Adding the implantable cardioverter-defibrillator to cardiac resynchronization therapy is associated with improved long-term survival in ischaemic, but not in non-ischaemic cardiomyopathy.

AIMS: Cardiac resynchronization therapy (CRT) improves symptoms, left ventricular function, and survival in patients with heart failure (HF) and wide QRS. The benefit of adding implantable cardioverter-defibrillator (ICD) backup is debated. We analysed the long-term outcome of patients with HF due to ischaemic cardiomyopathy (ICM) or non-ischaemic cardiomyopathy (NICM) treated with a CRT device with or without defibrillator backup. METHODS AND RESULTS: In this observational study, consecutive patients with an ejection fraction ≤35% and QRS width ≥120 ms receiving a CRT device at Aarhus University Hospital, Denmark from 2000 to 2010 were included. Baseline characteristics were retrieved from patient files and survival data were obtained from the Danish Civil Registration System. The primary outcome was all-cause mortality. The effect of ICD backup was estimated using Cox proportional hazards model, and the multivariate analyses were adjusted for a priori selected variables. We included 917 HF patients, 427 with NICM, and 490 with ICM. Median follow-up was 4.0 years. Adjusted hazard ratio (aHR) for all-cause mortality was 0.76 [95% confidence interval (95% CI), 0.60-0.97; P = 0.03] in all patients; 0.96 (95% CI, 0.60-1.51; P = 0.85) in patients with NICM, and 0.74 (95% CI, 0.56-0.97; P = 0.03) in patients with ICM. In patients with NICM, ICD backup seemed to be associated with improved survival among non-responders to CRT (P = 0.08), but not among responders (P = 0.61). CONCLUSION: Adding an ICD backup is associated with better survival in CRT recipients. This effect was evident among patients with ICM, but not in patients with NICM.

Normativity under change: Older persons with implantable cardioverter defibrillator.

BACKGROUND: In modern society, death has become 'forbidden' fed by the medical technology to conquer death. The technological paradigm is challenged by a social-liberal political ideology in postmodern Western societies. The question raised in this study was as follows: Which arguments, attitudes, values and paradoxes between modern and postmodern tendencies concerning treatment and care of older persons with an implantable cardioverter defibrillator appear in the literature? AIMS: The aim of this study was to describe and interpret how the field of tension concerning older persons with an implantable cardioverter defibrillator - especially end-of-life issues - has been expressed in the literature throughout the last decade. METHODS: Paul Ricoeur's reflexive interpretive approach was used to extract the meaningful content of the literature involving qualitative, quantitative and normative literature. Analysis and interpretation involved naive reading, structural analysis and critical interpretation. ETHICAL CONSIDERATIONS: The investigation complied with the principles outlined in the Declaration of Helsinki. FINDINGS AND DISCUSSIONS: The unifying theme was 'Normativity under change'. The sub-themes were 'Death has become legitimate', 'The technological imperative is challenged' and 'Patients and healthcare professionals need to talk about end-of-life issues'. There seems to be a considerable distance between the normative approach of how practice ought to be and findings in empirical studies. CONCLUSION: Modern as well as postmodern attitudes and perceptions illustrate contradictory tendencies regarding deactivation of the implantable cardioverter defibrillator and replacement of the implantable cardioverter defibrillator in older persons nearing the end of life. The tendencies challenge each other in a struggle to gain position. On the other hand, they can also complement each other because professionalism and health professional expertise cannot stand alone when the patient's life is at stake but must be unfolded in an alliance with the patient who needs to be understood and accepted in his vulnerability.

Radiofrequency ablation of accessory pathways in patients with the Wolff-Parkinson-White syndrome: the long-term mortality and risk of atrial fibrillation.

AIMS: To assess the long-term mortality and occurrence of post-ablation atrial fibrillation in patients undergoing a radiofrequency ablation for the Wolff-Parkinson-White (WPW) syndrome. METHODS AND RESULTS: A retrospective cohort study of patients (N = 362) subjected to radiofrequency ablation of the WPW syndrome at Aarhus University Hospital from 1990 to 2011. A comparison cohort (N = 3619) was generated from the Danish National Board of Health Central Population Registry. We found no significant difference in all-cause mortality when comparing the WPW group with the control group [hazard ratio (HR): 0.77 and confidence interval (CI): 0.47-1.25]. After radiofrequency ablation, the WPW group had a significantly higher risk of atrial fibrillation than the control group (HR: 4.77 and CI: 3.05-7.43). Atrial fibrillation prior to ablation (HR: 4.66 and CI: 2.09-10.41) and age over 50 years (HR: 9.79 and CI: 4.29-22.36) at the time of ablation were independent risk factors for post-ablation atrial fibrillation in the WPW group. CONCLUSION: Patients with radiofrequency ablation-treated WPW syndrome have a post-ablation mortality that is similar to the background population. The risk of atrial fibrillation remains high after radiofrequency ablation of the WPW syndrome.

Left and right ventricular lead positions are imprecisely determined by fluoroscopy in cardiac resynchronization therapy: a comparison with cardiac computed tomography.

AIMS: Fluoroscopy is the routine method for localizing left ventricular (LV) and right ventricular (RV) lead positions in cardiac resynchronization therapy (CRT). However, the ability of fluoroscopy to determine lead positions in a standard ventricular segmentation is unknown. We aimed to evaluate the accuracy and reproducibility of fluoroscopy to determine LV and RV lead positions in CRT when compared with cardiac computed tomography (CT). METHODS AND RESULTS: Fifty-nine patients undergoing CRT were included. Bi-plane fluoroscopy and cardiac CT were evaluated in all patients. Pacing lead positions were assessed in a standard LV 16-segment model and in a simplistic RV 8-segment model. Four patients with LV lead displacement were excluded from the agreement analysis of LV lead position. Agreement of LV lead position between fluoroscopy and cardiac CT was observed in 19 (35%) patients with fluoroscopy demonstrating a 1-segment and ≥2-segment error in 30 (55%) and 6 (11%) patients, respectively. Agreement of RV lead position was found in 13 (22%) patients with fluoroscopy showing a 1-segment and ≥ 2-segment error in 28 (47%) and 18 (31%) patients, respectively. The interobserver agreement on LV and RV lead positions was poor for fluoroscopy (kappa 0.20 and 0.23, respectively) and excellent for cardiac CT (kappa 0.87 and 0.85, respectively). CONCLUSION: Fluoroscopy is inaccurate and modestly reproducible when assessing LV and RV lead positions in a standard ventricular segmentation when compared with cardiac CT. Cardiac CT should be applied to determine the exact pacing site in future research evaluating the optimal pacing lead position in CRT.

Left ventricular performance during para-His pacing in patients with high-grade atrioventricular block: an acute study.

AIM: To compare changes in left ventricular (LV) performance and mechanical synchrony between atrial-based pacing with intrinsic conduction (AAI), dual-chamber para-His Pacing (DDD-PHP) and dual-chamber right ventricular septal pacing (DDD-RVS) in patients with high-grade atrioventricular block (AVB). METHODS AND RESULTS: Patients with high-grade AVB and QRS <120 ms, who had temporary intrinsic atrioventricular (AV) conduction the day after the implantation were included in the study. All patients received a biventricular pacemaker with a para-His lead in the LV port, and a RVS lead in the right ventricular port. Left ventricular three-dimensional echocardiograms, LV outlet tract-velocity time integrals (LVOT-VTI), and LV synchrony with tissue Doppler imaging were recorded during AAI, DDD-PHP, and DDD-RVS. Eleven patients were included. The mean LVOT-VTI was significant lower during DDD-RVS (19.2 ± 5.5 cm) as compared with DDD-PHP (21.4 ± 5.5 cm), P = 0.006 and AAI (21.6 ± 6.8 cm), P = 0.016. The LVEF was higher during AAI than during DDD-PHP (P= 0.02) and DDD-RVS (P< 0.01). The maximal time to peak velocity between basal segments was significant longer with DDD-RVS (95 ± 26 ms) than with AAI (72 ± 30 ms), P = 0.028, whereas no difference was observed between AAI and DDD-PHP (81 ± 42 ms), P = 0.20. CONCLUSIONS: Acutely, DDD-PHP preserves LV systolic performance and mechanical synchrony as compared with DDD-RVS.

Infection after pacemaker implantation: infection rates and risk factors associated with infection in a population-based cohort study of 46299 consecutive patients.

AIMS: Infection is a serious complication of pacemaker (PM) systems. Although the rate of infection has been debated, the figures are largely unknown. We therefore studied the incidence of PM infection and its associated risk factors in the Danish population. METHODS AND RESULTS: Since 1982, all PM implantation and removal procedures performed in Denmark have been prospectively recorded in the Danish Pacemaker Register. All patients (n = 46299) who underwent implantation between 1982 and 2007 were included. The total length of surveillance was 236,888 PM-years. The incidence of infection was calculated according to the total number of PM-years. The incidence of surgical site infection (≤ 365 days after PM implantation) was compared with later infection in first implant and replacement procedures. Multiple-record and multiple-event-per-subject proportional hazards analyses were used to identify the independent risk factors of PM infection. Surgical site infection occurred in 192 cases after first implantation (incidence rate 4.82/1000 PM-years), and in 133 cases after replacement (12.12/1000 PM-years). Infections occurring more than 365 days after the first implantation occurred in 153 cases (1.02/1000 PM-years), and in 118 cases after replacement (3.26/1000 PM-years). Independent factors associated with an increased risk of PM infection were a greater number of PM operations (including replacements), male sex, younger age, implantation during the earliest part of the study period, and absence of antibiotics (P< 0.001). CONCLUSION: The overall risk of infection after PM implantation was low. A greater number of operations augmented the risk of infection. This should be taken into account when considering revisions of PM systems.

Adverse effect of right ventricular pacing prevented by biventricular pacing during long-term follow-up: a randomized comparison.

AIMS: To investigate whether biventricular (BIV) pacing preserves left ventricular ejection fraction (LVEF) and reduces LV dyssynchrony when compared with standard dual-chamber right ventricular (RV) pacing in consecutive patients with high-grade atrioventricular block during 3 years of pacing. METHODS AND RESULTS: Fifty patients were randomized to RV pacing or BIV pacing. LVEF was measured using three-dimensional echocardiography. Tissue Doppler imaging was used to quantify LV dyssynchrony in terms of the standard deviation of the time-to-peak velocity (Ts-SD). LVEF differed significantly between the two groups during 3 years of pacing (ANOVA: P=0.003). LVEF in the RV group decreased from 59±5% at baseline to 53±11% (P=0.01), while LVEF remained unchanged in the BIV group (57±7% at baseline vs. 58±10% (P=0.40). After 3 years of follow-up, we observed no difference in LV dyssynchrony, LV remodelling or measurements of clinical heart failure (N-terminal pro-brain natriuretic peptide, walking test, and New York Heart Association functional class) between the two groups. However, in the RV group, but not in the BIV group, dyssynchrony increased significantly (P=0.005) during follow-up. Furthermore, adverse LV remodelling was observed in the RV group with increased systolic volume and thinning of the LV septum. CONCLUSION: BIV pacing preserves LVEF and minimizes LV dyssynchrony during long-term follow-up. Adverse remodelling observed during 3 years of RV pacing was prevented by BIV pacing. However, the adverse impact of RV pacing on LV function was not reflected in measures of clinical heart failure. CLINICAL TRIAL REGISTRATION: www.clinicaltrials.gov (identification number: NCT00228241).

Long-term clinical outcome and left ventricular lead position in cardiac resynchronization therapy.

AIMS: To identify the predictive value of a presumed optimal left ventricular lead positions (LV-Ps) on the long-term clinical outcome in patients with cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Clinical information was collected from patient files in consecutive patients treated with CRT from 1997 to 2007. A presumed optimal LV-Ps were defined as a position between 2 and 5 o'clock in the short-axis circumference and basal or mid-ventricular in the long axis. Symptomatic response was defined as improvement in NYHA class (>or=1) and echocardiographic response as improvement in left ventricular ejection fraction of >or=5% absolute. We included 567 patients [median age 66 years, 453 (80%) male]. The LV-Ps were optimal in 334 (59%) patients. The hazard ratio for all-cause mortality with an optimal LV-Ps was unadjusted 0.79 (0.59-1.06) and adjusted 0.99 (0.71-1.40). The odds ratio (OR) for symptomatic response with an optimal LV-Ps was unadjusted 1.13 (0.79-1.64) and adjusted 1.05 (0.67-1.64), and the OR for echocardiographic response was unadjusted 1.60 (1.02-2.49) and adjusted 1.42 (0.88-2.31). CONCLUSION: A presumed optimal LV-Ps between 2 and 5 o'clock in the short-axis circumference and basal or mid-ventricular in the long axis is not associated with a lower mortality or a better clinical response in patients treated with CRT.

Simple preimplant identification of optimum VV timing before cardiac resynchronization therapy: tissue Doppler imaging versus conventional 2D echocardiography.

AIMS: Optimum interventricular (VV) timing may potentially reduce the number of nonresponders to cardiac resynchronization therapy (CRT). We investigated whether optimum VV-timing interval could be determined before CRT implantation by means of tissue Doppler imaging (TDI) analysis and from visual assessment of conventional 2D echocardiography. METHODS AND RESULTS: Thirty consecutive patients prospectively underwent 2D, 3D, and TDI echocardiographic evaluation before and 1 month after CRT. By using 3D echocardiography, LVEF was found to be increased from 23.8 +/- 6% to 35.7 +/- 9% 1 month after CRT (P < 0.001). NYHA class improved from 3.0 +/- 0.6 to 1.8 +/- 0.6 (P < 0.001). In 93% (77-99% with 95% confidence limits) of the patients optimum VV timing was correctly predicted based on preimplant TDI identification of the region with delayed myocardial contraction. A similar result could be obtained in 83% (65-94%) of the patients simply by visual assessment of conventional black and white 2D echocardiography (ns). CONCLUSION: Preimplant TDI evaluation seems to be convenient for the determination of optimum VV timing. Further postimplant adjustment guided by TDI is hardly necessary unless patients do not experience clinical benefit. TDI may seem superior to visual assessment of dyssynchrony by means of conventional 2D echocardiography. However, this simple technique indicated optimum VV timing in the majority of cases in this study.

Very long term follow-up of cardiac resynchronization therapy: clinical outcome and predictors of mortality.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves symptoms, left ventricular ejection fraction (LVEF) and survival in patients with heart failure and wide QRS, however, long term clinical outcome is unknown. AIMS: To identify predictors of mortality and evaluate the effects of CRT after long term follow-up. METHODS: Consecutive patients treated with CRT between 1997 and 2002 were included. We collected clinical information from patient files. Patients who were still alive underwent echocardiography and clinical evaluation. RESULTS: We included 179 patients (median age 65.5 years, 144 male). Median follow-up for survival was 4.0 years. Mortality at one and five years was 15% and 53%, respectively. Predictors of mortality were, ischaemic heart disease (IHD), higher NYHA class and lower LVEF (<22.5%) at baseline, and no improvement in NYHA class at early follow-up. NYHA class remained stable from early to long term follow-up after a median of 5.1 years. In patients with non-IHD median LVEF increased significantly from early to long term follow-up (39% vs. 50% p=0.007). CONCLUSION: Predictors of mortality in patients with CRT are IHD, lower LVEF and higher NYHA class at baseline, and no symptomatic response to CRT. After 5 years follow-up, clinical effects are sustained, and in patients with non-IHD further improvements in LVEF are observed.

DDD(R)-pacing, but not AAI(R)-pacing induces left ventricular desynchronization in patients with sick sinus syndrome: tissue-Doppler and 3D echocardiographic evaluation in a randomized controlled comparison.

AIMS: Increasing evidence from randomized trials and experimental studies indicates that right ventricular (RV) pacing may induce congestive heart failure. We studied regional left ventricular (LV) dyssynchrony and global LV function in 50 consecutive patients with sick sinus syndrome (SSS) randomized to either atrial pacing [AAI(R)] or dual chamber RV-pacing [DDD(R)]. METHODS AND RESULTS: Fifty consecutive patients were randomized to AAI(R) or DDD(R)-pacing. Tissue-Doppler imaging was used to quantify LV dyssynchrony in terms of number of segments with delayed longitudinal contraction (DLC). Left ventricular ejection fraction (LVEF) was measured using three-dimensional echocardiography. Dyssynchrony was more pronounced in the DDD(R)-group than in the AAI(R)-group at the 12 months follow-up (P < 0.05). This reflected a significant increase of dyssynchrony in the DDD(R)-group from baseline to the 12 months follow-up (1.3 +/- 1 to 2.1 +/- 1 segments displaying DLC per patient), P < 0.05. No change was observed in the AAI(R)-group (1.6 +/- 2 to 1.3 +/- 2 segments displaying DLC per patient, NS). No difference in LVEF, NYHA or NT-proBNP was observed between AAI(R)- and DDD(R)-mode after 12 months of pacing although LVEF decreased significantly in the DDD(R)-group from baseline (63.1 +/- 8%) to the 12 months follow-up (59.3 +/- 8%, P < 0.05), while LVEF remained unchanged in the AAI(R)-group (61.5 +/- 11% at baseline vs. 62.3 +/- 7% after 12 months, NS. CONCLUSION: In patients with SSS, DDD(R)-pacing but not AAI(R)-pacing induces significant LV desynchronization and reduction of LVEF.

Multimodality imaging-guided left ventricular lead placement in cardiac resynchronization therapy: a randomized controlled trial.

AIM: Left ventricular (LV) lead position at the latest mechanically activated non-scarred myocardial LV region confers improved response to cardiac resynchronization therapy (CRT). We conducted a double-blind, randomized controlled trial to evaluate the clinical benefit of multimodality imaging-guided LV lead placement in CRT. METHODS AND RESULTS: Patients were allocated (1:1) to imaging-guided LV lead placement using cardiac computed tomography (CT) venography, 99m Technetium myocardial perfusion imaging, and speckle-tracking echocardiography radial strain to target the optimal coronary sinus (CS) branch closest to the non-scarred myocardial segment with latest mechanical activation (imaging group, n = 89) or to routine LV lead implantation in a posterolateral region with late electrical activation (control group, n = 93). The primary endpoint was clinical non-response to CRT [≥1 of the following after 6 months: (1) death, (2) heart failure hospitalization, or (3) no improvement in New York Heart Association class and <10% increase in 6-min walk distance]. Secondary outcomes included LV remodelling and the combination of all-cause mortality and hospitalization owing to heart failure during 1.8 ± 0.9 years. Analysis was intention-to-treat. In the imaging group, fewer patients reached the primary endpoint (26% vs. 42%, P = 0.02). More patients in the imaging group had the LV lead placed in the optimal CS branch (83% vs. 65%, P = 0.01). There were no between-group differences in reverse LV remodelling or the combined endpoint of death or hospitalizations for heart failure. CONCLUSIONS: Multimodality imaging-guided LV lead placement towards the CS branch closest to latest mechanically activated non-scarred myocardial LV segment reduces the proportion of clinical non-responders to CRT. Larger long-term multicentre studies are needed.

Optimization of heart failure medication after cardiac resynchronization therapy and the impact on long-term survival.

AIMS: Treatment with evidence-based heart failure (HF) medication reduces morbidity and mortality, yet they remain underused and underdosed. Cardiac resynchronization therapy (CRT) improves haemodynamics, and might allow for optimization of HF medication. We analysed treatment with HF medication after CRT implantation, long-term adherence to this treatment, and its association with patient survival. METHODS AND RESULTS: This observational study included 826 consecutive patients who received a CRT device at a tertiary centre. Data were obtained from patient files and prescription data from the Danish National Prescription Registry. Doses are expressed as percentages of target doses. We used Cox proportional hazard model to compute adjusted hazard ratios (aHRs) for survival with 95% confidence intervals (CIs), adjusted for potential confounders. During the median (quartiles) follow-up of 4.4 (3.0-6.7) years, 324 patients died. Daily doses of beta-blocker (BB) (53 (27-90) vs. 43 (22-75)%; P < 0.001) and angiotensin-converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB) (78 (45-100) vs. 74 (44-97)%; P = 0.02) had increased after 6-month follow-up compared with pre-implantation doses. After 4 years, adherence was 95% to BB and 94% to ACEi/ARB. Treatments with low (≤50%) and high (>50%) doses were associated with prolonged survival for BB (low: aHR 0.65 (0.47-0.90); P = 0.009, and high: aHR 0.50 (0.35-0.70); P < 0.001) and for ACEi/ARB (low: aHR 0.68 (0.46-1.00); P = 0.05, and high: aHR 0.55 (0.38-0.80); P = 0.002). CONCLUSION: After CRT implantation, optimization of HF treatment is possible, and long-term adherence to HF medication remains high. Higher doses of BB and ACEi/ARB were associated with prolonged survival.

Early detection of atrial high rate episodes predicts atrial fibrillation and thromboembolic events in patients with cardiac resynchronization therapy.

BACKGROUND: In patients without any history of atrial fibrillation (AF), detection of subclinical atrial high rate episodes (AHRE) by implanted devices has been associated with an increased thromboembolic risk. The predictive value of AHREs in patients with cardiac resynchronization therapy (CRT) is uncertain. OBJECTIVE: We aimed to investigate the prognostic value of early detected AHRE in patients with CRT. METHODS: This observational study included patients who received CRT and no history of AF. Patients had standard indication for CRT treatment. They were screened for early detected AHREs longer than 6 minutes occurring before 6-month follow-up, and the longest duration of AHREs was recorded. Information on clinical AF and thromboembolic events was obtained from the Danish National Patient Registry. The Cox regression model was used to compute hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: Of 394 eligible patients, 79 patients (20%) had early AHRE detected. During a median follow-up of 4.6 years, patients with early detected AHREs had an increased risk of clinical AF (HR 2.35; 95% CI 1.47-3.74; P < .001) and thromboembolic events (HR 2.30; 95% CI 1.09-4.83; P = .028). For patients with AHREs longer than 24 hours, these associations were stronger. The risk of mortality was not higher with early detected AHREs (HR 0.97; 95% CI 0.64-1.45; P = .87). Of the 27 patients with thromboembolic events, only 10 patients (37%) had AHREs detected within a 2-month period before the thromboembolic event. CONCLUSION: In patients without any history of AF, detection of early AHREs after CRT implantation is associated with a significantly increased risk of clinical AF and thromboembolic events, particularly AHRE longer than 24 hours.

Regional myocardial perfusion during chronic biventricular pacing and after acute change of the pacing mode in patients with congestive heart failure and bundle branch block treated with an atrioventricular sequential biventricular pacemaker.

BACKGROUND: Biventricular (BiV) pacing has been found to improve systolic function and exercise tolerance in patients with severe congestive heart failure and bundle branch block. The mechanisms behind this beneficial effect is still not sufficiently clarified. AIM: To evaluate the regional myocardial perfusion (MP) during BiV pacing and after acute change of the pacing mode to conventional dual chamber (DDD) pacing, and single chamber atrial (AAI) pacing in patients with severe congestive heart failure and prolonged QRS width treated with chronic BiV pacing. METHODS AND RESULTS: Fourteen patients (age 63+/-7 years, 13 male) were evaluated 13+/-7 months after implantation of a triple-chamber biventricular pacemaker. MP was quantified with 13N-labeled ammonia positron emission tomography during BiV pacing, DDD pacing, and AAI pacing. MP was assessed in the anterior, lateral, inferior, and septal regions, and the global mean MP was calculated. Clinical assessment was performed before pacemaker implantation and after at least 3 months of BiV pacing including a 6-min walk test (WT), New York Heart Association (NYHA) class functional score and echocardiography. Global mean MP (BiV: 0.65+/-0.20 vs. DDD: 0.65+/-0.21 vs. AAI: 0.65+/-0.18 mlg(-1)min(-1)) and MP in each of the four regions did not differ between the three pacing modes. The patients improved clinically during BiV pacing; 6 min WT increased (338+/-59 vs. 415+/-73 m, P<0.001), NYHA class score improved (class I/II/III/IV: 0/0/11/3 vs. 1/9/2/0, P<0.001), and left ventricular ejection fraction increased (21+/-5 vs. 29+/-8%, P=0.004). CONCLUSION: No differences in regional MP are detectable after chronic BiV pacing when the pacing mode is changed acutely in patients with severe congestive heart failure and bundle branch block. This finding indicates, that the clinical improvement caused by BiV pacing is not associated with any increase in the MP and thereby oxygen demand.

Empiric versus imaging guided left ventricular lead placement in cardiac resynchronization therapy (ImagingCRT): study protocol for a randomized controlled trial.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an established treatment in heart failure patients. However, a large proportion of patients remain nonresponsive to this pacing strategy. Left ventricular (LV) lead position is one of the main determinants of response to CRT. This study aims to clarify whether multimodality imaging guided LV lead placement improves clinical outcome after CRT. METHODS/DESIGN: The ImagingCRT study is a prospective, randomized, patient- and assessor-blinded, two-armed trial. The study is designed to investigate the effect of imaging guided left ventricular lead positioning on a clinical composite primary endpoint comprising all-cause mortality, hospitalization for heart failure, or unchanged or worsened functional capacity (no improvement in New York Heart Association class and <10% improvement in six-minute-walk test). Imaging guided LV lead positioning is targeted to the latest activated non-scarred myocardial region by speckle tracking echocardiography, single-photon emission computed tomography, and cardiac computed tomography. Secondary endpoints include changes in LV dimensions, ejection fraction and dyssynchrony. A total of 192 patients are included in the study. DISCUSSION: Despite tremendous advances in knowledge with CRT, the proportion of patients not responding to this treatment has remained stable since the introduction of CRT. ImagingCRT is a prospective, randomized study assessing the clinical and echocardiographic effect of multimodality imaging guided LV lead placement in CRT. The results are expected to make an important contribution in the pursuit of increasing response rate to CRT. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT01323686. The trial was registered March 25, 2011 and the first study subject was randomized April 11, 2011.

Non-contrast magnetic resonance imaging for guiding left ventricular lead position in cardiac resynchronization therapy.

PURPOSE: A left ventricular lead position concordant to viable myocardium at the site of latest mechanical activation is associated with a better response to cardiac resynchronization therapy (CRT). The present study aimed to guide left ventricular (LV) lead implantation into a vein over the area of latest mechanical activation with no transmural scar as determined by radial strain measured by non-contrast magnetic resonance imaging (MRI). METHODS: Patients admitted for CRT implantation underwent MRI on the day before pacemaker implantation. Time to peak radial strain in ventricular segments was measured to define the site of latest mechanical activation. Areas with peak radial strain less than 16.5% were defined as transmural scar. Venograms were visualized to define the optimal vein for LV lead positioning. Echocardiograms, 6-min hall walk test, and NYHA class were obtained at baseline and after 6 months of follow-up. RESULTS: Sixteen patients were included. In nine patients the lead was positioned at the primary target site, and in six patients a secondary was used owing to phrenic nerve stimulation (one patient), unstable lead position (two patients) and lack of suitable vein (three patients) at the primary target site. In three patients pre-implant MRI changed the implanters primary target vein. CONCLUSION: Non-contrast MRI can be used to detect the site of latest mechanical activation by radial strain to guide LV lead positioning in candidates for CRT. Image guided LV lead implantation in CRT patients may in some patients change the primary target tributary of the coronary sinus.

His and para-His pacing in AV block: feasibility and electrocardiographic findings.

PURPOSE: Right ventricular apical pacing induces a dyssynchronous activation of the left ventricle and is associated with adverse clinical outcome. We aimed to establish permanent His-bundle pacing or para-His pacing in patients with high-grade atrioventricular (AV) block. METHOD: We included patients with pacemaker indication due to second- or third-degree AV block, left ventricular ejection fraction >0.40, QRS duration <120 ms, and sinus rhythm. All patients received a pacemaker with one atrial lead, one right ventricular mid-septal lead, and one lead in the His bundle or in the para-His position. Pacing from apex was performed temporarily. Patients were followed for 12 months. RESULTS: Thirty-eight patients were included (mean age, 67 ± 10 years; 30 (79%) male). Mean implantation time was 85 ± 31 min, mean fluoroscopy time was 23 ± 13 min, and mean position attempts of the His bundle lead was 8 ± 5. In four patients, we established direct His-bundle pacing with a mean QRS of 100 ± 19 ms, and in 28 patients, para-His pacing was achieved with a mean QRS of 112 ± 18 ms, and in six patients, neither direct His-bundle pacing or para-His pacing could be achieved. The mean QRS duration was 153 ± 12 ms with mid-septal pacing and 161 ± 15 ms with apical pacing. CONCLUSION: Stable direct His-bundle pacing or para-His pacing is feasible in 85% of patients with narrow QRS and high-grade AV block and leads to a normal or near-normal ventricular activation pattern.

[Radio frequency of atrial fibrillation: results from 102 consecutive patients--secondary publication]. / Radiofrekvensablation af atrieflimren: resultater fra 102 konsekutive patienter--sekundaerpublikation.

Segmental pulmonary vein isolation (SPVI) and circumferential pulmonary vein isolation (CPVI) are the two main approaches to radiofrequency ablation in patients with atrial fibrillation (AF). The aim of this retrospective study was to investigate the safety level and patient outcome of both approaches. The overall freedom from symptoms was 73% and 25% after CPVI and SPVI, respectively. Our study concludes that CPVI is an effective treatment of highly symptomatic and drug-resistant AF and when used in laboratories by experienced electrophysiologists has a promising and reproducible outcome ratio and safety level.

Left ventricular lead performance in cardiac resynchronization therapy: impact of lead localization and complications.

INTRODUCTION: Cardiac resynchronization therapy (CRT) using left ventricular (LV) pacing from the coronary sinus tributary is increasingly and frequently used in patients with severe congestive heart failure. The present study investigates LV lead performance in different anatomic locations. METHODS: The LV pacing site was defined by bi-plane fluoroscopy. In the left anterior oblique view, the coronary sinus is encircling the mitral ring with the tributaries radiating out like the hands of a watch. Using this clockwise method, Group A had an LV pacing site before 3 o'clock and Group B at or after 3 o'clock. In right anterior oblique view, the LV was divided into three segments: basal, mid-ventricular, and apical. RESULTS: LV lead implantation was successful in all of 120 consecutive patients. Mean follow-up was 16.7 months. Implantation time decreased from mean 190 to 80 minutes during the period (P = 0.01). The mean LV lead stimulation threshold increased initially and stabilized afterwards. The threshold measured at last follow-up was higher than at implantation (2.3 vs 2.7 microJ, P = 0.04). Useful venograms were obtained in 94 patients. No significant difference in thresholds was observed between Groups A and B. Phrenic nerve stimulation was most commonly seen in Group B (8/70 vs 1/24, P = 0.001). CONCLUSION: Implantation of an LV lead for CRT is possible in patients with congestive heart failure and associated with an acceptable low complication rate. LV lead implantation is associated with a learning curve. At mid-term follow-up, LV lead performance is stable and unrelated to the LV implantation site.