High-grade AV Block Research Articles

High Grade AV Block Associated with Dipyridamole Infusion

The use of dipyridamole for thallium imaging has proved very successful in demonstrating coronary arterial disease [1]. Dipyridamole causes coronary arteriolar vasodilation by increasing interstitial adenosine levels by inhibition of both adenosine deaminase and facilitated cellular adenosine uptake. Differential flow changes occur in coronary arteries if a significant luminal stenosis exists [2]. Intravenous infusion of dipyridamole is safe although transient noncardiac side effects are common. These side effects are mostly mild and not need to treat although can be treated with aminophylline [5]. High-grade AV block after dipyridamole has been described in few case reports and mostly was associated with transient myocardial ischemia [2-4]. We describe a case of long-lasting high grade AV block following dipyridamole infusion. In context of near normal baseline ECG. In our case the AV block occurred without evidence of ischemia in myocardial perfusion imaging and we think it can be an unexpected adverse effect of dipyridamole and clinicians should be aware of AV block as a possible adverse effect of dipyridamole.

Strain echocardiography in predicting LV dysfunction in RV apical pacing

Right ventricular (RV) pacing is associated with a reduction in left ventricular (LV) systolic function, thought to be mediated by pacing-induced ventricular dyssynchrony. The prevalence of heart failure after RV pacing is reported to range from 31±3%. We studied 60 subjects with high-grade atrioventricular block and Complete Heart Block (CHB) scheduled to undergo right ventricular apical pacing. 2D echocardiography was done at baseline, 1 month and 12 months. Pacing-induced cardiomyopathy was defined as a reduction in LVEF to <45%. Strain was evaluated off-line from digitally stored images using all advanced software package (cardiac wall motion quantification (CMQ); Toshiba Medical Systems). Longitudinal strain for individual myocardial segments was measured from the apical four-chamber, two-chamber and long axis views (16 segment AHA/ASE model). None had LV dysfunction at baseline based on 2D and strain echo imaging. Subsequently 18 patients were detected to develop low GLS score (less than -14.5) at 1 month. On subsequent follow up at 1 year, all 18 patients developed LV dysfunction on 2D Echocardiography. Thus Strain imaging with GLS score helped in early detection of LV dysfunction in RV apical pacing subjects. Pacing-induced cardiomyopathy had significant association with high grade AV block with pacemaker dependency. It had no significant associations with other comorbidities like diabetes, hypertension, ischemic heart disease or with the type of medication intake. However there was a statistically significant association with heart failure.

Myocarditis with Complete Heart Block in a Child With COVID-19 Infection

INTRODUCTION Severe acute respiratory syndrome coronavirus 2 (COVID 19), also known as COVID 19, was first detected in 2019 as a result of a cluster of pneumonia cases in China. It is known to cause respiratory illness in a majority of cases, however myocardial involvement can be seen in 7% of cases, with even a smaller number in pediatric populations. CASE PRESENTATION We are presented with a 14 year old male with confirmed COVID 19 infection that is followed by a fulminant myocarditis resulting in High grade AV Block and subsequent pacemaker insertion, which is the first reported case in the pediatric population. DISCUSSION Cardiac injury resulting from a recent COVID 19 infection can result to a fulminant myocarditis. This can present as arrhythmia, seen in 16.7% of cases. The mainstay of treatment is still maintaining hemodynamic stability and initiating immunomodulatory support, however, specifically in this case resulting in third-degree AV block, pacemaker insertion may also be required. CONCLUSION Although severe cardiac involvement in COVID 19 infection is rare, a fulminant myocarditis is possible for some patients. KEYWORDS COVID 19, Myocarditis, pacemaker, arrhythmia

Sick Sinus Syndrome in a Female Patient with Chagas Disease. Case Report

Chagas disease is a zoonosis transmitted by Trypanosoma Cruzi, which has become a public health problem worldwide. The infection can be acute, chronic phases and reactivations, characterized by heart involvement. We report the case of a 33-year-old woman with stabbing chest pain, as well as hemiparesis in the left arm managed for 8 weeks, with persistent chest pain, electrocardiogram (ECG) showing a heart rate of 40 bpm. She is referred to a cardiologist who requests a Holter which shows pauses of 5.4 seconds and a transthoracic echocardiogram with LVEF 56%, PASP 24 mmHg; anti trypanosoma cruzi IgG antibodies were requested with a positive result, starting management based on nifurtimox; candidate patient for management with a double-chamber pacemaker, with remission of symptoms. In recent years, our knowledge about Chagas disease has expanded, electrocardiography is the most useful individual examination technique for these patients. Late manifestations include sinus node dysfunction leading to severe bradycardia, high-grade AV block, etc. Chagas disease should be suspected in all patients with an epidemiological history compatible with symptoms of cardiac involvement. and we believe that active intervention in endemic areas of the disease is especially relevant.

Inflammation begets isolated atrioventricular conduction disturbances in young an observation from indian registry data

Abstract Background High grade AV block is less commonly encountered in patients &amp;lt;60 years. The aetiological role of inflammatory conditions is not well studied in this group of patients. Purpose To determine the prevalence of myocardial inflammation in young patients presenting with High grade AV block and assess its response to immunosuppression. Methodology This is a prospective, registry based, observational study conducted at two centers from Jan 2020 to Dec 2021. Myocardial inflammation was detected using Cardiac PET, and/or histopathological examination. Those with evidence of inflammation were started on graded immunosuppression. Results 318 patients were enrolled. Mean EF was 55.2±7.0%. Cardiac PET was performed in 87/318 (27.3%). Myocardial inflammation was seen in 57/87 (65%). LV basal septum was most commonly involved. 44/57 (77%) were started on immunosuppressive therapy after excluding indolent tuberculosis.8 patients died during follow-up with all deaths being sudden in nature. 5/44 (11.3%) had reversal of CHB with resolution of cPET findings. Conclusion Significant proportion of young patients with High grade AV block have segmental myocardial inflammation. Immunosuppression helps restore AV conduction in some of these patients. Long-term studies are required to assess adverse impact of inflammation on cardiac contractile function. Funding Acknowledgement Type of funding sources: None.

Recurrences after stereotactic arrhythmia radioablation for refractory ventricular tachycardia

Abstract Introduction Stereotactic arrhythmia radioablation (STAR) has been recently introduced for the management of ventricular tachycardia (VT) refractory to antiarrhythmic drugs (AADs) and catheter ablation (CA). VT recurrences were recently reported after STAR but the mechanisms remain poorly known. Purpose We analyzed VT recurrences after STAR for refractory VT in order to assess the characteristics and delivered dose at sites of VT relapse. Methods From 09.2017 to 01.2020, 12 consecutive patients (pts) (66±8y, LVEF 40±14%) suffering from refractory VT were enrolled. The underlying cardiopathy was ischemic in 3, inflammatory in 3 and idiopathic in 6 pts. Nine (75%) out of 12 pts had a history of at least 1 electrical storm. Before STAR, an invasive electro-anatomical mapping (Carto3) of the VT substrate (VT-sub) was performed. A mean dose of 22±2Gy was delivered to the VT-sub using the Cyberknife® system. Results The ablation volume was 24±7cc and involved the basal interventricular septum (IVS) in 10 (83%) pts. During the first 6 months after STAR, VT burden decreased by 93% (mean value, from 640 to 46 VT/semester). After a median follow-up of 32±11 months, 10/12 (83%) developed ≥1 recurrence as a sustained VT and underwent a redo CA. Two (17%) pts presented 2 distinct VT recurrences from clearly different areas. VT recurrence was located at the border zone (BZ) of the treated VT-sub in 6 (50%) cases, involved both the BZ and a larger substrate in 2 (17%) cases, and occurred remote from the VT-sub in 4 (33%) cases (see Table 1). The dose delivered at sites of VT recurrence was 8.4±8.6 Gy with a large heterogeneity ranging from 0.11 to 28.37 Gy, for some pts due to dose constraints near critical structures (coronary arteries). Voltage mapping showed a small but significant reduction in both unipolar and bipolar EGM voltage in the irradiated area after STAR (before vs after, Bipolar: 1.8±1.2 vs 1.1±1.2 mV and Unipolar: 4.4±2.0 vs 3.4±2.3 mV, p=0.02 and 0.01 respectively). Importantly no pts developed a high-grade AV block after STAR despite IVS irradiation. Conclusion STAR appears to be an efficient tool for the management of refractory VT, leading to a strong VT burden reduction and no new high-grade AV block. Recurrences were nevertheless common, often at the border zone of the irradiated volume. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): CHUV

Single-chamber versus dual-chamber pacing in very elderly patients with sinus node disease and AV block: a real-world study

Abstract Background Elderly patients with sinus-node disease, have been reported to have better clinical outcomes with dual-chamber pacing compared with single chamber pacing. In contrast, randomized studies have shown no clinical benefit of dual-chamber pacing compared to single-chamber pacing in the elderly with high grade AV block., For truly elderly patients (&amp;gt;80 years), the optimal choice of pacing mode remains uncertain. In this real-world observational study, we analysed the clinical outcomes in a cohort of very elderly patients. Methods We analysed retrospective data of all new pacemaker implantations for sinus node disease or high-grade atrioventricular block in patients ≥80 years a district general hospital in south-east England, UK over a 7-year period. Patients with an existing diagnosis of stroke, congestive cardiac failure and/or atrial fibrillation (AF) were excluded from the study. Patients were categorised into two analysis cohorts based on pacing mode, i.e dual chamber (DDD) pacing versus single chamber (VVI) pacing. Clinical outcome data including all-cause mortality, new onset AF and CCF were recorded. Results A total of 208 patients were included in the study, of which 117 received (DDD) pacing vs 91 who underwent VVI pacing. The mean age was 85.8 years (84.63 DDD, 87.3 VVI, p=0.01). Single chamber pacing was associated with greater all-cause mortality (51.7% vs 31.5%, p=0.01). 23.1% of patients who underwent DDD pacing developed AF, vs 21.9% who underwent VVI pacing (p=0.85). Congestive cardiac failure was observed in 6.48% of patients who received DDD pacing vs 8.14% of patients who received VVI pacing, (p=0.66). Conclusions In this real-world observational study of very elderly patients with sinus node disease and/or high-grade AV block, single chamber pacing was associated with a greater all-cause mortality. However, the pacing mode did not affect the incidence of atrial fibrillation and congestive cardiac failure. Funding Acknowledgement Type of funding sources: None.

Left bundle branch area pacing as a first line pacing strategy, which patients should we consider?

Abstract Background A higher right ventricular (RV) pacing burden in those with permanent pacemakers results in accelerated pacing induced cardiomyopathy, in addition to increased incidence of heart failure and mortality [1–3]. This process may necessitate upgrade to a biventricular system in time, as the cardiomyopathy progresses. Physiological conduction system pacing targets such as His-bundle pacing (HBP) or Left Bundle Branch Area Pacing (LBBAP) have been shown to generate comparatively narrower QRS complexes and thus mitigate this cardiomyopathy development [4,5]. The 2021 ESC guidelines have a class 2b indication for consideration of HBP as an alternative to RV pacing in those with AV block and left ventricular ejection fraction &amp;gt;40%, who are anticipated to have &amp;gt;20% ventricular pacing burden [6]. Purpose To retrospectively identify ECG, echocardiographic, permanent pacemaker (PPM) setting and patient factors associated with high RV pacing burden that may aid selection of those who may benefit from conduction system pacing (CSP). Methods We retrospectively identified 300 consecutive patients who underwent cardiac implantable electronic device insertion in our Electrophysiology Lab from the years 2017–2018. We excluded patients who underwent generator replacements, in addition to those who had biventricular devices or implantable cardioverter defibrillators inserted. We collated ECG, echo, past medical history and pacing data for each patient over a three-year follow up period. Data were analysed using SPSS v.26. Results 160 patients met inclusion criteria. Those with an RV pacing burden &amp;gt;20% were categorised group one (n=85) and those with &amp;lt;20% in group two (n=75). Baseline characteristics of these two groups are compared in Table 1 and Table 2. Our analysis showed that significant differences between these groups included a lower mean HR (Table 1) (55.1±17.8 vs 57.63±17.4) with a more prolonged PR interval (225.7ms ± 8.34 vs. 188.6ms ± 6.62) or atrial fibrillation/flutter (AF/AFL) on admission ECG. There were more males with a greater mean age (High Ventricular Paced (VP) = 76.6 years ± 8.4 vs Low VP = 71.23 years ± 12.3) in the higher VP group, and they demonstrated more incidence of dilated RA/RV on echo (Enlarged RA = 30.5%; Enlarged RV = 23.6% vs 10% and 8.4% respectively). There were significant differences in PPM indications and setting between groups (Table 2), with the higher VP groups having PPM inserted for persistent high-grade AV block (CHB = 31.5% vs 4.9% and Mobitz 2 = 9.6% vs 0%) and had less MVP mode activated (Mode switch algorithm = 13.3% vs 71%). Conclusion Our data suggests that those with persistent high grade AV block such as Mobitz 2 or CHB should be considered for CSP. Other considerations include older age, male sex, dilated RV/RA, prolonged PR, lower intrinsic HR or AF/AFL on admission ECG. PPM mode switching settings to reduce RV pacing burden should be utilised where possible. Funding Acknowledgement Type of funding sources: None.

Short term outcomes of distal (ventricular) His bundle pacing: A single centre retrospective study

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Chronic right ventricular apical pacing can lead to pacing induced cardiomyopathy in a significant proportion of patients. Conduction system pacing may restore more physiological activation of the heart, and has recently been shown to have favourable outcomes in clinical trials. However there remains concern regarding the long-term outcomes due to lead displacement and high pacing thresholds. The most widely used technique in current practice is to pace the His bundle proximal to the tricuspid valve. Distal His bundle pacing has a number of advantages over proximal His pacing, including, lower capture thresholds, a more stable lead position, less far field atrial sensing and better spacing from the AV node in case ablation of this is required for AF rate control. Despite these, outcomes of distal His bundle pacing from the ventricular aspect are less well defined. Methods We performed a retrospective review of patients who underwent conduction system pacing between January 2020 and October 2021 at our centre. During this period all procedures were performed employing a distal His bundle pacing approach with the lead placed on the ventricular aspect of the tricuspid annulus. Data was collected at implant, follow-up at 1 month and then every 6 months. Results Out of 35 patients, 33 underwent successful His bundle pacing (acute success rate of 94%), 1 patient had left bundle branch pacing and another patient had an unsuccessful procedure. Mean age was 74 years, median LVEF 45% and median pre-implant QRS was 108ms. 80% of the cohort had a history of AF. The indications for pacing were as follows: AF - for pace &amp; ablate (60%); high grade AV block with narrow QRS and mild LVSD (17%); failed LV lead (14%); and other 9%. Mean procedure duration and fluoroscopy time were 78 minutes and 12.05 minutes, respectively. Median threshold at implant was 1.00V (IQR 0.719V). Selective His bundle pacing was achieved in 60% and non-selective in 34%. Mean follow-up duration was 150 days with median threshold at last f/up of 0.75V (IQR 0.750V). There were no acute procedural complications. 1 patient had a significant rise in threshold at follow-up and therefore required upgrade to CRT-P. Discussion Our data shows that distal His bundle pacing is a safe and effective technique for conduction system pacing. Thresholds appear stable at follow-up and failure rate was found to be comparable to biventricular pacing. We noted an initial learning curve for both implanter and physiologists with relatively poorer outcomes for the earlier cases. Longer term follow-up is ongoing, including functional assessment and follow-up to assess for remodelling with echocardiography. Prospective randomised trials are needed to compare conduction system pacing vs RV pacing in AF patients with HFpEF or mild LVSD undergoing AVN ablation, and vs biventricular pacing in the severe LVSD population.

Effects of positive endomyocardial biopsy on the survival and the outcomes of catheter ablation of ventricular tachycardia in patients with cardiac sarcoidosis

Abstract Funding Acknowledgements Type of funding sources: Private hospital(s). Main funding source(s): Heart center of Leipzig Background Cardiac sarcoidosis (CS) is frequently unrecognized cause of non-ischemic cardiomyopathy associated ventricular tachycardia (VT), who eventually require VT ablations because of refractory VTs; however, the reported long-term outcomes after VT ablation are conflicting. Because of the low diagnostic yield of the endomyocardial biopsy (EMB), diagnosis of CS is often based on clinical and imaging criteria, which can lead to misdiagnosing. Purpose and objectives The purpose of this study was to identity whether patients with histologically-proven CS (EMB+) have different patient, procedural characteristics and outcomes after VT ablation as compared to those in whom the diagnosis was based on clinical criteria only (EMB-). Methods Between 2015-2021, 153 patients with suspected CS were evaluated according to a specified protocol including CMR, 18FDG-PET, EMB, bronchoscopy and EBUS biopsy, and serum markers. Those who fulfilled the latest criteria for CS of the Japanese Circulation Society (JCS) were divided into 2 groups: EMB (+) CS proven by myocardial biopsy, and EMB (-) CS fulfilling the clinical criteria for CS. The following endpoints were defined: 1) VT recurrence after ablation; and 2) the composite endpoint of death, heart transplantation or LVAD implantation. Results We identified 76 patients fulfilling the JCS criteria for CS (mean age 50 ± 10.6 years, 38% female, EMB (+) 35.5%). The leading symptoms were as follows: sustained VT in 23 (30%), high-grade AV block in 23 (30%), heart failure in 18 (24%), and other in 12 pts (16%). EMB (+) and the EMB (-) patients had similar clinical characteristics except for the imaging findings. EMB (+) patients exhibit LGE in CMR in 96% vs. 73% in EMB (-); P=0.024, whereas 18FDG-PET showed abnormal myocardial activity in 91% in the EMB (+) vs. 65% in the EMB (-); P=0.028. The primary composite endpoint was reached in 7.4% in EMB (+) group and in 12.2 % in EMB (-) group; P = 0.7. VT ablation was performed in 15 cases: 9 ablations (33%) in EMB (+) vs. 6 ablations (12%) in EMB (-); P=0.037. At the end of the procedure, all inducible VTs were successfully ablated in 100% of the EMB (-) patients vs. 56% in EMB (+) patients; P=0.1. VT recurrence was 78% in EMB (+) group vs. 67% in EMB (-); P = 0.6. The only procedural difference between the groups was the presence of vast RV low-voltage areas in 67% of the EMB (+) vs. 0% in EMB (-); P = 0.028. Conclusions Patients with CS and positive EMB exhibit more often LGE in CMR, abnormal 18FDG-PET activity and required more frequently VT ablation. The procedural characteristics between both groups were similar, except for the frequently observed RV low-voltage areas in most EMB (+) patients, whereas the RV was not affected in any of the EMB (-) patients. In spite of these differences, the VT recurrence rates and the survival seemed not to be affected by the histological evidence of CS in EMB.

Multicenter Outcomes of Catheter Ablation for Atrioventricular Reciprocating Tachycardia Mediated by Twin Atrioventricular Nodes.

This study sought to describe the electrophysiologic properties and catheter ablation outcomes for atrioventricular reciprocating tacchycardia via twin atrioventricular nodes (T-AVRT). Although catheter ablation for T-AVRT is an established entity, there are few data on the electrophysiological properties and outcomes of this procedure. An international, multicenter study was conducted to collect retrospective procedural and outcomes data for catheter ablation of T-AVRT. Fifty-nine patients with T-AVRT were identified (median age at procedure, 8 years [interquartile range: 4.4-17.0 years]; 49% male). Of these, 55 (93%) were diagnosed with heterotaxy syndrome (right atrial isomerism in 39, left atrial isomerism in 8, and indeterminate in 8). Twenty-three (39%) had undergone Fontan operation (12 extracardiac, 11 lateral tunnel). After the Fontan operation, atrial access was conduit or baffle puncture in 15 (65%), fenestration in 5 (22%), and retrograde in 3 (13%). Acute success was achieved in 43 (91%) of 47 attempts (targeting an anterior node in 23 and posterior node in 24). There was no high-grade AV block or change in QRS duration. Over a median of 3.8 years, there were 3 recurrences. Of 7 patients with failed index procedure or recurrent T-AVRT, 6 (86%) were associated with anatomical hurdles such as prior Fontan or catheter course through an interrupted inferior vena cava-to-azygous vein continuation (P = 0.11). T-AVRT can be targeted successfully with low risk for recurrence. Complications were rare in this population. Anatomical challenges were common among patients with reduced short and long-term efficacy, representing opportunities for improvement in procedural timing and planning.

Long-Term Implications of Pacemaker Insertion in Younger Adults: A Single Centre Experience

The long-term implications of pacemaker insertion in younger adults are poorly described in the literature. We performed a retrospective analysis of consecutive younger adult patients (18-50 yrs) undergoing pacemaker implantation at a quaternary hospital between 1986-2020. Defibrillators and cardiac resynchronisation therapy devices were excluded. All clinical records, pacemaker checks and echocardiograms were reviewed. Eighty-one (81) patients (median age 41.0 yrs IQR=35-47.0, 53% male) underwent pacemaker implantation. Indications were complete heart block (41%), sinus node dysfunction (33%), high grade AV block (11%) and tachycardia-bradycardia syndrome (7%). During a median 7.9 (IQR=1.1-14.9) years follow-up, nine patients (11%) developed 13 late device-related complications (generator or lead malfunction requiring reoperation [n=11], device infection [n=1] and pocket revision [n=1]). Five (5) of these patients were <40 years old at time of pacemaker insertion. At long-term follow-up, a further nine patients (11%) experienced pacemaker-related morbidity from inadequate lead performance managed with device reprogramming. Sustained ventricular tachycardia was detected in two patients (2%). Deterioration in ventricular function (LVEF decline >10%) was observed in 14 patients (17%) and seven of these patients required subsequent biventricular upgrade. Furthermore, four patients (5%) developed new tricuspid regurgitation (>moderate-severe). Of 69 patients with available long-term pacing data, minimal pacemaker utilisation (pacing <5% at all checks) was observed in 13 (19%) patients. Pacemaker insertion in younger adults has significant long-term implications. Clinicians should carefully consider pacemaker insertion in this cohort given risk of device-related complications, potential for device under-utilisation and issues related to lead longevity. In addition, patients require close follow-up for development of structural abnormalities and arrhythmias.

Arrhythmia Mechanism in Acute Hyperglycemic Conditions

Acute hyperglycemia or stress hyperglycemia commonly occurs in critically ill patients and could be a marker of disease severity. Hyperglycemia at hospital admission is commonly found in patients with cardiovascular disease, regardless of their diabetic status; one of them is arrhythmia. Arrhythmia or dysrhythmia is a heart rhythm disorder that refers to any disturbance in the frequency, regularity, location of origin or electrical impulses conduction of the heart. Arrhythmias associated with stress hyperglycemia include atrial arrhythmias, supraventricular tachycardia (SVT), high-grade (atrioventricular) AV block, and ventricular arrhythmias. Type 2 diabetes was also associated with a significantly increased risk of arrhythmias and sudden death. Hyperglycemia plays an important role in arrhythmia through various mechanisms. In this review, we describe the correlation and mechanism by which arrhythmias may occur in hyperglycemic conditions

Long-term implications of pacemaker insertion in younger adults: a single centre experience

Abstract Background The long-term implications of pacemaker insertion in younger adults are poorly described in the literature. Methods We performed a retrospective analysis of consecutive younger adult patients (18–50 years) undergoing pacemaker implantation at a quaternary hospital between 1986–2020. Defibrillators and cardiac resynchronisation therapy devices were excluded. All clinical records, pacemaker checks and echocardiograms were reviewed. Results 81 patients (39.5±9.6 years, 53% male) underwent pacemaker implantation. Indications were complete heart block (41%), sinus node dysfunction (33%), high grade AV block (11%) and tachycardia-bradycardia syndrome (7%). During a median 7.6 (IQR=0.6–14.8) years follow-up, 9 patients (11%) developed 13 late device-related complications (generator or lead malfunction requiring reoperation (n=11), device infection (n=1) and pocket revision (n=1)). Five of these patients were &amp;lt;40 years old at time of pacemaker insertion. At long-term follow-up, a further 9 patients (11%) experienced significant symptoms from inadequate lead performance managed with device reprogramming. Sustained ventricular tachycardia was detected in 2 patients (2%). Deterioration in ventricular function (LVEF decline &amp;gt;10%) was observed in 14 patients (17%) and 7 of these patients required subsequent biventricular upgrade. Furthermore, 4 patients (5%) developed new tricuspid regurgitation (≥ moderate-severe). Of 69 patients with available long-term pacing data, minimal pacemaker utilisation (pacing &amp;lt;5% at all checks) was observed in 13 (19%) patients. Conclusions Pacemaker insertion in younger adults has significant long-term implications. Clinicians should carefully consider pacemaker insertion in this cohort given risk of device-related complications, potential for device under-utilisation and issues related to lead longevity. In addition, patients require close follow-up for development of structural abnormalities and arrhythmias. Funding Acknowledgement Type of funding sources: None.

The timing and mechanism of high-grade AV block post-TAVI: knowing your enemy

Abstract Background Complete atrioventricular block (AVB) requiring permanent pacemaker implantation (PPMI) is still a major limitation of transcatheter aortic valve implantation (TAVI) procedures. Although right-bundle branch block (RBBB), membranous septum (MS) length and self-expandable prothesis are recognizable risk factors, their predictability to PPMI is far from satisfactory. While some patients develop persistent intra-procedure high-grade AVB (H-AVB), others present much later with severe bradycardia. Purpose This study aims to describe and compare the characteristics of patients who develop AVB during or after TAVI. Methods Single centre prospective registry of 506 consecutive patients submitted to TAVI with no previous pacemaker between 2017 and 2020. Post-procedure PPMI (up to 30 days after discharge) was studied and divided into two groups according to the development of persistent intra-procedure H-AVB (Group A) or post procedure H-AVB (Group B). Baseline ECG, computed tomography and TAVI-related characteristics were analyzed. Results A total of 88 patients (17,3%), aging 83±6 years, 36.4% male, underwent post-TAVI PPMI (6 after discharge). Previous conduction disturbances were present in 50 (56.8%) patients and 25 (28.4%) had RBBB. 83% were submitted to self-expandable TAVI. Forty-two patients (47.7%) had persistent intra-procedure H-AVB (Group A) whereas 52.3% had post-procedure H-AVB (Group B). In patients with persistent intra procedure H-AVB previous RBBB was significantly more frequent (45.2%, n=19) when compared to patients with post-procedure H-AVB (13%, n=6; p=0.001). Contrarily, AF and previous left-bundle branch block (LBBB) were more likely in Group B. No difference in valvular calcification, MS length, prosthesis type or implantation technique was noted (picture 1). In the group with post-procedure H-AVB, 21.7% had transient AVB during TAVI and all developed de novo LBBB or first-degree AVB post-TAVI. Among these, 33 patients (71.7%) developed delayed H-AVB (&amp;gt;48h post-procedure) while the remaining presented earlier. Conclusions In patients with PPMI post-TAVI, those with persistent intra-procedure H-AVB had higher rates of previous RBBB, while those with post-procedure H-AVB frequently had a normal baseline ECG. Anatomical and procedural characteristics did not differ between groups. Further studies are needed to confirm these results. Funding Acknowledgement Type of funding sources: None.

MAGIC OF ADVANCED IMAGING AND IMMUNOTHERAPY IN CARDIAC SARCOIDOSIS

TOPIC: Cardiovascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: This case report emphasizes the role of advanced imaging and immunotherapy in the diagnosis and management of cardiac sarcoidosis (CS). CASE PRESENTATION: A 52-year-old healthy male presented with near-syncope for 5 days. He had a blood pressure of 164/67 mmHg and a heart rate of 43 bpm. Electrocardiogram revealed complete-heart-block (CHB) with a ventricular rate of 38/min. Troponin T and electrolytes were normal, and Lyme's serology was negative. Echocardiogram was normal. Cardiac magnetic resonance imaging (CMR) revealed late gadolinium enhancement (LGE) affecting the mid inferior segment at the right ventricle (RV) insertion site (Figure 1). A cardiac and whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scan showed focal areas of increased FDG uptake in the LV involving mid and basal anteroseptal segments, mid inferoseptal segment, basal inferolateral, and basal inferior segments with normal perfusion (Figure 2). The scan also revealed hypermetabolic bilateral hilar and mediastinal lymphadenopathy. A diagnosis of CS was made. An Implantable-Cardioverter-defibrillator (ICD) was placed and the patient was discharged on 40mg of prednisone and 20mg of leflunomide. Within 4 months, he went from 100% RV pacing to 0%. Eventually, the corticosteroid was tapered off. At follow-up after 1.5 years, RV pacing remained 0% on Leflunomide 20mg. DISCUSSION: One should always suspect CS in young patients with high-grade AV block. During the workup of CHB (Figure 3), the 2017 Japanese Circulation Society Working Group Criteria for diagnosing CS was followed (1). The patient had 2 characteristic findings strongly suggestive of sarcoidosis: (a) hilar lymphadenopathy and (b) significant tracer accumulation in the myocardium and hilar lymph nodes on FDG-PET scan. He also met 2 major criteria strongly suggestive of CS: (a) LGE on CMR and (b) abnormal myocardial FDG uptake. These findings, per the criteria, establish the clinical diagnosis of CS. The mainstay of treatment for CS is corticosteroids +/- steroid-sparing agents to decrease intra-cardiac inflammation (1). CHB patients with CS have a high risk of ventricular arrhythmias, hence should receive ICD (2). The addition of antimetabolite adjuvants is more effective than corticosteroids alone (3). They may reduce the total time of glucocorticoid therapy and keep patients in remission. CONCLUSIONS: Clinical diagnosis of CS can be established with FDG-PET imaging and CMR. CS patients with advanced heart block should receive ICD. Corticosteroids are the mainstay of treatment. Immunotherapy is an effective adjunct that can help taper the glucocorticoids and keep patients in remission. Early introduction of these agents should be considered in these patients. REFERENCE #1: 1. Trivieri MG et al. Challenges in Cardiac and Pulmonary Sarcoidosis: JACC State-of-the-Art Review. J Am Coll Cardiol 2020;76:1878-1901 REFERENCE #2: 2. Nordenswan H-K et al. Outcome of Cardiac Sarcoidosis Presenting With High-Grade Atrioventricular Block. Circulation: Arrhythmia and Electrophysiology 2018;11:e006145 REFERENCE #3: 3. Nagai S, Yokomatsu et al. Treatment with methotrexate and low-dose corticosteroids in sarcoidosis patients with cardiac lesions. Intern Med 2014;53:427-33. DISCLOSURES: No relevant relationships by Roy Chung, source=Web Response No relevant relationships by Sachin Kumar, source=Web Response No relevant relationships by Raunak Nair, source=Web Response

Clinically Significant High-Grade AV Block as a Reversible Cause for Acute Kidney Injury in Hospitalized Patients-A Propensity Score Matched Cohort.

Background. High-grade AV block (HGAVB) is a life-threatening condition. Acute kidney injury (AKI) which is usually caused by renal hypo-perfusion is associated with adverse outcomes. We aimed to investigate the association between AKI and HGAVB. Methods. This is a retrospective cohort comparing the incidence of AKI among patients with HGAVB requiring pacemaker implantation compared with propensity score matched controls. Primary outcome was the incidence of AKI at admission. Secondary outcomes were change in creatinine levels, AKI during stay, recovery from AKI, mortality and major adverse kidney events (MAKE). Results. In total, 80 HGAVB patients were compared to 400 controls. HGAVB patients had a higher proportion of admission AKI compared to controls (36.2% versus 21.1%, RR = 1.71 [1.21–2.41], p = 0.004). Creatinine changes from baseline to admission and to maximum during hospitalization, were also higher in HGAVB (p = 0.042 and p = 0.033). Recovery from AKI was more frequent among HGAVB patients (55.2% vs. 25.9%, RR = 2.13 [1.31–3.47], p = 0.004) with hospitalization time, MAKE and crude mortality similar (p > 0.158). Conclusions. AKI occurs in about one third of patients admitted with HGAVB, more frequent compared to controls. Patients with AKI accompanying HGAVB were likelier to recover from AKI. Further studies to explore this relationship could aid in clinical decision making for HGAVB patients.

Leadless pacemakers: does location matter?

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Leadless pacemakers (LPs) provide a viable alternative for patients who have an indication for pacing where transvenous pacing is not desirable or possible. Registries have demonstrated stable performance associated with LPs. There is preference towards implanting LPs into the trabeculated septum rather than the apex or free wall. We report our experience with the impact of the implantation site on acute and long-term electrical performance of LPs. Methods We ran a retrospective analysis on the first 100 LPS implanted at our centre. Two independent observers reviewed the fluoroscopic images and post-implant chest x-rays to classify the LPs’ positions. We obtained the recorded pacing threshold , R-wave amplitude and impedance of the devices at the time of implant and at the latest available routine device follow-up. We used one-way ANOVA testing to compare the acute and long-term electrical performance of the LPs between different implantation sites. Results We were able to classify the site of the LPs implants in a total of 90 patient. 84 Patients (60% male) 57.3± 22.16 years were included .23.8% of the patients presented with syncope. Indications for pacing were symptomatic sinus node dysfunction (33.3%), high grade AV block (34.5%), bradyarrhythmia associated with atrial tachyarrhythmias (28.6%) and other indications (3.6%). We had a 100% successful implant rate, 85.7% required ≤2 attempts and 71.4% required one attempt. A total of 32 implants were in the apex (38.1%), 26 in mid-septum (30.9 %), 13 in the apical septum (15.5%), 12 on the septal aspect of the right ventricular inflow (14.3%) and 1 implant (1.2%) in the septum of the RV outflow tract. The follow up period of the 84 patients was 3.09 ± 1.97 years. 100% of the LPs had the pacing thresholds &amp;lt;2.0 V @0.24 ms at the time of implant. Pacing threshold, R-wave amplitude, and impedance averaged at 0.67 ± 0.41 V, 10.86 ± 5.41 mV, and 775 ± 193.28 Ohms respectively at the time of implantation and 0.66 ± 0.39 V, 14.08 ± 6.14 mV, and 564.29 ± 96.76 Ohms at the last device check. There was no statistically significant difference in either the pacing thresholds or the impedance between implant sites. Post hocTukey’s analysis (excluding the outflow tract case) demonstrated significant statistical difference in the R-wave amplitudes between implants at the apex and the mid-septum both at the time of implantation (12.9 ± 6.1 mV and 8.53 ± 2.84 mV; p = 0.0196) and at follow up (15.97 ± 5.35 mV and 11.52 ± 5.01 mV; p = 0.0415). There were no differences between other sites Conclusions Our analysis demonstrated that aside from the difference between the sensed R wave amplitudes between LPs implanted at the apex and those implanted at mid-septum , there was no statistically significant difference in the acute or the long term electrical performance of implanted LPs regardless of the implantation site. A limitation to our analysis is the relatively low number of LP implants included in our analysis. Abstract Figure. Mean of parameters by validated position

Long-term outcome of patients with inflammatory cardiomyopathies implanted with cardiac defibrillators: a single centre experience

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Arrhythmia management remains a challenge in patients with inflammatory cardiomyopathies and little is known about the clinical characteristics affecting the arrhythmia burden on the long term. Purpose To identify clinical predictors of ICD therapies among patients with inflammatory cardiomyopathies. Methods We included all ICD patients implanted in our centre over the last 10 years in a context of inflammatory cardiomyopathy. For each patient, data from implant, device checks and clinical follow-ups were retrospectively collected. Results A total of 16 patients were identified (11 males, age at implant 50 ± 13 years). Based on the revised 2019 Japanese Circulation Society criteria, a diagnosis of cardiac sarcoidosis was established in all cases. Secondary prevention of sudden cardiac death was the indication for ICD implant in 50% of the patients. In 5 cases a CRT-D device was implanted because of concomitant left ventricular systolic dysfunction and a high grade AV block. During a median follow-up of 5.0 (0.9-6.6) years, 9 patients (56%) received ≥ 1 appropriate ICD treatment for ventricular tachycardia (VT) episodes (ATP only in 3 cases, ATP and shocks in 6 cases) with a median time lag from implant of 65.5 (57.0-314.8) days. Of these 9 patients, 6 were initially implanted for secondary prevention of sudden cardiac death. At the time of ICD therapies, 8 patients were under immunosuppressive treatment and 3 under antiarrhythmic drugs. A cardiac 18F-FDG PET scan was performed in 7 patients and an abnormal FDG uptake, compatible with an active inflammatory status, was documented in all cases. After optimisation of antiarrhythmic drugs, a VT ablation procedure was performed in 3 patients during the first 6 months following the ICD treatment because of recurrent VT. In another 3 patients, a VT ablation was performed 2-5 years after the first ICD treatment and was associated to stereotactic radiotherapy to achieve VT control. Conclusion In our series, patients affected by inflammatory cardiomyopathy and implanted with an ICD for secondary prevention of sudden cardiac death appear to be at high risk of ICD treatment especially during the first months after implantation. This could be the consequence of a more aggressive underlying inflammatory substrate, especially during the first phases of the disease, whereas the occurrence of VT episodes at later stage appear to be more scar-related. However, further studies on larger populations are required to confirm these observations.

Risk Factors for Postoperative Pacemaker Implantation After Rapid Deployment Aortic Valve Replacement: Results from the RADAR Registry.

Rapid deployment aortic valve replacement has been recently introduced in clinical practice. Different studies have reported a significant reduction in surgical times with excellent hemodynamic profiles and short-term results. However, an increase in permanent pacemaker requirements compared with conventional aortic valve replacement has been described. Nevertheless, risk factors for postoperative pacemaker implantation are not well known. The aim of this study is to report our early outcomes with rapid deployment aortic valve replacement within the RADAR Registry, especially focusing on risk factors for postoperative pacemaker implantation. Between April 2012 and January 2016, 164 patients undergoing isolated or combined aortic valve replacement with Edwards INTUITY Elite (Edwards Lifesciences, Irvine, CA, USA) were included in the RADAR Registry. Pre-, intra- and postoperative clinical data results and complications were recorded, especially focusing on risk factors for the development of postoperative complete or high-grade AV block requiring pacemaker implantation. Patients were followed up for up to 1year with evaluation of clinical and echocardiographic outcomes. A total of 164 consecutive patients were included in this study, where 128 patients (78.05%) had an isolated aortic valve replacement (group 1) and 36 (21.95%) a concomitant procedure (group 2). The surgical approach was ministernotomy in 61 patients (37.20%) and median sternotomy in 100 patients (60.98%). Complications with valve implantation were observed in three patients. Postoperative complete or high-degree AV block requiring a permanent pacemaker implantation developed in ten patients (6.9%). Seven patients died in-hospital (4.27%). No significant differences between groups were found in terms of stroke, postoperative infection, mortality, atrial fibrillation and postoperative atrioventricular block. Seven patients presented acute renal impairment (5.51%) in group 1 versus seven patients (20%) in group 2 (p = 0.007). In multivariate analysis, low weight and preoperative arrhythmia (atrial fibrillation, bifascicular block, left bundle branch block) emerged as risk factors for postoperative AV block requiring a pacer. In median follow-up of 1year, seven (4.27%) patients died, and no cases of structural valve deterioration or endocarditis were observed. Significant patient-prosthesis mismatch was found in seven (4.27%) patients. Initial experience with rapid deployment aortic valve replacement in the RADAR Registry demonstrates low rates of implantation complications and good perioperative and 1-year clinical and echocardiographic outcomes. Incidence of postoperative AV block requiring a pacer correlated with low weight and preoperative arrythmias (atrial fibrillation, bifascicular block and left bundle branch block). Avoidance of oversizing and careful consideration of implantation of this technology in patients with pre-existing arrythmias could minimize the risk for postoperative pacemaker implantation.