Pseudo repetitive non-reentrant ventriculoatrial synchrony: Current challenges.

BACKGROUND: We recently described a novel pacemaker-mediated arrhythmia in Abbott cardiac implantable electronic devices (CIED), called pseudo-RNRVAS, that mimics repetitive non-reentrant ventriculoatrial synchrony (RNRVAS), but can appear in patients with ventriculoatrial (VA) block. It is caused by sinus-p-waves, trapped in the post-ventricular atrial refractory period (PVARP), which mimic VA conduction. The p-waves are followed by atrial pacing during the myocardial refractory time, which can trigger atrial fibrillation (AF). Pseudo-RNRVAS and RNRVAS are probably more common than appreciated, but the recognition and differentiation of the two can be challenging because most CIEDs do not recognize and store them. OBJECTIVE: We illustrate practical challenges in the assessment of Pseudo-RNRVAS and provide programming options that proved safe and effective for preventing Pseudo-RNRVAS and reducing the risk for typical RNRVAS. METHODS AND RESULTS: We illustrate in 10 patients the characteristics of Pseudo-RNRVAS and their treatment. The outcome regarding the recurrence of pseudo-RNRVAS after 6 months of follow-up was collected. Inappropriate atrial pacing during pseudo-RNRVAS resulted in AF in six patients. After shortening the PVARP in nine, inactivation/reduction of rate response in four, and reduction of the basic pacing rate in one patient, pseudo-RNRVAS was avoided in eight patients and reduced in one. In one patient AF became permanent. CONCLUSIONS: Pseudo-RNRVAS is a pacemaker-mediated arrhythmia that can appear in patients without VA conduction and may lead to AF. The suggested adjustments of pacing parameters were safe and effective in preventing the arrhythmia.

Predicted Need for Atrial and Ventricular Pacing Per Indication Group in Patients With Dual-Chamber Pacemakers.

BACKGROUND: Bradyarrhythmias are adequately treated with pacemakers. There are different pacing modes (single-chamber, dual-chamber, cardiac resynchronisation therapy [CRT] and conduction system pacing [CSP]) and a choice between leadless or transvenous pacemakers. The expected pacing need is important for determining optimal pacing mode and device type. This study aimed to evaluate atrial pacing (AP) and ventricular pacing (VP) percentages over time for the most common pacing indications. METHODS: Included patients were aged ≥18 years with a dual-chamber rate-modulated [DDD(R)] pacemaker implantation and ≥1 year of follow-up at a tertiary centre between January 2008 and January 2020. Baseline characteristics, AP and VP at yearly follow-up visits up to 6 years after implantation were retrieved from the medical records. RESULTS: A total of 381 patients were included. Primary pacing indications were incomplete atrioventricular block (AVB) in 85 (22%), complete AVB in 156 (41%) and sinus node dysfunction (SND) in 140 (37%) patients. Mean age at implantation was 71±14, 69±17 and 68±14 years, respectively (p=0.23). Median follow-up was 42 months (25-68 months). Overall, AP was highest in SND with median 37% (7%-75%) versus 7% (1%-26%) in incomplete AVB and 3% (1%-16%) in complete AVB (p<0.001); VP was highest in complete AVB with median 98% (43%-100%) versus 44% (7%-94%) in incomplete AVB and 3% (1%-14%) in SND (p<0.001). Ventricular pacing significantly increased over time in patients with incomplete AVB and SND (both p=0.001). CONCLUSIONS: These results confirm the pathophysiology of different pacing indications, causing clear differences in pacing need and expected battery longevity. They may help guide optimal pacing mode and suitability for leadless or physiological pacing.

Cross stimulation and unusual ventricular activation in a patient with dual chamber pacemaker.

Cross stimulation is defined as stimulation of one cardiac chamber when the stimulation of the other chamber is expected. We present a case of an eighty three year old patient with history of dual chamber pacemaker implantation with recent generator change which showed interesting ECG findings.

Dual-chamber pacing using a hybrid transvenous and leadless pacing approach.

An elderly gentleman with a dual-chamber pacemaker presented to our institution with symptoms of symptomatic bradycardia and high-grade atrioventricular (AV) block. Device interrogation revealed failure to capture in the right ventricle (RV) lead with bipolar pacing, high RV pacing threshold with unipolar pacing, and high impedance suggesting lead fracture. The atrial lead function was normal. Given his advanced age, gait instability, and dementia, the decision was made to proceed with Micra AV pacemaker implantation, while programming his dual-chamber pacemaker to AAIR mode, thus maintaining AV synchrony by tracking paced atrial impulses and providing ventricular pacing.

The risk factors of new-onset atrial fibrillation after pacemaker implantation.

OBJECTIVE: The aim of this study was to determine the incidence of newly detected atrial fibrillation (AF) in patients following dual-chamber pacemaker (PPM) implantation and to define the clinical predictors of new-onset AF in a Chinese cohort. METHODS: A total of 219 patients without documented AF that underwent dual-chamber PPM implantation for sick sinus syndrome (SSS) (n = 88) or atrioventricular block (AVB) (n = 131) were prospectively studied. All patients were invited to follow-up at 1 month, 3 months and 6 months after the pacemaker implantation procedure, and once every 6 months thereafter. An atrial high-rate episode (AHRE) ≥5 min and an atrial rate ≥180 bpm was defined as AF. RESULTS: During follow-up of 884 ± 180 days, AF was detected in 56 (26%) patients. Using Kaplan-Meier survival curves with Log-rank test, SSS patients with a cumulative percentage of ventricular pacing (Cum % VP) ≥60% had a significantly higher rate of new-onset AF compared to AVB patients (p = 0.026) and SSS patients with Cum % VP <60% (p = 0.018). On multivariate Cox regression analysis, higher Cum % VP independently predicted higher morbidity of newly detected AF (hazard ratio [HR] 1.01; confidence interval [CI] 1.00 ~ 1.02; p = 0.035) among SSS patients. Larger left atrial (LA) dimension was a predictor of newly detected AF (HR 1.06; CI 1.01 ~ 1.14; p = 0.046) in AVB patients. CONCLUSION: The incidence of AF following dual-chamber PPM implantation was relatively high in this Chinese cohort. High Cum % VP and larger LA dimension could independently predict new-onset AF after dual-chamber PPM implantation in SSS and AVB patients, respectively.

Reversible left ventricular dysfunction due to endless loop tachycardia in patient with dual chamber pacemaker- A case report.

A 60 years male patient underwent permanent pacemaker [DDDR -with dual chamber pacing (D) with dual chamber sensing (D) with dual mode of response (D) with rate responsive pacing(R) -St Jude's medical (Abbott- Endurity 2160)] implantation for complete heart block (CHB). After 4 months patient was admitted for congestive heart failure. 12 Lead electrocardiograms (ECG) was suggestive of tachycardia at 130 beats per minute (regular rhythm), with ventricular complexes preceded by pacing spikes and maintenance of 1:1 atrio-ventricular relationship. Echocardiography showed global hypokinesia of left ventricular (LV) myocardium with reduced LV ejection fraction. LV dysfunction and heart failure were attributed to tachy-cardiomyopathy. Pacemaker telemetry data demonstrated that the tachycardia was likely to be pacemaker-mediated endless loop tachycardia (ELT). ELT in this case was perpetuated secondary to shortening of post ventricular atrial refractory period (PVARP), intact retrograde ventriculo-atrial (VA) conduction and addition of antiarrhythmic drugs prolonging retrograde VA conduction. Rate response (Dynamic) PVARP was reprogrammed allowing PVARP extension. Following this ELT was terminated. LV ejection fraction was normalized on subsequent follow up visit after seven days.

Clinical implications of elective replacement indicator setting changes in patients with dual-chamber pacemaker devices.

OBJECTIVE: This study sought to determine if single-chamber operation and/or loss of rate response (RR) during elective replacement indicator (ERI) in patients with dual-chamber pacemakers lead to increased symptom burden, healthcare utilization, and atrial fibrillation (AF). BACKGROUND: Dual-chamber pacemakers often change from dual- to single-chamber pacing mode and/or lose RR functionality at ERI to preserve battery. Single-chamber pacing increases the incidence of heart failure, AF, and pacemaker syndrome suggesting these changes may be deleterious. METHODS: A retrospective analysis of 700 patients was completed. Three comparisons were analyzed: Comparison 1: mode change and RR loss versus no change; Comparison 2: RR loss only versus no change; Comparison 3: mode change only versus no change (in patients with no RR programmed at baseline). RESULTS: In Comparison 1, 121 (46%) patients with setting changes experienced symptoms (most often dyspnea and fatigue/exercise intolerance) versus 3 (4%) without setting changes (p < .0001). Similar results were noted in Comparisons 2 and 3 (p = .0016 and p = .0001, respectively). In Comparison 1, patients with setting change sought provider contact more than patients without setting changes (p = .0001). A significant difference was not noted in Comparison 2 or 3. Overall 14 (2%) patients were hospitalized, all of whom had setting changes. CONCLUSIONS: Setting changes at ERI including a change from dual- to single-chamber pacing and/or loss of RR results in a significantly increased symptom burden and increased healthcare utilization.

Treatment with corticosteroids is associated with an increase in ventricular arrhythmia burden in patients with clinically manifest cardiac sarcoidosis: Insights from implantable cardioverter-defibrillator diagnostics.

INTRODUCTION: We sought to explore the relationship between ventricular tachycardia (VT) and premature ventricular complex (PVC) burden (from implantable cardioverter-defibrillator diagnostics), before and during corticosteroid use in patients with newly diagnosed clinically manifest cardiac sarcoidosis (CS). METHODS: A single-centre, prospective cohort study was performed in consecutive patients who met all of the following criteria: (1) presentation with clinically manifest CS, (2) abnormal myocardial fluoro-deoxyglucose (FDG) uptake on positron emission tomography scan, (3) plan for implantation with implantable cardioverter-defibrillator device that reports accurate PVC count, (4) plan to initiate corticosteroids after the device healing period. Data were collected during each device interrogation visit for all patients in the study. For each inter-visit period the total number of episodes of VT-sustained and nonsustained, and the number of PVCs was obtained. Each inter-visit period was classified into one of the following three periods: (1) New diagnosis of treatment-naive active disease without corticosteroids during the period. (2) Known treatment-naive active disease with corticosteroids initiated during the inter-visit period. (3) On corticosteroid therapy during the entire period. RESULTS: A total of 20 patients with a mean age of 59.7 ± 7.7 years were recruited and 82 inter-visit periods were analyzed. All patients were corticosteroid responders based on FDG uptake. The maximum left ventricular standardized uptake value was 11.14 ± 5.19 before corticosteroid initiation and 4.07 ± 0.88 after (p < .001). Patients with active untreated CS had an average of 496.4 ± 879.1 PVCs per day. After treatment with corticosteroids, the average PVC count increased to 1332.4 ± 1865.7/day during Period 2 (p = .036) and to 1590.1 ± 2362.2 per day during Period 3 (p = .008). There was also a statistically significant increase in episodes of nonsustained ventricular tachycardia (NSVT) before and after treatment with corticosteroids (p = .017). There were too few episodes of sustained ventricular arrhythmia to analyze. Overall, 18 out of 20 patients (90%) had an increase in PVC burden after corticosteroid initiation. CONCLUSION: This study demonstrated, on average, a threefold increase in daily PVC count in clinically manifest CS patients during treatment with corticosteroids compared to pretreatment. There was also a significant increase in episodes of NSVT. Clinicians and patients with active manifest CS should be aware that corticosteroids are unlikely to lead to a reduction in the burdens of PVC and NSVT.

Phrenic nerve stimulation during right ventricular outflow tract pacing: A rare but possible complication.

Phrenic nerve stimulation (PNS) caused by a right ventricular (RV) lead is an uncommon complication of pacemaker implantations. We demonstrated a case of left PNS caused by an RV lead placed in the RV outflow tract (RVOT). The PNS was dependent on ventricular capture. This case highlighted a risk of PNS even during RVOT pacing.

An unexpected complication of intracardiac device implantation: Contralateral pneumothorax and pneumopericardium.

A 62-year-old man developed concomitant right-sided pneumothorax and pneumopericardium after undergoing implantation of a left-sided dual-chamber pacemaker. The case is reported for its rarity. The possible mechanisms and management options for this extremely rare complication are discussed.

[Clinical Value of Algorithms of Minimization of Right Ventricular Pacing in Patients With Sick Sinus Syndrome and History of Atrial Fibrillation].

PURPOSE: to assess effectiveness of algorithms of minimization of right ventricular pacing (MRVP) for prevention of progression of atrial fibrillation (AF), lowering of frequency of hospitalizations due to cardiovascular causes, and mortality in patients with sick sinus syndrome (SSS) and history of paroxysmal AF compared with standard compared with dual-chamber pacing (DDDR). MATERIALS AND METHODS: We included in this single-center prospective study 74 consecutive patients with indications to permanent DDDR pacing because of SSS combined with documented history of paroxysmal AF. Patients were randomized in the groups of DDDR pacing (n=36) and with activated algorithms of MRVP (n=38). Pacemaker check up was made after 6 months during 1 year after device implantation. Primary composite endpoint included development of persistent AF, hospitalization due to cardiovascular causes, and all cause death. RESULTS: During follow-up there was no statistically significant difference in achievement of the primary endpoint (27.8 and 18.4% in groups of DDDR pacing and activated algorithms of MRVP respectively (relative risk 1.29% confidence interval 0.43 to 3.86; p=0.25). Rate of development of persistent AF in both groups was comparable (8.6 and 5.3% in DDDR and MRVP groups, respectively; p=0.47). Median AF burden was 6.0 (0;42) and 6.0 (0;42) min/day in DDDR and MRVP groups, respectively (p=0.67). CONCLUSION: Our study failed to demonstrate advantages of the use of algorithms of decreasing "unmotivated" right ventricular pacing over standard regimen of standard DDDR pacing in patients with SSS and history of paroxysmal AF.

[A series of cases--too old for a pacemaker?]. / Eine Case Serie--Zu alt für einen Schrittmacher?

We report three patients with an age above 90 years presented with symptomatic bradycardia and higher grade AV block in our clinic. The oldest patient was 100 years. All three patients could be supplied safely and without complications with a dual chamber pacemaker. Our case series shows that a dual chamber pacemaker implantation is safe and feasible in patients in very advanced age. A surgical management with local anesthetic (lidocaine), fentanyl and midazolam in individual cases is possible. This and a short hospital stay reduce the risk of delirium. It is a group of patients, which will increase in the future and requires more intensive care than the standard pacemaker patient.

[A case of swallow syncope]. / La syncope de déglutition : cas clinique.

Syncope accounts for nearly 5 % of the emergency intake causes. Swallow syncope is a rare form of cardio-neurogenic syncope. Less than a hundred cases were reported since its first description in the mid-18th century. We present the case of an 83-year-old patient with recurrent syncope occurring during meals. Telemetry monitoring revealed a severe bradycardia with complete AV block and a pause of 8 seconds. A dual chamber pacemaker was implanted and the syncopal episodes were abolished. We shall briefly review the diagnostic methods, mechanisms, and therapy of swallow syncope.

La syncope représente près de 5 % des causes d'admission aux urgences. La syncope de déglutition est une forme rare de syncope d'origine cardio-neurogénique : moins d'une centaine de cas ont été rapportés depuis sa première description au milieu du 18ème siècle. Nous décrivons le cas d'un patient de 83 ans qui présente, depuis plusieurs mois, des syncopes au cours des repas. L'exploration a mis en évidence un trouble du rythme de type bradycardie sévère avec un bloc auriculo-ventriculaire et une pause de plus de 8 secondes enregistrée lors de la surveillance télémétrique. L'implantation d'un pacemaker double chambre a permis de mettre fin aux épisodes syncopaux. Cet article fait le point sur les méthodes diagnostiques, les mécanismes et le traitement des syncopes de déglutition.

Reduction of unnecessary right ventricular pacing by managed ventricular pacing and search AV+ algorithms in pacemaker patients: 12-month follow-up results of a randomized study.

AIMS: The present study was to assess the reduction of right ventricular pacing (RVP) by pacemaker algorithms of Managed Ventricular Pacing (MVP) and Search AV+ (SAV+) interval over a period of 12 months. METHODS AND RESULTS: A total of 385 patients indicated for a dual-chamber pacemaker (DC-PM) were enrolled in the prospective, randomized COMPARE study at 29 centres in China between June 2009 and April 2011. Patients implanted with DC-PMs were randomized in a 1 : 1 ratio to the MVP group or the SAV+ group. The percentage of VP (%VP) was obtained from the device diagnostic data at 1-, 6-, and 12-month follow-ups and was expressed as the median %VP over all beats in patients with sinus node dysfunction (SND) and atrioventricular block (AVB) excluding persistent third-degree AVB. Of 385 enrolled patients, 253 had SND and 72 had AVB. The %VP in the MVP group was significantly lower than that in the SAV+ group at 1-, 6-, and 12-month follow-ups, respectively. At 12-month follow-up, the median %VP in SND patients was 0.20% in the MVP group and 1.4% in the SAV+ group (P < 0.0001) and the median %VP in AVB patients was 11.8% in the MVP group and 98.1% in the SAV+ group (P < 0.001). There was no statistical difference in %VP from 1- to 12-month follow-up. A trend in the correlation between %VP and AT/AF burden was observed. CONCLUSION: Over 12-month follow-up, the %VP was lower for MVP than SAV+ in patients with either SND or AVB. The sustainable %VP reduction has potential implications in reducing the development of heart failure and/or atrial arrhythmia morbidity.

Evaluation of left ventricular longitudinal function and synchrony after dual chamber pacemaker implantation.

BACKGROUND AND OBJECTIVE: To evaluate left ventricular (LV) longitudinal function and dyssynchrony mechanisms after dual chamber pacemaker implantation. MATERIALS AND METHODS: The speckle tracking imaging technique was used for quantification of global longitudinal function of the left ventricle and for dyssynchrony evaluation before pacemaker implantation and after 3-month follow-up. The study group consisted of 98 patients with conventional indications for dual chamber pacemaker implantation. RESULTS: Speckle tracking echocardiographic methods and image postprocessing revealed impairment of global longitudinal strain and significant LV dyssynchrony derived from 12 basal and mid-septum segments usually untraceable with conventional echocardiographic methods. Despite good physical performance and ejection fraction, global longitudinal strain significantly decreased in all patients from -15.08±0.46 to -13.56±0.5 (P<0.05) as well as mitral annulus movement decreased from 11.57±2.41 to 8.46±1.74cm/s (P<0.001) and from 12.55±2.75 to 10.78±2.82mm (P<0.001). It was expected that patients with dual chamber pacemaker will develop inter- and intraventricular dyssynchrony, but our study showed that pacing lead position did not prevent from LV dysynchronisation and only changed the mechanism. CONCLUSIONS: Global longitudinal strain and LV dyssynchrony assessment enables us to detect early signs of LV dysfunction. Mechanisms of dyssynchrony development will be useful for pacemaker programing choices in order to prevent further dyssynchronisation.