Comparison of ICD shock rates in Japanese and non-Japanese patients in the PainFree SST study.

BACKGROUND: The PainFree Smart Shock Technology (SST) study showed a low implantable cardioverter-defibrillator (ICD) inappropriate shock rate. However, the majority of patients were from Western countries with patient characteristics different from those in Japan. ICD shock rates using the novel SST algorithms in Japanese patients are still unknown. METHODS: All 2,770 patients in the PainFree SST study (Japan [JPN]: N = 181, other geographies [OJPN]: N = 2,589) were included in this analysis. RESULTS: Japanese patients had higher average left ventricular ejection fraction (P < 0.0001), higher prevalence of secondary prevention indications (P < 0.0001), nonischemic cardiomyopathy (P < 0.0001), and permanent atrial fibrillation (P < 0.0001). The appropriate shock rate at 12 months was not different between JPN and OJPN: 6.4% and 6.3%, respectively (P = 0.95). The inappropriate shock rate at 12 months was significantly higher in Japanese patients (2.9% vs 1.7%, P = 0.017). However, after propensity score matching to adjust for the difference in baseline characteristics, the difference in inappropriate shock rate was not statistically significant (P = 0.51). CONCLUSIONS: There was no difference in the appropriate shock rate between Japan and other geographies. The inappropriate shock rate in Japan was low, although it was slightly higher compared to other geographies due to baseline characteristics, including a higher prevalence of permanent AF. There was not a statistically significant difference after adjusting for baseline characteristics.

Defibrillator shocks and their effect on objective and subjective patient outcomes: Results of the PainFree SST clinical trial.

BACKGROUND: The effect of implantable cardioverter-defibrillator (ICD) shock on device-measured activity and patient-reported outcomes is unknown. OBJECTIVE: The purpose of this study was to analyze the acute and long-term effects of ICD shock on objective behavioral data (ie, device-based physical activity) and subjective patient-reported outcomes (eg, quality of life and shock anxiety). METHODS: The PainFree Smart Shock Technology (SST) clinical trial included 2770 patients with a single- or dual-chamber ICD or cardiac resynchronization therapy - defibrillator device who were followed for 22 ± 9 months. Participants completed measures of quality of life (EuroQol-5D [EQ-5D] questionnaire) and shock anxiety (Florida Shock Anxiety Scale) at baseline, biannual visits, and monthly for 6 months after an ICD shock. Daily physical activity data were obtained from a built-in device accelerometer. RESULTS: The average daily activity was 185.3 ± 119.4 min/d. Activity was significantly reduced after an ICD shock (P < .0001) and recovered to a normal level after ∼90 days. An ICD shock was also associated with decreased quality of life (EQ5-D health score) and increased EQ-5D anxiety scores, but it did not affect mobility, self-care, activity, or pain. Similarly, shock anxiety (Florida Shock Anxiety Scale) increased in shocked patients and remained significantly elevated at 24 months, regardless of appropriate or inappropriate shock delivery. CONCLUSION: ICD shocks have a long-lasting adverse effect on both objective, device-measured physical activity and subjective patient-reported outcomes of quality of life and shock anxiety. Successful management of patients with an ICD requires attention to clinically relevant behavioral and psychological outcomes to expedite recovery and return to activities of daily living.

Inappropriate shocks in single-chamber and subcutaneous implantable cardioverter-defibrillators: a systematic review and meta-analysis.

AIMS: Single-chamber (VR-ICD) and subcutaneous (S-ICD) implantable cardioverter-defibrillators are effective to protect patients against sudden death but expose them to higher risk of inappropriate shock (IS). We sought to quantify the annual rate and influencing factors of ISs in VR- and S-ICDs from the literature. METHODS AND RESULTS: PubMed, Embase, and Cochrane Library were searched for full text articles with IS rates. Poisson distribution estimated proportion of patients with ISs; rates were annualized based on follow-up duration. Random effects meta-analysis accounted for study-to-study variation. Out of 3264 articles, 16 qualified for the meta-analysis. Across studies, 6.4% [95% confidence interval (CI) 5.1-7.9%] of patients received an IS per year. Meta-regression analyses demonstrated that IS rates were lower in more recent studies [rate ratio (RR) per year: 0.93, 95% CI: 0.87-0.98; P = 0.01] and trended lower in studies with longer follow-up (RR per year: 0.78, 95% CI: 0.60-1.01; P = 0.06). Use of S-ICDs (RR: 1.81, 95% CI: 0.86-3.81; P = 0.12) and ventricular tachycardia zone programmed on (RR: 1.13, 95% CI: 0.65-1.97; P = 0.66) were not associated with a significantly increased change in risk. The IS rate observed in one of the more recent studies was significantly lower than predicted after accounting for covariates (RR: 0.29, 95% CI: 0.14-0.60; P < 0.001). CONCLUSIONS: A comprehensive review of the literature shows that 6.4% of patients with ICDs experienced their first IS annually. One of the 16 studies was better than predicted with the lowest reported rate (1.9%) and could not be explained by timing of the study or other covariates.

Extended detection time to reduce shocks is safe in secondary prevention patients: The secondary prevention substudy of PainFree SST.

BACKGROUND: Prolonged ventricular fibrillation (VF) detection has been shown to reduce implantable cardioverter-defibrillator (ICD) therapies and improve prognosis in primary prevention ICD patients. Data in secondary prevention patients are limited. OBJECTIVE: The PainFree SST secondary prevention study is the largest trial of secondary prevention patients randomized between standard and prolonged detection to assess the safety of this strategy in these patients. METHODS: A total of 705 secondary prevention patients implanted with an ICD in the PainFree SST trial were enrolled in this substudy; 353 patients were randomized to VF detection of 18/24 intervals and 352 patients to 30/40. All other VF parameters were standardized by protocol. RESULTS: The 1-year arrhythmic syncope-free rates in the standard and prolonged groups were 97.7% vs 96.9%, respectively, (P = .0034 for noninferiority). Freedom from all-cause syncope was 96% in both arms (P = .0013 for noninferiority). There was no difference in the time to first appropriate or inappropriate VF therapy. However, the rates of treated VF episodes were lower in the prolonged arm (1.48 per patient per year vs 0.44 per patient per year, P = .0001). A trend toward lower mortality in the prolonged group was not statistically different (5.6% 1 year, 12% 2 years vs 3.8% 1 year, 7.7% 2 years, adjusted hazard ratio = 0.60, P = .061). CONCLUSION: This large prospective randomized study shows that prolonged detection can safely be programmed in secondary prevention ICD patients with new or existing devices. This programming strategy decreases the rate of treated events and is not associated with an increased risk of syncope or mortality.

Low inappropriate shock rates in patients with single- and dual/triple-chamber implantable cardioverter-defibrillators using a novel suite of detection algorithms: PainFree SST trial primary results.

BACKGROUND: The benefits of implantable cardioverter-defibrillators (ICDs) have been well demonstrated in many clinical trials, and ICD shocks for ventricular tachyarrhythmias save lives. However, inappropriate and unnecessary shock delivery remains a significant clinical issue with considerable consequences for patients and the healthcare system. OBJECTIVE: The purpose of the PainFree SmartShock Technology (SST) study was to investigate new-generation ICDs to reduce inappropriate and unnecessary shocks through novel discrimination algorithms with modern programming strategies. METHODS: This prospective, multicenter clinical trial enrolled 2790 patients with approved indication for ICD implantation (79% male, mean age 65 years; 69% primary prevention indication, 27% single-chamber ICD, 33% replacement or upgrade). Patients were followed for a minimum of 12 months, and mean follow-up was 22 months. The primary end-point of the study was the percentage of patients remaining free of inappropriate shocks at 1 year postimplant, analyzed separately for dual/triple-chamber ICDs (N = 2019) and single-chamber ICDs (N = 751). RESULTS: The inappropriate shock rate at 1 year was 1.5% for patients with dual/triple-chamber ICDs and 2.5% for patients with single-chamber devices. Two years postimplant, the inappropriate shock rate was 2.8% for patients with dual-/triple chamber ICDs and 3.7% for those with single-chamber ICDs. The most common cause of an inappropriate shock in both groups was atrial fibrillation or flutter. CONCLUSION: In a large patient cohort receiving ICDs for primary or secondary prevention, the adoption of novel enhanced detection algorithms in conjunction with routine implementation of modern programming strategies led to a very low inappropriate shock rate.

New image processing and noise reduction technology allows reduction of radiation exposure in complex electrophysiologic interventions while maintaining optimal image quality: a randomized clinical trial.

BACKGROUND: Despite their carcinogenic potential, X-rays remain indispensable for electrophysiologic (EP) procedures. OBJECTIVE: The purpose of this study was to evaluate the dose reduction and image quality of a novel X-ray technology using advanced image processing and dose reduction technology in an EP laboratory. METHODS: In this single-center, randomized, unblinded, parallel controlled trial, consecutive patients undergoing catheter ablation for complex arrhythmias were eligible. The Philips Allura FD20 system allows switching between the reference (Allura Xper) and the novel X-ray imaging technology (Allura Clarity). Primary end-point was overall procedural patient dose, expressed in dose area product (DAP) and air kerma (AK). Operator dose, procedural success, and necessity to switch to higher dose settings were secondary end-points. RESULTS: A total of 136 patients were randomly assigned to the novel imaging group (n = 68) or the reference group (n = 68). Baseline characteristics were similar, except patients in the novel imaging group were younger (58 vs 65 years, P < .01). Median DAP and AK were 43% and 40% lower in the novel imaging group, respectively (P < .0001). A 50% operator dose reduction was achieved in the novel imaging group (P < .001). Fluoroscopy time, number of exposure frames, and procedure duration were equivalent between the two groups, indicating that the image quality was similarly adequate in both groups. Procedural success was achieved in 91% of patients in both groups; one pericardial tamponade occurred in the novel imaging group. CONCLUSION: The novel imaging technology, Allura Clarity, significantly reduces patient and operator dose in complex EP procedures while maintaining image quality.

Safety, efficacy, and performance of new discrimination algorithms to reduce inappropriate and unnecessary shocks: the PainFree SST clinical study design.

INTRODUCTION: Implantable cardioverter defibrillator (ICD) shock therapy improves survival of patients at risk for sudden cardiac death. The high sensitivity of ICDs to detect tachycardia events is accompanied by reduced specificity resulting in inappropriate and unnecessary shocks. Up to 30% of ICD patients may experience inappropriate shocks, which are most commonly caused by lead noise, oversensing of T-waves, and supraventricular tachycardias. The new Protecta ICD and cardiac resynchronization therapy devices have been designed to minimize inappropriate and unnecessary shocks through novel SmartShock(TM) technology algorithms targeting these causes. METHODS: The PainFree SST study is a prospective, multicentre clinical trial, which will be conducted in two consecutive phases. Phase I will assess safety and any delay that may arise in ventricular fibrillation (VF) arrhythmia detection time using new algorithms. Phase II will evaluate reduction of inappropriate and unnecessary shocks at 1 year of follow-up. Additional objectives will include Quality of Life, healthcare utilization, safety of extending the ventricular tachyarrhythmia/VF interval detection duration (18 out of 24 vs. 30 out of 40 intervals), and reasons for inappropriate shock. Up to 2000 subjects in 150 centres worldwide will be enrolled with a follow-up of at least 1 year. Subjects enrolled in Phase I will continue in Phase II of the study and data from all enrolled subjects will contribute to the analysis of Phase II objectives. CONCLUSION: Inappropriate and unnecessary shock delivery remains a significant clinical issue for patients receiving device therapies, which has considerable consequences for patients and the healthcare system. The PainFree SST study will investigate the ability of new algorithms to reduce inappropriate shocks. Results from this study are expected in mid-2013.

Risk of chronic anxiety in implantable defibrillator patients: a multi-center study.

BACKGROUND: Little is known about the prevalence of chronic anxiety in patients with an implantable cardioverter defibrillator (ICD). In a multi-center, prospective study, we examined 1) the prevalence of chronic anxiety (i.e., patients anxious at implantation and 12 months), and 2) predictors of chronic anxiety. METHODS: ICD patients (N=284; 21.1% women) anxious (cut-off ≥ 40 on the State Trait Anxiety Inventory (STAI)) at the time of implantation qualified for inclusion in the current study. Patients completed the Type D Scale at baseline and the STAI (state measure) at baseline and 12 months. RESULTS: Of 284 patients anxious at baseline, 53.9% (153/284) remained anxious at 12-month follow-up. Diabetes (OR:2.49; 95%CI:1.16-5.36), cardiac resynchronization therapy (CRT) (OR:2.03; 95%CI:1.02-4.05), and Type D personality (OR:1.87; 95%CI:1.09-3.19) were independent predictors of 12-month anxiety, adjusting for demographic and clinical variables including ICD therapy during follow-up. Shocks (both appropriate and inappropriate during follow-up) were not associated with chronic anxiety at 12 months (OR:0.94; 95%CI:0.42-2.12). The prevalence of chronic anxiety in the 96 patients with no risk factors was 34.4% and 63.8% in the 120 patients with either diabetes, CRT, or Type D personality. CONCLUSIONS: More than 50% of ICD patients anxious at the time of implantation were still anxious at 12 months, indicating a high level of chronicity. Diabetes, CRT, and Type D personality were independent predictors of chronic anxiety. ICD patients anxious at implantation should be closely monitored and offered adjunctive psychosocial intervention if symptoms do not remit spontaneously in order to prevent adverse health outcomes.

Three-dimensional CT overlay in comparison to CartoMerge for pulmonary vein antrum isolation.

INTRODUCTION: Three-dimensional (3D) navigation systems are widely used for pulmonary vein antrum isolation (PVAI). To circumvent left atrial (LA) mapping, 3D CT reconstructions of the LA can be superimposed directly (CT overlay) on the fluoroscopy image to guide ablation catheters and to mark ablation sites. METHODS AND RESULTS: Sixty-eight patients (pts) with symptomatic AF refractory to medical therapy were randomly assigned to CT overlay (group 1, n = 38) or CartoMerge (group 2, n = 30). In group 1 registration of the CT image was performed with contrast injections in 2 orthogonal projections. In group 2, visualization of all pulmonary vein (PV) ostia was done by PV angiography, followed by merging of the CT image and the Carto shell. We compared procedural success, procedure time, fluoroscopy time and radiation burden, measured as dose area product (DAP). Baseline characteristics were comparable in both groups. Procedural success, defined as disappearance of PV potentials in all PVs, was achieved in 37/38 (97%) of group 1 patients and 27/30 (90%) patients in group 2 (P = NS). Total procedure time was significantly shorter in group 1 compared to group 2 (129 +/- 34 vs 181 +/- 30 min, P < 0.0001). Although fluoroscopy time tended to be longer in the CT overlay group (47 +/- 16 vs 40 +/- 13 min, P = 0.06), proper use of diaphragmation resulted in comparable radiation values for both groups (DAP 53 +/- 27 vs 56 +/- 35 Gy cm(2), P = 0.76). CONCLUSIONS: CT overlay for PV isolation is feasible and may, in comparison to conventional LA navigation systems, shorten procedural time without increases in radiation burden.

Initiation of ventricular tachycardia by interruption of pacemaker-mediated tachycardia in a patient with a dual-chamber implantable cardioverter defibrillator.

A 74-year-old man with a dual-chamber implantable cardioverter defibrillator implanted 3 years before experienced multiple ventricular tachycardias (VTs). All episodes were initiated by pacemaker-mediated tachycardia (PMT) that was either stopped by atrial undersensing or the tachycardia termination algorithm of the device. After the termination of PMT, two rapid ventricular paced beats, the first initiated by artificial triggering and the second due to retrograde conduction of the first one, initiated VT that was successfully terminated by antitachycardia pacing or a direct current shock of the device. All episodes revealed this pattern of initiation with a short-long-short ventricular sequence inducing VT.

Risk of ventricular arrhythmia after implantable defibrillator treatment in anxious type D patients.

OBJECTIVES: We sought to examine the combination of adverse psychological factors (anxiety, depression, and distressed or Type D personality) as a predictor of ventricular arrhythmias in patients with implantable cardioverter-defibrillators (ICDs). BACKGROUND: Little is known about the role of psychological factors and their clustering in the occurrence of life-threatening arrhythmias. METHODS: In this prospective study, 391 patients with an ICD (81% men, age 62.3 +/- 10.4 years) completed anxiety, depression, and Type D personality scales at the time of implantation. The end point was occurrence of ventricular arrhythmia, defined as appropriate ICD therapies, in the first year after implantation. RESULTS: Ventricular arrhythmias occurred in 19% (n = 75) of patients. Increased symptoms of depression (p = 0.81) or anxiety (p = 0.31) did not predict arrhythmias. However, anxious patients with a Type D personality had a significantly increased rate of ventricular arrhythmias (21 of 71; 29.6%) as compared with other ICD patients (54 of 320; 16.9%; hazard ratio [HR]: 1.89; 95% confidence interval [CI]: 1.14 to 3.13; p = 0.013). When controlled for the effects of sex, age, ischemic etiology, left ventricular dysfunction, prolonged QRS duration, and medication, anxious Type D patients (HR: 1.72; 95% CI: 1.03 to 2.89; p = 0.039) and secondary prevention patients (HR: 1.91; 95% CI: 1.14 to 3.20; p = 0.014) were at increased risk of ventricular arrhythmias. CONCLUSIONS: Personality modulated the effect of emotional distress; anxiety predicted a 70% increase in risk of arrhythmia in Type D patients but not in other patients. Anxious Type D patients may be identified and offered additional behavioral support after ICD implantation.

Timing of the left ventricular electrogram and acute hemodynamic changes during implant of cardiac resynchronization therapy devices.

STUDY OBJECTIVE: To examine the relationship between timing of the left ventricular (LV) electrogram (EGM) and its acute hemodynamic effect on instantaneous change in LV pressure (LVdP/dt(MAX)). PATIENTS AND METHODS: In 30 patients (mean = age 67 +/- 7.9 years) who underwent implant of cardiac resynchronization therapy systems, the right ventricular (RV) lead was implanted at the RV apex (n = 23) or RV septum (n = 7). The LV lead was placed in a posterior (n = 14) or posterolateral (n = 16) coronary sinus tributary. QRS duration, interval from Q wave to intrinsic deflection of the LV EGM (Q-LV), and interval between intrinsic deflection of RV EGM and LV EGM (RV-LV interval) were measured. The measurements were correlated with the hemodynamic effects of optimized biventricular (BiV) stimulation, using the Pearson correlation coefficient. RESULTS: The mean LVdP/dt(MAX) at baseline was 734 +/- 180 mmHg/s, and increased to 905 +/- 165 mmHg/s during simultaneous BiV pacing, and to 933 +/- 172 mmHg/s after V-V interval optimization. The Pearson correlation coefficient R between QRS duration, the Q-LV interval, and the RV-LV interval at the respective LVdP/dt(MAX) was 0.291 (P = 0.66), 0.348 (P = 0.030), and 0.340 (P = 0.033). CONCLUSIONS: Similar significant correlations were observed between the acute hemodynamic effect of optimized BiV stimulation and the Q-LV and the RV-LV intervals. However, individual measurements showed an 80-ms cut-off for the Q-LV interval, beyond which the increase in LVdP/dt(MAX) was <10%.

Atrial fibrillation therapy in patients with a CRT defibrillator with wireless telemetry.

BACKGROUND: Atrial fibrillation (AF) is a major cause of morbidity and mortality, especially in patients with congestive heart failure. OBJECTIVES: The purposes of this international, prospective multicenter study were to evaluate the efficacy of atrial shock therapy in patients with a cardiac resynchronization therapy defibrillator (CRT-D) and to evaluate the safety of the new CRT-D. The effectiveness of a new wireless telemetry system was also evaluated. METHODS: A total of 282 patients, without permanent AF, who had indications for a CRT-D were included. Atrial shock therapy was tested on both spontaneous and induced AF episodes. The effectiveness of the Medtronic wireless telemetry system (Conexus; Medtronic Inc., Minneapolis, MN, USA) was also tested. Secondary endpoints included the heart failure Clinical Composite Response, system performance evaluation, and adverse event summary. RESULTS: Atrial shock therapy was successful in 168 of 171 episodes (98.2%). Of these, 138 episodes were induced and 33 were spontaneous. Successful cardioversion occurred in 137 of the 138 induced-AF episodes (86.1% with 12 joule (J), 13.1% with 24 J, and 0.7% with 35 J). During the first 3 months of implant, there were 43 system-related complications in 37 subjects out of 278 subjects. There were 1,999 Conexus telemetry uses recorded during this study. This includes 282 uses during the implant procedure. There were no cases of complete loss of telemetry or any adverse events reported using this system. CONCLUSION: We achieved an atrial shock efficacy of 98.2% in patients who met standard CRT-D indications. The wireless telemetry performed well with no reported unanticipated adverse device effects.

A case of catecholaminergic polymorphic ventricular tachycardia caused by two calsequestrin 2 mutations.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an uncommon heritable disease presenting with syncope or sudden cardiac death. Two genes involved in calcium homeostasis, the ryanodine receptor gene and the calsequestrin 2 (CASQ2) gene, have been implicated in this disease. We describe a young man presenting with exercise-induced syncope, clinically diagnosed as CPVT. Genetic analysis revealed two mutations, p.Y55C (c.164A>G) and p.P308L (c.923C>T), in the CASQ2 gene. Subsequent familial analysis indicates a compound heterozygous form of inheritance.

Stimulation rate and the optimal interventricular interval during cardiac resynchronization therapy in patients with chronic atrial fibrillation.

BACKGROUND: Optimization of cardiac resynchronization therapy (CRT) with respect to the interventricular (V-V) interval is mainly limited to pacing at a resting heart rate. We studied the effect of higher stimulation rates with univentricular and biventricular (BiV) pacing modes including the effect of the V-V interval optimization. METHODS: In 36 patients with heart failure and chronic atrial fibrillation (AF), the effects of right ventricular (RV), left ventricular (LV), simultaneous BiV, and optimized sequential BiV (BiVopt) pacing were measured. The effect of the pacing mode and the optimal V-V interval was determined at stimulation rates of 70, 90, and 110 ppm using invasive measurement of the maximum rate of left ventricular pressure rise (LV dP/dt(max)). RESULTS: The average LV dP/dt (max) for all pacing modalities at stimulation rates of 70, 90, and 110 ppm was 781 +/- 176, 833 +/- 197, and 884 +/- 223 mmHg/s for RV pacing; 893 +/- 178, 942 +/- 186, and 981 +/- 194 mmHg/s for LV pacing; 904 +/- 179, 973 +/- 187, and 1052 +/- 206 mmHg/s for simultaneous BiV pacing; and 941 +/- 186, 1010 +/- 198, and 1081 +/- 206 mmHg/s for BiVopt pacing, respectively. In BiVopt pacing, the corresponding optimal V-V interval decreased from 34 +/- 29, 28 +/- 28, and21 +/- 27ms at stimulation rates of 70, 90, and 110 ppm, respectively. In two individuals, LV dP/dt(max) decreased when the pacing rate was increased from 90 to 110 ppm. CONCLUSION: In patients with AF and heart failure, LV dP/dt(max) increases for all pacing modalities at increasing stimulation rates in most, but not all, patients. The rise in LV dP/dt(max) with increasing stimulation rates is higher in biventricular (BiV and BiVopt) than in univentricular (LV and RV) pacing. The optimal V-V interval at sequential biventricular pacing decreases with increasing stimulation rates.

The optimized V-V interval determined by interventricular conduction times versus invasive measurement by LVdP/dtMAX.

INTRODUCTION: We compared the calculated optimal V-V interval derived from intracardiac electrograms (IEGM) with the optimized V-V interval determined by invasive measurement of LVdP/dt(MAX). METHODS AND RESULTS: Thirty-two patients with heart failure (six females, ages 68 +/- 7.8 years) had a CRT device implanted. After implantation of the atrial, right and a left ventricular lead, the optimal V-V interval was calculated using the QuickOpt formula (St. Jude Medical, Sylmar, CA, USA) applied to the respective IEGM recordings (V-V(IEGM)), and also determined by invasive measurement of LVdP/dt(MAX) (V-V(dP/dt)). The optimal V-V(IEGM) and V-V(dP/dt) intervals were 52.7 +/- 18 ms and 24.0 +/- 33 ms, respectively (P = 0.017), without correlation between the two. The baseline LVdP/dt(MAX) was 748 +/- 191 mmHg/s. The mean value of LVdP/dt(MAX) at invasive optimization was 947 +/- 198 mmHg/s, and at the calculated optimal V-V(IEGM) interval 920 +/- 191 mmHg/s (P < 0.0001). In spite of this significant difference, there was a good correlation between both methods (R = 0.991, P < 0.0001). However, a similarly good correlation existed between the maximum value of LVdP/dt(MAX) and LVdP/dt(MAX) at a fixed V-V interval of 0 ms (R = 0.993, P < 0.0001), or LVdP/dt(MAX) at a randomly selected V-V interval between 0 and +80 ms (R = 0.991, P < 0.0001). CONCLUSION: Optimizing the V-V interval with the IEGM method does not yield better hemodynamic results than simultaneous BiV pacing. Although a good correlation between LVdP/dt(MAX) determined with V-V(IEGM) and V-V(dP/dt) can be constructed, there is no correlation with the optimal settings of V-V interval in the individual patient.

Coronary sinus atresia and persistent left superior vena cava with the presence of thrombus complicating implantation of a left ventricular pacing lead.

A 68-year-old male with heart failure and a suitable candidate for resynchronization therapy was referred to our hospital because of a failed coronary sinus (CS) lead implant. Catheterization of the CS initially also failed in our department but a left coronary angiogram revealed atresia of the CS and drainage of the coronary venous system via a persistent left superior vena cava (PLSVC). Implantation of a CS lead through the PLSVC could be accomplished after a selective angiogram, even in spite of the presence of a large thrombus at the junction of PLSVC and CS.

The influence of myocardial scar and dyssynchrony on reverse remodeling in cardiac resynchronization therapy.

AIM: The influence of location and extent of transmural scar and its relation with dyssynchrony in cardiac resynchronization therapy (CRT) was investigated as posterolateral scar tissue has been invoked as a cause of non-response to CRT. METHODS AND RESULTS: Fifty-seven patients eligible for CRT were assessed for transmural scar with gadolinium-enhanced MRI and for left ventricular (LV) dyssynchrony with tissue Doppler. After implant, both atrioventricular and interventricular pacing intervals were optimized. LV reverse remodeling was defined as >/=10% decrease in LV end-systolic volume after 3 months. Sixteen patients had transmural scar in the posterolateral (PL) area (LV lead location), 14 at a remote site (non-PL) and 27 patients had no scar. LV reverse remodeling was observed in respectively 25%, 64% and 89% (P = 0.0001). Univariate analyses showed a relation with LV dyssynchrony (P = 0.004) and with absence of PL scar (P = 0.04) but not with QRS duration and the extent of LV scar tissue. In multivariate analysis, only LV dyssynchrony (OR: 19.62; 95% CI: 2.5-151.9; P = 0.004) independently predicted LV reverse remodeling. CONCLUSION: In this study LV dyssynchrony remains the most important determinant of response to CRT, even in the presence of posterolateral scar provided atrioventricular and interventricular pacing intervals are optimized.

Morphology of the RV electrogram during LV pacing is related to the hemodynamic effect in cardiac resynchronization therapy.

BACKGROUND: Biventricular (BiV) pacing and left ventricular (LV) pacing both improve LV function in patients with heart failure and LV dyssynchrony. We studied the hemodynamic effect of the atrioventricular (AV) interval and the associated changes in the right ventricular (RV) electrogram (EGM) during LV pacing and compared this with the hemodynamic effect of optimized sequential BiV pacing. METHODS: In 16 patients with New York Heart Association (NYHA) class II to IV, sinus rhythm with normal AV conduction, left bundle branch block (LBBB), QRS > 130 ms, and optimal medical therapy, the changes in RV EGM during LV pacing with varying AV intervals were studied. The hemodynamic effect associated with these changes was evaluated by invasive measurement of LVdP/dt(max) and compared with the result of optimized sequential BiV pacing in the same patient. RESULTS: All patients showed electrocardiographic fusion during LV pacing. The morphology of the RV EGM showed changes in the RV activation that indicated a shift in the extent of fusion from LV pacing. These changes were associated with significant changes in LVdP/dt(max). Baseline LV dP/dt(max) was 734 +/- 177 mmHg/s, which increased to 927 +/- 202 mmHg/s (P<0.0001) with optimized LV pacing and to 920 +/- 209 mmHg/s (P<0.0001) with optimized sequential BiV pacing. CONCLUSION: The RV EGM is a proper indicator for intrinsic activation over the right bundle during LV pacing and reveals the transition to fusion in the RV EGM that is associated with a decrease in LVdP/dt(max). The hemodynamic effect of optimized LV pacing is equal to optimized sequential BiV pacing.