Single operator experience, learning curve, outcomes, and insights gained with conduction system pacing.

BACKGROUND: Conduction system pacing (CSP) is increasingly utilized to prevent and correct dyssynchrony. Barriers to CSP adoption include limited training, methodologic variability, laboratory slot allocation, and few data on learning curves. We report learning curves/clinical outcomes from a single experienced electrophysiologist who was new to CSP, and share gained insights. METHODS: Retrospective analysis of all patients who underwent attempted CSP implantation (2016-2023). Patient characteristics, ECGs, echocardiograms, fluoroscopy/procedure times, lead data were recorded at implant and follow-up. RESULTS: CSP leads were implanted successfully in 167/191(87.4%) patients with a follow-up of 278 ± 378 days. His-bundle pacing (HBP = 59) and left-bundle-area pacing (LBAP = 108) had similar procedure/fluoroscopy times, QRS duration decreases, and ejection fraction improvements (all p > NS). Eight HBP lead revisions were required for high capture thresholds LBAP demonstrated lower pacing thresholds, higher lead impedances, and greater R-wave amplitudes at implant and follow-up. After 25 HBP cases, implant pacing thresholds, fluoroscopy, procedural times did not decrease. After 25 LBAP cases, there were significant decreases in all these parameters (p < 0.05). A separate analysis in LBAP patients with recorded Purkinje signals showed no differences in paced ECG characteristics between patients with pre- QRS Purkinje signals versus patients with Purkinje signals post-QRS onset. CONCLUSIONS: Experienced implanters who are new to CSP can achieve steady-state procedural/fluoroscopy times after a learning curve of 25 implants. LBAP showed lower capture thresholds and higher success rates. Adequate depth of lead deployment (as determined by published parameters) does not require Purkinje potential to be pre-QRS. Operators new to CSP.can forego HBP and directly implement LBAP.

Beyond biventricular pacing: Exploring the advantages of his-bundle pacing and left bundle branch pacing in heart failure-A systematic review and meta-analysis.

BACKGROUND: This meta-analysis compares His-Purkinje system pacing (HPSP), a novel cardiac resynchronization therapy (CRT) technique that targets the intrinsic conduction system of the heart, with conventional biventricular pacing (BiVP) in heart failure (HF) patients with left ventricular (LV) dysfunction and dyssynchrony. METHODS: We searched multiple databases up to May 2023 and identified 18 studies (five randomized controlled trials and 13 observational studies) involving 1291 patients. The outcome measures were QRS duration, left ventricular ejection fraction (LVEF) improvement, left ventricular end-diastolic diameter (LVEDD) change, HF hospitalization, and New York Heart Association (NYHA) functional class improvement. We used a random-effects model to calculate odds ratios (OR), and mean differences (MD) with 95% confidence intervals (CI). We also assessed the methodological quality of the studies. RESULTS: The mean LVEF was 30.7% and the mean follow-up duration was 8.1 months. Among LBBP, HBP, and BiVP, HBP provided the shortest QRS duration [MD: -18.84 ms, 95% CI: -28.74 to -8.94; p = 0.0002], while LBBP showed the greatest improvement in LVEF [MD: 5.74, 95% CI: 2.74 to 7.46; p < 0.0001], LVEDD [MD: -5.55 mm, 95% CI: -7.51 to -3.59; p < 0.00001], and NYHA functional class [MD: -0.58, 95% CI: -0.80 to --0.35; p < 0.00001]. However, there was no significant difference in HF hospitalization between HPSP and BiVP. CONCLUSION: LBBP as modality of HPSP demonstrated superior outcomes in achieving electrical ventricular synchrony and systolic function, as well as alleviating HF symptoms, compared to other pacing techniques.

Evaluating Goldberger's triad as a marker of congestive heart failure: A systematic review and retrospective study.

BACKGROUND: In 1982, Drs. Barold and Goldberger described an ECG triad associated with left ventricular dysfunction (LVD) consisting of high precordial QRS voltage, low limb lead voltage, and poor precordial R wave progression. Studies have since attempted to replicate the originally reported sensitivity (70%), specificity (>99%), and positive predictive value (PPV, 100%) of Goldberger's triad (GT) with variable results. PURPOSE: To assess sensitivity, specificity and PPV of GT as a screening tool for LVD in the current era. METHODS: We performed: (1) A systematic review of the published studies; (2) Searched our hospital ECG database (GE MUSE) for diagnoses of "low limb-voltage" and "left ventricular hypertrophy" from 2017 to 2022; identified ECGs were analyzed for GT criteria and their medical records were screened for LVD. (3) ECG analysis of patients with known idiopathic LVD for the GT. RESULTS: A total of 11,115 patients from 8 studies were included in the systematic review of published studies and showed widely varying sensitivity, specificity and PPV. A total of 4576 ECGs (in GE MUSE) from 372 patients met initial screening criteria of low limb lead voltage and LVH; only 12 patients had ECGs that satisfied GT. Of these 12, only 1 patient had evidence of LVD, yielding a PPV of 8%. Finally, of the 40 patients with known LVD, only 1 met the ECG criteria for GT, resulting in a sensitivity of 2.5%. CONCLUSION: Our literature review does not support the original results of GT. ECGs from our database that met GT (searched by low limb-voltage and left ventricular hypertrophy) over a span of 5 years were rare. When present, the PPV of GT was 8%. In patients with established LVD, the sensitivity was 2.5%. These data do not validate GT as tool to identify LVD in the current era.

Conduction system pacing versus biventricular pacing: Reduced repolarization heterogeneity in addition to improved depolarization.

INTRODUCTION: His-bundle pacing (HBP) and left-bundle-area pacing (LBAP) are conduction system pacing (CSP) modalities increasingly used as alternatives to conventional biventricular pacing (BiVP). While effects of CSP on ventricular depolarization have been reported, effects on ventricular repolarization have not. METHODS: QRS duration (QRSd) and validated ECG parameters of ventricular repolarization associated with arrhythmic risk (T-peak-to-T-endTransmural , T-peak-to-T-endTotal , T-peak dispersion, QTc, QTc dispersion) were analyzed post-implant in 107 patients: 60 with CSP (HBP: n = 35, LBAP: n = 25) and 47 with BiVP. T-wave memory resolution and QTc shortening were analyzed on ECGs obtained ≥25 days post-implant. Twenty blinded measurements were obtained by both authors to assess Interobserver variability. RESULTS: Although QRSd was shorter with HBP versus LBAP (119 ± 7 ms vs. 132 ± 9 ms, p = .02), there were no significant differences in any repolarization parameters between these methods of CSP. However, when comparing CSP (HBP + LBAP) to BiVP, both QRSd (125 ± 5 ms vs. 147 ± 7 ms, p < .0001) and repolarization parameters (T-peak-to-T-endTransmural : 83 ± 5 ms vs. 107 ± 8 ms; T-peak-to-T-endTotal : 110 ± 7 ms vs. 137 ± 10 ms; QTc: 470 ± 12 ms vs. 506 ± 12 ms; all p ≤ .0001) were significantly shorter with CSP. Improved T-peak-to-T-end values were unrelated to pre-implant QRSd or LV function. Interobserver variability was 4.6 ± 1.9 ms. Frontal QRS-T angle narrowing (132° to 104°, p = .001) and QTc shortening (483 ± 13 ms to 464 ± 12 ms, p = .008) were seen only with CSP. CONCLUSIONS: In addition to improved depolarization, CSP reduced repolarization heterogeneity and provided greater T-wave memory resolution as compared to BiVP. Both modalities of CSP (HBP + LBAP) resulted in comparably reduced repolarization heterogeneity regardless of baseline QRSd and LV function. These observations may confer lower arrhythmogenic risk and warrant further study.

An unusual case of non-reentrant atrioventricular nodal tachycardia.

INTRODUCTION: Although uncommonly encountered, dual atrioventricular nodal non-reentrant tachycardia (DAVNNRT) is a well-described arrhythmia that can manifest in patients with dual atrioventricular nodal pathways physiology. This arrhythmia is characterized on electrocardiogram (ECG) by a single P wave followed by two conducted QRS complexes (so-called "double fire"), and on intracardiac electrograms by a single atrial electrogram followed by two separate His deflections and ventricular electrograms. METHODS/RESULTS: We report a rare case of "triple-fire" atrioventricular non-reentrant tachycardia in which a patient was found to have three distinct atrioventricular nodal pathways and multiple triple fire responses, both on surface ECG and intracardiac electrograms. CONCLUSION: Multiple pathways physiology and it's clinical ramifications are discussed.

Dyssynchronous Heart Failure: A Clinical Review.

PURPOSE OF THE REVIEW: Dyssynchrony occurs when portions of the cardiac chambers contract in an uncoordinated fashion. Ventricular dyssynchrony primarily impacts the left ventricle and may result in heart failure. This entity is recognized as a major contributor to the development and progression of heart failure. A hallmark of dyssynchronous heart failure (HFd) is left ventricular recovery after dyssynchrony is corrected. This review discusses the current understanding of pathophysiology of HFd and provides clinical examples and current techniques for treatment. RECENT FINDINGS: Data show that HFd responds poorly to medical therapy. Cardiac resynchronization therapy (CRT) in the form of conventional biventricular pacing (BVP) is of proven benefit in HFd, but is limited by a significant non-responder rate. Recently, conduction system pacing (His bundle or left bundle branch area pacing) has also shown promise in correcting HFd. HFd should be recognized as a distinct etiology of heart failure; HFd responds best to CRT.

Ventricular tachycardia induced by a backup pacing stimulus in a patient with a dual chamber pacemaker with AutoCapture.

Manufacturers of cardiac implantable electronic devices have incorporated automatic features to allow for remote monitoring, improve device longevity, and additional safety. Algorithms to automatically measure capture threshold and adjust output to preserve battery life are one such feature. Automatic features may occasionally result in unexpected or undesirable clinical outcomes. We report on a patient who developed ventricular tachycardia inadvertently induced by the AutoCapture. feature of an Abbott/St. Jude Medical (SJM) pacemaker.

Tricuspid regurgitation associated with implantable electrical device insertion: A systematic review and meta-analysis.

BACKGROUND: Implantable cardioverter defibrillator (ICD) and permanent pacemaker (PPM) lead placement may worsen or result in tricuspid regurgitation (TR). While the association between lead placement and the incidence of TR has been established, current understanding of this problem remains incomplete. This systematic review and meta-analysis sought to pool the existing evidence to better understand the occurrence and severity of TR associated with cardiac implantable electrical device (CIED) insertion. METHODS: An electronic search was performed to identify all relevant studies published from 2000 to 2018. Overall, 15 studies were selected for the analysis comprising 4019 patients with data reported on TR development following ICD or PPM lead placement. Demographic information, perioperative clinical variables, and clinical outcome measures, including pre and postoperative echocardiographic TR grade changes, were extracted and pooled for systematic review. RESULTS: Mean patient age was 69 years [95% CI: 64.62-73.59], and 63% [95% CI: 57-68] were male. Devices implanted included ICD in 57% [95%CI: 43-70] and PPM in 41% [95%CI: 31-52]. The most common indications for pacemaker implantation were sick sinus syndrome in 22% [95% CI: 22-37] and AV block in 21% [95%CI:12-34. The commonest indications for ICD implantation were primary and secondary prevention of sudden cardiac death. Atrial fibrillation was present in 37% [95%CI: 28-46] and congestive heart failure in 15% [95%CI: 2-57]. Baseline distribution of TR grades were as follows: grade 0/1 TR in 89% [95%CI: 82-93], grade 2 TR in 8% [95%CI: 5-13], grade 3 TR in 2% [95%CI: 0-7] and grade 4 TR in 2% [95%CI: 1-4]. Post-procedure, grade 0/ 1 TR decreased to 68% [95% CI: 51-81] (p < 0.01), grade 2 TR increased to 21% [15-28] (p < 0.01), grade 3 TR increased to 13% [95%CI: 5-32] (p = 0.02), and grade 4 TR increased to 7% [95%CI: 5-9] (p < 0.01). CONCLUSION: ICD and PPM lead placement is associated with increased TR post-procedure. Further studies are warranted to evaluate changes in TR grade in the long term.

Underdiagnosis of VT due to cycle length variation among cardiac sarcoidosis patients having ICD: Problem with stability discriminator.

BACKGROUND: Implantable cardioverter defibrillator (ICD) is recommended for patients with ventricular tachycardia (VT) due to cardiac sarcoidosis (CS). Programming supraventricular tachycardia (SVT) discriminators (onset, stability, and morphology/template match) is generally recommended to minimize inappropriate therapies. However, VT in patients with CS is known to show cycle length variability (CLV) and pleomorphism. OBJECTIVE: To determine whether the stability criterion, designed to prevent inappropriate therapy during atrial fibrillation with rapid ventricular rates, could potentially lead to incorrect classification of VT as SVT and inappropriately delay or inhibit ICD therapy. METHODS: Cases of biopsy-proven CS with VT were analyzed. For patients with implanted devices, all recorded electrograms of tachycardia episodes and ICD therapies were analyzed at last follow up. RESULTS: A total of 142 patients were included (mean age 38 years, 87 males). One hundred and three of 142 patients had implanted devices (ICD or CRT-D). Thirty eight of 103 (36.9%) patients received appropriate ICD therapies over 3 ± 2.2 years follow up. Four of 38 (10.5%) of patients experienced delayed-detection or underdetection of VT related to CLV, resulting in VT counters being repeatedly "reset" (classified as "unstable" rhythms). Retrospective analysis of other VT episodes in 70 of 103 (68%) patients revealed that 25 of 80 (31.3%) episodes had > 50 ms cycle length oscillations. CONCLUSION: Among CS patients with VT, CLV is a common occurrence seen in two-thirds of VT episodes. Routine programming of the stability criterion may result in underdetection of VT in a subset of such patients. We recommend that the stability criterion should be programmed "OFF" for patients with CS, unless the patient has documented atrial fibrillation.

Atrial fibrillation post central retinal artery occlusion: Role of implantable loop recorders.

OBJECTIVE: This study evaluated the risk of subclinical atrial fibrillation (AF) in patients with central retinal artery occlusion (CRAO) compared to those with cryptogenic stroke using implantable loop recorders (ILR). METHODS: We conducted a retrospective analysis of 273 consecutive patients who had ILRs inserted at our institution for either cryptogenic stroke (n = 227) or CRAO (n = 46). Our primary endpoint was a time to event analysis for the new diagnosis of AF by ILR. Univariable and multivariable Cox proportional hazard models were used to determine the predictors of time-to-AF. RESULTS: A total of 64 patients were found to have newly diagnosed AF by remote monitoring of the ILR. AF was detected in 57 of 227 (25%) cryptogenic stroke patients by the end of a maximum 5.1 years follow-up and in seven of 46 (15%) CRAO patients by the end of a maximum 3.6 years follow-up (P = .215, log-rank test). The Kaplan-Meier estimates for freedom from AF was 59.4% for CRAO and 66.6% for cryptogenic stroke (P = NS, log-rank test). Baseline variables predicting AF included older patients, higher CHADS2 VASC score, longer PR interval on initial EKG evaluation, and mitral annular calcification on transthoracic echocardiogram. CONCLUSIONS: Patients with CRAO are at risk for subclinical AF, similar to those with cryptogenic stroke. Long-term monitoring to detect AF may lead to changes in pharmacotherapy to reduce the risk for subsequent stroke.

Dual atrioventricular nodal pathways physiology and high-grade heart block.

We report of case of an 87 year old lady with preexisting RBBB who developed LBBB after transcatheter aortic valve replacement (TAVR) for the treatment of severe aortic stenosis. She underwent pacemaker implantation, and subsequently developed high-grade atrioventricular (AV) block. Dual chamber pacing in the setting of complete heart block with a long programmed AV delay showed retrograde P waves. Ventricular pacing showed intact retrograde conduction. Shortening the programmed AV delay resulted in loss of retrograde P waves during dual chamber pacing. These findings are discussed.

Changes in left ventricular synchrony and systolic function in dilated cardiomyopathy patients with fragmented QRS complexes.

AIMS: Fragmented QRS (f-QRS) complexes are associated with adverse cardiovascular events in patients with coronary heart disease; however, the effects on patients with dilated cardiomyopathy (DCM) remain elusive. This study is to investigate the changes of left ventricular (LV) synchrony and systolic function in DCM patients with f-QRS complexes. METHODS AND RESULTS: Twenty DCM patients with f-QRS complexes and 29 DCM patients without f-QRS (n-QRS) complexes were enrolled. The LV segmental longitudinal, radial and circumferential time to peak strain and general longitudinal systolic strain, radial strain, circumferential strain were measured, respectively, by speckle tracking imaging. The LV segmental standard deviations and maximal differences were also calculated. The LV dyssynchrony was defined as the time in peak anteroseptal wall to posterior wall strain >130 ms or longitudinal strain delay index >25%. The mean QRS durations in f-QRS and n-QRS groups were not different (P = ns). The incidence of LV dyssynchrony was 15/20 (75%) vs. 5/29 (17%) in two groups (P < 0.01). Two patients died of sudden death in f-QRS group during 2 years follow-up; however, no death in n-QRS group (P < 0.05). Patients in f-QRS group showed worsening LV dyssynchrony in f-QRS group after 2 years follow-up (P < 0.05). Overall, LV function was comparable at baseline (P = ns), but had significantly worsened only in the f-QRS group (P < 0.05). CONCLUSION: The f-QRS complex is significantly associated with LV dyssynchrony in DCM patients and can be used as a reliable index to evaluate ventricular synchrony and predict the prognosis in DCM patients with narrow QRS complexes.

Pleomorphism during Ventricular Tachycardia: A Distinguishing Feature between Cardiac Sarcoidosis and Idiopathic VT.

BACKGROUND: Ventricular tachycardia (VT), a common manifestation of cardiac sarcoidosis (CS), is associated with high morbidity and mortality. It could be mistaken for idiopathic VT (IVT) in the absence of systemic manifestations and overt cardiac structural abnormality. We studied the electrocardiogram (ECG) characteristics of VT in CS that may distinguish from IVT and also explored the relationship of the ECG characteristics with imaging findings in patients with CS. METHODS AND RESULTS: Twelve-lead ECG characteristics of VT in CS patients (Group I = 37) were compared with IVT (Group II = 49). QRS duration, axis, morphology, VT cycle length, and cycle length variation (CLV) were analyzed. In Group I, 18 (49%) had pleomorphic VT (PLVT) and none in Group II. CLV was seen only in Group I (24%). Mean QRS duration (milliseconds) and cycle length (milliseconds) were greater in Group I (QRSd 152.49 [39.3] vs 140.9 [19.2]) and (332.2 [136.5] vs 312.9 [56.2]), the differences not statistically significant. In Group I, myocardial scar was present in 22 of 25 patients and myocardial inflammation in 28 of 29 patients as assessed by cardiac magnetic resonance imaging (delayed enhancement) and 18-fluorodeoxyglucose positron emission computed tomography, respectively. PLVT was seen more commonly in patients with involvement of >1 myocardial region than focal involvement (58% and 30%, respectively, with myocardial scar and 50% and 40%, respectively, with myocardial inflammation). CONCLUSION: Pleomorphism and CLV during VT may be distinguishing features between IVT and VTs of CS origin.

Superiority of automatic remote monitoring compared with in-person evaluation for scheduled ICD follow-up in the TRUST trial - testing execution of the recommendations.

AIMS: To test recommended implantable cardioverter defibrillator (ICD) follow-up methods by 'in-person evaluations' (IPE) vs. 'remote Home Monitoring' (HM). METHODS AND RESULTS: ICD patients were randomized 2:1 to automatic HM or to Conventional monitoring, with follow-up checks scheduled at 3, 6, 9, 12, and 15 months post-implant. Conventional patients were evaluated with IPE only. Home Monitoring patients were assessed remotely only for 1 year between 3 and 15 month evaluations. Adherence to follow-up was measured. HM and Conventional patients were similar (age 63 years, 72% male, left ventricular ejection fraction 29%, primary prevention 73%, DDD 57%). Conventional management suffered greater patient attrition during the trial (20.1 vs. 14.2% in HM, P = 0.007). Three month follow-up occurred in 84% in both groups. There was 100% adherence (5 of 5 checks) in 47.3% Conventional vs. 59.7% HM (P < 0.001). Between 3 and 15 months, HM exhibited superior (2.2×) adherence to scheduled follow-up [incidence of failed follow up was 146 of 2421 (6.0%) in HM vs. 145 of 1098 (13.2%) in Conventional, P < 0.001] and punctuality. In HM (daily transmission success rate median 91%), transmission loss caused only 22 of 2275 (0.97%) failed HM evaluations between 3 and 15 months; others resulted from clinic oversight. Overall IPE failure rate in Conventional [193 of 1841 (10.5%) exceeded that in HM [97 of 1484 (6.5%), P < 0.001] by 62%, i.e. HM patients remained more loyal to IPE when this was mandated. CONCLUSION: Automatic remote monitoring better preserves patient retention and adherence to scheduled follow-up compared with IPE. CLINICAL TRIAL REGISTRATION: NCT00336284.

Dual atrioventricular nodal pathways physiology: a review of relevant anatomy, electrophysiology, and electrocardiographic manifestations.

More than half a century has passed since the concept of dual atrioventricular (AV) nodal pathways physiology was conceived. Dual AV nodal pathways have been shown to be responsible for many clinical arrhythmia syndromes, most notably AV nodal reentrant tachycardia. Although there has been a considerable amount of research on this topic, the subject of dual AV nodal pathways physiology remains heavily debated and discussed. Despite advances in understanding arrhythmia mechanisms and the widespread use of invasive electrophysiologic studies, there is still disagreement on the anatomy and physiology of the AV node that is the basis of discontinuous antegrade AV conduction. The purpose of this paper is to review the concept of dual AV nodal pathways physiology and its varied electrocardiographic manifestations.

Ablation Versus Antiarrhythmic Drugs as First-Line Therapy for Treatment-Naive Atrial Fibrillation: A Systematic Review and Meta-Analysis.

Evidence on the relative safety and efficacy of atrial fibrillation catheter ablation and antiarrhythmic drugs (AADs) as the first-line therapy for patients with treatment-naive atrial fibrillation (AF) remains disputed. Digital databases were queried to identify relevant randomized controlled trials. The incidence of recurrent AF, major adverse cardiovascular events, and its components (all-cause death, nonfatal stroke, and bleeding) were compared using the DerSimonian and Laird method under the random-effects model to calculate pooled unadjusted risk ratio (RR) with 95% confidence intervals (CIs). A total of 6 randomized controlled trials consisting of 1,120 patients (574 ablation and 549 AADs) were included in the final analysis. Over a median follow-up of 1 year, the risk of any AF recurrence (RR 0.54, 95% CI 0.39 to 0.75) was significantly lower in patients receiving ablation than in patients receiving AADs. However, there was similar risk of major adverse cardiovascular events (RR 2.65, 95% CI 0.61 to 11.46), trial-defined composite end point of adverse events (RR 0.71, 95% CI 0.28 to 1.80), stroke (RR 2.42, 95% CI 0.22 to 26.51), all-cause mortality (RR 1.98, 95% CI 0.28 to 13.90), and procedure/medication failure (RR 2.65, 95% CI 0.61 to 11.46) with both therapies. In conclusion, in patients presenting with treatment-naive AF, ablation as a first-line therapy lowers the risk of AF recurrence with no associated increase in major adverse events, stroke, and mortality compared with AADs.

Same-day discovery of implantable cardioverter defibrillator dysfunction in the TRUST remote monitoring trial: influence of contrasting messaging systems.

AIMS: Assess whether automatic remote home monitoring (HM) permits same-day evaluation of implantable cardioverter defibrillator (ICD) system dysfunction. METHODS AND RESULTS: Compromised ICD system integrity (generator/lead) demands prompt evaluation. Home monitoring promises earlier discovery but may be limited by technological differences and follow-up mechanism. We tested whether HM enabled event review within 24 h, and contrasted differing messaging mechanisms. Nine hundred and eight patients in the TRUST prospective multicentre trial were followed by HM for 15 months. ICD system problems automatically triggered notifications: repeatedly ('redundant') for impedance deviations and elective replacement indication (ERI), but only a single transmission for '30 J ineffective'. Detection time from event onset to physician evaluation was measured. Forty-three system-related alerts occurred; 42% were asymptomatic, 42% were actionable, and 22 of 43 (51%) were viewed within 24 h. Redundant notifications were: 1 ERI, 9 shock impedance, 2 ventricular and 6 atrial pacing impedance. Most (11/18; 61%) were detected in <24 h. Others elicited daily notifications without interruption until resolution. For single transmissions, 11 of 25 (44%) events were detected on the same day. Most (56%, 14/25) were detected between 1 and 39 days (mean 10.0 ± 13.0 days). Ten of 14 events were detected by HM and 4 at the time of office visits. These observations suggest single transmissions were vulnerable to detection failure. Mean detection time of redundant events was 1.1 ± 1.8 vs. single transmission 5.6 ± 10.9 days (P = 0.05). Hence, redundant notification avoided late detection. CONCLUSION: Same-day discovery of ICD dysfunction, even if asymptomatic, was achievable. For those events not evaluated within 24 h, repetitive messaging promoted earlier discovery. Reorganization of clinical follow-up methods may maintain early reaction ability.

Reuse of explanted, resterilized implantable cardioverter-defibrillators: a cohort study.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) often have clinically useful battery life remaining when explanted because of upgrades, infection, or patient death. OBJECTIVE: To show that explanted ICDs can be resterilized and reused. DESIGN: Retrospective cohort study. SETTING: Multicenter ICD acquisition and single-center ICD reimplantation. PATIENTS: Indigent persons in India who had class I indications for cardiac resynchronization therapy with an ICD and were unable to afford such a device. MEASUREMENTS: Device longevity after reimplantation, device-related complications, number of appropriate therapies, patient clinical characteristics, and deaths. RESULTS: Eighty-one consecutive consenting patients (mean age, 52.6 years; 66 male patients) received 106 explanted devices. Twenty-two patients received a second device and 3 patients received a third device after the prior one reached replacement voltage. Mean time to ICD replacement was 1287.4 days. Follow-up data were available for 75 of 81 (92.6%) patients. Mean follow-up duration for all devices was 824.9 days. No infectious complications occurred; 1 lead dislodgement and 1 lead fracture required repeated surgery. Appropriate therapy (shocks or antitachycardia pacing) was delivered by 64 of 106 (60.4%) devices in 44 of 81 (54.3%) patients. Nine of 81 (11.1%) patients died; mean time from implantation to death was 771.3 days. LIMITATIONS: This is a retrospective report of a single-center experience with a modest number of patients and devices. Follow-up data were missing for 6 patients. No records were kept of the number of devices obtained through postmortem versus antemortem explantation or whether explantation was due to infection or upgrade. Complete data were not available on exact battery voltage at the time of reimplantation, left ventricular ejection fraction, or number of inappropriate shocks. A control group was not possible. CONCLUSION: Explanted ICDs with 3 or more years of estimated remaining battery life can be reused after they are cleaned and resterilized. These devices functioned normally and delivered life-saving therapies, without an increased risk for complications. These preliminary data deserve further validation and, if confirmed, could have important societal and economic implications. PRIMARY FUNDING SOURCE: None.

Safety of Adenosine for the Treatment of Supraventricular Tachycardia in Hospitalized Patients with COVID-19 Pneumonia.

Coronavirus disease 2019 (COVID-19) is associated with pulmonary involvement and cardiac arrhythmias, including supraventricular tachycardia (SVT). Adenosine is commonly used to treat SVT and is generally safe, but is rarely associated with bronchospasm. There are no data regarding the safety of adenosine use in patients with COVID-19 pneumonia and physicians may hesitate to use it in such patients. We surveyed resident physicians and cardiology attendings regarding their level of comfort in administering adenosine to hospitalized COVID-19 patients. We compared a study group of 42 COVID-19 hospitalized patients who received adenosine for SVT to a matched (for age, sex, and co-morbidities) control group of 42 non-COVID-19 hospitalized patients during the same period, all of whom received IV adenosine for SVT. Escalation of care following intravenous adenosine administration was defined as increased/new pressor requirement, need for higher O2 flow rates, need for endotracheal intubation, new nebulizer therapy, or transfer to intensive care unit within 2 h of adenosine administration. Survey results showed that 82% (59/72) of residents and 62% (16/26) of cardiologists expressed hesitation/significant concerns regarding administering adenosine in hospitalized COVID-19 patients. Adenosine use was associated with escalation of care in 47.6% (20/42) COVID-19 as compared to 50% (21/42) non-COVID-19 patients (odds ratio 0.95, 95% CI 0.45-2.01, p = NS). Escalation of care was more likely in patients who were on higher FiO2, on prior nebulizer therapy, required supplemental oxygen, or were already on a ventilator. In conclusion, we identified significant hesitation among physicians regarding the use of adenosine for SVT in hospitalized COVID-19 patients. In this study, there was no evidence of increased harm from administering adenosine to patients with SVT and COVID-19. This finding needs to be confirmed in larger studies. Based on the current evidence, adenosine for treatment of SVT in this setting should not be avoided. Key Points: Question: Given the known bronchospastic effects of adenosine, is the use of adenosine safe for treatment of supraventricular tachycardia in hospitalized patients with COVID-19? Findings: A survey of residents and cardiology attending identified that a majority expressed some level of apprehension in using adenosine for SVT in COVID-19 patients. In our matched cohort study, we found adenosine use to be comparably safe in COVID-19 and non-COVID-19 hospitalized patients. Meaning: Based on current evidence, adenosine for treatment of SVT in this setting should not be avoided.

Adverse outcomes of atrial fibrillation ablation in heart failure patients with and without cardiac amyloidosis: a Nationwide Readmissions Database analysis (2015-2019).

Aims: Atrial fibrillation (AF) in patients with cardiac amyloidosis (CA) has been linked with a worse prognosis. The current study aimed to determine the outcomes of AF catheter ablation in patients with CA. Methods and results: The Nationwide Readmissions Database (2015-2019) was used to identify patients with AF and concomitant heart failure. Among these, patients who underwent catheter ablation were classified into two groups, patients with and without CA. The adjusted odds ratio (aOR) of index admission and 30-day readmission outcomes was calculated using a propensity score matching (PSM) analysis. A total of 148 134 patients with AF undergoing catheter ablation were identified on crude analysis. Using PSM analysis, 616 patients (293 CA-AF, 323 non-CA-AF) were selected based on a balanced distribution of baseline comorbidities. At index admission, AF ablation in patients with CA was associated with significantly higher adjusted odds of net adverse clinical events (NACE) [adjusted odds ratio (aOR) 4.21, 95% CI 1.7-5.20], in-hospital mortality (aOR 9.03, 95% CI 1.12-72.70), and pericardial effusion (aOR 3.30, 95% CI 1.57-6.93) compared with non-CA-AF. There was no significant difference in the odds of stroke, cardiac tamponade, and major bleeding between the two groups. At 30-day readmission, the incidence of NACE and mortality remained high in patients undergoing AF ablation in CA. Conclusion: Compared with non-CA, AF ablation in CA patients is associated with relatively higher in-hospital all-cause mortality and net adverse events both at index admission and up to 30-day follow-up.