Optimizing conduction system pacing lead placement utilizing the image overlay technique.

The His-bundle has several locations from which conduction system pacing can be achieved. Some locations offer better sensing, thresholds and paced QRS durations. Existing techniques to aid repositioning of an already deployed, but sub-optimally placed lead, include either simple memory of the initial lead position combined with its observation on an x-ray review screen or utilizing an additional vascular access and pacing lead with the first lead serving as a real-time marker (Two-lead technique). We describe a novel, readily available, cost-efficient, imaging-based approach to assist in the re-positioning of a pacing lead for His-bundle pacing (the Image Overlay Technique).

High sensitivity troponin and COVID-19 outcomes.

BACKGROUND: Recent reports have demonstrated high troponin levels in patients affected with COVID-19. In the present study, we aimed to determine the association between admission and peak troponin levels and COVID-19 outcomes. METHODS: This was an observational multi-ethnic multi-centre study in a UK cohort of 434 patients admitted and diagnosed COVID-19 positive, across six hospitals in London, UK during the second half of March 2020. RESULTS: Myocardial injury, defined as positive troponin during admission was observed in 288 (66.4%) patients. Age (OR: 1.68 [1.49-1.88], p < .001), hypertension (OR: 1.81 [1.10-2.99], p = .020) and moderate chronic kidney disease (OR: 9.12 [95% CI: 4.24-19.64], p < .001) independently predicted myocardial injury. After adjustment, patients with positive peak troponin were more likely to need non-invasive and mechanical ventilation (OR: 2.40 [95% CI: 1.27-4.56], p = .007, and OR: 6.81 [95% CI: 3.40-13.62], p < .001, respectively) and urgent renal replacement therapy (OR: 4.14 [95% CI: 1.34-12.78], p = .013). With regards to events, and after adjustment, positive peak troponin levels were independently associated with acute kidney injury (OR: 6.76 [95% CI: 3.40-13.47], p < .001), venous thromboembolism (OR: 11.99 [95% CI: 3.20-44.88], p < .001), development of atrial fibrillation (OR: 10.66 [95% CI: 1.33-85.32], p = .026) and death during admission (OR: 2.40 [95% CI: 1.34-4.29], p = .003). Similar associations were observed for admission troponin. In addition, median length of stay in days was shorter for patients with negative troponin levels: 8 (5-13) negative, 14 (7-23) low-positive levels and 16 (10-23) high-positive (p < .001). CONCLUSIONS: Admission and peak troponin appear to be predictors for cardiovascular and non-cardiovascular events and outcomes in COVID-19 patients, and their utilisation may have an impact on patient management.

Ethnicity and COVID-19 cardiovascular complications: a multi-center UK cohort.

BACKGROUND: Recent reports suggest an association between ethnicity and COVID-19 mortality. In the present multi-center study, we aimed to assess the differences underlying this association, and ascertain whether ethnicity also mediates other aspects of COVID-19 like cardiovascular complications. METHODS: Data were collected from a mixed-ethnicity UK cohort of 613 patients admitted and diagnosed COVID-19 positive, across six hospitals in London during the second half of March 2020: 292 were White Caucasian ethnicity, 203 were Asian and 118 were of Afro-Caribbean ethnicity. RESULTS: Caucasian patients were older (P<0.001) and less likely to have hypertension (P=0.038), while Afro-Caribbean patients had higher prevalence of diabetes mellitus (P<0.001). Asian patients were more likely to present with venous thromboembolic disease (adj.OR=4.10, 95% CI 1.49-11.27, P=0.006). On the other hand, Afro-Caribbean had more heart failure (adj.OR=3.64, 95% CI 1.50-8.84, P=0.004) and myocardial injury (adj.OR=2.64, 95% CI 1.10-6.35, P=0.030). Importantly, our adjusted multi-variate Cox regression analysis revealed significantly higher all-cause mortality both for Asian (adj.HR=1.89, 95% CI 1.23-2.91, P=0.004) and Afro-Caribbean ethnicity (adj.HR=2.09, 95% CI 1.30-3.37, P=0.002). CONCLUSIONS: Our data show that COVID-19 may have different presentations and follow different clinical trajectories depending on the ethnicity of the affected subject. Awareness of complications more likely to arise in specific ethnicities will allow a more timely diagnosis and preventive measures for patients at risk. Due to increased mortality, individuals of Afro-Caribbean and Asian ethnicity should be considered as high-risk groups. This may have an impact on health-resource allocation and planning, definition of vulnerable groups, disease management, and the protection of healthcare workers at the frontline.

Multicenter Randomized Controlled Crossover Trial Comparing Hemodynamic Optimization Against Echocardiographic Optimization of AV and VV Delay of Cardiac Resynchronization Therapy: The BRAVO Trial.

OBJECTIVES: BRAVO (British Randomized Controlled Trial of AV and VV Optimization) is a multicenter, randomized, crossover, noninferiority trial comparing echocardiographic optimization of atrioventricular (AV) and interventricular delay with a noninvasive blood pressure method. BACKGROUND: Cardiac resynchronization therapy including AV delay optimization confers clinical benefit, but the optimization requires time and expertise to perform. METHODS: This study randomized patients to echocardiographic optimization or hemodynamic optimization using multiple-replicate beat-by-beat noninvasive blood pressure at baseline; after 6 months, participants were crossed over to the other optimization arm of the trial. The primary outcome was exercise capacity, quantified as peak exercise oxygen uptake. Secondary outcome measures were echocardiographic left ventricular (LV) remodeling, quality-of-life scores, and N-terminal pro-B-type natriuretic peptide. RESULTS: A total of 401 patients were enrolled, the median age was 69 years, 78% of patients were men, and the New York Heart Association functional class was II in 84% and III in 16%. The primary endpoint, peak oxygen uptake, met the criterion for noninferiority (pnoninferiority = 0.0001), with no significant difference between the hemodynamically optimized arm and echocardiographically optimized arm of the trial (mean difference 0.1 ml/kg/min). Secondary endpoints for noninferiority were also met for symptoms (mean difference in Minnesota score 1; pnoninferiority = 0.002) and hormonal changes (mean change in N-terminal pro-B-type natriuretic peptide -10 pg/ml; pnoninferiority = 0.002). There was no significant difference in LV size (mean change in LV systolic dimension 1 mm; pnoninferiority < 0.001; LV diastolic dimension 0 mm; pnoninferiority <0.001). In 30% of patients the AV delay identified as optimal was more than 20 ms from the nominal setting of 120 ms. CONCLUSIONS: Optimization of cardiac resynchronization therapy devices by using noninvasive blood pressure is noninferior to echocardiographic optimization. Therefore, noninvasive hemodynamic optimization is an acceptable alternative that has the potential to be automated and thus more easily implemented. (British Randomized Controlled Trial of AV and VV Optimization [BRAVO]; NCT01258829).

Inter- and intravein differences in cardiac output with cardiac resynchronization pacing using a multipolar LV pacing lead.

BACKGROUND: Quadripolar left ventricular pacing leads permit a variety of pacing configurations from different sites within a coronary vein. There may be advantages to selecting a specific pacing vector. This study examines whether the range of cardiac outputs obtained at cardiac resynchronization therapy (CRT) implantation is greater between different poles within a vein, or greater between two different veins. METHODS AND RESULTS: The cardiac index (CI, L/min/m(2) ) was measured during CRT implantation using a noninvasive cardiac output monitor (NICOM™, Cheetah Medical Inc., Newton Center, MA, USA) and a quadripolar left ventricle (LV) lead, in 22 patients with sinus rhythm. CI was recorded during right atrial-biventricular pacing at 70/min with fixed atrioventricular and ventriculo-ventricular delay, from each LV electrode in one vein, and then from an alternate vein. Phrenic nerve stimulation (PNS) occurred in nine of 15 posterior and three of 21 anterior veins (P = 0.005). At least one electrode in each vein had no PNS. The mean (standard deviation [SD]) difference between best and worst CI within any one vein was 13.1% (±9%). The mean (SD) difference between the best CI in one vein compared to the other was 9.8% (±8%; P = 0.043). In 16 of 22 patients, the range of CI was greater between poles within one vein, rather than between two veins (best of one vein compared to best from the other). In four of 22 patients, the range was greater between veins (P = 0.0003). CONCLUSION: A greater range of CI is found within a single vein than between two different veins. This finding has implications both for the approach to implant technique and postimplant programming and optimization.

The benefits of using a bismuth-containing, radiation-absorbing drape in cardiac resynchronization implant procedures.

BACKGROUND: Radiation exposure is a major concern in cardiac device implantation, especially cardiac resynchronization therapy (CRT) procedures. The RadPad™ (Worldwide Innovations & Technologies, Inc., Kansas City, MO, USA), a radiation-attenuating adhesive drape, has been shown to be beneficial in several clinical settings involving fluoroscopy, but less is known about the actual benefits in CRT procedures. METHODS: Consecutive CRT implants performed with and without a RadPad™ drape over a 10-month period were analyzed. Two thermoluminescent dosimeters (TLDs) were attached to each implanting physician at several locations (adjacent to eyes, center abdomen [outside lead apron], left and right index fingers, and dorsum of the right foot). Results were corrected for background using control TLDs, and normalized to dose-area product (DAP). RESULTS: Thirty-six patients (31 male), 16 with and 20 without the RadPad™, were included in the study. No technical problems were caused by the presence of the radiation-absorbing drape. Time required to position the drape never exceeded 30 seconds, no acute skin reactions were noted, and no radiation-absorbing drape became displaced. Despite a trend toward longer fluoroscopy times and higher DAPs in the radiation-absorbing drape group, radiation exposure was significantly reduced: 65% in the case of the hands and body (P < 0.001), and 40% the eyes (P < 0.01). CONCLUSION: The use of a radiation-absorbing drape results in a significant reduction in radiation dose to the implanting physician during CRT procedures. Not only is the dose to the hands reduced, but also the eye and body doses are significantly reduced. The routine use of radiation-absorbing drapes should be considered for all CRT implant procedures in the light of these findings.

Development of a technique for left ventricular endocardial pacing via puncture of the interventricular septum.

BACKGROUND: Left ventricular (LV) pacing through the coronary sinus is the standard approach for cardiac resynchronization therapy. When this route is unavailable, the alternatives have major limitations. LV endocardial pacing through the interventriuclar septum may offer a simpler solution. We describe an initial case series to demonstrate technical feasibility and to describe our refinement of the puncture technique. METHODS AND RESULTS: Ten patients with previous failed coronary sinus lead implant or with nonresponse to cardiac resynchronization therapy and a suboptimal LV lead position were selected. All patients were anticoagulated. Left ventriculography and coronary angiography were performed to identify LV borders and septal vessels. Subclavian vein access was used for a superior approach ventricular transseptal puncture under fluoroscopic guidance, using a steerable sheath and a standard transseptal needle, radiofrequency needle, or radiofrequency energy delivered through a guidewire. An active-fixation pacing lead was successfully delivered to the endocardial wall of the lateral LV in all patients (9 men; age, 62±10 years). LV lead implant procedure time shortened with experience. The use of radiofrequency energy delivered through a guidewire was the most effective technique. Mean threshold and R wave at implant were 0.8±0.3 V and 10.8±3.9 mV. At follow-up (mean, 8.7 months; minimum, 0; and maximum 19), thresholds were stable, and there were no thromboembolic events. Of 9 patients, 8 were classed as clinical responders (1 had inadequate follow-up to assess response). CONCLUSIONS: LV endocardial pacing through a ventricular septal puncture is a feasible approach for cardiac resynchronization therapy.