Electroanatomic visualization of coronary arteries: a case series to elicit safety, feasibility, and diagnostic value in complex ablation procedures

AIMS

The goal of this case series was to evaluate the feasibility, safety, and advantages of a wire-based approach for the live visualization of coronary arteries (CAs) in an electroanatomic mapping (EAM) system and to assess its diagnostic information.

METHODS AND RESULTS

For this single-centre case series, we included procedures in which close proximity of a possible ablation site to any epicardial vessel was suspected. An uncoated-tip guidewire was introduced into the relevant CAs after exclusion of critical CA stenosis by coronary angiography. By connecting this wire to the EAM system using a clip and pin connection, mapping and live visualization of the wire tip is possible, as well as the assessment of the local electrograms within the respective CAs. Procedural wire insertion and intracoronary mapping was performed by EP specialists and was assisted to judge the relevance of CA disease by an interventional cardiologist. A total of nine procedures in nine patients were included in this case series, four ventricular tachycardia ablation procedures and five procedures for the ablation of premature ventricular contractions. The left CAs were mapped in eight cases and the right CA was mapped in one case. In two cases, epicardial mapping was combined with visualization of the right or left CAs. There were no complications attributed to coronary wiring and mapping in this case.

CONCLUSION

We demonstrated the feasibility and safety of CA visualization and integration in an EAM. The live visualization of the CAs added valuable information without the need for preprocedural planning or the purchase of separate software. Electroanatomic visualization was achieved intraprocedurally in a safe and straightforward manner, adding critical diagnostic information without excessive costs or risks.

Electroanatomic visualization of coronary arteries: a case series to elicit safety, feasibility and diagnostic value in complex ablation procedures

Funding Acknowledgements

Type of funding sources: None.

Background

Although three dimensional (3D) electroanatomic mapping systems allow detailed assessment of anatomy and substrates, ablation still carries substantial risk when close proximity to coronary arteries is suspected. 3D integration of coronary anatomy in mapping systems is still cumbersome, highlighting the need for an option of ad hoc acquirement of coronary artery anatomy. The goal of this case series was to evaluate the feasibility of a wire-based approach to the live visualization of coronary arteries and to assess its diagnostic information regarding procedure guiding.

Methods

For this single center case series, we included procedures in which close proximity of an ablation site to an epicardial vessel had to be suspected. An uninsulated-tip wire was then introduced into the relevant coronaries via diagnostic catheters after exclusion of critical stenosis by coronary angiography. The wire was connected to an impedance based 3D mapping system using a clamp and standard pin connection. Integrating this setup in the mapping system allows for live visualization of the wire tip, as well as the assessment of local electrograms within the respective vessel.

Results

We included a total of 9 procedures (4 ventricular tachycardia (VT) ablation procedures and 5 procedures for the ablation of premature ventricular contractions (PVCs)). The left coronary arteries were mapped in 8 cases, the right coronary artery was mapped in one case. In the majority of cases, the arrhythmogenic substrate was found in the left ventricle (5/9) or left ventricular summit area and the distal coronary sinus respectively (3/9). In two cases, epicardial mapping was performed combined with visualization of the right or left coronary arteries, respectively. There were no complications attributed to coronary wiring and mapping in this case series.

In two cases, the diagnostic information from mapping of the coronary arteries could be used to rule out an epicardial origin of arrhythmia. In the majority of cases, coronary visualization was used to ascertain a proper distance between the ablation site and the vessel.

Discussion

In this case series, we could demonstrate the feasibility and safety of coronary artery visualization and its integration in a 3D mapping system. The data obtained was used for diagnostic, as well as safety aspects. The electrograms from the wire were used to quickly assess relative timing of arrhythmias, thus allowing for an estimation of possible epicardial origin.

Conclusion

Applying the same caveats as for any other wiring of coronary arteries, their electroanatomic visualization is achieved in a safe and straightforward manner, with minimal technical requirements. Mapping of the coronary arteries adds critical diagnostic information and their real-time visualization is feasible without exceeding costs or risks

[Localization of ventricular premature contractions by 12-lead ECG]

The advances in imaging and 3D mapping systems in the last decade allowed a better correlation of ventricular premature contractions (PVCs) with anatomical structures. With regard to PVCs, interpretation of the 12-lead ECG is still crucial for the management of patients and the planning of therapies. Although there is an armamentarium of indices and algorithms to exactly pinpoint the origin of a PVC in advance, a thorough understanding of cardiac anatomy and impulse propagation, together with an awareness of the surface ECGs limitations, provides a sufficiently close approximation. PVCs from the diaphragmatic part of the ventricular cavae exhibit a superiorly directed axis, whereas PVCs from superior parts of the heart show an inferior axis. A right bundle branch block morphology or positive concordance of the precordial leads yields a high probability of left ventricular origin of a PVC. A left bundle branch block morphology is indicative of a right ventricular or septal origin of a PVC. Using the transition zone, one can estimate the origin of a PVC with regard to anterior or posterior regions of the heart: A late precordial transition is indicative of a right ventricular origin, an early precordial transition suggests a left ventricular focus. An absent transition in the sense of negative concordance is indicative for an apical origin. The intertwined course of the ventricular outflow tracts makes PVC localization more difficult. Here, shape and height of the R‑wave in V₁-V₃ help to narrow the origin down. PVCs from structures like the papillary muscles, the moderator band or infundibular bands are challenging to interpret and evidence of the limitations of the surface ECG. Based on the information gained by the aforementioned approach, a prediction of prognosis and possible treatment success is possible.

Geospatial Distribution and Predictors of Mortality in Hospitalized Patients With COVID-19: A Cohort Study

BACKGROUND

The global coronavirus disease 2019 (COVID-19) pandemic offers the opportunity to assess how hospitals manage the care of hospitalized patients with varying demographics and clinical presentations. The goal of this study was to demonstrate the impact of densely populated residential areas on hospitalization and to identify predictors of length of stay and mortality in hospitalized patients with COVID-19 in one of the hardest hit counties internationally.

METHODS

This was a single-center cohort study of 1325 sequentially hospitalized patients with COVID-19 in New York between March 2, 2020, to May 11, 2020. Geospatial distribution of study patients' residences relative to population density in the region were mapped, and data analysis included hospital length of stay, need and duration of invasive mechanical ventilation (IMV), and mortality. Logistic regression models were constructed to predict discharge dispositions in the remaining active study patients.

RESULTS

The median age of the study cohort (interquartile range [IQR]) was 62 (49-75) years, and more than half were male (57%) with history of hypertension (60%), obesity (41%), and diabetes (42%). Geographic residence of the study patients was disproportionately associated with areas of higher population density (r s = 0.235; P = .004), with noted "hot spots" in the region. Study patients were predominantly hypertensive (MAP > 90 mmHg; 670, 51%) on presentation with lymphopenia (590, 55%), hyponatremia (411, 31%), and kidney dysfunction (estimated glomerular filtration rate < 60 mL/min/1.73 m2; 381, 29%). Of the patients with a disposition (1188/1325), 15% (182/1188) required IMV and 21% (250/1188) developed acute kidney injury. In patients on IMV, the median (IQR) hospital length of stay in survivors (22 [16.5-29.5] days) was significantly longer than that of nonsurvivors (15 [10-23.75] days), but this was not due to prolonged time on the ventilator. The overall mortality in all hospitalized patients was 15%, and in patients receiving IMV it was 48%, which is predicted to minimally rise from 48% to 49% based on logistic regression models constructed to project disposition in the remaining patients on ventilators. Acute kidney injury during hospitalization (odds ratioE, 3.23) was the strongest predictor of mortality in patients requiring IMV.

CONCLUSIONS

This is the first study to collectively utilize the demographics, clinical characteristics, and hospital course of COVID-19 patients to identify predictors of poor outcomes that can be used for resource allocation in future waves of the pandemic.

Clinical characteristics and six-month outcomes of nursing home residents with low activities of daily living dependency

BACKGROUND

Up to 30% of nursing home residents have very little dependency in activities of daily living (ADLs). We compared the characteristics and six-month outcomes of a sample of low-ADL--dependent nursing home residents (LDR) with other residents.

METHODS

This is a cross-sectional, six-month follow-up study using secondary data analysis. We combined the separate 1990 and 1993 cohorts in the Resident Assessment Instrument evaluation study. In each case these data were collected in the same 254 nursing homes in 10 states. We studied residents with a length of stay greater than 60 days and age 65 years and older (N = 3955). We compared the baseline characteristics of LDR (n = 985) with all other residents. We then compared six-month outcomes of LDR with other residents and characteristics of LDR with poor outcomes (death or worsened ADL disability) with LDR who remained stable.

RESULTS

The LDR had a significantly decreased frequency of geriatric syndromes (i.e., cognitive impairment, urinary incontinence, under-nutrition, vision problems, poor balance, and pressure ulcers) and neurological disease but had the same frequency of non-neurological chronic diseases and were on more medications. Thirty-one percent had poor six-month outcomes associated with baseline poor cognition, incontinence, poor appetite, and presence of vascular disease, daily pain, shortness of breath, and multiple medications.

CONCLUSION

Our research identified 29% of nursing home residents with higher physical function (LDR) who had fewer geriatric syndromes and neurological disease diagnoses; 69% of these remained stable at 6 months. Those LDR with a higher risk of poor outcomes could be prospectively identified. LDR who remained stable for 6 months may represent a group who could potentially be maintained in the community.

Human ribosomal protein L5 contains defined nuclear localization and export signals

Ribosomal protein L5 is part of the 60 S ribosomal subunit and localizes in both the cytoplasm and the nucleus of eukaryotic cells, accumulating particularly in the nucleoli. L5 is known to bind specifically to 5 S rRNA and is involved in nucleocytoplasmic transport of this rRNA. Here, we report a detailed analysis of the domain organization of the human ribosomal protein L5. We show that a signal that mediates nuclear import and nucleolar localization maps to amino acids 21-37 within the 297-amino acid L5 protein. Furthermore, carboxyl-terminal residues at positions 255-297 serve as an additional nuclear/nucleolar targeting signal. Domains involved in 5 S rRNA binding are located at both the amino terminus and the carboxyl terminus of L5. Microinjection studies in somatic cells demonstrate that a nuclear export signal (NES) that maps to amino acids 101-111 resides in the central region of L5. This NES is characterized by a pronounced clustering of critical leucine residues, which creates a peptide motif not previously observed in other leucine-rich NESs. Finally, we present a refined model of the multidomain structure of human ribosomal protein L5.

Targeting and quality of nursing home care. A five-nation study

The objective of this study was to demonstrate that appropriate targeting and quality monitoring of institutional care of the elderly is possible using person-based information on residents of nursing homes. This cross-sectional study used Minimum Data Set (MDS) assessments of nursing home residents in 6 US states, Copenhagen, Reykjavik, and selected locations in Italy and Japan. The outcome measures were life expectancy at age 65, population over 65, percentage over 65's in nursing homes, and clinical characteristics of nursing home residents from a multinational database of RAI/MDS assessments. We found that Japan has the highest life expectancy, and the second lowest expenditure on health care. The United States has the highest expenditure on health care and intermediate life expectancy. Italy has the highest proportion of population over 65 and the lowest proportion of over 65's in nursing homes. Iceland, a relatively young country, has the highest proportion of over 65's in nursing homes. Residents in Italy and the United States had the most severe physical, cognitive and clinical characteristics, those in Iceland the least. There was wide variation in markers of quality of care, with no country either uniformly good or bad across multiple measures. In conclusion, headline statistics comparing nations' percentage of Gross Domestic Product (GDP) spent on health care, age structure of the population, percentage of over 65's in nursing homes and clinical characteristics bear no consistent relationship. Local policy and practice also affect quality of care. Standardized assessment enables comparisons at local, national and international levels making possible further research on targeting and the appropriate use of institutional care, thus permitting a range of efficiency measures to be developed to inform policy.

Chemotactic response of human alveolar macrophages and blood monocytes elicited by exposure to sulfur dioxide

An experimental study was undertaken to investigate the in vitro effect of sulfur dioxide on the chemotactic activity of alveolar macrophages (AM) and blood monocytes (BM). The cells were placed on a polycarbonate membrane and exposed to SO2 0.5, 1.5 and 2.5 ppm for 15 min. Control experiments were performed with exposure of the cells to synthetic air with 5% CO2. After gas exposure the cells were incubated with the chemotactic active agent C5a in 5% carbon dioxide (CO2) at 37 degrees C for 60 min. The numbers of AM and BM passing actively through the membrane were quantified using light microscopy. Our results show a dose-dependent reduction in the migration rate of cells under SO2 exposure. SO2 0.5 ppm induced a 29% and SO2 2.5 ppm a 53% decrease in migration of AM compared with the control exposure to synthetic air (P < 0.01). Identical experiments with BM resulted in a decrease in migration of up to 57% (P < 0.01). At SO2 concentrations of up to 2.5 ppm no significant cytotoxic effects were observed for AM or BM. The data demonstrate that exposure to SO2 may reduce the chemotactic activity of AM and BM. Our results further suggest that the decrease in cell migration induced by SO2 is due to changes in chemotactic mechanisms and not to cell death.

The structure of social engagement among nursing home residents

This research tests the reliability and construct validity of social engagement, a new quality of life measure embedded in the federally mandated Resident Assessment Instrument (RAI) for the nursing home population. The sample consisted of 1,848 residents from 268 homes in 10 states with data collected by trained research nurses. Three resident groups were formed based on residents' cognitive and ADL functioning. Social engagement was significantly related to average time spent in activities across all three groups. We hypothesized a four-factor model with social engagement distinct from mood problems, conflicted relationships, and behavior problems. LISREL confirmatory factor analysis found the data to be consistent with this hypothesis (Fit Index > .98). Intercorrelations between factors showed that for high-functioning residents, engagement was negatively related to conflict but was positively related to conflict among the most impaired. The validity of the social engagement measure and its stability across types of residents suggest its potential utility as a marker of nursing home quality.

[The chemotactic behavior of alveolar macrophages and blood monocytes after exposures to different NO2 concentrations]

The chemotaxis of alveolar macrophages (AM) and blood monocytes (BM) is important in the elimination of particles and microorganisms which have invaded the lung. The effect of nitrogen dioxide (NO2) on chemotaxis was tested on AM obtained by diagnostic bronchoscopy from five patients suspected of having bronchial carcinoma (four men, one woman; mean age 59 +/- 10 years). Blood monocytes were also studied with blood from seven healthy subjects (five men, two women; mean age 32 +/- 10 years). These cells were placed on polycarbonate membranes for 15 min each, exposed to NO2 concentrations between 1.0 and 5.0 parts per million (ppm), and then incubated with complement component C5a as chemotactically active agent. The number of AM or BM which actively migrated through the polycarbonate membrane under the influence of C5a was measured by means of a light microscope. The migration rate of AM (compared to air exposure) was reduced by 33% with 1.0 ppm NO2 and by 61% with 5.0 ppm. The migration rate of BM in similar conditions was reduced by as much as 55%. There was no significant cytotoxic effect of NO2 exposure at 1.0 and 3.0 ppm. With 5.0 ppm 13.0 +/- 3.0 cells were no longer viable. These results indicate that NO2 concentrations relevant to indoor conditions affect the chemotaxis of AM and BM after short-time NO2 exposures. The data further suggest that NO2 exposures of these cells depressed chemotactic mechanisms without relevant cytotoxicity.

Monitoring of neuromuscular transmission by electromyography (II). Evoked compound EMG area, amplitude and duration compared to mechanical twitch recording during onset and recovery of pancuronium-induced blockade in the cat

The feasibility of the compound electromyogram (EMG) was evaluated during onset and recovery from pancuronium block in the tibialis anterior muscle of ten cats. The evoked EMG area, amplitude and duration of the total response and of the major negative deflection were evaluated and compared to the mechanomyogram during 0.1 Hz and train-of-four (TOF) stimulation. EMG areas and amplitudes were found to be linearly and similarly related to the mechanomyogram during onset and recovery. Slopes of the regression lines ranged between 1.00-1.02 and between 1.10-1.22 during onset and recovery, respectively, with high individual correlation coefficients (> 0.95). The TOF ratio of the mechanomyogram was linearly related to the EMG TOF ratio during onset and to the square root of the EMG TOF ratio during recovery, with no differences between EMG areas and amplitudes, suggesting a higher initial recovery of the TOF ratio of the mechanomyogram during recovery. EMG duration increased as the level of block increased but was unsuitable for neuromuscular monitoring. Evaluation of the agreement between the two methods showed that the EMG may be from 15% below to 10% above the mechanomyogram during onset and from 40% below to 45% above the mechanomyogram during recovery, in spite of high correlation coefficients. In contrast, agreement between EMG parameters was found to be high. In conclusion, EMG is more reliable than the mechanomyogram for evaluation of neuromuscular transmission in the cat. EMG amplitudes and areas both reflect the degree of neuromuscular blockade equally well.

A new nerve stimulator (Myotest)

The Myotest is a new nerve stimulator which can give train-of-four, single twitch (1 and 10 s) and tetanic stimuli. Power is supplied by standard batteries, which allow 200 h effective use. The impulse is unipolar constant current, and the amplitude can be adjusted between 0 and 40 mA. These factors, plus the electronic control of stimulus administration, make the nerve stimulator easy to use, and facilitate the interpretation of responses, especially to tetanic and post-tetanic stimulation.

Incorporation of uranium. II. Distribution of uranium absorbed through the lungs and the skin

In experiments on mice, rabbits, and piglets the distribution of uranium was studied at different times after exposure. Uranium was administered by inhalation (mice) and through the skin (rabbits and piglets).

These investigations show that the uptakes of uranium in different organs of the three species are highly dependent on the amounts administered. There seems to be a saturation effect in the spleen and bone tissue whenever the uranium concentration in the blood exceeds a certain level. The effect in the kidney is completely different. If, in a series of animals, the quantity of uranium is continuously increased, the uptakes by the kidneys increase more rapidly than the quantities administered. This observation seems to be consistent with the toxic effects of uranium on the capillary system in the renal cortex.

Polyphloretin phosphate, a compound which reduces permeability, was investigated with respect to its effect on the uptake of uranium deposited in skin wounds in rabbits and piglets. It significantly reduced the absorption of uranium, even from depots in deep wounds.

The findings are discussed with reference to the routine screening of persons exposed to uranium at AB Atomenergi.