cannot be estimated.
Increased pulmonary artery pressures have shown to be associated with non-response to CRT . As ejection fraction is influenced by the afterload, it is expected for increasing pulmonary pressures to be associated with decreasing RVEF. A significant negative correlation was indeed observed between PAP and RVEF in our study. However, this correlation was modest and not as strong as other parameters such as LVEF, suggesting that factors other than pulmonary hypertension play a role in RV function. There was a trend for non-response to CRT and adverse outcomes in patients with increased pulmonary pressures, but statistical significance was not reached, probably explained by the smaller study population compared to other studies . On the other hand, markers of RV function were significantly associated with response and adverse events. This suggests that RV function is more important than pulmonary pressure alone for both mechanical response and long-term prognosis in patients on CRT.
Late gadolinium enhancement CMR detects myocardial infarction accurately, with superior histological correlation compared to nuclear techniques . This has become an active area of research in the CRT setting, with several subsequent studies documenting the value of scar burden, location and transmurality of myocardial infarctions as a predictor of response to CRT [20–24]. Consistent with this work, our study showed myocardial infarction and scar burden (as determined by percentage of LGE mass) to portend an adverse response to CRT. Although the amount of septal and lateral scar was associated with non-response to therapy (OR 0.99, 95% CI 0.98-1.00, p = 0.02; and OR 0.98, 95% CI 0.97-1.00, p = 0.02, respectively), scar location did not remain significant after including the total amount of scar in a multivariate model.
The lack of response observed with the above parameters did not translate into poorer outcomes. It is possible that this study was underpowered to detect more adverse events, as larger studies have shown ischaemic heart disease and location of myocardial infarction to portend a worse prognosis in CRT [25–27].
Atrial fibrillation was the other predictor of outcomes besides RV dysfunction. This mirrors findings of long term studies of patients on CRT . It is recognised that AF with a high ventricular rate may impair the delivery of biventricular pacing, and consequently undermine the clinical benefit of CRT . Despite the paucity of data from randomized control trials in AF populations, recent guidelines support the use of CRT in AF patients, although restricted to a slightly wider QRS duration > 130 ms . A recent European registry suggests that around 20% of patients undergoing CRT are actually in permanent AF, which is in keeping with our findings . Of note, all but one AF patient in this study had QRS > 130 ms. Rate control was satisfactory in our AF cohort, the ventricular delivery rate was high (median 97%, IQR 91-99%), and none of the patients underwent AV nodal ablation. Unlike RV dysfunction, AF was not associated with a lower response rate, suggesting that the impact of AF on adverse outcomes was not altered by device implantation.
In addition to the hard clinical endpoints, we assessed the role of RV function on response to CRT. Response is a contentious topic, with various proposed definitions but no consensus amongst different criteria. The response rate varies widely, depending on the study population and the response criteria used. In a recent paper comparing 15 response criteria from the most cited papers, the response rate ranged from 32% to 91%. The same study showed that the agreement between different criteria was poor in 75% of the time, especially between clinical and echocardiographic criteria . For our study, we used LVEF to assess response because it is an objective parameter and is also one of the selection criteria for CRT. In keeping with previous work, response for this study was an improvement in LVEF ≥ 5% at 12 months [12, 13]. The response rate observed was relatively low (48%), but still in accordance with the available literature . Using this criterion, RV dysfunction predicted a failure of response to CRT in terms of LV remodelling, thus supporting previous echocardiographic and radionuclide studies [5–7]. It is possible that significant RV dysfunction marks extensive and irreversible adverse remodelling, preventing reverse remodelling and functional recovery after CRT implantation. Improvement in LVEF ≥ 5% was significantly associated with event-free survival in this cohort of patients (likelihood ratio 4.7, p = 0.01). Mechanical remodelling thus appears to be a good surrogate marker of response to therapy, in line with a recently published analysis of the MADIT-CRT trial, where it was demonstrated that echocardiographic improvement in LV volumes and ejection fraction was associated with improved outcomes .
This was a retrospective study with a relatively small number of patients and events limiting multivariate analysis on outcomes. Nonetheless, both RVEF and TAPSE emerged as the most significant prognostic markers, suggesting that RV function as assessed by CMR has a powerful role in advanced HF undergoing CRT.
This was a single centre study in a tertiary referral hospital, but it allowed for consistent CMR scanning protocols, and consistent patient selection for CRT and close follow-up of all patients. To ensure a representative cohort, consecutive patients were identified.
The CRT devices implanted during this time period were non-MRI compatible and hence necessitated an alternative imaging modality for consequent follow-up. The development of CMR-compatible CRT devices could overcome this current limitation and may provide new insights on the response of both left and right ventricle to CRT.
Right ventricular function appears an important predictor of response and major adverse events following CRT implantation. As current selection criteria only include patients with poor LV function, it is reasonable to assume that RV function will act as an important discriminative prognostic marker in patients undergoing CRT. Furthermore, poor RV function appears to identify a subgroup of patients with extensive ventricular remodelling unlikely to change their natural history. Therefore, CRT may be of no benefit in this subgroup of patients. The presence and amount of myocardial fibrosis, by contrast, was a predictor of response but did not predict outcomes.
The results of this study suggest that assessment of RV function can provide valuable information pre CRT implantation. Further work in larger cohorts is required to ascertain the precise role of RV evaluation in the selection of patients for CRT as well as the mechanisms for this dysfunction.
List of abbreviations
cardiovascular magnetic resonance
cardiac resynchronization therapy
left bundle brunch block
pulmonary artery systolic pressure
tricuspid annular plane systolic excursion.
This project was supported by the NIHR Cardiovascular Biomedical Research Unit of Royal Brompton & Harefield NHS Foundation Trust and Imperial College London. Research support was also received from the BHF and CORDA.
- Cazeau S, Leclercq C, Lavergne T, Walker S, Varma C, Linde C, Garrigue S, Kappenberger L, Haywood GA, Santini M, Bailleul C, Daubert JC: Effects of multisite biventricular pacing in patients with heart failure and intraventricular conduction delay. N Engl J Med. 2001, 344: 873-80. 10.1056/NEJM200103223441202.View ArticlePubMedGoogle Scholar
- Cleland JG, Daubert JC, Erdmann E, Freemantle N, Gras D, Kappenberger L, Tavazzi L: Cardiac Resynchronization-Heart Failure (CARE-HF) Study Investigators. The effect of cardiac resynchronization on morbidity and mortality in heart failure. N Engl J Med. 2005, 352: 1539-1549. 10.1056/NEJMoa050496.View ArticlePubMedGoogle Scholar
- Epstein AE, Dimarco JP, Ellenbogen KA, et al: ACC/AHA/HRS 2008 guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: executive summary. Heart Rhythm. 2008, 5: 934-955. 10.1016/j.hrthm.2008.04.015.View ArticlePubMedGoogle Scholar
- Field ME, Solomon SD, Lewis EF, Kramer DB, Baughman KL, Stevenson LW, Tedrow UB: Right ventricular dysfunction and adverse outcome in patients with advanced heart failure. J Card Fail. 2006, 12: 616-620. 10.1016/j.cardfail.2006.06.472.View ArticlePubMedGoogle Scholar
- Scuteri L, Rordorf R, Marsan NA, Landolina M, Magrini G, Klersy C, Frattini F, Petracci B, Vicentini A, Campana C, Tavazzi L, Ghio S: Relevance of echocardiographic evaluation of right ventricular function in patients undergoing cardiac resynchronization therapy. Pacing Clin Electrophysiol. 2009, 32: 1040-1049. 10.1111/j.1540-8159.2009.02436.x.View ArticlePubMedGoogle Scholar
- Ghio S, Freemantle N, Scelsi L, Serio A, Magrini G, Pasotti M, Shankar A, Cleland JG, Tavazzi L: Long-term left ventricular reverse remodelling with cardiac resynchronization therapy: results from the CARE-HF trial. Eur J Heart Fail. 2009, 11: 480-488. 10.1093/eurjhf/hfp034.View ArticlePubMedGoogle Scholar
- Burri H, Domenichini G, Sunthorn H, Fleury E, Stettler C, Foulkes I, Shah D: Right ventricular systolic function and cardiac resynchronization therapy. Europace. 2010, 12: 389-394. 10.1093/europace/eup401.View ArticlePubMedGoogle Scholar
- Hudsmith LE, Petersen SE, Francis JM, Robson MD, Neubauer S: Normal human left and right ventricular and left atrial dimensions using steady state free precession magnetic resonance imaging. J Cardiovasc Magn Reson. 2005, 7: 775-782. 10.1080/10976640500295516.View ArticlePubMedGoogle Scholar
- Maceira AM, Prasad SK, Khan M, Pennell DJ: Normalized left ventricular systolic and diastolic function by steady state free precession cardiovascular magnetic resonance. J Cardiovasc Magn Reson. 2006, 8: 417-426. 10.1080/10976640600572889.View ArticlePubMedGoogle Scholar
- Maceira AM, Prasad SK, Khan M, Pennell DJ: Reference right ventricular systolic and diastolic function normalized to age, gender and body surface area from steady-state free precession cardiovascular magnetic resonance. Eur Heart J. 2006, 27: 2879-2888. 10.1093/eurheartj/ehl336.View ArticlePubMedGoogle Scholar
- O'Hanlon R, Grasso A, Roughton M, Moon JC, Clark S, Wage R, Webb J, Kulkarni M, Dawson D, Sulaibeekh L, Chandrasekaran B, Bucciarelli-Ducci C, Pasquale F, Cowie MR, McKenna WJ, Sheppard MN, Elliott PM, Pennell DJ, Prasad SK: Prognostic significance of myocardial fibrosis in hypertrophic cardiomyopathy. J Am Coll Cardiol. 2010, 56: 867-74. 10.1016/j.jacc.2010.05.010.View ArticlePubMedGoogle Scholar
- Bax JJ, Marwick TH, Molhoek SG, Bleeker GB, van Erven L, Boersma E, Steendijk P, van der Wall EE, Schalij MJ: Left ventricular dyssynchrony predicts benefit of cardiac resynchronization therapy in patients with end-stage heart failure before pacemaker implantation. Am J Cardiol. 2003, 92: 1238-1240. 10.1016/j.amjcard.2003.06.016.View ArticlePubMedGoogle Scholar
- Bleeker GB, Bax JJ, Fung JW, van der Wall EE, Zhang Q, Schalij MJ, Chan JY, Yu CM: Clinical versus echocardiographic parameters to assess response to cardiac resynchronization therapy. Am J Cardiol. 2006, 97: 260-263. 10.1016/j.amjcard.2005.08.030.View ArticlePubMedGoogle Scholar
- Santamore WP, Dell'Italia LJ: Ventricular interdependence: significant left ventricular contributions to right ventricular systolic function. Prog Cardiovasc Dis. 1998, 40: 289-308. 10.1016/S0033-0620(98)80049-2.View ArticlePubMedGoogle Scholar
- Kaul S, Tei C, Hopkins JM, Shah PM: Assessment of right ventricular function using two-dimensional echocardiography. Am Heart J. 1984, 107: 526-531. 10.1016/0002-8703(84)90095-4.View ArticlePubMedGoogle Scholar
- Pinedo M, Villacorta E, Tapia C, Arnold R, López J, Revilla A, Gómez I, Fulquet E, San Román JA: Inter- and intra-observer variability in the echocardiographic evaluation of right ventricular function. Rev Esp Cardiol. 2010, 63: 802-809.View ArticlePubMedGoogle Scholar
- Ghio S, Recusani F, Klersy C, Sebastiani R, Laudisa ML, Campana C, Gavazzi A, Tavazzi L: Prognostic usefulness of the tricuspid annular plane systolic excursion in patients with congestive heart failure secondary to idiopathic or ischemic dilated cardiomyopathy. Am J Cardiol. 2000, 85: 837-842. 10.1016/S0002-9149(99)00877-2.View ArticlePubMedGoogle Scholar
- Tedrow UB, Kramer DB, Stevenson LW, Stevenson WG, Baughman KL, Epstein LM, Lewis EF: Relation of right ventricular peak systolic pressure to major adverse events in patients undergoing cardiac resynchronization therapy. Am J Cardiol. 2006, 97: 1737-40. 10.1016/j.amjcard.2006.01.033.View ArticlePubMedGoogle Scholar
- Wagner A, Mahrholdt H, Holly TA, Elliott MD, Regenfus M, Parker M, Klocke FJ, Bonow RO, Kim RJ, Judd RM: Contrast-enhanced MRI and routine single photon emission computed tomography (SPECT) perfusion imaging for detection of subendocardial myocardial infarcts: an imaging study. Lancet. 2003, 361: 374-9. 10.1016/S0140-6736(03)12389-6.View ArticlePubMedGoogle Scholar
- Bleeker GB, Kaandorp TA, Lamb HJ, Boersma E, Steendijk P, de Roos A, van der Wall EE, Schalij MJ, Bax JJ: Effect of posterolateral scar tissue on clinical and echocardiographic improvement after cardiac resynchronization therapy. Circulation. 2006, 113: 969-76. 10.1161/CIRCULATIONAHA.105.543678.View ArticlePubMedGoogle Scholar
- Ypenburg C, Roes SD, Bleeker GB, Kaandorp TA, de Roos A, Schalij MJ, van der Wall EE, Bax JJ: Effect of total scar burden on contrast-enhanced magnetic resonance imaging on response to cardiac resynchronization therapy. Am J Cardiol. 2007, 99: 657-660. 10.1016/j.amjcard.2006.09.115.View ArticlePubMedGoogle Scholar
- White JA, Yee R, Yuan X, Krahn A, Skanes A, Parker M, Klein G, Drangova M: Delayed enhancement magnetic resonance imaging predicts response to cardiac resynchronization therapy in patients with intraventricular dyssynchrony. J Am Coll Cardiol. 2006, 48: 1953-1960. 10.1016/j.jacc.2006.07.046.View ArticlePubMedGoogle Scholar
- Chalil S, Foley PW, Muyhaldeen SA, Patel KC, Yousef ZR, Smith RE, Frenneaux MP, Leyva F: Late gadolinium enhancement-cardiovascular magnetic resonance as a predictor of response to cardiac resynchronization therapy in patients with ischaemic cardiomyopathy. Europace. 2007, 9: 1031-1037. 10.1093/europace/eum133.View ArticlePubMedGoogle Scholar
- Marsan NA, Westenberg JJ, Ypenburg C, van Bommel RJ, Roes S, Delgado V, Tops LF, van der Geest RJ, Boersma E, de Roos A, Schalij MJ, Bax JJ: Magnetic resonance imaging and response to cardiac resynchronization therapy: relative merits of left ventricular dyssynchrony and scar tissue. Eur Heart J. 2009, 30: 2360-7. 10.1093/eurheartj/ehp280.View ArticlePubMedGoogle Scholar
- Leyva F, Foley PW, Chalil S, Ratib K, Smith RE, Prinzen F, Auricchio A: Cardiac resynchronization therapy guided by late gadolinium-enhancement cardiovascular magnetic resonance. J Cardiovasc Magn Reson. 2011, 13: 29-10.1186/1532-429X-13-29.PubMed CentralView ArticlePubMedGoogle Scholar
- Woo GW, Petersen-Stejskal S, Johnson JW, Conti JB, Aranda JA, Curtis AB: Ventricular reverse remodeling and 6-month outcomes in patients receiving cardiac resynchronization therapy: analysis of the MIRACLE study. J Interv Card Electrophysiol. 2005, 12: 107-113. 10.1007/s10840-005-6545-3.View ArticlePubMedGoogle Scholar
- Zhang Q, Fung JW, Chan JY, Yip G, Lam YY, Liang YJ, Yu CM: Difference in long-term clinical outcome after cardiac resynchronisation therapy between ischaemic and non-ischaemic aetiologies of heart failure. Heart. 2009, 95: 113-118. 10.1136/hrt.2008.145698.View ArticlePubMedGoogle Scholar
- Van Bommel RJ, Borleffs CJ, Ypenburg C, Marsan NA, Delgado V, Bertini M, van der Wall EE, Schalij MJ, Bax JJ: Morbidity and mortality in heart failure patients treated with cardiac resynchronization therapy: influence of pre-implantation characteristics on long-term outcome. Eur Heart J. 2010, 31: 2783-90. 10.1093/eurheartj/ehq252.View ArticlePubMedGoogle Scholar
- Koplan BA, Kaplan AJ, Weiner S, Jones PW, Seth M, Christman SA: Heart failure decompensation and all-cause mortality in relation to percent biventricular pacing in patients with heart failure: is a goal of 100% biventricular pacing necessary?. J Am Coll Cardiol. 2009, 53: 355-60. 10.1016/j.jacc.2008.09.043.View ArticlePubMedGoogle Scholar
- Dickstein K, Vardas PE, Auricchio A, Daubert JC, Linde C, McMurray J, Ponikowski P, Priori SG, Sutton R, van Veldhuisen DJ, ESC Committee for Practice Guidelines, Vahanian A, Auricchio A, Bax J, Ceconi C, Dean V, Filippatos G, Funck-Brentano C, Hobbs R, Kearney P, McDonagh T, Popescu BA, Reiner Z, Sechtem U, Sirnes PA, Tendera M, Vardas P, Widimsky P, Tendera M, Anker SD, Blanc JJ, Gasparini M, Hoes AW, Israel CW, Kalarus Z, Merkely B, Swedberg K, Camm AJ: 2010 Focused Update of ESC Guidelines on device therapy in heart failure: an update of the 2008 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure and the 2007 ESC Guidelines for cardiac and resynchronization therapy. Europace. 2010, 12: 1526-36.View ArticlePubMedGoogle Scholar
- Dickstein K, Bogale N, Priori S, Auricchio A, Cleland JG, Gitt A, Limbourg T, Linde C, van Veldhuisen DJ, Brugada J: The European cardiac resynchronization therapy survey. Eur Heart J. 2009, 30: 2450-60. 10.1093/eurheartj/ehp359.View ArticlePubMedGoogle Scholar
- Fornwalt BK, Sprague WW, BeDell P, Suever JD, Gerritse B, Merlino JD, Fyfe DA, León AR, Oshinski JN: Agreement is poor among current criteria used to define response to cardiac resynchronization therapy. Circulation. 2010, 121: 1985-91. 10.1161/CIRCULATIONAHA.109.910778.PubMed CentralView ArticlePubMedGoogle Scholar
- Solomon SD, Foster E, Bourgoun M, Shah A, Viloria E, Brown MW, Hall WJ, Pfeffer MA, Moss AJ: Effect of cardiac resynchronization therapy on reverse remodeling and relation to outcome: multicenter automatic defibrillator implantation trial: cardiac resynchronization therapy. Circulation. 2010, 122: 985-92. 10.1161/CIRCULATIONAHA.110.955039.View ArticlePubMedGoogle Scholar
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