High predictive value of paced QRS frequency in verification of left bundle branch pacing.

BACKGROUND: Left bundle branch area pacing (LBBAP) is a newer technique to deliver more synchronous left ventricular activation. Several criteria have been proposed, but not fully validated, to confirm LBBAP during implantation of the pacing lead. Spectral analysis has been used to characterize the frequency components of the clinical QRS utilizing the Fourier transform algorithm. We hypothesized that higher frequency content of the paced QRS complex may show predictive value of successful LBBAP. METHODS: We evaluated 84 patients with ejection fraction > 50%, who underwent LBB lead placement (n = 42) using ≥ 1 current criteria and right ventricular midseptal (RVsp) lead placement (n = 42) from 2000 to 2022. Time frequency analysis (Matlab) was used to determine the frequency content of the paced QRS complex. The centroid frequency (CF), which is the weighted average QRS frequency, was calculated. RESULTS: Patients in RVsp group had a longer paced QRS duration (155.6 ± 28.0 vs 127.1 ± 17.2, p < 0.002) compared to the LBBAP group. Of all standard ECG leads, the paced QRS in V2 gave the greatest difference of the CF of the LBBAP group at 8.8 ± 1.6 Hz versus 5.7 ± 0.7 Hz of the RVsp group. This difference was significant by both univariate (p < 0.003) and multivariate (p < 0.010) analysis. Predictive value of the CF for successful LBB pacing in lead V2 was highest with an AUC of 0.98. The sensitivity and specificity were 88.1% and 97.6%, respectively. CONCLUSION: Spectral analysis predicts successful LBBAP with higher frequency content when compared to RVsp pacing. Given the limitations to the current criteria to confirm LBBAP, intraprocedural use of frequency content analysis of the paced QRS complex in patients may prove useful at verifying LBB capture if verified by prospective clinical trials.

Risk factors associated with higher mortality in patients with cardiac implantable electronic device infection.

INTRODUCTION: Cardiac Implantable Electronic Devices (CIEDs) are widely used for the management of advanced heart failure and ventricular arrhythmias. CIED-Infection (CIED-I) has very high mortality, especially in the subsets of patients with limited health-care access and delayed presentation. The purpose of this study is to identify the risk-predictors mortality in subjects with CIED-I. METHODS: We performed a retrospective cohort study of a regional database in patients presenting with CIED infections to tertiary care medical centers across Western New York, USA from 2012 to 2020. The clinical outcomes included recurrent device infection (any admission for CIED-I after the first hospitalization for device infection), septic complications (pulmonary embolism, respiratory failure, septic shock, decompensated HF, acute kidney injury) and mortality outcomes (death during hospitalization, within 30 days from CIED-I, and within 1 year from CIED-I). We studied associations between categorical variables and hard outcomes using χ2 tests and used one-way analysis of variance to measure between-groups differences. RESULTS: We identified 296 patients with CIED-I, among which 218 (74%) were male, 237 (80%) were white and the mean age at the time of infection was 69.2 ± 13.7 years. One-third of the patients were referred from the regional facilities. Staphylococcus aureus was responsible for most infections, followed by Enterococcus fecalis. On multivariate analysis, the covariates associated with significantly increased mortality risk included referral from regional facility (OR: 2.0;1.0-4.0), hypertension (Odds ratio, OR: 3.2;1.3-8.8), right ventricular dysfunction (OR: 2.6;1.2-5.1), end-stage renal disease (OR: 2.6;1.1-6.2), immunosuppression (OR: 11.4;2.5-53.3), and septic shock as a complication of CIED-I (OR: 3.9;1.3-10.8). CONCLUSION: Hypertension, right ventricular dysfunction, immunosuppression, and end-stage renal disease are associated with higher mortality after CIED-I. Disproportionately higher mortality was also noted in subjects referred from the regional facilities. This underscores the importance of early clinical risk-assessment, and the need for a robust referral infrastructure to improve patient outcomes.

Sex-Specific Considerations in Drug and Device Therapy of Cardiac Arrhythmias: JACC Focus Seminar 6/7.

Sex and gender are important factors influencing the epidemiology and outcomes of cardiovascular care in various cardiac arrhythmias. Observed sex-related differences are influenced by the effects of both biologically determined sex and culturally defined gender. Under-representation of women in clinical trials and incomplete understanding of the mechanisms behind sex differences have led to inadequate evidence to guide effective sex-specific treatment. This lack of information has contributed to disparities in clinical care. In this review, we examine the effect of sex and gender on the clinical presentation and outcomes with drug and device therapy in various arrhythmias, while acknowledging the paucity of data on the effect of gender. We evaluate the implications of sex on the clinical management of arrhythmias covered by guideline documents, highlight recent data that warrant consideration for additional sex-specific recommendations, and illustrate knowledge gaps that require further study.

A Validated Model to Identify Patients With Low Likelihood of High-Risk Coronary Artery Disease Anatomy.

In stable coronary artery disease (CAD), revascularization improves outcomes only for patients with high-risk coronary anatomy (HRCA). We sought to derive and validate a prediction model, incorporating clinical and exercise stress test characteristics, to identify patients with HRCA. We conducted a retrospective analysis of patients undergoing exercise stress testing at Cleveland Clinic (2005 to 2014), followed by invasive coronary angiography within 3 months. We excluded patients with acute coronary syndrome, known CAD or ejection fraction <50%. HRCA was defined as left main, 3-vessel, or 2-vessel disease involving the proximal left anterior descending artery. Clinical and stress test predictors of HRCA were identified in a multivariable logistic regression model, internally validated with 1,000-fold bootstrapping. The model was then externally validated at the University of Pittsburgh Medical Center (2017 to 2019). The model was derived from 2,758 patients with complete data. HRCA was identified in 418 patients (15.2%) in the derivation cohort. The model consisted of 10 variables: age, male gender, hypertension, hypercholesterolemia, diabetes mellitus, family history of premature CAD, high-density lipoprotein, chest pain, exercise time, and Duke Treadmill Score. Bias-corrected c-statistic was 0.79 (95% confidence interval 0.77 to 0.81) with excellent calibration. In all, 762 patients (27.6%) had a predicted probability and observed prevalence of HRCA <5%. In the validation cohort, the model had a c-statistic of 0.79 (95% confidence interval 0.74 to 0.85) and 210 patients had an observed prevalence of HRCA <5% (40%). In conclusion, an externally validated prediction model, based on clinical characteristics and exercise stress test variables, can identify stable patients with CAD who have HRCA.

From background to solutions: Eliminating sex gaps in clinical electrophysiology practice.

Sex, a biological construct, and gender, a sociocultural construct, both influence the epidemiology and outcomes of various cardiac arrhythmias, leading to disparities that have been observed in clinical practice. Addressing disparities is crucial to improve the quality of clinical care. We recognize gender equality as the ultimate goal to ensuring equitable health care and propose the following strategies to achieve the goal: sex- and gender-stratified research, quality improvement initiatives, implicit bias training, promotion of women into leadership positions in cardiology, peer support, and shared decision-making to help mitigate disparities. However, further research on how to improve the widespread adoption and implementation of such strategies in the clinical setting is required.

Biventricular Strain Imaging with Cardiac MRI in Genotyped and Histology Validated Amyloid Cardiomyopathy.

Cardiac amyloidosis (CA) is a common and potentially fatal infiltrative cardiomyopathy. Contrast-enhanced cardiac MRI (CMR) is used as a diagnostic tool. However, utility of CMR for the comprehensive analysis of biventricular strains and strain rates is not reported as extensively as echocardiography. In addition, RV strain analysis using CMR has not been described previously. OBJECTIVES: We sought to study the global and regional indices of biventricular strain and strain rates in endomyocardial biopsy (EMB)-proven, genotyped cases of CA. METHODS: A database of 80 EMBs was curated from 2012 to 2019 based on histology. A total of 19 EMBs positive for CA were subjected to further tissue-characterization with histology, and compared with four normal biopsy specimens. Samples were genotyped for ATTR- or AL-subtypes. Five patients, with both echocardiography and contrast-enhanced CMR performed 72-h apart, were subjected to comprehensive analysis of biventricular strain and strain-rates. RESULTS: Histology confirmed that the selected samples were indeed positive for cardiac amyloid. Echocardiography showed reduced global and regional left-ventricular (LV) longitudinal strain indices. CMR with tissue-characterization of LV showed global reductions in circumferential, radial and longitudinal strains and strain-rates, following a general trend with the echocardiographic findings. The basal right-ventricular (RV) segments had reduced circumferential strains with no changes in longitudinal strain. CONCLUSIONS: In addition to providing a clinical diagnosis of CA based on contrast clearance-dynamics, CMR can be a potent tool for accurate functional assessment of global and regional changes in strain and strain-rates involving both LV and RV. Further studies are warranted to validate and curate the strain imaging capacity of CMR in CA.

What clinical trials of ablation for atrial fibrillation tell us - and what they do not.

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in clinical practice. Radiofrequency and cryoballoon catheter ablation are therapeutic options in addition to antiarrhythmic drug therapy for the treatment of AF. Ablation is effective at reducing recurrent atrial arrhythmias and also in the reduction of AF burden. Besides arrhythmia control, improvement in quality of life and clinical outcomes are also desirable goals with AF treatment. Randomized clinical trials have evaluated ablation in several patient populations, including symptomatic patients as first-line or second-line therapy, asymptomatic patients, and patients with heart failure. These trials clarify the durability of ablation in arrhythmia control, clarify quality-of-life improvement, and identify patient populations in whom ablation may be expected to improve clinical outcomes. In this review, we summarize the major clinical trials involving ablation; discuss the strengths, weakness, and clinical implications of these trials; and highlight the knowledge gaps in our current understanding of AF ablation for future clinical studies.

Indication-specific event rates among hospitalized patients undergoing continuous cardiac monitoring.

BACKGROUND: Cardiac telemetry monitoring is widely utilized for a variety of clinical indications, yet indication-specific event rates for monitored patients are seldomly reported. HYPOTHESIS: High-risk hospitalized patients for clinical deterioration can be identified using standardized telemetry monitoring indications. METHODS: Adjudicated data from events triggering emergency response team (ERT) activation were systematically characterized at the Cleveland Clinic from among standardized telemetry indications ordered over a 13-month period. RESULTS: Among 72 199 orders created for telemetry monitored patients, ERT activation occurred in 2677 patients (3.7%), of which 1326 (49.5%) were cardiac-related. Patients with deep venous thrombosis or pulmonary embolism (DVT/PE) demonstrated the highest overall event rate (ERT: n = 41 of 593 pts [6.9%]; 25/41 cardiac related [61%]). Cardiac-related events were proportionally highest among patients with coronary disease awaiting revascularization (ERT: n = 19 of 847 patients [2.2%]; 13/19 cardiac-related [68.4%]). Arrhythmia-specific events were highest among patients who underwent cardiac surgery (n = 78 of 193 cardiac-related ERT [40.4%]), and patients with known or suspected tachyarrhythmias (n = 318 of 788 cardiac-related ERT [40.4%]). Bubble plot analysis identified patients hospitalized with DVT/PE, drug or alcohol exposures, and acute coronary syndrome as among the highest overall and cardiac-related events while identifying patients with respiratory disorder monitoring indications as carrying the highest noncardiac event rate. CONCLUSION: High-risk hospitalized patients can be identified by telemetry indication and prioritized according to concerns for cardiac, arrhythmia-specific and noncardiac clinical deterioration. This is particularly useful when monitored bed resources are constrained.

Initial arterial pH as a predictor of neurologic outcome after out-of-hospital cardiac arrest: A propensity-adjusted analysis.

BACKGROUND: Lower pH after out-of-hospital cardiac arrest (OHCA) has been associated with worsening neurologic outcome, with <7.2 identified as an "unfavorable resuscitation feature" in consensus treatment algorithms despite conflicting data. This study aimed to describe the relationship between decremental post-resuscitation pH and neurologic outcomes after OHCA. METHODS: Consecutive OHCA patients treated with targeted temperature management (TTM) at multiple US centers from 2008 to 2017 were evaluated. Poor neurologic outcome at hospital discharge was defined as cerebral performance category ≥3. The exposure was initial arterial pH after return of spontaneous circulation (ROSC) analyzed in decremental 0.05 thresholds. Potential confounders (demographics, history, resuscitation characteristics, initial studies) were defined a priori and controlled for via ATT-weighting on the inverse propensity score plus direct adjustment for the linear propensity score. RESULTS: Of 723 patients, 589 (80%) experienced poor neurologic outcome at hospital discharge. After propensity-adjustment with excellent covariate balance, the adjusted odds ratios for poor neurologic outcome by pH threshold were: ≤7.3: 2.0 (1.0-4.0); ≤7.25: 1.9 (1.2-3.1); ≤7.2: 2.1 (1.3-3.3); ≤7.15: 1.9 (1.2-3.1); ≤7.1: 2.4 (1.4-4.1); ≤7.05: 3.1 (1.5-6.3); ≤7.0: 4.5 (1.8-12). CONCLUSIONS: No increased hazard of progressively poor neurologic outcomes was observed in resuscitated OHCA patients treated with TTM until the initial post-ROSC arterial pH was at least ≤7.1. This threshold is more acidic than in current guidelines, suggesting the possibility that post-arrest pH may be utilized presently as an inappropriately-pessimistic prognosticator.

Atrial Tachyarrhythmias Among Patients With Left Ventricular Assist Devices: Prevalence, Clinical Outcomes, and Impact of Rhythm Control Strategies.

OBJECTIVES: This study sought to describe the burden of atrial fibrillation (AF)/atrial flutter (AFL) in patients with left ventricular assist devices (LVAD) and to evaluate the impact of rhythm control strategies. BACKGROUND: AF and AFL among patients with LVADs are poorly characterized. METHODS: Retrospective multivariable survival analysis of all LVAD recipients at the Cleveland Clinic from January 1, 2004 to June 30, 2016 examining the association of death, thromboembolism, and major bleeding with AF/AFL and exposure to rhythm control measures. RESULTS: Among 418 patients (median age: 58 [interquartile range: 50 to 67] years, 80% male) with median follow-up of 445 (interquartile range: 165 to 936) days, AF (n = 287 of 418, 69%) and AFL (n = 61 of 418, 15%) were highly prevalent. Patients with AF/AFL (n = 302 of 418, 72%) and without AF/AFL (n = 116 of 418, 28%) had similar mortality (39% vs. 38%; p = 0.88) and major bleeding (46% vs. 49%; p = 0.53); AF/AFL patients had fewer thromboembolic events (13% vs. 23%; p < 0.01). Paroxysmal or persistent AF/AFL was present in 238 patients (57%), and rhythm control exposure (n = 166, 70%) was not associated with decreased mortality (39% vs. 43%; p = 0.57), thromboembolism (13% vs. 17%; p = 0.41), or bleeding (49% vs. 39%; p = 0.16). In the multivariable survival analysis only prior valve surgery (hazard ratio: 2.0; 95% confidence interval: 1.3 to 3.0; p = 0.002) was associated with increased hazard; AF/AFL had no association with risk of death, thromboembolism, or bleeding. CONCLUSIONS: Though highly prevalent among LVAD patients, AF/AFL was not associated with increased mortality, thromboembolism, or bleeding, and among paroxysmal/persistent AF patients, rhythm control measures were not associated with improved outcomes.

Feasibility and Usability of Patch-based Continuous Cardiac Rhythm Monitoring in Comparison with Traditional Telemetry in Noncritically Ill Hospitalized Patients.

Research on traditional cardiac telemetry demonstrates that excessive alarms are related to lead failures and noise-related interruptions. Patch-based continuous cardiac rhythm monitoring (CCRM) has emerged in outpatient ambulatory monitoring situations as a means to improve recording fidelity. In this study, patients hospitalized but not in the intensive care unit were simultaneously monitored via telemetry in parallel with the use of the Vital Signs Patch™ (VSP) CCRM system (LifeWatch Services, Rosemont, IL, USA), applying standardized monitoring and notifications provided by an off-site central monitoring unit (CMU). Among 11 patients (55% male; age: 66.8 ± 12.5 years), there were 42 CMU detections and 98 VSP detections. The VSP device was successfully applied by nursing with connectivity established in all 11 patients (100%). There were no VSP device-related adverse events or skin eruptions during the study. The CMU agreed with 59 (60%) of 98 VSP detections. Among those detections marked by disagreement 30 (77%) of 39 VSP detections were related to clinically meaningful arrhythmias (atrial: n = 9; ventricular: n = 7; brady-: n = 14) undetected by VSP due to noise. In two patients (18%), there were four clinically meaningful atrial fibrillation detections not recorded by the CMU. In conclusion, patch-based CCRM requires further development and review to replace traditional cardiac telemetry monitoring but could evolve into an appropriate method to detect clinically meaningful events missed by traditional methods if noise issues can be mitigated.

Repeat ablation or medical management alone for recurrent arrhythmias after ablation of persistent atrial fibrillation.

INTRODUCTION: Management of persistent atrial fibrillation (PersAF) remains challenging, and many patients are left on medical therapy after a failed first ablation. In patients with recurrent symptomatic arrhythmias after PersAF ablation, we aimed to compare outcomes of repeat ablation and medical therapy versus medical therapy alone. METHODS AND RESULTS: All 682 consecutive patients with recurrent symptomatic arrhythmia after a first ablation for PersAF at our institution (2005-2012) were included. Repeat ablation with continuation of medical therapy was performed in 364 patients (Group 1) and 318 were only medically managed (Group 2). The outcome of interest was freedom from arrhythmia recurrence beyond a 3-month blanking period. Separate analyses were performed to assess this endpoint totally off antiarrhythmics (primary endpoint) or alternatively with/without use of antiarrhythmics (secondary endpoint). Over a median follow-up of 26 months, 41.5% of Group 1 patients met the primary endpoint and remained free from arrhythmia recurrence off antiarrhythmics (vs. 14.5% in Group 2, P < 0.0001). At last follow-up, antiarrhythmics continued to be required for rhythm control in 40.1% and 46.2% of patients in Groups 1 and 2, respectively (P < 0.0001). The secondary endpoint was met in 60.2% versus 32.1% of patients in Groups 1 and 2, respectively (P < 0.0001). In multivariable Cox analyses, repeat ablation was associated with significant reduction in arrhythmia recurrences compared to medical therapy alone (HR 0.48, 95% CI 0.35-0.65, P < 0.0001). CONCLUSION: In patients with recurrent symptomatic arrhythmia after ablation of PersAF, repeat ablation was associated with significant reduction in arrhythmia recurrences compared to routine medical therapy alone.