High efficiency single-catheter workflow for radiofrequency atrial fibrillation ablation in the QDOT catheter era.

BACKGROUND: High-power short-duration (HPSD) ablation may improve the consistency and efficiency of pulmonary vein isolation (PVI). The novel QDOT Micro™ catheter (Biosense Webster, Inc.) with temperature feedback and microelectrodes aims to enhance PVI efficiency and safety. This study wants to evaluate the feasibility, safety, and efficiency of a standardized single-catheter workflow for PVI using QDOT (Q-FLOW). METHODS: The Q-FLOW includes single transeptal access, radiofrequency encircling of the PVs using a power of 50 W in a temperature/flow-controlled mode, and validation of the circles with microelectrodes. A 1:1 propensity-matched cohort of patients treated with conventional power-controlled ablation using a circular mapping catheter (CMC-FLOW) was used to compare procedural and clinical outcomes. RESULTS: A total of 150 consecutive atrial fibrillation patients (paroxysmal 67%, persistent 33%) were included. First-pass isolation rate was 86%. Procedural time, X-ray time, and dose were significantly lower for the Q-FLOW vs the CMC-FLOW (67.2 ± 17.9 vs 88.3 ± 19.2 min, P < 0.001; 3.0 ± 1.9 vs 5.0 ± 2.4 min, P < 0.001; 4.3 ± 1.9 vs 6.4 ± 2.3 Gycm2, P < 0.001). Complications were numerically but not significantly lower in the Q-FLOW group (2 [1.3%] vs 7 [4.7%], P = 0.091). There was no difference in arrhythmia recurrence at 12 months (atrial arrhythmia-free survival rate, 87.5% vs 84.4%, P = 0.565). CONCLUSION: A streamlined single-catheter workflow for PVI using QDOT was feasible and safe, resulting in a high rate of first-pass isolation and a low complication rate. The Q-FLOW further improved the efficiency of PVI compared to the standard CMC-FLOW, without difference in the 12-month outcome.

The Impact of Radiofrequency Wide Circumferential Pulmonary Vein Isolation on Left Atrial Geometry in Patients with Recurrent Atrial Fibrillation.

PURPOSE: The aim of the study was to investigate the effect of wide area circumferential radiofrequency catheter ablation (WACA) pulmonary vein isolation on left atrium (LA) geometry. METHODS: Seventy-one patients underwent WACA, for recurrent paroxysmal (n = 31) and persistent (n = 40) atrial fibrillation (AF). A three-dimension rotational angiography of the LA was obtained immediately prior to index and repeat procedure. RESULTS: Significant reduction of LA volume (65.6 ± 14 mL/m2 vs. 62.2 ± 15 mL/m2, p < 0.001) and surface (74.4 ± 11.2 vs. 70.4 ± 11.2 cm2/m2, p < 0.001) was noted. LA sphericity increased significantly (82 ± 2% vs. 83 ± 2%, p = 0.004) in all 71 patients. Patients with paroxysmal AF showed significant reduction of LA volume (121.8 ± 25.7 vs. 116 ± 32 mL, p = 0.008) and increase of LA sphericity (82.3 ± 2.1 vs. 83.1 ± 2%, p = 0.009). Patients with persistent AF showed significant decrease of LA volume (133.5 ± 32 vs. 126 ± 32 mL, p = 0.005) and LA surface area (76.3 ± 12.3 vs. 71.8 ± 12.4 cm2/m2, p = 0.005). LA sphericity (82.4 ± 2.8 vs. 83 ± 2.4%, p = ns) remained unchanged. CONCLUSIONS: WACA results into significant reduction of LA volume and surface area. Increased LA sphericity is observed in paroxysmal AF only.

Catheter Ablation of Atrial Fibrillation in Patients with Previous Lobectomy or Partial Lung Resection: Long-Term Results of an International Multicenter Study.

INTRODUCTION: Data regarding the efficacy of catheter ablation in patients with atrial fibrillation (AF) and patients' previous history of pulmonary lobectomy/pneumonectomy are scanty. We sought to evaluate the efficacy and long-term follow-up of catheter ablation in this highly selected group of patients. MATERIAL AND METHODS: Twenty consecutive patients (8 females, 40%; median age 65.2 years old) with a history of pneumonectomy/lobectomy and paroxysmal or persistent AF, treated by means of pulmonary vein isolation (PVI) at ten participating centers were included. Procedural success, intra-procedural complications, and AF recurrences were considered. RESULTS: Fifteen patients had a previous lobectomy and five patients had a complete pneumonectomy. A large proportion (65%) of PV stumps were electrically active and represented a source of firing in 20% of cases. PVI was performed by radiofrequency ablation in 13 patients (65%) and by cryoablation in the remaining 7 cases. Over a median follow up of 29.7 months, a total of 7 (33%) AF recurrences were recorded with neither a difference between patients treated with cryoablation or radiofrequency ablation or between the two genders. CONCLUSIONS: Catheter ablation by radiofrequency ablation or cryoablation in patients with pulmonary stumps is feasible and safe. Long-term outcomes are favorable, and a similar efficacy of catheter ablation has been noticed in both males and females.

Clinical symptoms of limited exercise capacity linked to AAI-DDD functionality: An in silico and in vivo approach.

BACKGROUND: Exercise capacity is an important aspect of quality of life in patients undergoing pacemaker implantation. Device algorithms for ventricular pacing avoidance have been developed to avoid unnecessary and potentially harmful effects of right ventricular pacing. However, little data exists on the immediate response of these algorithms to sudden AV block during exercise. METHODS: The ventricular pacing avoidance algorithms of four pacemaker manufacturers were tested in an ex-vivo model. The RSIM-1500-USB Device-Interactive Heart Simulator (Rivertek Medical Systems, Inc.) was used to simulate three different scenarios: the first one starting with an initially conducted atrial pacing rate of 60 min-1 , the second one starting with an atrial rate of 120 min-1 and finally a scenario starting with an atrial rate of 150 min-1 . In all three scenarios, the initially conducted atrial rate was followed by a sudden, long lasting episode of third-degree AV-block. The response to those scenarios was recorded for each of the (brand-specific) ventricular pacing avoidance algorithms. RESULTS: In the first scenario, the simulation resulted in a ventricular pause of 1333 ms (Boston Scientific), 2000 ms (Medtronic and Microport), and 2340 ms (Biotronik). In the second and third scenario, different results were observed across devices. All simulations of the second and third scenario resulted in repetitive 2:1 block response (during eight cycles) in Boston Scientific and Biotronik devices. These scenarios were confirmed in patient cases. CONCLUSION: Simulator based observations of unanticipated pacemaker-induced 2:1 block response during exercise may explain clinical symptoms experienced by some patients having a two-chamber pacemaker.

The industrialization of ablation: a highly standardized and reproducible workflow for radiofrequency ablation of atrial fibrillation.

BACKGROUND OR PURPOSE: The purpose of this analysis was to report on efficacy of a standardized workflow for atrial fibrillation (AF) ablation using technology advances such as 3D imaging and contact force sensing in a real-world setting. METHODS: Consecutive AF ablations from 2014 to 2015 at a high-volume site in Belgium were included. The workflow consisted of a pre-specified procedure sequence including 3D modeling followed by radiofrequency encircling of the pulmonary veins (25 W posterior wall, 35 W anterior wall) with a THERMOCOOL SMARTTOUCH® Catheter guided by CARTO VISITAG™ Module (2.5 mm/5 s stability, 50% > 7 g) and ablation index (targets: 550 anterior wall, 400 posterior wall). Efficiency endpoints were procedure time, fluoroscopy time, and radiation dose. The primary effectiveness endpoint was freedom from atrial arrhythmia recurrence. RESULTS: A total of 605 paroxysmal AF (PAF) and 182 persistent AF (PsAF) patients were followed for 436 ± 199 days. Mean procedure times were short (PAF: 96.1 ± 26.2 min; PsAF: 109.2 ± 35.6 min) with most procedures (90.6% PAF; 81.3% PsAF) completed in ≤ 120 min. Minimal fluoroscopy was utilized (PAF: 6.1 ± 3.8 min, 5.9 ± 3.4 Gy*cm2; PsAF: 6.9 ± 4.7 min, 7.4 ± 4.9 Gy*cm2). Freedom from atrial arrhythmia recurrence was higher for PAF than PsAF patients (OR: 2.0, 95% CI: 1.4-2.9, p = 0.0003), but adjusted mean rates were high in both groups (81.0% vs. 67.9%). Rates were adjusted for prior ablation and age (at 65 years). CONCLUSION: AF ablation using a standardized workflow resulted in low procedure times and variability, with minimal fluoroscopy exposure. Long-term freedom from atrial arrhythmia recurrence was high in both PAF and PsAF populations.

Intensive recreational athletes in the prospective multinational ICD Sports Safety Registry: Results from the European cohort.

BACKGROUND: In the ICD Sports Safety Registry, death, arrhythmia- or shock-related physical injury did not occur in athletes who continue competitive sports after implantable cardioverter-defibrillator (ICD) implantation. However, data from non-competitive ICD recipients is lacking. This report describes arrhythmic events and lead performance in intensive recreational athletes with ICDs enrolled in the European recreational arm of the Registry, and compares their outcome with those of the competitive athletes in the Registry. METHODS: The Registry recruited 317 competitive athletes ≥ 18 years old, receiving an ICD for primary or secondary prevention (234 US; 83 non-US). In Europe, Israel and Australia only, an additional cohort of 80 'auto-competitive' recreational athletes was also included, engaged in intense physical activity on a regular basis (≥2×/week and/or ≥ 2 h/week) with the explicit aim to improve their physical performance limits. Athletes were followed for a median of 44 and 49 months, respectively. ICD shock data and clinical outcomes were adjudicated by three electrophysiologists. RESULTS: Compared with competitive athletes, recreational athletes were older (median 44 vs. 37 years; p = 0.0004), more frequently men (79% vs. 68%; p = 0.06), with less idiopathic ventricular fibrillation or catecholaminergic polymorphic ventricular tachycardia (1.3% vs. 15.4%), less congenital heart disease (1.3% vs. 6.9%) and more arrhythmogenic right ventricular cardiomyopathy (23.8% vs. 13.6%) ( p < 0.001). They more often had a prophylactic ICD implant (51.4% vs. 26.9%; p < 0.0001) or were given a beta-blocker (95% vs. 65%; p < 0.0001). Left ventricular ejection fraction, ICD rate cut-off and time from implant were similar. Recreational athletes performed fewer hours of sports per week (median 4.5 vs. 6 h; p = 0.0004) and fewer participated in sports with burst-performances ( vs. endurance) as their main sports: 4% vs. 65% ( p < 0.0001). None of the athletes in either group died, required external resuscitation or was injured due to arrhythmia or shock. Freedom from definite or probable lead malfunction was similar (5-year 97% vs. 96%; 10-year 93% vs. 91%). Recreational athletes received fewer total shocks (13.8% vs. 26.5%, p = 0.01) due to fewer inappropriate shocks (2.5% vs. 12%; p = 0.01). The proportion receiving appropriate shocks was similar (12.5% vs. 15.5%, p = 0.51). Recreational athletes received fewer total (6.3% vs. 20.2%; p = 0.003), appropriate (3.8% vs. 11.4%; p = 0.06) and inappropriate (2.5% vs. 9.5%; p = 0.04) shocks during physical activity. Ventricular tachycardia/fibrillation storms during physical activity occurred in 0/80 recreational vs. 7/317 competitive athletes. Appropriate shocks during physical activity were related to underlying disease ( p = 0.004) and competitive versus recreational sports ( p = 0.004), but there was no relation with age, gender, type of indication, beta-blocker use or burst/endurance sports. The proportion of athletes who stopped sports due to shocks was similar (3.8% vs. 7.5%, p = 0.32). CONCLUSIONS: Participants in recreational sports had less frequent appropriate and inappropriate shocks during physical activity than participants in competitive sports. Shocks did not cause death or injury. Recreational athletes with ICDs can engage in sports without severe adverse outcomes unless other reasons preclude continuation.

Left atrial volume computed by 3D rotational angiography best predicts atrial fibrillation recurrence after circumferential pulmonary vein isolation.

Left atrium (LA) size is a well-studied predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI). Yet, there is still little agreement on the best imaging technique to size the LA, and on the most appropriate sizing parameter. Volumetric assessment of LA with three-dimensional rotational angiography (3DRA LA volume index) might be a valid alternative to the commonly used transthoracic echocardiography (TTE LA volume index). The aim of our study was to investigate whether LA volume by 3DRA at the time of PVI is able to predict the risk of atrial fibrillation recurrence. We analysed 352 consecutive patients with symptomatic paroxysmal or persistent atrial fibrillation referred for PVI to our Institution. In all patients, LA volume index (LAVI) was assessed by TTE and by 3DRA. Sinus rhythm was restored after PVI in 348 patients (99%). Average TTE-LAVI and 3DRA-LAVI were 37 ± 12 and 83 ± 18 ml/m2, respectively. At a median follow-up of 19 (12, 24) months, 27% of patients had AF recurrence after the first PVI. At the univariate analysis, persistent AF (p < 0.01), use of anti-arrhythmic drugs (AAD) (p < 0.05) and 3DRA-LAVI (p < 0.01) were significantly associated with AF recurrence. In contrast, none of the echocardiographic parameters considered, including TTE-LAVI, was associated with AF recurrence (p = 0.29). At the multivariate analysis, 3DRA-LAVI was the only independent predictor for AF recurrence (HR 1.01 [1.00-1.03], p = 0.017). Left atrial volume measured with 3DRA is superior to TTE assessment and to AF history in predicting atrial fibrillation recurrence after PVI.

Functional Treatment or Cast Immobilization After Minimally Invasive Repair of an Acute Achilles Tendon Rupture: Prospective, Randomized Trial.

BACKGROUND: Operative repair of an acute Achilles tendon rupture (ATR) reduces the risk of re-rupture and has therefore gained popularity as a standard treatment for ATR, especially in the young and physically active patient. There is ongoing controversy over the best surgical technique and postoperative treatment. In this prospective, randomized trial, we compared cast immobilization and functional treatment with early mobilization and weightbearing after using a minimally invasive surgical technique in patients with ATR. METHODS: All patients with ATR were included. Exclusion criteria were systemic immunosuppressive therapy, re-ruptures, and severe comorbidity. All included patients underwent minimally invasive surgery, after which a below-knee splint with the foot in 10 degrees of plantar flexion was applied for the first week. Patients were then randomized to the cast immobilization group (IG) for 6 weeks or to the functional group (FG) for 6 weeks. Sixty patients were included. Median age was 43 years (range, 19-65), and 78% were male. Most ATRs were sports related. Data were collected preoperatively and during the outpatient checks at 1, 3, and 6 weeks; 3 and 6 months; and 1 year. Outcome parameters were return to work or sport, complications including re-rupture, Achilles rupture performance score (ARPS), loss of strength, range of motion, subjective result, and quality-of-life (QoL) scores. RESULTS: In our follow-up period, we did not see differences in strength, QoL scores, return to work or sports, or ARPS between the 2 treatment groups. The patients in the FG reported more complaints, mostly pain, in the first weeks after surgery, probably because of the exercise program starting 1 week postsurgery. The overall complication rate was low. In each group, we had 1 re-rupture; in the IG, however, 2 patients had a deep venous thrombosis, despite low-molecular-weight heparin. CONCLUSION: The minimally invasive repair of ATR was a safe and reliable technique with good results. Early mobilization seemed to be as safe as more traditional postoperative immobilization with equal patient satisfaction. Although not significantly different, we saw more major complications in the IG. LEVEL OF EVIDENCE: Level I, prospective randomized trial.

Three-dimensional Rotational Angiography as a Periprocedural Imaging Tool in Atrial Fibrillation Ablation.

Atrial fibrillation (AF) ablation relies increasingly on three-dimensional (3D) visualisation tools to help guide an operator in performing a procedure safely and successfully. Current generation non-fluoroscopic navigation systems can be used as stand-alone tools, but also offer the capability to integrate information from additional imaging studies in order to enhance 3D model accuracy. Between available imaging modalities, 3D rotational angiography offers a set of interesting features such as near realtime availability, applicability in high-volume workflows, integration with other imaging systems (fluoroscopic or non-fluoroscopic) and very low incremental cost per procedure. Applicability of this imaging approach in AF ablation, as a complement or substitute to other imaging/navigation tools, is reviewed.

Adenosine plus dipyridamole: a novel strategy to enhance adenosine-induced conduction recovery after pulmonary vein isolation.

AIMS: Intravenous administration of adenosine after a pulmonary vein (PV) isolation procedure can unmask residual, so-called 'dormant', conduction that would otherwise remain unnoticed. Elimination of these dormant potentials is challenging because of the transient effect of adenosine, often requiring repeated injections. We tested the hypothesis that dipyridamole, a drug which inhibits adenosine deamination, can provoke longer-lasting unmasking of dormant conduction. METHODS AND RESULTS: In 191 patients with drug refractory paroxysmal atrial fibrillation, a bolus of 12-24 mg of adenosine was administered after all 764 PVs were isolated. In the case of transient dormant conduction, a short infusion of dipyridamole 50 mg was given and a bolus of adenosine was repeated. In all cases, re-isolation was attempted guided by the activation pattern in the PV on a circular mapping catheter. Duration of adenosine-induced dormant conduction before and after dipyridamole was recorded as the time between administration of adenosine and cessation of dormant conduction either spontaneously or by catheter ablation. Transient dormant conduction was re-established by a single bolus of adenosine in 24 of 191 patients (12.6%). Mean duration of adenosine-induced dormant conduction before dipyridamole was 13.1 ± 6.4 s, whereas it was significantly longer at 218.9 ± 165.6 s after dipyridamole (P < 0.0001). Eighteen of the 24 PVs were re-isolated by catheter ablation before spontaneous cessation of dormant conduction, and in 6 cases dormant conduction disappeared spontaneously before PV re-isolation was achieved. CONCLUSION: Dipyridamole significantly prolongs the effect of adenosine to unmask dormant conduction after PV isolation and may thus facilitate its elimination by catheter ablation.

Combined administration of quinidine and propafenone for atrial fibrillation: the CAQ-PAF study.

Propafenone and its 5-hydroxy metabolite exhibit different electrophysiological properties. Objectives of the CAQ-PAF study were (1) to develop a strategy favoring propafenone instead of 5-hydroxypropafenone in plasma following oral administration of propafenone and (2) to evaluate the potential of low-dose quinidine to chronically inhibit CYP2D6. Patients (n = 102) with atrial fibrillation received propafenone 150 mg 3 times daily with either quinidine 100 mg twice daily or placebo. Throughout the study (follow-up, 199 ± 155 days), quinidine successfully inhibited CYP2D6: propafenone concentrations were 3 times higher in patients receiving quinidine (1033 ± 611 ng/mL vs 328 ± 229 ng/mL; P < .001). Moreover, 80% (n = 10) of patients with propafenone levels greater than 1500 ng/mL were in sinus rhythm at 1 year. In contrast, recurrence of atrial fibrillation occurred in 22 of 23 patients with propafenone levels less than 1000 ng/mL (P < .0001). Thus, chronic inhibition of CYP2D6 is achievable with low-dose quinidine in humans. Increased plasma levels of propafenone may be highly beneficial to prevent recurrence of atrial fibrillation.

Current practice of ventricular tachycardia ablation in patients with implantable cardioverter-defibrillators.

We performed a survey on current practice of ventricular tachycardia (VT) ablation in patients with implantable cardioverter-defibrillators among the European Heart Rhythm Association Research Network. The main indication for the procedure is the occurrence of multiple shocks or electrical storm, while prophylactic ablation is only rarely performed. The epicardial approach is seldom used and mostly only after failure of endocardial ablation. The main ablation strategy is targeting the clinical VT only by substrate mapping and ablation, and by targeting fractionated potentials with utilization of modern electroanatomical mapping systems. Still, a considerable number of centres frequently perform the procedure using conventional mapping catheters only.

Ablation of a therapy-resistant posteroseptal accessory atrioventricular pathway: going for gold.

Posteroseptal accessory pathways are sometimes resistant to ablation because of the complex anatomy of this region. Ex-vivo experiments have demonstrated that gold-tip radiofrequency ablation catheters create deeper lesions than conventional platinum-iridium tip catheters. This case of a 62-year-old man with Wolf-Parkinson-White syndrome illustrates that the ability to create such lesions can be a very useful option when previous attempts with platinum-iridium tip catheters have failed.

Screening for, and management of, possible arrhythmogenic syndromes (channelopathies/ion channel diseases).

This survey assesses the current management strategies for individuals with electrocardiographic features, suggesting an arrhythmogenic syndrome [including long QT syndrome (LQTS), Brugada syndrome (BS), catecholaminergic polymorphic ventricular tachycardia (CPVT) or short QT syndrome] or family members of patients with a known arrhythmogenic syndrome, in 44 large European centres. The principal findings of this survey were: (i) the number of new patients with arrhythmogenic syndromes (symptomatic and asymptomatic) is relatively small; (ii) the clinical work-up of these patients consists mainly of non-invasive tests; (iii) a relatively high use of genetic testing is noted, especially in LQTS and CPVT; (iv) EP testing is commonly performed in asymptomatic BS patients and in family members of symptomatic BS patients; and (v) the majority of European electrophysiologists focus on first-degree relatives when dealing with family members of an index patient.

Performance and survival of transvenous defibrillation leads: need for a European data registry.

Although the use of implantable cardioverter defibrillator (ICD) therapy has increased over the last decades, the reporting of ICD lead performance is inadequate. So far, there is neither a European nor worldwide registry on ICD leads. The published long-term results from national or multicentre registries encompass relatively small patient cohorts. Nevertheless, the failure of ICD leads may have substantial clinical consequences, including failure to sense, failure to pace, failure to defibrillate, inappropriate shocks, and even death of the patient. The reported ICD lead survival varies significantly between studies: 91-99% at 2 years, 85-95% at 5 years, and 60-72% at 8 years. Thus, the true incidence of lead malfunction cannot be defined as outlined in the present review. One current initiative of the European Heart Rhythm Association is to initiate and develop a Europe-wide registry to monitor, over a prolonged follow-up period, the performance of ICDs and ICD leads.

Novel use of a subcutaneous shock lead to create an epicardial implantable cardioverter/defibrillator system via a limited thoracotomy.

We report the case of a novel use of a subcutaneous shock lead to create an epicardial implantable cardioverter/defibrillator (ICD) system via a limited thoracotomy in a patient with poor vascular access. Performance of the system is comparable to the conventional ICD system without the disadvantages of other available epicardial ICD systems.

Twiddling with an implantable cardioverter-defibrillator.

A 64-year-old woman underwent implantation of a single-chamber implantable cardioverter-defibrillator. The active fixation lead was positioned in the right ventricular apex and the generator in a left pre-pectoral pocket. Device interrogation 4weeks after implantation revealed inappropriate sensing and failure of pacing. A chest X-ray showed the entire lead coiled behind the device. The patient admitted manipulating the device and a diagnosis of Twiddler's syndrome was made. After repositioning the lead, the generator was re-located in the sub-pectoral position to help prevent recurrence by reducing the ability to externally manipulate the device.

Myocardial gene expression in heart failure patients treated with cardiac resynchronization therapy responders versus nonresponders.

OBJECTIVES: We studied whether functional improvement after cardiac resynchronization therapy (CRT) is associated with reversal of the heart failure (HF) gene program. BACKGROUND: Cardiac resynchronization therapy improves exercise tolerance and survival in patients with advanced congestive HF and dyssynchrony. METHODS: Twenty-four patients referred for CRT underwent left ventricular (LV) endomyocardial biopsies immediately before CRT implantation (baseline). In addition, 17 of them underwent LV endomyocardial biopsy procurement 4 months later (follow-up). In 6 control patients with normal LV function, LV biopsies were obtained at the time of coronary artery bypass grafting. The LV messenger ribonucleic acid (mRNA) levels of contractile and calcium regulatory genes were measured by quantitative real time polymerase chain reaction and normalized for glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The HF patients showing an improvement in New York Heart Association (NYHA) functional class by >1 score and a relative increase in LV ejection fraction > or =25% at 4 months after CRT were considered as responders. RESULTS: The HF patients were characterized by lower LV mRNA levels of alpha-myosin heavy chain (alpha-MHC), beta-myosin heavy chain (beta-MHC), sarcoplasmic reticulum calcium ATPase 2alpha (SERCA), phospholamban (PLN), and higher brain natriuretic peptide (BNP) mRNA levels as compared with control subjects. Responders to CRT (n = 11) showed an increase in LVEF (p < 0.001), a decrease in left ventricular end-diastolic diameter (p = 0.003), and NYHA functional class (p = 0.002), and a reduction in N-terminal proBNP levels (p = 0.032) as compared with baseline. This was associated with an increase in mRNA levels of alpha-MHC (p = 0.035), SERCA (p = 0.032), a decrease in BNP mRNA levels (p = 0.002), and an increase in the ratio of alpha-/beta-MHC (p = 0.018) and SERCA/PLN (p = 0.012). No significant changes in molecular profile were observed in nonresponders. CONCLUSIONS: In HF patients with electromechanical cardiac dyssynchrony, functional improvement related to CRT is associated with favorable changes in established molecular markers of HF, including genes that regulate contractile function and pathologic hypertrophy.