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Biomedical subjects

Christoph Stellbrink

Publications and source records attributed to Christoph Stellbrink.

At least 19 recordsLinked to original sources
PubMed2006

Left bundle branch block as a risk factor for progression to heart failure.

The prevalence of conduction disturbances, particularly left bundle branch block (LBBB), is strongly correlated with age and with the presence of cardiovascular disease. LBBB has been reported to affect approximately 25% of the heart failure (HF) population and it is likely that the deleterious role of such conduction disorders in the progression to HF has been underestimated. The purpose of this article is to review the data from the literature indicating that LBBB may have a causative role, mediated through the resulting intra-ventricular asynchrony, in the deterioration of cardiac function and the development of cardiac remodelling and HF. It also aims to address the potential for future clinical therapies for this conduction disorder.

Bundle-Branch Block↗
PubMed2006

A new method to investigate the response to the morphology discrimination algorithm in patients with ICD.

BACKGROUND: Inappropriate therapy for supraventricular tachyarrhythmia is still a major problem in implantable cardioverter defibrillators (ICD). The morphology discrimination algorithm compares the morphology of a tachycardia electrogram with a stored template on a beat-to-beat basis. However, algorithm responders could not yet be identified prior to the occurrence of first tachycardia episodes. We analyzed whether rapid atrial pacing and/or exercise testing can be used for identification of responders and compared the results with ICD detected tachycardia. METHODS: 22 patients (16 male, 61+/-14 years) with dual-chamber ICDs have been enrolled. Patients underwent a standardized bicycle exercise testing and an atrial pacing protocol. For both tests, morphology match scores of 8 consecutive beats were analyzed for each 10-bpm-step increment above sinus rhythm. Patients were categorized as responders, if morphology match was > or = 90% of tested heart rates. During follow-up, ICD stored episodes with morphology discrimination activated were evaluated. RESULTS: There were no significant differences between morphology match (85+/-29% vs. 84+/-27%) and linear regression slope B (-0.19+/-0.87 vs. -0.20+/-0.48) during exercise testing and atrial pacing. 16 patients (73%) were classified as responders. During follow-up (739+/-338 days) 121 sustained supraventricular (n=88) and ventricular tachycardia (n=33) were detected in 10 patients (45%). Specificity for tachycardia discrimination was 78% overall, 100% in responders and 22% in non-responders. CONCLUSION: Exercise testing and atrial pacing were equally suitable for identification of patients who seem to respond to the morphology discrimination algorithm with a high specificity for ventricular tachycardia discrimination. Thus, morphology match tests are suggested to optimize tachycardia discrimination and to reduce inadequate therapies.

Algorithms↗
PubMed2006

First multi-centre evaluation of a knowledge-based implant-assistant for implantable cardioverter-defibrillators.

AIMS: Modern implantable cardioverter-defibrillators (ICDs) place increasing demands on the physician, as their complexity requires more and more knowledge and effort in handling them. To overcome this problem an implant-assistant has been developed, which transfers clinical data entered by the physician into a complete set of parameters for programming a dual-chamber ICD (Tachos-DR, Biotronik, Berlin, Germany) at DFT testing (DFT-Prog) and first permanent programming (Perm-Prog) after implant. METHODS AND RESULTS: Routine ICD implantations were initially evaluated by clinical experts at 19 centres in USA and Europe from 178 patient files. The rating of parameters was related to the number of parameters available in each patient. For DFT-Prog, 98.4% of parameter suggestions were identical to experts' expectations, an additional 1.0% were accepted, 0.5% were rejected, and none was considered harmful. This resulted in an overall acceptance of 94.4% of the DFT-Prog. For Perm-Prog, 96.1% of parameters were identical to those advised by experts, an additional 2.4% were accepted, 1.5% rejected, and seven parameters (0.04%) were considered potentially harmful by experts with an overall acceptance of 86.5%. Adaptation of the implant-assistant increased the overall acceptance to 100% for DFT-Prog and 90.6% for first Perm-Prog without any potentially harmful suggestions. CONCLUSION: The ICD implant-assistant, which allows the physician to programme ICDs directly from clinical data, is a promising method to simplify the programming of modern ICDs.

Defibrillators, Implantable↗
PubMed2006

Quality of anticoagulation with unfractionated heparin plus phenprocoumon for the prevention of thromboembolic complications in cardioversion for non-valvular atrial fibrillation. Sub-analysis from the Anticoagulation in Cardioversion using Enoxaparin (ACE) trial.

INTRODUCTION: Anticoagulation in cardioversion for atrial fibrillation is performed using unfractionated heparin and oral anticoagulants. TEE-guided cardioversion, after achievement of therapeutic anticoagulation (1-3 days), may be an alternative to the traditional procedure (3-week anticoagulation followed by cardioversion). The quality of anticoagulation in atrial fibrillation has not been investigated in a randomised trial with TEE-guided cardioversion. We analysed respective data from the ACE trial on the quality of conventional anticoagulation, where most participating centres chose the TEE-guided approach. MATERIALS AND METHODS: In a randomised, prospective, multicentre trial, we analysed the efficacy of unfractionated heparin plus phenprocoumon in 248 patients on an intention-to-treat basis. There were 2373 evaluable anticoagulation measurements (out of 2925 measurements) and 4 categories of anticoagulation quality (under-, target, over- and severe over-anticoagulation). Of patients with evaluable measurements, 88% received short-term anticoagulation (4 weeks) in TEE-guided cardioversion. RESULTS: The median time to achieve therapeutic anticoagulation (aPTT> or =60 and <80 s or INR> or =2 and <3) was 3 days. Anticoagulation values were out of therapeutic range in 69.5% of measurements during 4- or 7-week follow-up, and never within therapeutic range in 10% of patients. Of the 15 primary endpoints observed (death, thromboembolism and major bleeding complications), only 3 were in patients with anticoagulation measurements within therapeutic range. CONCLUSIONS: In this study setting, with predominance of 4 weeks anticoagulation in TEE-guided cardioversion for atrial fibrillation, therapeutic anticoagulation was reached within 3 days using conventional anticoagulation. Despite careful dose adjustments, anticoagulation was out of therapeutic range in almost 70% of total measurements and 80% of primary endpoints.

Aged↗
PubMed2006

Multicentre evaluation of a rule-based data filter for home monitoring of implanted cardioverter defibrillators.

We developed a rule-based data filter for the automatic interpretation of data transmitted from implantable cardioverter defibrillators (ICDs). The feasibility and user acceptability of the data filter were tested in a multicentre study. Fifteen European centres analysed 10 cases each. The cases represented ICD follow-up findings, e.g. new tachycardia, battery depletion or sensing defects. The mean follow-up period was 68 days (SD 35). A questionnaire was used to collect information regarding the functionality and general concept of automatic data interpretation. A score of five or above (range 1-9) was classified as acceptable. According to the questionnaires, there was a high degree of satisfaction with the general concept of automatic data interpretation (mean 6.7, SD 1.2) and with user guidance (mean 7.1, SD 0.8). Safety (mean 7.0, SD 1.4) and accuracy (mean 6.7, SD 1.4) of the evaluation of device-related and clinical problems were regarded as high. Support in daily routine was considered to be high (mean 7.3, SD 1.1) as the system was easy to understand (mean 7.5, SD 0.9). The results indicated a high user acceptance with easy system handling.

Attitude of Health Personnel↗
PubMed2005

[Cardiac resynchronization therapy-always with ICD?].

Sudden cardiac death is responsible for about 50% of all deaths in heart failure. In studies on primary and secondary prevention of sudden cardiac death, the implantable cardioverter defibrillator (ICD) has proven superior to antiarrhythmic drug therapy mainly in patients with coronary artery disease and reduced left ventricular function. Thus, in recent years the question arose whether prophylactic ICD treatment can reduce mortality as well in an unselected patient group with heart failure of any etiology. This is even more important for patients that are candidates for cardiac resynchronization therapy because, first, presence of an intraventricular conduction delay indicates an increased risk of sudden death and, second, the additional operative morbidity of ICD implantation is minimal compared to implant of a biventricular pacemaker. Recent studies have proven the benefit of conventional ICD treatment in patients with heart failure as well as the benefit of biventricular pacing in heart failure patients with ventricular conduction delay. In the present article, these studies and their influence on the system choice in cardiac resynchronization therapy are discussed.

Arrhythmias, Cardiac↗
PubMed2005

Effect of cardiac resynchronization therapy on sleep quality, quality of life, and symptomatic depression in patients with chronic heart failure and Cheyne-Stokes respiration.

Patients with heart failure (HF) often suffer from sleep-related breathing disorders (SRBD) like Cheyne-Stokes respiration (CSR). Cardiac resynchronization therapy (CRT) improves myocardial function and exercise capacity in patients with HF and conduction disturbances. As CRT has been shown to reduce CSR in patients with HF, it is not clear whether CRT improves quality of life and symptomatic depression by improvement of apnea/hypopnea index (AHI) and sleep quality. Forty-two HF patients with conduction disturbance before CRT were screened for CSR and evaluated for sleep quality [Pittsburgh Sleep Quality Index (PSQI)], quality of life score [36-item short form (SF-36)], depression, and exercise capacity (VO2 peak) and ejection fraction (EF). Eighteen patients (three females, age 61+/-10, body mass index 24+/-4 kg m(-2), EF 24+/-4%, QRS complex duration 156+/-32 ms) presented CSR with an AHI of 18+/-8 (11 CSR, 7 mixed). Fourteen patients showed no SRBD (PSQI<5,AHI<5). All patients received CRT and were reevaluated after 18+/-7 weeks. CSR worsen quality of life in seven of eight terms compared to patients without SRBD. Symptomatic depressive symptoms (Beck Depression Inventory>10) were only present in patients with CSR. CRT results in improvement of peak VO2 and EF. There was no difference between patients with CSR and without SRBD on exercise capacity or EF under CRT, whereas CRT led to a significant decrease in AHI (18+/-8 to 3+/-2, p<0.0001), PSQI (18+/-4 to 6+/-3, p=0.0007), with reduction of depression score (12+/-3 to 4.8+/-3, p=0.004). In patients with HF, CSR is associated with symptomatic depressive syndromes and impaired quality of life. CRT reduced CSR with improvement of sleep quality and symptomatic depression.

Cardiac Pacing, Artificial↗
PubMed2005

Impact of sleep-related breathing disorders on health-related quality of life in patients with chronic heart failure.

BACKGROUND: Quality of life in patients with chronic heart failure (HF) is often severely compromised. Sleep-related breathing disorders (SRBD) like Cheyne-Stokes Respiration (CSR) or obstructive sleep apnea (OSAS) are often observed in patients with severe HF resulting in fragmentation of sleep, excessive daytime sleepiness and an increased mortality. While an apnea/hypopnea-index (AHI) >30/h represents an independent predictor of poor prognosis, clinical relevance of even minor SRBD with an AHI <30/h remains unclear with respect to quality of life, exercise capacity or depression rate. METHODS: Sixty-nine consecutive ambulatory patients with stable HF (NYHA II-III, EF 25%) underwent two night polygraphies with a six-channel ambulatory recording. Spiroergometry was performed, and patients were examined for sleep quality (PSQI), depressed mood (BDI) and health-related quality of life (SF-36). The data were compared to 10 age-matched healthy controls and 11 patients with OSAS (AHI 14-29/h) not suffering from HF. RESULTS: Fifty-one patients completed follow up. 52% were positively diagnosed for SRBD (AHI 16-30/h: 12 patients CSR, 5 patients OSAS, 9 patients mixed); 25 patients (48%) showed no relevant SRBD. Patients with HF and SRBD had lower quality of life than patients without SRBD and HF. The severity of SRBD as indicated by the AHI significantly correlated with quality of life measures: Bodily pain, physical functioning and social functioning showed largest impairment in patients with HF and SRBD. Furthermore, elevated depression rates in correlation to the AHI were only observed in patients with SRBD similar to patients with OSAS without HF. CONCLUSION: Even minor SRBD in patients with HF independently influence quality of life and correlate with estimation of depression and sleep disturbances.

Adult↗
PubMed2005

Anticoagulation during cardioversion in patients with atrial fibrillation: current clinical practice.

The role of anticoagulation in the long-term treatment of atrial fibrillation (AF) has been well established in prospective randomized trials. Less certainty exists on the optimal anticoagulation in the setting of AF cardioversion. Current guidelines advocate anticoagulation for 3-4 weeks before and after cardioversion of AF of >48 hours' duration. Alternatively, early cardioversion may be performed after exclusion of left atrial thrombi by transesophageal echocardiography. However, with conventional anticoagulation, the risk of bleeding has to be considered and, thus, anticoagulation is frequently underused in the clinical setting. Moreover, the role of cardioversion has been questioned by recent trials suggesting no benefit of sinus rhythm restoration over rate control in AF. This article aims to summarize the currently available data on anticoagulation in cardioversion of AF in the context of these new studies and points to some new drugs such as low-molecular weight heparins and oral thrombin inhibitors that may lead to safer anticoagulation for prevention of thromboembolic complications of AF in the future.

Anticoagulants↗
PubMed2004

Cardiac resynchronization therapy improves central sleep apnea and Cheyne-Stokes respiration in patients with chronic heart failure.

OBJECTIVES: We studied the effects of cardiac resynchronization therapy (CRT) on heart failure (HF) patients with central sleep apnea (CSA). BACKGROUND: Patients with advanced HF often suffer from CSA with Cheyne-Stokes respiration. Cardiac resynchronization therapy improves myocardial function and exercise capacity in HF patients with conduction disturbances. The relationship between CRT and CSA is currently unknown. METHODS: Twenty-four patients (7 females; 62 +/- 11 years) with HF, a reduced left ventricular ejection fraction (24 +/- 6%), and left bundle branch block (QRS duration 173 +/- 22 ms) received a CRT device. The number of apneas and hypopneas per hour (apnea-hypopnea index [AHI]) and minimal oxygen saturation (SaO2min) were quantified by cardiorespiratory polygraphy. Fourteen patients showed CSA (AHI >5/h), and 10 patients had an AHI <5/h without CSA. Subjective sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI). Data were evaluated before and after 17 +/- 7 weeks of CRT. RESULTS: In patients with CSA, CRT led to a significant decrease in AHI (19.2 +/- 10.3 to 4.6 +/- 4.4, p < 0.001) and PSQI (10.4 +/- 1.6 to 3.9 +/- 2.4, p < 0.001) without Cheyne-Stokes respiration and to a significant increase in SaO2min (84 +/- 5% to 89 +/- 2%, p < 0.001). There was no significant change in AHI (1.7 +/- 0.7 to 1.5 +/- 1.6), PSQI (2.4 +/- 0.5 to 2.6 +/- 0.9), and SaO2min (90 +/- 2% to 91 +/- 1%) in patients without CSA. CONCLUSIONS: Cardiac resynchronization therapy leads to a reduction of CSA and to increased sleep quality in patients with HF and sleep-related breathing disorders. This may have prognostic implications in patients receiving CRT.

Aged↗
PubMed2004

Comparison of left ventricular lead placement via the coronary venous approach versus lateral thoracotomy in patients receiving cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is a new therapeutic option in patients with heart failure and ventricular conduction delay. We compared the long-term performance of left ventricular (LV) pacing via the coronary venous (CV) approach and a limited lateral thoracotomy (LLT). Data from 81 patients (age 65 +/- 12 years; 52 men, New York Heart Association class 3.0 +/- 0.4, ejection fraction 24 +/- 6%) were retrospectively analyzed for 1 year after implantation of a CRT system. Twenty-five patients received LLT leads and 56 patients received CV leads. Postoperative hospitalization was shorter after CV lead implantation (8 +/- 4 vs 12 +/- 5 days, p <0.01). No significant differences in LV pacing and sensing performance between both approaches were observed after 12 months. Reinterventions were necessary in 7 patients after CV implantation compared with only 1 reintervention (4%) in the LLT group (p = NS). Postoperative chest radiographs revealed an anterior lead position in 11 of 25 patients (44%) in the LLT group versus 3 of 56 patients (5.4%) in the CV group (p = 0.00007). Echocardiographic data demonstrated a significant increase in LV ejection fraction in the CV group (from 26.1 +/- 5.2% to 35.3 +/- 14.3% at 12 months, p <0.001, n = 42) in contrast to the LLT group (from 24.5 +/- 6.2% to 28.5 +/- 7.5% at 12 months, p = NS, n = 16) at 12-month follow-up. Cardiopulmonary exercise testing in 35 patients showed significantly more improvement in peak oxygen consumption after 12 months in the CV group (15.5 +/- 3.1 vs 13.6 +/- 2.6 ml/min/kg at implant, n = 22) compared with the LLT group (12.7 +/- 1.5 vs 11.8 ml/min/kg at implant, n = 13, p = 0.004). At 1-year follow-up the mortality rate was 24% (6 of 25) after LLT lead implantation versus 12.5% (7 of 56) after CV implantation (p = NS). Our data show that the LLT approach for LV lead placement in CRT systems has the advantage of a lower incidence of reinterventions. Hospitalization was longer, increase in functional capacity smaller, and mortality at 1-year follow-up higher, which were potentially related to a more anterior lead position. Therefore, CV leads are preferable to LLT leads.

Aged↗
PubMed2004

Safety and efficacy of enoxaparin compared with unfractionated heparin and oral anticoagulants for prevention of thromboembolic complications in cardioversion of nonvalvular atrial fibrillation: the Anticoagulation in Cardioversion using Enoxaparin (ACE) trial.

BACKGROUND: Anticoagulation in cardioversion of atrial fibrillation is currently performed with unfractionated heparin (UFH) and oral anticoagulants, with or without guidance by transesophageal echocardiography (TEE). Low-molecular-weight heparins may reduce the risk of bleeding, may obviate the need for intravenous access, and do not require frequent anticoagulation monitoring. METHODS AND RESULTS: In a randomized, prospective multicenter trial, we compared the safety and efficacy of enoxaparin administered subcutaneously with intravenous UFH followed by the oral anticoagulant phenprocoumon in 496 patients scheduled for cardioversion of atrial fibrillation of >48 hours' and < or =1 year's duration. Patients were stratified to cardioversion with (n=431) and without (n=65) guidance by TEE. The study aimed to demonstrate noninferiority of enoxaparin compared with UFH+phenprocoumon with regard to the incidence of embolic events, all-cause death, and major bleeding complications. Secondary end points included successful cardioversion, maintenance of sinus rhythm until study end, and minor bleeding complications. Of 496 randomized patients, 428 were analyzed per protocol. Enoxaparin was noninferior to UFH+phenprocoumon with regard to the incidence of the composite primary end point in a per-protocol analysis (7 of 216 patients versus 12 of 212 patients, respectively; P=0.016) and in an intention-to-treat analysis (7 of 248 patients versus 12 of 248 patients, respectively; P=0.013). There was no significant difference between the 2 groups in the number of patients reverted to sinus rhythm. CONCLUSIONS: Enoxaparin is noninferior to UFH+phenprocoumon for prevention of ischemic and embolic events, bleeding complications, and death in TEE-guided cardioversion of atrial fibrillation. Its easier application and more stable anticoagulation may make it the preferred drug for initiation of anticoagulation in this setting.

Administration, Oral↗
PubMed2004

Effects of cardiac resynchronization therapy on myocardial blood flow measured by oxygen-15 water positron emission tomography in idiopathic-dilated cardiomyopathy and left bundle branch block.

Regional and global myocardial blood flow and coronary vascular resistance were determined in patients with idiopathic-dilated cardiomyopathy and left bundle branch block before and during cardiac resynchronization therapy (CRT) using oxygen-15 water positron emission tomography. The investigated parameters did not exhibit regional heterogeneity and were not influenced by CRT. This implies that the beneficial effects of CRT do not require additional oxygen demand or regional reallocation of oxidative metabolism.

Blood Flow Velocity↗
PubMed2004

Cardiac resynchronization therapy optimization by finger plethysmography.

OBJECTIVES: We tested a simple noninvasive method for cardiac resynchronization therapy (CRT) optimization using standard finger photoplethysmography (FPPG). BACKGROUND: CRT can increase left ventricular cardiac output in patients with heart failure and ventricular conduction delay. Optimal therapy delivery depends on an appropriate AV delay. Multiple invasive and noninvasive methods have been attempted to identify patients and the best AV delay for CRT, but all suffer from a combination of high patient risk, cost, complexity, and low reproducibility. METHODS: FPPG and invasive aortic pressure data were simultaneously collected from 57 heart failure patients during intrinsic rhythm alternating with very brief periods of pacing at 4 to 5 AV delays. After correcting data for artifacts, the median percentage responses for each AV delay were classified as positive, negative, or neutral compared to baseline (Wilcoxon rank test). RESULTS: FPPG correctly identified positive aortic pulse pressure responses with 71% sensitivity (95% CI: 60-80%) and 90% specificity (95% CI: 84-94%) and negative aortic pulse pressure responses with 57% sensitivity (95% CI: 44-69%) and 96% specificity (95% CI: 91-98%). The magnitude of FPPG changes were strongly correlated with positive aortic pulse pressure changes (R(2) = 0.73, P < .0001) but less well correlated with negative aortic pulse pressure changes (R(2) = 0.43, P < .0001). FPPG selected 78% of the patients having positive aortic pulse pressure changes to CRT and identified the AV delay giving maximum aortic pulse pressure change in all selected patients. CONCLUSIONS: FPPG can provide a simple noninvasive method for identifying significant changes in aortic pulse pressure with high specificity, including identifying patients in whom aortic pulse pressure increases with CRT and the AV delay giving the maximum aortic pulse pressure.

Aorta↗
PubMed2004

Clinical experience with a new detection algorithm for differentiation of supraventricular from ventricular tachycardia in a dual-chamber defibrillator.

INTRODUCTION: Inadequate therapy for supraventricular tachyarrhythmias (SVT) is a frequent problem of implantable cardioverter defibrillators (ICD). Dual-chamber ICDs have been developed to improve discrimination of SVT from ventricular tachycardia (VT). We investigated the positive predictivity, sensitivity, and specificity of a new algorithm, the SMART detection trade mark algorithm, incorporated in the Phylax AV (Biotronik) dual-chamber ICD. METHODS AND RESULTS: Two hundred nine patients (185 men, age 64 +/- 11 years) received a Phylax AV ICD with SMART detection trade mark activated. In 138 of these patients, 1,245 sustained tachycardia episodes with a detailed electrogram were stored in the device during a follow-up period of 10 +/- 6 months. Episodes were correctly classified as ventricular fibrillation (VF, n = 178) in 52 patients, VT (n = 641) in 98 patients, and SVT (n = 385) in 48 patients by the algorithm. Forty-one true SVT episodes (3.3%) were misclassified as VT: atrial fibrillation (n = 7) and flutter (n = 1), sinus tachycardia (n = 12), and other SVT (n = 21). The positive predictivity for VF/VT was 94.5% (95% CI 92.7-95.8) uncorrected and 94.5% (95% CI 92.9-95.8%) corrected with the generalized equation estimation (GEE) method. The positive predictivity for SVT was 100%. The specificity was 88.9% (95% CI 85.6-91.6%) uncorrected and 89.0% (95% CI 85.6-91.6%) corrected with the GEE method with a sensitivity of 100%. CONCLUSION: The SMART detection trade mark algorithm was safe and reliable for the detection of all ventricular tachycardias. Although its specificity was high, it should be improved with regard to SVT to avoid inappropriate ICD therapies.

Adult↗
PubMed2004

Current status of cardiac resynchronization therapy.

PURPOSE OF REVIEW: Cardiac resynchronization therapy with biventricular pacing has rapidly emerged as an indispensable treatment option in patients with moderate-to-advanced heart failure and left bundle branch block. New findings on the pathophysiology of cardiac resynchronization therapy and its clinical effects are reviewed. RECENT FINDINGS: Several randomized trials have evaluated the effects of cardiac resynchronization therapy on cardiac haemodynamics and clinical parameters in selected heart failure patients with left bundle branch block. The effects of cardiac resynchronization therapy on mechanical synchrony have been evaluated by different imaging modalities, such as echocardiography and radionuclide angiography. Cardiac resynchronization therapy leads to improved haemodynamics at a diminished energy cost, and improves functional mitral regurgitation. This haemodynamic improvement is associated with a significantly better quality of life, improved exercise capacity, and less frequent hospitalization. Recent preliminary data suggest a positive effect on cardiac mortality. However, approximately a third of implanted patients do not benefit from cardiac resynchronization therapy, and therefore additional criteria for the identification of mechanical dyssynchrony are needed to identify those patients who will respond before implantation. SUMMARY: Many randomized trials have confirmed the benefits of cardiac resynchronization therapy in selected heart failure patients. The successful resynchronization of the ventricular activation-contraction sequence is the major determinant of acute haemodynamic and long-term clinical improvement. The diagnostic sensitivity and specificity of the non-invasive identification of mechanical dyssynchrony may be improved by echocardiography, but further research is needed to identify the optimal strategy for patient identification.

Journal Article↗