A cross-sectional nationwide survey of guideline based syncope units in the Netherlands: the SU-19 score-a novel validation for best practices.

AIMS: We aimed to identify all syncope units (SUs) in the Netherlands and assess the extent to which these SUs fulfil the essential requirements outlined by the consensus statements of the European Heart Rhythm Association and the European Society of Cardiology syncope guidelines. For this, we developed the SU-19 score, a novel guideline based validation tool for best practice. METHODS AND RESULTS: All outpatient clinics of cardiology, neurology, and internal medicine in the Netherlands were screened for presence of any form of structured specialized syncope care. If present, these were included as SUs and requested to complete a questionnaire regarding syncope care. We assessed all SUs using the SU-19 score regarding structure (3 points), available tests (12 points), and initial evaluation (4 points). Twenty SUs were identified in the Netherlands, both academic (5/20) and non-academic hospitals (15/20), 17/20 reported multidisciplinary involvement during initial evaluation. In 19/20, neurology, cardiology, or both were responsible for the syncope management. Non-physicians were involved performing the head-up tilt test (44%) and initial evaluation (40%). The mean SU-19 score was 18.0 ± 1.1, 45% achieved the maximum score of 19 points. Variations were observed in protocols for active standing test, carotid sinus massage, and head-up tilt test. CONCLUSION: There is a network of 20 SUs in the Netherlands. Forty-five per cent fully met the SU-19 score (mean 18.0 ± 1.1). Slight variety existed in protocols for autonomic function tests. Neurology and cardiology were mostly involved in syncope management. Non-physicians play an important role in syncope care.

MR feature tracking in patients with MRI-conditional pacing systems: The impact of pacing.

PURPOSE: To develop feature tracking (FT) software to perform strain analysis on conventional (nontagged) cardiac magnetic resonance imaging (MRI) function images. With the advent of MRI-conditional pacemaker systems, effects of cardiac pacing on myocardial strain can be studied using MR. In this study the impact of pacing on left ventricular (LV) strain was investigated using MR-FT in patients with an MRI-conditional cardiac implantable electronic device (CIED). MATERIALS AND METHODS: FT was performed on 32 1.5T MR studies (16 patients with an MRI-conditional CIED and 16 control patients with normal scans). Short- and long-axis steady state free precession (SSFP) cines were used for the FT analysis. Strain was assessed using CVI(42) software (Circle Cardiovascular Imaging, Alberta, Canada). In addition, the intra- and interobserver variability was determined using the intraclass correlation coefficient. RESULTS: Of the 16 patients with an MRI-conditional CIED, five patients were paced during the MRI exam. Despite the occasional presence of susceptibility artifacts induced by the CIED, radial, circumferential, and longitudinal strain parameters could be derived for all patients. Peak radial strain and peak circumferential strain were reduced during pacing when compared to the control group; for radial strain: 20.1 ± 4.7% vs. 33.1 ± 6.9%, P < 0.001, and for circumferential strain -7.5 ± 3.5% vs. -14.9 ± 3.2%, P < 0.05. Peak strain parameters were reproducible on an intra- and interobserver level. CONCLUSION: MR-FT is feasible in patients with an MRI-conditional CIED and can be used to quantify regional wall motion. J. MAGN. RESON. IMAGING 2016;44:964-971.

New-generation atrial antitachycardia pacing (Reactive ATP) is associated with reduced risk of persistent or permanent atrial fibrillation in patients with bradycardia: Results from the MINERVA randomized multicenter international trial.

BACKGROUND: Atrial fibrillation (AF) is a frequent comorbidity in patients with pacemaker and is a recognized cause of mortality, morbidity, and quality-of-life impairment. The international MINimizE Right Ventricular pacing to prevent Atrial fibrillation and heart failure trial established that atrial preventive pacing and atrial antitachycardia pacing (DDDRP) in combination with managed ventricular pacing (MVP) reduce permanent AF occurrence in comparison with standard dual-chamber pacing (DDDR). OBJECTIVE: We aimed to determine the role of new-generation atrial antitachycardia pacing (Reactive ATP) in preventing AF disease progression. METHODS: Patients with dual-chamber pacemaker and with previous atrial tachyarrhythmias were randomly assigned to DDDR (n = 385 (33%)), MVP (n = 398 (34%)), or DDDRP+MVP (n = 383 (33%)) group. The incidence of permanent AF, as defined by the study investigator, or persistent AF, defined as ≥7 consecutive days with AF, was estimated using the Kaplan-Meier method, while its association with patients' characteristics was evaluated via multivariable Cox regression. RESULTS: At 2 years, the incidence of permanent or persistent AF was 26% (95% confidence interval [CI] 22%-31%) in the DDDR group, 25% (95% CI 21%-30%) in the MVP group, and 15% (95% CI 12%-20%) in the DDDRP+MVP group (P < .001 vs. DDDR; P = .002 vs. MVP). Generalized estimating equation-adjusted Reactive ATP efficacy was 44.4% (95% CI 41.3%-47.6%). Multivariate modeling identified high Reactive ATP efficacy (>44.4%) as a significant predictor of reduced permanent or persistent AF risk (hazard ratio 0.32; 95% CI 0.13-0.781; P = .012) and episodes' characteristics, such as long atrial arrhythmia cycle length, regularity, and the number of rhythm transitions, as predictors of high ATP efficacy. CONCLUSION: In patients with bradycardia, DDDRP+MVP delays AF disease progression, with Reactive ATP efficacy being an independent predictor of permanent or persistent AF reduction.

Mid-term follow up of thromboembolic complications in left ventricular endocardial cardiac resynchronization therapy.

BACKGROUND: Endocardial left ventricular (LV) pacing for cardiac resynchronization therapy (CRT) has been proposed as an alternative to traditional LV transvenous epicardial pacing with equal or superior cardiac performance. The risks of cerebral thromboembolism and possible interference with mitral valve function moderate its clinical application. OBJECTIVE: The purpose of this study was to investigate cerebral thromboembolic complications after LV endocardial lead placement. Mitral regurgitation (MR) was the secondary outcome measure. METHODS: CRT candidates with a failed coronary sinus approach or nonresponders to conventional CRT underwent endocardial LV lead implantation (45 atrial transseptal, 6 transapical). Coumarin was prescribed with a targeted international normalized ratio between 3.5 and 4.5. Patient records were checked and general practitioners were contacted regarding cerebral thromboembolic complications. MR was evaluated by echocardiography at baseline and after 6 months. RESULTS: In 7 patients, 6 ischemic strokes and 2 transient ischemic attacks occurred, corresponding to 6.1 thromboembolic events per 100 patient-years (95% confidence interval 3.4-15.8). One patient refused hospital admission; all other patients had a subtherapeutic anticoagulation level at the time of the event. No major bleeding complications occurred. There was no change in the grade of MR (grade 2, P = .727) after 6 months. CONCLUSION: Endocardial LV lead placement in patients with advanced heart failure is associated with thromboembolic risk. However, all but 1 patient had a subtherapeutic level of anticoagulation. Endocardial LV lead placement is not associated with aggravation of MR.

Increase of ventricular output inducing ventricular afterpotential sensing and ventricular safety pacing in a biventricular implanted cardioverter defibrillator.

Programming maximum right ventricular output in a patient with a biventricular implanted cardioverter defibrillator resulted in ventricular oversensing and ventricular safety pacing in the same cardiac cycle.

Toward understanding response to cardiac resynchronization therapy: left ventricular dyssynchrony is only one of multiple mechanisms.

AIM: To date, most published echocardiographic methods have assessed left ventricular (LV) dyssynchrony (DYS) alone as a predictor for response to cardiac resynchronization therapy (CRT). We hypothesized that the response is instead dictated by multiple correctable factors. METHODS AND RESULTS: A total of 161 patients (66 +/- 10 years, EF 24 +/- 6%, QRS > 120 ms) were investigated pre- and post-CRT (median of 6 months). Reduction in NYHA Class >/=1 or LV reverse remodelling (end-systolic volume reduction >/= 10%) defined response. Four different pathological mechanisms were identified. Group1: LVDYS characterized by a pre-ejection septal flash (SF) (87 patients, 54%). Elimination of SF (77 of 87 patients) resulted in reverse remodelling in 100%. Group 2: short-AV delay (21 patients, 13%) resolution (19 of 21 patients) resulted in reverse remodelling in 16 of 19. Group 3: long-AV delay (16 patients, 10%) resolution (14 of 16 patients) resulted in NYHA Class reduction >/=1 in 11 with reverse remodelling in five patients. Group 4: exaggerated LV-RV interaction (15 patients, 9%) reduced post-CRT. All responded clinically with fall in pulmonary artery pressure (P = 0.003) but did not volume respond. Group 5: patients with none of the above correctable mechanisms (22 patients, 14%). None responded to CRT. CONCLUSION: CRT response is dictated by correction of multiple independent mechanisms of which LVDYS is only one. Long-axis DYS measurements alone failed to detect 40% of responders.

Right ventricular outflow and apical pacing comparably worsen the echocardiographic normal left ventricle.

AIMS: A depressed left ventricular function (LVF) is sometimes observed during right ventricular apical (RVA) pacing, but any prediction of this adverse effect cannot be done. Right ventricular outflow tract (RVOT) pacing is thought to deteriorate LVF less frequently because of a more normal LV activation pattern. This study aims to assess the acute effects of RVA and RVOT pacing on LVF in order to determine the contribution of echocardiography for the selection of the optimum pacing site during pacemaker (PM) implantation. METHODS AND RESULTS: Fourteen patients with a DDD-pacemaker (7 RVA, 7 RVOT) and normal LVF without other cardiac abnormalities were studied. PM dependency, because of sick sinus syndrome with normal atrioventricular and intraventricular conduction, was absent in all, allowing acute programming changes. Wall motion score (WMS), longitudinal LV strain, and tissue Doppler imaging for electromechanical delay were assessed with echocardiography during AAI pacing constituting baseline and DDD pacing. The WMS was normal at baseline (AAI pacing) in all patients and LV dyssynchrony was absent. Acute RVA and RVOT pacing deteriorated WMS, electromechanical delay, and longitudinal LV strain, but no difference of the deterioration between both pacing sites was present and dyssynchrony did not emerge. CONCLUSION: Both acute RVA and RVOT pacing negatively affect WMS, longitudinal LV strain, and mechanical activation times, without clear differences between both pacing sites. Thus echocardiographic techniques do not facilitate the selection between RVOT and RVA pacing to exclude adverse effects on LVF during PM implantation in patients with a normal LVF.

Transseptal endocardial left ventricular pacing: an alternative technique for coronary sinus lead placement in cardiac resynchronization therapy.

BACKGROUND: Coronary sinus (CS) lead placement for transvenous left ventricular (LV) pacing in cardiac resynchronization therapy (CRT) has a failure rate at implant and short-term follow-up between 10% and 15%. OBJECTIVE: The purpose of this study was to assess the feasibility of transseptal endocardial LV pacing in patients in whom transvenous CS lead placement had failed. METHODS: An atrial transseptal LV lead placement was attempted in 10 patients (six females, age 69.4 +/- 9.6 years), in whom CS lead placement for CRT had failed. After transseptal puncture and septal dilatation from the femoral route, the left atrium was cannulated with a combination of catheters and guide wires from the left or right subclavian vein. After advancement of this guide catheter into the LV, a standard bipolar screw-in lead could be implanted in the posterolateral wall. All patients were maintained on anticoagulant therapy with warfarin after implant. RESULTS: An LV lead could be successfully implanted in nine of the 10 patients. The stimulation threshold was 0.78 +/- 0.24 V, and the R-wave amplitude was 14.2 +/- 9.7 mV. At 2 months' follow-up, the stimulation threshold was 1.48 +/- 0.35 V with a 0.064 +/- 0.027 ms pulse width. There was no phrenic nerve stimulation observed in any of the patients. There were no thromboembolic complications at follow-up. CONCLUSIONS: LV transseptal endocardial lead implantation from the pectoral area is a feasible approach in patients with a failed CS approach and in whom epicardial surgical lead placement is not an option. Longer follow-up is warranted to determine the risk of thromboembolic complications.

A technique of lead insertion for low atrial septal pacing.

BACKGROUND: Pacing in the low right atrial septum (LAS) appears superior to right atrial appendage or free wall stimulation for the prevention of paroxysmal atrial fibrillation. However, insertion of active fixation lead in the low right atrial septal position is difficult and time consuming, inhibiting application of this pacing method in daily practice. METHODS: The technique of handling and positioning of a new "over the wire" lead system is presented with emphasis on electrocardiographic P wave pattern and fluoroscopic landmarks. RESULTS: The initial results demonstrate an acute implantation and short-term success of LAS pacing of >90% in the first 100 patients without major complications. Pacing thresholds at 3 and 6 months were fully comparable with that of the conventional atrial pacing, whereas impedance and atrial sensing signals were significantly higher at 3 and 6 months follow-up. CONCLUSION: These favorable initial results justify recommanding chronic LAS pacing with the active fixation atrial lead and providinge guidelines and fluoroscopic landmarks for the implantation. Insertion of the atrial active fixation lead positioned with the Locatortrade mark tool strongly supports the implantation procedure.

Electrocardiographic characteristics in low atrial septum pacing.

AIM: The aim of the study was to compare P-wave morphology and duration in pacing from the low right atrial septal wall and the high right atrial appendage (RAA). METHODS: The electrocardiogram (ECG) of 50 patients with low atrial septum (LAS) pacing and that of 50 patients with RAA pacing were compared with their electrocardiogram during sinus rhythm. RESULTS: In the frontal plane, patients with LAS pacing showed a superior P-wave axis between -60 degrees and -90 degrees . In all patients with RAA pacing, a P-wave axis between 0 degrees and +90 degrees was observed as in sinus rhythm. In the horizontal plane, all patients with LAS pacing had an anterior P-wave axis between +90 degrees and +210 degrees , whereas all patients with RAA pacing had a posterior P-wave axis between -30 degrees and -90 degrees . The terminal part of biphasic P waves in lead V 1 in LAS pacing was always positive, a pattern that was never observed in P waves of sinus origin or in RAA pacing. P-wave duration was longer with RAA pacing compared with LAS pacing (115 +/- 19 vs 80 +/- 14 milliseconds [ P < .01]). CONCLUSION: The total atrial activation time during LAS pacing is shorter than that during RAA pacing. The electrical atrial activation sequences in LAS pacing and RAA pacing are significantly different. The morphology of biphasic P waves in lead V1 during LAS pacing suggests that the initial part of activation occurs in the left atrium and the terminal part in the right atrium.

Electrical characteristics of low atrial septum pacing compared with right atrial appendage pacing.

AIM: The study was designed to compare the electrical characteristics of atrial leads placed in the low atrial septum (LAS) with those placed in the right atrial appendage (RAA) associated with dual chamber pacing. METHODS: In 86 patients an active-fixation (St. Jude Medical's Tendril DX model 1388T) atrial lead was positioned in RAA and in 86 patients the same model atrial lead was placed in the LAS. Pacing thresholds, sensing thresholds, impedances and the Far Field paced R-Wave (FFRW) amplitude and timing were compared at 6 weeks and at 3 and 6 months. RESULTS: The pacing threshold did not differ between groups. Sensed voltage of the P-wave was higher in the LAS compared with the RAA at 3 and 6 months (P=0.004). Impedance was higher in the LAS at 6 weeks and 3 months (P=0.002) but this difference was no longer significant at 6 months (P=0.05). The atrial sensed FFRW voltage was significantly higher in the LAS position compared with the RAA at 3 and 6 months follow-up (P=0.0002). FFRW voltage>1 mV was seen in 87% of the RAA pacing group and in 94% of the LAS pacing group (P=ns). The time between the ventricular pacing stimulus and the sensed FFRW in the atrium, (V spike-FFRW) in RAA was longer than in LAS at all follow-up measurements (P=0.006). CONCLUSIONS: The electrical characteristics of LAS pacing makes this alternative position in the atrium safe and feasible. Though statistical differences were found in P-wave sensing (LAS higher voltage than in the RAA) and FFRW sensing was higher in the LAS compared with the RAA this did not interfere with the clinical applicability of the LAS as alternative pacing site.