Prioritizing elective cardiovascular procedures during the COVID-19 pandemic: The cardiovascular medically necessary, time-sensitive procedure scorecard.

BACKGROUND: Following the surge of the coronavirus disease 2019 (COVID-19) pandemic, government regulations, and recommendations from professional societies have conditioned the resumption of elective surgical and cardiovascular (CV) procedures on having strategies to prioritize cases because of concerns regarding the availability of sufficient resources and the risk of COVID-19 transmission. OBJECTIVES: We evaluated the use of a scoring system for standardized triage of elective CV procedures. METHODS: We retrospectively reviewed records of patients scheduled for elective CV procedures that were prioritized ad hoc to be either performed or deferred when New Jersey state orders limited the performance of elective procedures due to the COVID-19 pandemic. Patients in both groups were scored using our proposed CV medically necessary, time-sensitive (MeNTS) procedure scorecard, designed to stratify procedures based on a composite measure of hospital resource utilization, risk of COVID-19 exposure, and time sensitivity. RESULTS: A total of 109 scheduled elective procedures were either deferred (n = 58) or performed (n = 51). The median and mean cumulative CV MeNTS scores for the group of performed cases were significantly lower than for the deferred group (26 (interquartile range (IQR) 22-31) vs. 33 (IQR 28-39), p < .001, and 26.4 (SE 0.34) vs. 32.9 (SE 0.35), p < .001, respectively). CONCLUSIONS: The CV MeNTS procedure score was able to stratify elective cases that were either performed or deferred using an ad hoc strategy. Our findings suggest that the CV MeNTS procedure scorecard may be useful for the fair triage of elective CV cases during the time when available capacity may be limited due to the COVID-19 pandemic.

Retrograde buddy wire technique for coronary sinus lead placement--an approach to overcome coronary vein angulation.

Implantation of a left ventricular pacing lead via the coronary sinus to deliver cardiac resynchronization therapy has become standard therapy for patients with New York Heart Association (NYHA) Class III or IV heart failure and significant intraventricular conduction delay. Biventricular pacing has been shown to provide both symptomatic and mortality benefit in appropriately selected patients. There is significant variability in the anatomy of the coronary sinus and the epicardial coronary venous system. Although a suitable candidate vein may be identified during coronary venography, efforts toward successful guidewire placement or lead placement may be hampered by anatomic obstacles. In this case report, we provide a solution to overcome severe tortuosity encountered at the vein-coronary sinus junction and angulation of the proximal vein. The use of a second coronary sinus sheath and a retrogradely placed guidewire may overcome this anatomic obstacle of vessel tortuosity, when placement by other means has proven unsuccessful.

A prospective randomized trial of defibrillation thresholds from the right ventricular outflow tract and the right ventricular apex.

BACKGROUND: Right ventricular outflow tract (RVOT) pacing has been suggested to improve hemodynamics and to help prevent pacing-induced cardiomyopathy. Pacing from the RVOT is feasible and equivalent in terms of sensing and stimulation threshold. However, physicians have been reluctant to use RVOT pacing because of concerns that defibrillation efficacy might be adversely affected. To date, there have been no randomized-controlled trials published comparing the defibrillation threshold in leads implanted in the RVOT and the right ventricular apex (RVA). OBJECTIVE: The purpose of this study was to compare defibrillation thresholds (DFT) in the RVOT and RVA. Ventricular sensing and stimulation thresholds were also compared. METHODS: This prospective, randomized, multicenter study included 87 patients (70 males, age 69 +/- 11 years). At implantation, the patient's ventricular implantable cardioverter-defibrillator (ICD) lead position was randomized to either the RVOT or RVA. A four-shock Bayesian up-down method was used to determine the DFT. Patients were followed for 3 months postimplant. RESULTS: DFTs were not significantly different in leads implanted in the RVOT (median 8.8 J [6.28, 12.9] vs. 7.9 J [6.20, 12.6], P = 0.65). Threshold and impedance measurements were stable in both RVOT and RVA groups from implant to follow-up. All ICD leads remained stable chronically at the 3-month follow-up. CONCLUSION: DFTs in leads placed in the RVOT and RVA are comparable. RVOT ICD lead placement is safe and exhibits similar lead stability, threshold, and impedance measurements as the traditional RVA location.

Percent right ventricular pacing predicts outcomes in the DAVID trial.

BACKGROUND: The Dual-Chamber and VVI Implantable Defibrillator (DAVID) trial demonstrated a worse outcome in patients with implantable cardioverter-defibrillators (ICDs) programmed to DDDR at 70 bpm compared with patients who had ICDs programmed to VVI backup pacing at 40 bpm. Pacing was more frequent in the DDDR group. OBJECTIVES: The purpose of this study was to determine whether right ventricular pacing (RV) is an independent predictor of outcome in the DAVID trial. METHODS: We evaluated the relationship of percent RV pacing to the composite endpoint of death or hospitalization for congestive heart failure. Patients who had a 3-month follow-up and who had not yet reached an endpoint were included in the study. Using Cox regression analysis (VVI group N = 195; DDDR group N = 185), we examined multiple factors, including percent RV pacing at 3-month follow-up, that might be associated with adverse outcomes. RESULTS: Percent RV pacing as a continuous variable was correlated with the primary endpoint. As a dichotomous variable, the best separation for predicting endpoints occurred with DDDR RV pacing > 40% vs DDDR RV pacing < or = 40% (P = .025). Patients with DDDR RV pacing < or = 40% had similar or better outcomes to the VVI backup group (P = .07). Correction for baseline variables predictive of the composite outcome in the (nonpaced) VVI group (use of nitrates, increased heart rate, and increased age) did not change the findings for RV pacing (P = .008). In contrast, atrial pacing was not predictive of worse outcomes. CONCLUSION: These results suggest, but do not prove, a causal relationship between frequent RV pacing and adverse outcomes in patients with left ventricular ejection fraction < or = 40%.

Automatic measurement of atrial pacing thresholds in dual-chamber pacemakers: clinical experience with atrial capture management.

BACKGROUND: The Medtronic EnPulse pacemaker incorporates the new atrial capture management (ACM) algorithm to automatically measure atrial capture thresholds and subsequently manage atrial pacing outputs. OBJECTIVES: The purpose of this study was to evaluate the clinical performance of ACM. METHODS: Two hundred patients with an indication for a dual-chamber pacemaker underwent implantation. ACM thresholds and manually measured atrial pacing thresholds were assessed at follow-up visits. Clinical equivalence was defined as the ACM-measured threshold being within -0.25 V to +0.5 V of the manually measured threshold. The clinician analyzed all ACM measurements performed in-office for evidence of proarrhythmia. RESULTS: All 200 implanted patients had a 1-month visit, and validated manual and in-office ACM threshold data were available for 123 patients. The ACM threshold was 0.595 +/- 0.252 V, and the manual threshold was 0.584 +/- 0.233 V. The mean difference was 0.010 V with a 95% confidence interval of (-0.001, 0.021). The mean difference over all visits was 0.011 V. For all patients, the individual threshold differences were within the range of clinical equivalence at all visits. No atrial arrhythmias were observed during 892 ACM tests in 193 patients. CONCLUSION: This study demonstrated that the ACM algorithm is safe, accurate, and reliable over time. ACM was demonstrated to be clinically equivalent to the manual atrial threshold test in all patients at 1 month and over the entire follow-up period of up to 6 months. ACM ensures atrial capture, may save time during follow-up, and can be used to manage atrial pacing outputs.

Reduction of RV pacing by continuous optimization of the AV interval.

BACKGROUND: In patients requiring permanent pacing, preservation of intrinsic ventricular activation is preferred whenever possible. The Search AV+ (SAV+) algorithm in Medtronic EnPulsetrade mark dual-chamber pacemakers can increase atrioventricular (AV) intervals to 320 ms in patients with intact or intermittent AV conduction. This prospective, multicenter study compared the percentage of ventricular pacing with and without AV interval extension. METHODS: Among 197 patients enrolled in the study, the percentage of ventricular-paced beats was evaluated via device diagnostics at the 1-month follow-up. Patient cohorts were defined by clinician assessment of conduction via a 1:1 AV conduction test at the 2-week follow-up. The observed percentage of ventricular pacing with SAV + ON and the predicted percentage of ventricular pacing with SAV + OFF were determined from the SAV + histogram data for the period between the 2-week and 1-month follow-up visits. RESULTS: Of 197 patients, 110 (55.8%) had intact 1:1 AV conduction, of which 109 had 1-month data. SAV + remained ON in 99/109 patients; 10 patients had intrinsic A-V conduction intervals beyond SAV + nominal and therefore SAV + disabled. The mean percentage of ventricular pacing in the 109 patients was SAV+ ON = 23.1% (median 3.7%) versus SAV + OFF = 97.2% (median 99.7%). In 87 patients without 1:1 AV conduction, SAV + was programmed OFF in 6, automatically disabled in 52, and remained ON in 29. In 8 of these patients, 80-100% reduction in ventricular pacing was observed with SAV + ON. CONCLUSION: The Search AV+ algorithm in the EnPulse pacemaker effectively promotes intrinsic ventricular activation and substantially reduces unnecessary ventricular pacing.