Comparison of infection and complication rates associated with transvenous vs. subcutaneous defibrillators in patients with stage 4 chronic kidney disease: a multicenter long-term retrospective follow-up.

Background: Patients with progressive chronic kidney disease (CKD) are at higher risk of infections and complications from cardiac implantable electronic devices (CIED). In patients with a primary or secondary prophylactic indication, implantable cardiac defibrillators (ICD) can prevent sudden cardiac deaths (SCD). We retrospectively compared transvenous-ICD (TV-ICD) and intermuscularly implanted subcutaneous-ICD (S-ICD) associated infections and complication rates together with hospitalizations in recipients with stage 4 kidney disease. Methods: We retrospectively analyzed 70 patients from six German centers with stage 4 CKD who received either a prophylactic TV-ICD with a single right ventricular lead, 49 patients, or a S-ICD, 21 patients. Follow-Ups (FU) were performed bi-annually. Results: The TV-ICD patients were significantly older. This group had more patients with a history of atrial arrhythmias and more were prescribed anti-arrhythmic medication compared with the S-ICD group. There were no significant differences for other baseline characteristics. The median and interquartile range of FU durations were 55.2 (57.6-69.3) months. During FU, patients with a TV-ICD system experienced significantly more device associated infections (n = 8, 16.3% vs. n = 0; p < 0.05), device-associated complications (n = 13, 26.5% vs. n = 1, 4.8%; p < 0.05) and device associated hospitalizations (n = 10, 20.4% vs. n = 1, 4.8%; p < 0.05). Conclusion: In this long-term FU of patients with stage 4 CKD and an indication for a prophylactic ICD, the S-ICD was associated with significantly fewer device associated infections, complications and hospitalizations compared with TV-ICDs.

Acute coronary occlusion with vs. without ST-elevation: impact on procedural outcomes and long-term all-cause mortality.

BACKGROUND: Acute total occlusion (ATO) is diagnosed in a substantial proportion of patients with Non-ST-elevation myocardial infarction (NSTEMI). We compared procedural outcomes and long- term mortality in patients with ST-elevation myocardial infarction (STEMI) with NSTEMI with vs. without ATO. METHODS: We included patients with acute myocardial infarction undergoing invasive coronary angiography between 2004 and 2019 at our center. ATO was defined as TIMI 0-1 flow in the infarct-related artery or TIMI 2-3 flow with highly elevated peak troponin (>100-folds the upper reference limit). Association between presentation and long-term mortality was evaluated using multivariable adjusted Cox regression analysis. RESULTS: From 2269 acute myocardial infarction patients (mean age 66 ± 13.2 years, 74% male), 664 patients with STEMI and 1605 patients with NSTEMI (471 [29.3%] with ATO) were included. ATO(+)NSTEMI had higher frequency of cardiogenic shock and no-reflow than ATO(-)NSTEMI with similar rates compared to STEMI patients (cardiogenic shock: 2.76 vs. 0.27 vs. 2.86%, p < 0.0001, p = 1; no-reflow: 4.03 vs. 0.18 vs. 3.17%, p < 0.0001, p = 0.54). ATO(+)NSTEMI and STEMI were associated with 60% and 55% increased incident mortality, as compared to ATO(-)NSTEMI (ATO(+)NSTEMI: 1.60[1.27-2.02], p < 0.0001, STEMI: 1.55[1.24-1.94], p < 0.0001). Likewise, left ventricular ejection fraction (48.5 ± 12.7 vs. 49.1±11 vs. 50.6 ± 11.8%, p = 0.5, p = 0.018) and global longitudinal strain (-15.2±-5.74 vs. -15.5±-4.84 vs. -16.3±-5.30%, p = 0.48, p = 0.016) in ATO(+)NSTEMI were comparable to STEMI but significantly worse than in ATO(-)NSTEMI. CONCLUSION: NSTEMI patients with ATO have unfavorable procedural outcomes, resulting in increased long-term mortality, resembling STEMI. Our findings suggest that the occlusion perspective provides more appropriate classification of acute myocardial infarction than differentiation into STEMI vs. NSTEMI.

Effectiveness of single- vs dual-coil implantable defibrillator leads: An observational analysis from the SIMPLE study.

INTRODUCTION: Dual-coil leads (DC-leads) were the standard of choice since the first nonthoracotomy implantable cardioverter/defibrillator (ICD). We used contemporary data to determine if DC-leads offer any advantage over single-coil leads (SC-leads), in terms of defibrillation efficacy, safety, clinical outcome, and complication rates. METHODS AND RESULTS: In the Shockless IMPLant Evaluation study, 2500 patients received a first implanted ICD and were randomized to implantation with or without defibrillation testing. Two thousand and four hundred seventy-five patients received SC-coil or DC-coil leads (SC-leads in 1025/2475 patients; 41.4%). In patients who underwent defibrillation testing (n = 1204), patients with both lead types were equally likely to achieve an adequate defibrillation safety margin (88.8% vs 91.2%; P = 0.16). There was no overall effect of lead type on the primary study endpoint of "failed appropriate shock or arrhythmic death" (adjusted HR 1.18; 95% CI, 0.86-1.62; P = 0.300), and on all-cause mortality (SC-leads: 5.34%/year; DC-leads: 5.48%/year; adjusted HR 1.16; 95% CI, 0.94-1.43; P = 0.168). However, among patients without prior heart failure (HF), and SC-leads had a significantly higher risk of failed appropriate shock or arrhythmic death (adjusted HR 7.02; 95% CI, 2.41-20.5). There were no differences in complication rates. CONCLUSION: In this nonrandomized evaluation, there was no overall difference in defibrillation efficacy, safety, outcome, and complication rates between SC-leads and DC-leads. However, DC-leads were associated with a reduction in the composite of failed appropriate shock or arrhythmic death in the subgroup of non-HF patients. Considering riskier future lead extraction with DC-leads, SC-leads appears to be preferable in the majority of patients.

Cardiac contractility modulation treatment in patients with symptomatic heart failure despite optimal medical therapy and cardiac resynchronization therapy (CRT).

BACKGROUND: A significant proportion of patients receiving CRT are non-responders. We evaluated the efficacy of Cardiac Contractility Modulation in subjects with reduced LVEF who, despite cardiac resynchronization therapy (CRT), continued to experience clinically significant symptoms. METHODS: This was a multi-center, open label, treatment-only, feasibility study of 17 CRT non-responders who received CCM therapy. Changes in NYHA class, ejection fraction (EF), Minnesota Living with Heart Failure Questionnaire (MLWHFQ) score, and exercise tolerance (6 minute walk test; 6MWT and peak VO2) were analyzed over 6 months. Mortality and hospitalization rates were determined. RESULTS: Patients (82% male) were 69.4 ±â€¯9.6 years of age with baseline EF = 22.8 ±â€¯6.5%. Among primary endpoints, peak VO2 increased 1.1 ±â€¯1.6 ml/kg/min (p = 0.03) and MLWHFQ improved (-16 ±â€¯16 points; p < 0.01). Mean NYHA class improved (-0.33 ±â€¯0.49; p = 0.02), 6MWT increased (52 ±â€¯60 m; p < 0.01), while EF trended up (2.9 ±â€¯5.8%; p = 0.08) at 6 months. During the 6-month follow-up period, there were 18 hospitalizations in 9 subjects and 2 patients died. CONCLUSIONS: Patients with heart failure and reduced ejection fraction who remain moderately to severely symptomatic despite use of CRT, may benefit from CCM therapy with improvement in quality of life and exercise tolerance. A larger prospective study in this population is warranted.

Cardiac contractility modulation in heart failure patients: Randomized comparison of signal delivery through one vs. two ventricular leads.

BACKGROUND: Cardiac contractility modulation (CCM) is an electrical stimulation treatment for symptomatic heart failure (HF) patients. The procedure involves implantation of two ventricular leads for delivery of CCM impulses. The purpose of this study is to compare the efficacy and safety of CCM when the signal is delivered through one vs. two ventricular leads. METHODS: This prospective blinded randomized trial enrolled 48 patients. Eligible subjects had symptoms despite optimal HF medications, left ventricular ejection fraction <40% and peakVO2≥9ml O2/kg/min. All patients received a CCM system with two ventricular leads, and were randomized to CCM active through both or just one ventricular lead; 25 patients were randomized to receive signal delivery through two leads (Group A) and 23 patients to signal delivery through one lead (Group B). The study compared the mean changes from baseline to 6 months follow-up in peakVO2, New York Heart Association (NYHA) classification, and quality of life (by MLWHFQ). RESULTS: Following 6 months, similar and significant (p<0.05) improvements from baseline in NYHA (-0.7±0.5 vs. -0.9±0.7) and MLWHFQ (-14±20 vs. -16±22) were observed in Group A and in Group B. PeakVO2 showed improvement trends in both groups (0.34±1.52 vs. 0.10±2.21ml/kg/min; p=ns). No patient died. Serious adverse event rates (20 events in 10 subjects) were not different between groups. No statistically significant difference was found in any of the study endpoints. CONCLUSIONS: The efficacy and safety of CCM in this study were similar when the signal was delivered through either one or two ventricular leads. These results support the potential use of a single ventricular lead for delivery of CCM.

Long-term survival with Cardiac Contractility Modulation in patients with NYHA II or III symptoms and normal QRS duration.

AIMS: Cardiac Contractility Modulation (CCM) is a treatment for heart failure based on electrical signals applied during the absolute refractory period. CCM improves myocardial molecular and biochemical characteristics of heart failure and improves exercise tolerance and quality of life. However, the long term impact on survival has not been described. METHODS AND RESULTS: Survival was determined retrospectively from a cohort of 68 consecutive heart failure cases with NYHA II or III symptoms and QRS duration ≤130ms, implanted with a CCM device between May 2002 and July 2013 in either Bochum or Ludenscheid, Germany. Results were compared with predicted survival (Seattle Heart Failure Model; SHFM) pre-implant for each patient. Mean follow-up was 4.5years (range 0.25-10.3years). Baseline characteristics were as follows: mean age 61years, 88% male, 68% with ischemic heart disease, 78% with an ICD, mean NYHA class 2.9±0.3, LVEF 26%±6% (range 15-40%) and mean QRS duration 106±11ms. Mortality rates (Kaplan-Meier analysis) at 1-, 2- and 5-years were lower with CCM than predicted by SHFM for the cohort (0% with CCM vs. 6.1% per SHFM, 3.5% vs. 11.8%, and 14.2% vs. 27.7%, respectively, p=0.007). CONCLUSIONS: Long-term mortality rates in heart failure patients with NYHA (II-III) and QRS≤130ms are lower when treated by CCM than predicted for the cohort. These findings warrant substantiation in a prospective study.

Implantable defibrillators with enhanced detection algorithms: detection performance and safety results from the PainFree SST study.

BACKGROUND: Implantable defibrillators (ICD) are highly effective in reducing arrhythmia-related mortality. ICD shock therapy has been shown to increase psychological distress, health care utilization, and is associated with increased mortality. The Protecta ICDs (Medtronic Inc., Minneapolis, MN, USA) have algorithms designed to reduce unnecessary and inappropriate shock therapy. METHODS AND RESULTS: The PainFree SmartShock™ Technology (PainFree SST) study is a prospective, multicenter, clinical trial with two consecutive phases, a premarket phase safety study and a postmarket phase effectiveness study. We report the results of the PainFree SST safety study. The premarket phase aimed to investigate safety in the first year postimplant, and to determine if the novel algorithms (T-wave discrimination, right ventricular lead noise discrimination and confirmation+) affect appropriate ventricular fibrillation (VF) detection. Patients (total: n = 246 [male 78%, mean age 63 year, primary prevention indication in 76%]) were implanted either with a Protecta XT dual-chamber ICD (n = 114 [46%]) or a defibrillator with cardiac resynchronization therapy (n = 132 [54%]). Appropriate VF detection was measured during VF induction at implantation when the novel algorithms were programmed ON. A two-second delay in VF detection was classified as clinically significant. No delay in VF detection was observed with all algorithms programmed ON. No unanticipated serious adverse device effects occurred during first year postimplant. CONCLUSION: The results of the premarket phase of the PainFree SST trial demonstrate the safety of the Protecta XT defibrillators. Detection of induced VF was not delayed with SmartShock™ algorithms ON.

Predictors of Recurrence After Catheter Ablation of Persistent Atrial Fibrillation.

Catheter ablation of atrial fibrillation (AF) has been increasingly used to treat symptomatic patients.Within the last years a growing interest in ablation of persistent AF forms has evolved.Factors that may influence outcome of these procedures to treat persistent AF may be patient-specific (pre-procedural),procedure-related or may involve different post-ablation followup strategies. In this review potential factors predicting recurrence of AF after ablation of persistent AF have been evaluated.In essence, data is limited mostly due to incongruent definitions of persistent AF.Left atrial dimensions, duration of continuous AF and AF cycle length may be patient-specific predictors of outcome. Intra-procedural parameters involved in recurrence prediction may be extent of ablation (effective pulmonary vein isolation appears mandatory) and termination of AF during ablation. Timing and number of cardioversion if persistent AF recurs may predict outcome, as well. Many studies have identified strators for higher recurrence rates in rather small patient groups and need to be further evaluated in larger patient collectives.

Catheter ablation of electrical storm.

Electrical storm (ES) is defined as the occurrence of ≥ three distinct episodes of ventricular arrhythmia (VA) in patients with implanted defibrillators within 24 h. Whereas conventional strategies for acute rhythm stabilization may be effective in some patients the occurrence of ES impairs survival and predicts recurrent VA. Catheter ablation in the setting of ES is complex and involves decisive strategies for individualized ablation approaches adapted to the patient's cardiac abnormalities. Success rates have been documented to be between 79 and 94% in larger studies and effective ablation improves survival and freedom from any VA. Ablation should be considered early in the treatment plan and availability may be improved by interhospital collaboration with highly experienced VA intervention centers.

Shift in the pattern of autonomic atrial innervation in subjects with persistent atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a multifactorial disease of the atria. OBJECTIVE: We studied the differences in the atrial autonomic innervation pattern in subjects with AF compared with sinus rhythm (SR). METHODS: Preparation of postmortem isolated hearts of subjects with documented persistent AF (group A) and SR (group B) included: (1) histological sectioning of predefined areas and quantification of nerve density, and (2) differentiation using immunohistochemistry in adrenergic (sympathetic, tyrosine-hydroxylase antibody), cholinergic (parasympathetic, choline-acetyltransferase antibody) and mixed (adrenergic and cholinergic staining) nerves. RESULTS: Characteristics of subjects in group A (N = 15) and group B (N = 24) did not differ. The mean overall nerve density was similar between groups (A: 0.31 ± 0.25/mm(2); B: 0.35 ± 0.25/mm(2); P = .87). Nerve density appeared higher in the region of the pulmonary vein ostia and antrum (group A: 0.38 ± 0.21/mm(2); group B: 0.32 ± 0.19/mm(2),) compared with other locations of the right and left atrium. A total of 2,224 (group A: 685; group B: 1539) nerves were differentiated using immunohistochemistry. There was a high degree of colocalization of adrenergic and cholinergic nerves (group A: 80% mixed staining, group B: 69% mixed staining). In group A hearts there was a significantly lower density of predominantly cholinergic nerves (0.025 ± 0.052/mm(2) vs. 0.058 ± 0.099/mm(2); P = .008) and a higher density of nerves containing adrenergic components (0.24 ± 0.18/mm(2) vs. 0.18 ± 0.17/mm(2), P = .046). CONCLUSION: Overall autonomic nerve density did not differ between atria with persistent AF compared with SR. On a morphological level, we detected a shift toward a lower density of cholinergic nerves and a higher density of nerves containing adrenergic components in AF subjects.

Catheter ablation of electrical storm in a collaborative hospital network.

An electrical storm (ES) is defined as multiple ventricular arrhythmia episodes leading to implantable cardioverter defibrillator interventions. Although conventional rhythm stabilization might be of help acutely, ES involves high mortality and morbidity. We evaluated the effect of catheter ablation strategies in the setting of an interhospital collaborative network on the recurrence of ventricular arrhythmia episodes and mortality in patients with ES. Consecutive patients presenting for invasive treatment of ES from December 2007 to December 2009 were included. All patients underwent catheter ablation of ventricular arrhythmia. The strategies were adapted to the individual cardiac pathologic features. The follow-up examination constituted periodic implantable cardioverter defibrillator interrogation. A total of 32 patients were included. Of the 32 patients, 29 (91%) had monomorphic ventricular tachycardia and 3 ventricular fibrillation. The mean number of implantable cardioverter defibrillator-treated episodes within 7 days before ablation was 16 ± 11. Of the 32 patients, 27 underwent ablation within 24 hours after admission, and 5 underwent acute ablation within 8 hours. In 3 patients, epicardial ablation was performed. In all but 2 patients (6%), the clinical arrhythmia was successfully ablated. During a median follow-up of 15 months, 10 patients (31%) had recurrences of sustained ventricular arrhythmia, including 2 patients (6%) with recurrent ES. Three patients (9%) died during the follow-up period. In conclusion, catheter ablation effectively suppressed ventricular arrhythmia midterm recurrences in patients presenting with ES. Catheter ablation is complex in these severely sick patients. The recurrence rate of ventricular arrhythmia appears to be 31% and the mortality rate to be 9%. Collaborative hospital networks to increase the prompt availability of ES ablation might help to optimize the ES outcome.

One-year results of transcatheter aortic valve implantation in severe symptomatic aortic valve stenosis.

Transcatheter aortic valve implantation (TAVI) is an alternative therapy for symptomatic severe aortic valve stenosis in high-risk patients with several co-morbidities. We evaluated the 1-year effects of TAVI on quality of life, exercise capacity, neurohormonal activation, and myocardial hypertrophy. From June 2008 to October 2009, consecutive patients aged ≥75 years with symptomatic severe aortic valve stenosis (area <1 cm(2)) and a logistic euroSCORE ≥15% or aged >60 years with additional specified risk factors underwent TAVI. An aortic valve prosthesis (CoreValve) was inserted in a retrograde fashion. Examinations were performed before and 30 days and 1 year after TAVI. An assessment of the quality of life (Minnesota Living with Heart Failure Questionnaire), a 6-minute walking test, measurement of B-type natriuretic peptide, and echocardiography were performed. In 51 patients (mean age 78 ± 6.6 years, mean left ventricular ejection fraction 58.4 ± 12.2%), the follow-up examinations were performed after TAVI. The 1-year follow-up visit after TAVI revealed significantly improved quality of life (baseline Minnesota Living with Heart Failure Questionnaire score 39.6 ± 19 vs 26.1 ± 18, p <0.001) and more distance covered in the 6-minute walking test (baseline 185 ± 106 vs 266 ± 118 m, p <0.001). The B-type natriuretic peptide level had decreased (baseline 642 ± 634 vs 323 ± 266 pg/ml, p <0.001), and the left ventricular mass index had decreased (156 ± 45 vs 130 ± 42 g/m(2), p <0.001). The left ventricular diameter and ejection fraction remained unchanged. In conclusion, TAVI leads to significantly reduced neurohormonal activation, regression of myocardial hypertrophy, and lasting enhancement of quality of life and exercise capacity in patients with symptomatic and severe aortic stenosis 1 year after intervention.

Termination of ventricular tachycardia by far-field stimulation in humans: a feasibility study.

BACKGROUND: Although a low-energy cardioversion (LEC) shock from an implantable cardioverter-defibrillator (ICD) can terminate ventricular tachycardia (VT), it frequently triggers ventricular fibrillation (VF) and is therefore not used in clinical practice. We tested whether a modified LEC shock with a very short duration (0.12-0.36 ms), termed "field stimulus," can terminate VT without triggering VF. METHODS: In 13 sedated patients with implanted ICDs, we attempted to induce VT and to terminate the arrhythmias by field stimuli during hospital predischarge tests. RESULTS: In eight patients, 27 VT episodes were induced and treated with a total of 46 high-voltage (25-200 V) field stimuli, which terminated 11 VT episodes (41% efficacy) and never accelerated VT into VF. VT episodes slower than 230 beats per minute (bpm) (median rate) were terminated more successfully than faster arrhythmia episodes (69% vs 15%, P < 0.01). The strength of the field stimulus had no major influence on the effectiveness. We therefore postulate that suboptimal timing of field stimuli (delivered simultaneously with a sensed event in the right ventricular apex) was the main reason for failed VT terminations. CONCLUSION: A short (0.12-0.36 ms), high-voltage (50-100 V) field stimulus delivered from the shock coil of an implanted ICD system can safely terminate VT, especially for VT rates below 230 bpm. We believe that it would be reasonable to test the effectiveness of automatic field-stimulus therapy from implanted ICDs in VT episodes up to 230 bpm that are not susceptible to termination by antitachycardia pacing.

Bleeding complications associated with glycoprotein IIb/IIIa inhibitors in patients 80 years of age and older undergoing percutaneous coronary intervention.

BACKGROUND: Treatment of symptomatic coronary artery disease with percutaneous intervention requires antithrombotic therapy. Patients with elevated thromboembolic risk benefit from therapy with glycoprotein IIb/IIIa inhibitors. The safety and effectiveness of glycoprotein IIb/IIIa inhibition have been well documented in clinical trials. Drug-induced bleeding complications in elderly patients have not been specifically addressed. METHODS: Between 2006 and 2009, a total of 439 unselected patients 80 years of age and older undergoing percutaneous intervention for symptomatic coronary artery disease were included in the present nonrandomized retrospective study. In one-half of the patients, glycoprotein IIb/IIIa inhibitors were administered peri-interventionally. The in-hospital occurrence of bleeding complications (access site, gastrointestinal and cerebral) were analyzed in the groups with and without glycoprotein IIb/IIIa inhibitors. RESULTS: The mean age of the patients was 84 years. Nearly all patients (95%) received dual antiplatelet therapy. Patients treated with glycoprotein IIb/IIIa inhibitors had more complex coronary lesions and bypass graft interventions, and a tendency toward more access site bleeding complications than patients without inhibitors, which included femoral hematomas (4.6% versus 2.3%, respectively; P not significant) and femoral pseudoaneurysms (6% versus 3.2%, respectively; P not significant). The rate of blood transfusion was equal in both groups (0.9%). Major hemorrhagic events did not occur. Vessel closure devices were used more often in patients without glycoprotein inhibition. CONCLUSIONS: An increase in minor bleedings must be expected when using glycoprotein IIb/IIIa inhibitors in patients 80 years of age and older. However, this issue must not prevent this treatment option from being offered to elderly patients. There appears to be no elevated risk for major bleeding complications. Broadened use of vascular closure devices in this specific patient population may lower the rate of access site complications.

Usefulness of a limited linear ablation of post-myocardial infarction ventricular tachycardia using a standardized approach based on sinus rhythm mapping.

The ablation of ventricular tachycardia (VT) can be achieved using anatomically guided approaches using differentiated mapping and ablation techniques. The aim of this study was to evaluate the efficacy of limited linear ablation in the VT exit region identified during sinus rhythm mapping alone. One hundred fifteen consecutive patients presenting for ablation of post-myocardial infarction VT were included. After induction of the target VT during invasive electrophysiology, left ventricular substrate mapping during sinus rhythm to identify scar and border zone on the basis of endocardial bipolar voltage was performed. The exit site of the target VT was regionalized by a simplified vector pace mapping approach and targeted using limited linear ablation within the scar border zone. Seventy-seven percent of all inducible VT was successfully ablated. In 71 patients (62%), no sustained VT was inducible at the end of ablation procedure (complete success). During a median follow-up period of 16 + or - 10 months, 89 patients (77%) had no documented sustained ventricular arrhythmia. Seven patients (2%) had recurrences of the initially ablated VT, and 16 (14%) had new-onset VT. Patients with complete success had a significantly lower number of ventricular arrhythmia reoccurrences than patients with incomplete ablation success (11% vs 37%, p = 0.002). In conclusion, postinfarct VT was effectively ablated in 97% of patients without mapping during ongoing VT using a simplified regional linear ablation approach targeting the scar border zone. Freedom from any ventricular arrhythmia was achieved in 77% of patients during midterm follow-up.

Non-invasive determination of the optimized atrioventricular delay in patients with implanted biventricular pacing devices.

BACKGROUND: Biventricular (BiV) is extensively used in the treatment of congestive heart failure but so far no recommendations for optimized programming of atrioventricular-delay (AVD) settings have been proposed. Can AVD optimization be performed using a simple formula based on non-invasive doppler-echocardiography? METHODS: 25 patients (ejection fraction 30+/-8%) received BiV ICDs. Doppler-echocardiographic evaluation of diastolic and systolic flow was performed for different AVDs (30ms to 150ms) and different stimulation sites (left ventricular (LV), right ventricular and BiV). The optimal atrioventricular delay was calculated applying a simple formula based on systolic and diastolic mechanical delays determined during doppler-echocardiography. RESULTS: The mean optimal AVD was calculated to be 112+/-29ms (50 to 180ms) for BiV, 95+/-30ms (65 to 150ms) for LV and 75+/-28ms (40 to 125ms) for right ventricular pacing with wide interindividual variations. Compared to suboptimal AVDs diastolic optimization improved preejection and ejection intervals independent to pacing site. Optimization of the AVD significantly increased ejection time during BiV pacing (279ms versus 266ms; p<0.05). Compared to LV or right ventricular pacing BiV pacing produced the shortest mean pre-ejection and longest ejection intervals as parameters of improved systolic ventricular contractile synchrony. Diastolic filling times were longest during BiV pacing compared to LV or RV pacing. CONCLUSIONS: Individual programming of BiV pacing devices increases hemodynamic benefit when implementing the inter-individually widely varying electromechanical delays. Optimization applying a simple formula not only improves diastolic ventricular filling but also increases systolic functional parameters.

Long-term sinus rhythm stability after intraoperative ablation of permanent atrial fibrillation.

INTRODUCTION: Short- and medium-term sinus rhythm (SR) rates after intraoperative radiofrequency ablation to treat permanent atrial fibrillation (AF) are well documented. Is rhythm success stable during a long-term follow-up? METHODS AND RESULTS: A total of 130 patients who had undergone intraoperative radiofrequency cooled-tip endocardial ablation (SICTRA) of permanent AF (mean AF duration 6+/-5 years) concomitant to open heart surgery more than 3 years ago were followed up using electrocardiogram (ECG), Holter-ECG, and echocardiography and compared with 12-month follow-up data. In 55% of patients, only the left atrium and in 45%, both atria were treated using SICTRA. Mitral valve replacement was performed in 21, mitral valve reconstruction in 25, aortic valve replacement in 13, CABG procedures in 51 (including 11 patients with additional mitral valve surgery), and complex procedures in 20 patients. Sixty-nine percent of patients (90/130) were in stable SR after a median period of 48 months, whereas 28% (36/130) were in AF and 3% (4/130) were in atrial flutter. In between the 12-month follow-up and the long-term follow-up, seven patients converted to AF after having documented SR, two patients converted to typical right atrial flutter after being in SR, and two patients from AF to left atrial macroreentry. After left and biatrial SICTRA, SR rates were comparable (73% vs 66%, P = 0.45). Echocardiography revealed 73% of patients in SR to have effective left atrial contraction. CONCLUSIONS: SICTRA restores long-term stable SR in 69% of all patients. Nine percent of patients reconverted back to atrial arrhythmia after having documented SR at 12 months.

A comparison of chronaxies for ventricular fibrillation induction, defibrillation, and cardiac stimulation: unexpected findings and their implications.

INTRODUCTION: A low-energy (

Patient-tailored implantable cardioverter defibrillator testing using the upper limit of vulnerability: the TULIP protocol.

AIMS: We evaluated the feasibility of the TULIP (Threshold test using Upper Limit during ImPlantation) protocol, which was designed to provide a confirmed, low defibrillation energy value during implantable cardioverter defibrillator (ICD) implantation with only two induced ventricular fibrillation (VF) episodes. METHODS AND RESULTS: Ninety-eight patients (62 +/- 12 years, 86 male) from 13 clinical centres underwent an active can ICD implantation. A single coupling interval derived from electrocardiogram lead II during ventricular pacing was used for VF induction shocks at 13, 11, 9, and 6 J in a step-down manner until the upper limit of VF induction (ULVI) was determined. If ULVI >or=9 J, a defibrillation energy of ULVI + 4 J was tested. For ULVI <9 J, the defibrillation test energy was 9 J. In 79/98 patients (80.6%), two induced VF episodes were sufficient to obtain confirmed defibrillation energy of 11.1 +/- 3.3 J. The mean strength of the successful VF induction shock was 6.8 +/- 4.3 J, the coupling interval was 303 +/- 35 ms, and the number of delivered induction shocks until the first VF induction was 3.9 +/- 1.6. CONCLUSION: TULIP is a safe and simple device testing procedure allowing the determination of confirmed, low defibrillation energy in most patients with two VF episodes induced at a single coupling interval.

Randomized, double blind study of non-excitatory, cardiac contractility modulation electrical impulses for symptomatic heart failure.

AIMS: We performed a randomized, double blind, crossover study of cardiac contractility modulation (CCM) signals in heart failure patients. METHODS AND RESULTS: One hundred and sixty-four subjects with ejection fraction (EF) < 35% and NYHA Class II (24%) or III (76%) symptoms received a CCM pulse generator. Patients were randomly assigned to Group 1 (n = 80, CCM treatment 3 months, sham treatment second 3 months) or Group 2 (n = 84, sham treatment 3 months, CCM treatment second 3 months). The co-primary endpoints were changes in peak oxygen consumption (VO2,peak) and Minnesota Living with Heart Failure Questionnaire (MLWHFQ). Baseline EF (29.3 +/- 6.7% vs. 29.8 +/- 7.8%), VO2,peak (14.1 +/- 3.0 vs. 13.6 +/- 2.7 mL/kg/min), and MLWHFQ (38.9 +/- 27.4 vs. 36.5 +/- 27.1) were similar between the groups. VO2,peak increased similarly in both groups during the first 3 months (0.40 +/- 3.0 vs. 0.37 +/- 3.3 mL/kg/min, placebo effect). During the next 3 months, VO2,peak decreased in the group switched to sham (-0.86 +/- 3.06 mL/kg/min) and increased in patients switched to active treatment (0.16 +/- 2.50 mL/kg/min). MLWHFQ trended better with treatment (-12.06 +/- 15.33 vs. -9.70 +/- 16.71) during the first 3 months, increased during the second 3 months in the group switched to sham (+4.70 +/- 16.57), and decreased further in patients switched to active treatment (-0.70 +/- 15.13). A comparison of values at the end of active treatment periods vs. end of sham treatment periods indicates statistically significantly improved VO2,peak and MLWHFQ (P = 0.03 for each parameter). CONCLUSION: In patients with heart failure and left ventricular dysfunction, CCM signals appear safe; exercise tolerance and quality of life (MLWHFQ) were significantly better while patients were receiving active treatment with CCM for a 3-month period.