The effect of leadless pacing on LV and RV systolic function is not inferior to conventional RV pacing

Introduction

Leadless right ventricular (RV) pacing has been recently proposed as alternative to conventional pacemakers (PM's). While RV pacing with a conventional PM is known to cause deterioration of left ventricular (LV) and RV systolic function over time, the effects of leadless PM's are currently under-explored. In this prospective and randomized study, we hypothesized that the effect of leadless RV pacing over time on both LV and RV systolic function is not inferior to conventional RV pacing.

Methods

Fifty-one age-matched patients with a guideline indication for a PM were prospectively recruited and randomized to undergo implantation of either (i) a leadless PM, or (ii) a conventional PM. Patients underwent echocardiography prior to (BL), and at 6 and 12 months (M6 & M12) after PM implantation. All imaging after implantation was performed during active pacing. Analysis included LV ejection fraction (LVEF), LV global longitudinal strain (GLS), and RV free wall (FW) strain.

Results

Twenty-seven patients were implanted with a leadless PM, while twenty-four received a conventional PM. Median age was 82 (80–87) years. At BL, average LVEF and LV GLS were normal and similar in both groups. At M12, both LVEF (−12%) and LV GLS strain (−5%) decreased significantly in both study groups (ANOVA p<0.0001, see Figure 1). RV FW strain decreased only significantly in patients with conventional PM (−4%; ANOVA p=0.031, see Figure 1; post-hoc test BL vs. M12: p=0.029). None of the tested variables, at none of the time points, showed significant difference between the leadless and conventional PM study groups (all p>0.05). Median pacing percentage was 68.2% and similar in both study groups (at all time-points p>0.05).

Conclusions

Both patients with leadless and conventional PM's demonstrate a decrease in LV and RV systolic function, 12 months after implantation. While LV function decrease was similar between both groups, RV function decrease was most prominent in patients treated with conventional PM's. Our data suggest that leadless pacing is not inferior to conventional pacing with regard to the effect on cardiac function.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Research Foundation Flanders (FWO) post-doc grant

Sequential left ventricular electro-mechanical changes in left bundle branch pacing vs right ventricular pacing a two-center study

Background

Left bundle branch pacing (LBBP) has been proved to maintain electrical synchrony better than RVP during mid to long-term follow-up, but little is known about the left ventricular (LV) mechanical changes over time. This study investigates if LBBP causes less sequential electro-mechanical alterations in LV that develop over time, compared with both conventional (CRVP) and leadless (LRVP) RVP.

Methods

Sixty-five patients with pacing indication for bradycardia were prospectively enrolled: Twenty-two were treated with LBBP, 23 with CRVP and 20 with LRVP. QRS duration (QRSd) was measured at baseline and during follow-up. All patients underwent echocardiography at baseline, one week after implantation and at one-year follow-up. LV volumes, ejection fraction (EF) and global longitudinal strain (GLS) were measured. Septal flash (SF), apical rocking and septal longitudinal strain patterns were assessed visually by two experienced readers.

Results

All the patients presented with normal strain pattern and no signs of SF or apical rocking at baseline. 100% of CRVP and 95% of LRVP patients had stage1 or 2 septal deformation patterns at week 1, and the majority (72.3% CRVP and 83.3% LRVP) progressed to stage≥2 at 12 months. On the contrary, over 2/3 of LBBP patients preserved normal strain patterns at week 1, and less than 1/3 had stage-1 pattern, 2 out of whom progressed to stage-2 during follow-up (Figure 1). At week 1 and 12 months, all RVP patients had SF, and most of them also exhibited apical rocking (87%-94.4% in CRVP and 80%-94.4% in LRVP). However, much less septal flash and apical rocking was induced in LBBP patients at week 1 and last follow-up (27.3%-37.5% and 22.7%-25%, P<0.001 vs RVP). Baseline QRSd were similar among three groups. At week 1, the paced QRSd increased least in LBBP compared to CRVP and LRVP and remained as such at 12 months. During one year follow-up, LVEF and LV GLS decreased more in CRVP group compared to LBBP (both P<0.05) (Figure 2).

Conclusion

LBBP causes less sequential changes in LV deformation patterns, septal flash and apical rocking, compared to CRVP and LRVP. With this, LBBP appears to preserve LV function better than RVP. CRVP and LRVP did not differ in electro-mechanical changes or LV remodeling.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Research Foundation Flanders (FWO) project grant

Left bundle branch pacing is superior in preserving ventricular mechanical synchrony and cardiac function than right ventricular pacing: a two-center experience

Background

Left bundle branch pacing (LBBP) has emerged as a novel pacing modality. Although it has been proved to maintain electrical synchrony better than right ventricular pacing (RVP), little is known about the impact on mechanical synchrony. This study investigates if LBBP preserves mechanical synchrony and cardiac function better compared to conventional (CRVP) and leadless (LRVP) RVP.

Methods

Sixty-five patients with pacing indication for bradycardia were prospectively enrolled: Twenty-two were treated with LBBP, 23 with CRVP and 20 with LRVP. All patients underwent echocardiography before and after implantation and at one-year follow-up. Left ventricular (LV) volumes, ejection fraction (EF) and global longitudinal strain (GLS) were measured. Regional septal (SW) and lateral wall work (LW) was calculated as the average from the respective basal and mid-ventricular segments in the apical four-chamber and three-chamber view. The lateral-septal work difference (LSWD) was used as a measure of mechanical dyssynchrony.

Results

At baseline, the QRS duration and LSWD were similar in all three groups. During follow-up, the QRS duration increased least in LBBP compared to CRVP and LRVP (+28.1±18.3ms vs +58.2±31.4 and 47.1±26.1ms, both P<0.01). SW was markedly decreased in CRVP and LRVP while LW work remained unchanged, resulting in a large LSWD compared to LBBP (1308.4±732.9 mmHg*% and 1451.3±606.1 mmHg*% vs. 286.0±479.9mmHg*%, both P<0.001). During one year follow-up, LVEF and LV GLS decreased more in CRVP compared to LBBP (both P<0.05).

Conclusion

LBBP causes less LV dyssynchrony than CRVP and LRVP as it preserves a more physiologic conduction pattern. With this, LBBP appears to preserve LV function better than CRVP. CRVP and LRVP did not differ in mechanical dyssynchrony or LV remodelling.

Funding Acknowledgement

Type of funding sources: None.

Left bundle branch pacing preserves ventricular mechanical synchrony better than right ventricular pacing-a two-center study

Funding Acknowledgements

Type of funding sources: None.

Background

Left bundle branch pacing (LBBP) has emerged as a novel pacing method. We sought to evaluate left ventricular (LV) mechanical synchrony under permanent LBBP and compare it with conventional and leadless right ventricular pacing (CRVP, LRVP).

Methods

Sixty-four patients with pacing indication for bradycardia were prospectively enrolled. Twenty-two patients received LBBP in the basal ventricular septum. Twenty-three patients received CRVP and 19 LRVP. All patients underwent echocardiography before and after device implantation. Myocardial work was estimated by pressure-strain analysis. Regional work in the septum (SEP) and lateral wall (LW) was calculated as the average from the respective basal and mid-ventricular segments in the apical four-chamber and three-chamber view. The absolute difference between work in LW and SEP (LW-S-work difference) was used as a measure of asymmetry in workload.

Results

Baseline characteristics were similar among the three groups. The electrocardiogram during LBBP showed a right bundle branch block pattern; during CRVP and LRVP a left bundle branch block pattern. The paced QRS duration was 114.27±9.9 ms in the LBBP group, significantly shorter than that in the CRVP and LRVP groups (153.9±25.26 ms and 159.1±13.99ms, respectively, both p<0.001). The SEP work decreased in all groups during ventricular pacing (all P<0.05), while the LW work remained similar. The paced LW-S work difference and work difference change between pacing on and off were more significant in the CRVP (1012.9±566.0mmHg*%) and LRVP group (1066.1±472.6mmHg*%) than the LBBP group (260.5±239.8mmHg*%, both P<0.001). In addition, LW-S work difference during ventricular pacing and work difference change between pacing and baseline were comparable in CRVP and LRVP group.

Conclusion

LBBP causes less LV dyssynchrony than CRVP and LRVP as it preserves a more physiologic conduction pattern. CRVP and LRVP did not differ in this respect. Further studies need to prove that LBBP has advantages over RVP with regards to preservation of LV synchrony and contractility.

Real-world experience on the safety and effectiveness of Micra TPS in patients with pre-existing in situ CIEDs

Background

The Micra pre-market study showed that the Micra transcatheter pacing system could be safely implanted in patients with pacing indications. Patients with pre-existing cardiac implantable electronic devices (CIED) were excluded from this clinical trial; however, this group of patients might benefit from a leadless pacemaker especially when a lead fails or after incidence of system-related infections.

Objective

To determine the outcome of patients with a pre-existing CIED or lead that remains in situ at the time of Micra implant attempt.

Methods

Patients who had a pre-existing CIED and/or lead at the time of Micra implantation attempt were identified from the Micra Post-Approval Registry and Micra Acute Performance studies. Baseline characteristics were summarized, and a Fine-Gray competing risk model was used to compare risk for major complication through 24 months for patients with and without a pre-existing CIED.

Results

Of the 2323 patients included in the analysis, 111 patients had a pre-existing CIED or lead at the time of Micra implantation attempt that remained in situ. Types of pre-existing devices included 81 pacemakers (45 single chamber, 32 dual chamber, 4 of unknown type), 10 ICDs (2 single chamber, 2 dual chamber, 6 unknown type), 10 CRT devices (6 CRT-P, 4 CRT-D), 3 generators of unknown type, and 7 patients had only leads remaining. Patients with pre-existing devices were younger and less likely to have a pacing indication of bradyarrhythmia with atrial fibrillation compared to patients without pre-existing devices (p<0.001 for both). Patients with prior devices were more likely to have a condition precluding implant of a transvenous pacemaker (67.6% vs. 21.3%, p<0.001). The presence of a pre-existing CIED did not impact the outcome of the Micra TPS implant procedure: implant success was >99% for both cohorts. Mean follow-up duration was 21.2±14.3 months (range 0–56) for pre-existing devices patients and 23.3±15.8 months (range 0–62) for other patients. The rate of major complications through 24 months was 1.8% for patients with and 3.8% for patients without prior devices (p=0.36). There were no major complications related to device malfunction or device-device interaction. There were 6 system revisions in 4 patients with preexisting devices and 52 revisions in 51 patients without preexisting devices. Pacing thresholds for patients with and without prior devices were similar at implant (0.72 and 0.63, respectively; p=0.31) and remained stable through 12 months.

Conclusion

Micra can be safely and successfully implanted in patients with a pre-existing CIED remaining in situ. It should be considered a treatment option for patients in whom CIED extraction may be deemed high risk.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Medtronic, Inc. Risk of major complications

Leadless pacemaker implant in patients requiring CIED extraction: outcomes based upon timing of extraction

Background

Previous results from global Micra Transcatheter Pacemaker clinical trials have demonstrated leadless pacing as a safe and attractive option for patients with prior cardiac implantable electronic device (CIED) infection and extraction. Whether outcomes differ based upon the timing of prior device extraction has not been studied.

Purpose

To describe characteristics and outcomes of patients undergoing CIED extraction during or prior to Micra implantation.

Methods

Patients who underwent CIED explant and Micra implantation were identified from the Micra Post-Approval Registry and Micra Acute Performance studies. Baseline characteristics were summarized. A Fine-Gray competing risk model was used to compare risk for major complication through 24 months.

Results

Of the 2739 patients included in the studies, 99 (3.6%) patients had CIED extraction the day of Micra implantation (same day) and 127 (4.6%) patients had CIED extraction within 30 days prior to Micra implantation (prior). Although infection was the primary reason for CIED extraction in both groups, a larger proportion of prior patients underwent extraction for this reason (87.4% vs. 42.4%). In contrast, more same day patients underwent CIED extraction for physician/elective reasons (16.2% vs. 3.1%). Same day patients prior device history included pacemaker (42 dual chamber and 30 single chamber), ICD (1 single chamber and 4 dual chamber), CRT (7 CRT-ICD and 13 CRT-P) while prior patients device history included pacemaker (29 single chamber, 80 dual chamber), ICD (3 dual chamber), CRT (5 CRT-ICD and 7 CRT-P). Overall, patients with extraction were aged 72.8±14.3 years, predominantly male (65.9%), and medical history was similar between groups, with the exception to CHF, which was higher for the same day group (18.2% vs 6.3%, P=0.021). The implant success rate was 98.0% for same day patients and 100% for prior patients. Median procedure duration was not significantly different between the groups (26.0 minutes and 25.0 minutes for same day and prior, respectively). Average follow-up duration was 16.5±13.8 months (range 0–53.4) for same day patients and 18.2±15.2 months (range 0–58.3) for subsequent patients. The rate of acute major complications (<30 days) was 5.1% for same day and 3.2% for prior. Through 24 months, the rate of major complications was 6.4% for same day and 6.0% for prior (HR: 1.19, 95% CI: 0.40 – 3.50, P=0.76, Figure). The rate of major complications related to infection was low and did not differ by group (1.01% vs. 1.57%, P=1.00)

Conclusion

The Micra leadless pacemaker was implanted with a high success rate following CIED extraction. Outcomes following CIED extraction appear similar, whether the extraction is performed during or prior to Micra implant.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Medtronic, Inc. Risk of major complications

Left ventricular remodeling in mitral valve prolapse patients: implications of apical papillary muscle implantation

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

Mitral valve prolapse (MVP) causes left ventricle (LV) remodeling even in the absence of significant mitral regurgitation.

PURPOSE

We sought to evaluate whether apical implantation of the papillary muscle (PM) has an influence on the pattern and severity of MVP-related LV remodeling.

METHODS

All MVP patients who underwent Cardiovascular Magnetic Resonance at our institution between December 2008 and December 2019 were included, thoroughly reviewed and grouped according to apical/non-apical PM implantation.

RESULTS

Apical PM implantation was found in 53/92 patients (58%) and associated with mitral leaflet thickening (p < 0.01) and a trend toward higher prevalence of mitral annular disjunction (p = 0.05). Whereas there were no differences between groups concerning ventricular volumes and ejection fraction, mitral valve prolapse location or severity of mitral valve insufficiency, patients with apical PM implantation showed more lateral wall remodeling with mid lateral wall thinning (2.1 [1.8-2.5]mm vs. 4.0 [3.5-5.0]mm, p < 0.01), increased LV eccentricity and a lower Global Circumferential Strain at this level (15 ± 3% vs. 20 ± 3%, p < 0.01). In long-axis direction, increased end-diastolic mid lateral wall angulation was found (i.e., angle <155° measured in the thinnest point of the mid lateral wall in 4-chamber view) with a higher angle variation during systole (25 ± 11° vs. 17 ± 8° p < 0.01). Remarkably, PM fibrosis was significantly more frequent in patients with apical PM implantation (i.e., 66% vs. 28%, p < 0.01). Importantly, PM fibrosis was observed in the apically implanted PM in the vast majority of cases (86%), showing a strong association between PM fibrosis and its apical implantation. Finally, a higher burden of premature ventricular complexes (>5%) and non-sustained ventricular tachyarrhythmias was found in patients with apical PM implantation: 53% vs. 25% (p = 0.04) and 38% vs. 18% (p = 0.04), respectively.

CONCLUSIONS

Apical PM implantation is part of the phenotypic spectrum of MVP, significantly impacts LV remodeling and potentially may be related to increased ventricular arrhythmogenicity.

A leadless pacemaker in the real-world setting: Patient profile and performance over time

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Medtronic, Inc.

OnBehalf

Micra Acute Performance EMEA Investigators

Background

The first in-man implant of the Micra leadless pacemaker occurred in December 2013. While prior trials demonstrated a high implant success rate and favorable safety and efficacy results; whether the patient population and outcomes have changed over time is not well studied.

Purpose

To characterize the evolution of patient profile and outcomes for patients receiving a leadless pacemaker through the pre-market and post-market environment.

Methods

Patients undergoing a Micra leadless pacemaker implant attempt from the initial Micra Investigational Device Exemption [IDE] and current Micra studies (Micra post-approval registry [PAR], Micra acute performance [MAP] study) were analyzed. Patient characteristics and pericardial effusions regardless of severity were summarized.

Results

The 3466 patients included in the analysis underwent a Micra implant attempt and were enrolled during consecutive timeframes: patients from the Micra IDE study (n = 726) underwent a Micra implant attempt from 2013-2015, patients from the PAR (n = 1814) from 2015-2018, and patients from Micra MAP cohort (n = 926) from 2018 – 2020.  Implant success was >99.0% in all 3 studies. Median age ranged from 78 – 79 years among the 3 studies without significant difference. There were more patients requiring dialysis in the MAP cohort compared to the PAR or IDE cohorts (10.3%, 7.9%, and 3.9%, respectively; P < 0.001), but fewer patients with congestive heart failure (8.3%, 13.1%, and 18.0%; P < 0.001). Pacing indication was significantly different between the studies, with fewer patients in MAP having an indication of bradyarrhythmia associated with atrial fibrillation (AF) and more having an indication associated with atrioventricular block without AF (P < 0.001). The number of patients considered to be precluded for a transvenous pacemaker implant increased significantly from the initial IDE study to the PAR and MAP studies (6.2%, 23.9%, and 44.1%, respectively, P < 0.001).  Implant site placement was mostly apical for the IDE but shifted to mostly septal placement in the PAR and MAP (septal placement: 33.3%, 64.0%, and 79.5%, respectively). The rate of pericardial effusion regardless of severity was 1.79% (n = 13) in the IDE, 0.83% (n = 15) in the PAR, and 0.97% (n = 9) in MAP (figure). Mean pacing thresholds among MAP EMEA patients were low (0.61 ± 0.40V) at implant and remained stable through 12 months (0.62 +/- 0.41V).

Conclusion

Despite patient differences over time, the Micra leadless pacemaker was implanted with a high success rate and a low perforation rate, in-line with prior reports. Abstract Figure. Pericardial effusion rate by study

Leadless pacemaker implant in patients with a history of open heart surgery: experience with the Micra transcatheter pacemaker

Background

The Micra transcatheter pacemaker has demonstrated a favorable safety and efficacy profile relative to transvenous pacing. Patients with a history of open heart surgery have a higher risk of complications with transvenous pacemakers during follow-up. The experience with leadless pacemakers among a large cohort of patients with a history of open heart surgery has not been reported.

Objective

To report outcomes in patients with a history of open heart surgery undergoing Micra implant.

Methods

Patients undergoing Micra implant from the Micra Transcatheter Pacing Post-Approval Registry (PAR) were included in the analysis. Baseline and procedural characteristics, major complications, and electrical performance were compared among patients with vs. without history of cardiac surgery.

Results

A total of 331 out of 1815 (18.2%) patients had a history of open heart surgery, underwent Micra implant, and were followed for 19.4±10.4 months. The mean age was 74.6±13.5 years, 40% were female. The most common cardiac surgery was aortic valve surgery (71%) followed by mitral valve surgery (39%). Patients with prior open-heart surgery were more likely to have contraindications to transvenous pacing, were more likely to be on oral anticoagulants, and had more co-morbidities including atrial fibrillation, heart failure, and coronary artery disease (all p<0.005). Implantation was successful in 327 of 331 patients (98.8%) with a median procedure time of 29 minutes. Mean pacing capture thresholds (PCTs) at implant were 0.66±0.51V and remained stable through follow-up. There were 11 major complications in 10 cardiac surgery patients, with no device or procedure-related infections reported. The major complication rate was 3.1% (Figure) and was not significantly different than that of patients without a history of open heart surgery (HR: 0.85, P=0.640). There was 1 cardiac perforation (with no intervention required) in the open heart surgery group (0.3%) and there were 14 cardiac perforations (0.94%, P=0.332) in the non-open heart surgery group of which 10 required intervention.

Conclusion

The Micra transcatheter pacemaker can be safely implanted in patients with a history of open heart surgery, with a similar long-term safety profile to patients without a history of open heart surgery. Importantly, there were no device-related infections reported in either group.

Risk of Major Complication

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Medtronic, Inc.

298Atrioventricular synchronous pacing in leadless ventricular pacemaker is safe and effective in patients with paroxysmal AV block and atrial arrhythmias

Funding Acknowledgements

Medtronic, Inc.

Background/Introduction

Accelerometer (ACC)-based AV synchronous pacing by tracking atrial activity is feasible using a leadless ventricular pacemaker. Patients may experience variable AV conduction (AVC) and/or atrial arrhythmias during the lifetime of their device. ACC-based AV synchronous pacing should facilitate AVC and pace appropriately in those two common rhythms.

Purpose

To characterize the behavior of ACC-based AV synchronous pacing algorithms during paroxysmal AV block (AVB) and atrial arrhythmias.

Methods

The MARVEL2 (Micra Atrial tRacking using a Ventricular accELerometer) was a 5-hour acute study to assess the efficacy of atrial tracking with a temporarily downloaded algorithm into a Micra leadless pacemaker. Patients with a history of AVB were eligible for inclusion. The MARVEL2 algorithm included a mode-switching algorithm that switched between VDD and VVI-40 depending upon AVC status. The AVC algorithm requires 2 ventricular paces (VP) at 40 bpm out of 4 pacing cycles to switch to VDD.

Results

Overall, 75 patients (age 77.5 ± 11.8 years, 40% female, median time from Micra implant 9.7 months) from 12 centers worldwide were enrolled. During study procedures, 40 patients (53%) had normal sinus rhythm with complete AVB, 18 (24%) had 1:1 AVC, 5 (7%) had varying AVC status, 8 (11%) had atrial arrhythmias, and 2 other rhythms.  Two patients with complete AVB had the AVC mode switch feature disabled due to an idioventricular rate >40 bpm.  Among the 40 subjects with a predominant 3rd degree AVB and normal sinus function the median %VP was 99.9% compared to 0.2% among those with 1:1 AVC (Figure). In the patients with 1:1 AVC, there were 64 opportunities to AVC mode switch with 48 switching to VDI-40. In the other 16 cases (2 patients) the mode remained VDD due to sinus bradycardia varying between 40-45 bpm. High %VP was observed in 2 patients with 1:1 AVC and sinus bradycardia <40 bpm. The AVC mode switch minimized %VP (<1%) in patients with PR intervals > 300 ms (N = 2). Among patients with varying AVC, the algorithm appropriately switched to VDD when the ventricular rate was paced at 40 bpm. During infrequent AVB or AF with ventricular response >40 bpm, VVI-40 mode was maintained.

In patients with AF, the ACC signal was of low amplitude and there was infrequent sensing, resulting in VP at the lower rate (50 bpm). In the one patient with atrial flutter, the ACC was intermittently detected, resulting in VP at 67 bpm (IQR 66-67 bpm).

Conclusion(s)

The mode switching algorithm in the MARVEL2 reduced %VP in patients with 1:1 AVC and appropriately switched to VDD during complete AVB.  If greater AV synchrony or rate support is required, disabling the AVC algorithm may be appropriate for low grade AVB or idioventricular rhythms. In the presence of atrial arrhythmias, the algorithm paced near the lower rate.

Abstract Figure. Distribution of VP% by heart rhythm

Predictors of a high defibrillation threshold test during routine ICD implantation

BACKGROUND

There is growing evidence that routine defibrillation threshold (DFT) testing during implantable cardioverter defibrillator (ICD) implantation is not necessary. However a small group of patients might be at risk if no DFT testing is performed.

METHODS

Patients with a new pectoral ICD implantation in our hospital between 2006 and 2014 were included in a retrospective registry. A clinical high DFT was defined as a safety margin <10 J of the maximal device output. Logistic regression for prediction of high DFT was performed using patient characteristics, clinical, echocardiographic and device-related parameters.

RESULTS

DFT testing was performed in 788/864 (91.2%) procedures. In 76 (8.8%) patients no DFT testing was performed mainly due to atrial fibrillation, intra-cardiac thrombus, hemodynamic instability or logistical reasons. A high DFT was present in 44 (5.6%) patients. A QRS duration ≥150 ms, a low left ventricular ejection fraction (LVEF ≤25%), a severely dilated left ventricle ≥60 mm and right sided pre-pectoral implantations were univariate predictors of a high DFT. Independent predictors of a high DFT were a LVEF ≤25% (HR 2.195, 95%CI 1.085-4.443) and right sided pre-pectoral implantations (HR 3.135, 95% CI 1.186-8.287).

CONCLUSIONS

A high DFT is still present in about 5% of patients and is more frequent in patients with a severely dilated left ventricle, a very low LVEF, right sided pre-pectoral implantation and wider QRS duration. It might be clinically important to continue DFT testing in these high risk patients.

[Inadvertent implantation of a defibrillation lead in the left ventricle through a patent foramen ovale]

Inadvertent insertion of a defibrillation lead in the left ventricle is a rare complication generally underdiagnosed after device implantation. Management is not strictly codified due to the small number of observed cases. We report the case of a 78 year-old man in whom the diagnosis has been performed lately during an echocardiography.

[Clinical case of the month. Purulent pericarditis in a patient with pulmonary sarcoidosis]

We report the case of a patient, suffering from pulmonary sarcoidosis, who developed a purulent pericarditis complicated with a cardiac tamponade. The widespread use of antibiotics has progressively reduced the number of purulent pericarditis. However, it remains a serious disease that has to be rapidly diagnosed to be treated timely. We will review the required tests for the diagnosis and the treatment of this pathology that leads to death otherwise. The link with pulmonary sardoidosis is uncertain.

[The student diagnostic vignette. Electrocardiographical criteria for the diagnosis of ventricular tachycardia]

Recording of a regular wide QRS tachycardia is often source of panic and anxiety for the young clinician who has to make the differential diagnosis between ventricular tachycardia and supraventricular tachycardia with aberration associated with fundamentally different vital prognosis. Most of the time, a rigorous approach and a systematic analysis of the electrocardiogram associated with clinical examination allow to obtain the correct diagnosis.

[The long QT syndrome]

The congenital long QT syndrome (LQTS) is a hereditary cardiac disease characterized by a prolongation of the QT interval > 440 ms at rest ECG associated with a high risk of ventricular arrhythmias (torsade de pointe). Clinical manifestations are syncope and sudden cardiac death. The implicated genes encode cardiac ion channel subunits or proteins involved in modulating ionic currents. The diagnosis of LQTS can be complex in borderline cases. Etiology, pathogenesis, diagnosis and treatment are discussed.

[How I treat...paroxysmal narrow complex QRS tachycardia]

Paroxysmal narrow complex QRS tachycardias are a clinical entity characterized by abrupt onset and termination of palpitations, dyspnea, dizziness. They depend on mechanisms of reentry within the atrio-ventricular node or with the participation of an accessory pathway (reciprocating orthodromic tachycardia). We review the clinical and electrocardiographical diagnosis as well as the acute and long term treatment of these tachycardias.

[Adherence to the rules for antithrombotic treatment in atrial fibrillation]

Adherence to the rules for antithrombotic ment in atrial fibrillation patients significantly reduces the risk of stroke. We review the criteria for the use of anti-vitamin K as well as its daily management in patients with atrial fibrillation.

[First episode of atrial fibrillation]

We report the case of a patient seen at the outpatient clinic for a first episode of atrial fibrillation. We discussed the steps of the treatment including anticoagulation, rate and rhythm control.

Functional connectivity in the default network during resting state is preserved in a vegetative but not in a brain dead patient

Recent studies on spontaneous fluctuations in the functional MRI blood oxygen level-dependent (BOLD) signal in awake healthy subjects showed the presence of coherent fluctuations among functionally defined neuroanatomical networks. However, the functional significance of these spontaneous BOLD fluctuations remains poorly understood. By means of 3 T functional MRI, we demonstrate absent cortico-thalamic BOLD functional connectivity (i.e. between posterior cingulate/precuneal cortex and medial thalamus), but preserved cortico-cortical connectivity within the default network in a case of vegetative state (VS) studied 2.5 years following cardio-respiratory arrest, as documented by extensive behavioral and paraclinical assessments. In the VS patient, as in age-matched controls, anticorrelations could also be observed between posterior cingulate/precuneus and a previously identified task-positive cortical network. Both correlations and anticorrelations were significantly reduced in VS as compared to controls. A similar approach in a brain dead patient did not show any such long-distance functional connectivity. We conclude that some slow coherent BOLD fluctuations previously identified in healthy awake human brain can be found in alive but unaware patients, and are thus unlikely to be uniquely due to ongoing modifications of conscious thoughts. Future studies are needed to give a full characterization of default network connectivity in the VS patients population.

[Arrhythmogenic right ventricular dysplasia]

Arrhythmogenic right ventricular dysplasia is an unfrequent disease that associates ventricular tachycardia with left bundle branch block morphology and right ventricular fibro-fatty degeneration. The etiology, pathogenesis, criteria for diagnosis and treatment are discussed.

[Ghrelin and obesity]

Ghrelin is a peptide hormone secreted by the stomach. It was initially described as a stimulant of growth hormone secretion. Soon, however, it was discovered to play an important role in feeding behaviour in animals and in appetite regulation in man: ghrelin stimulates appetite, and as such is an orexigenic peptide implicated in energy balance mechanisms and weight gain. Abnormal ghrelin activity leads to over- or underweight. Additionally, the efficacy of different treatment strategies against obesity seems to be related to modifications in plasma ghrelin levels. This review summarizes the current knowledge about ghrelin and its implications in obesity medicine.