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).

Management and complications of complete heart block in pregnancy

Although rare, increasing numbers of women with pacemakers are becoming pregnant. We describe the complications of a woman with arrhythmia and a pacemaker for complete heart block experienced before, during, between and after her pregnancies. We illustrate the benefits of multidisciplinary care, good communication and regular assessment in a stable, but complex woman.

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.

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.

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.

Pause for thought? Syncope and sinus arrest as the presenting feature of temporal lobe epilepsy

Some forms of focal epilepsy, including temporal lobe epilepsy, are rarely associated with ictal bradycardia and sinus node arrest. We report a case of a previously healthy man presenting with syncope in whom telemetry revealed sinus arrest. Initial treatment was with permanent pacemaker implantation and it was only following a subsequent grand mal seizure that other symptoms suggestive of temporal lobe epilepsy were documented. Anti-epileptic medication was subsequently commenced with resolution of all symptoms. There are few previously reported cases of syncope and documented sinus node arrest as the presenting feature of temporal lobe epilepsy.