Left bundle branch area pacing as a first line pacing strategy, which patients should we consider?

Background

A higher right ventricular (RV) pacing burden in those with permanent pacemakers results in accelerated pacing induced cardiomyopathy, in addition to increased incidence of heart failure and mortality [1–3]. This process may necessitate upgrade to a biventricular system in time, as the cardiomyopathy progresses. Physiological conduction system pacing targets such as His-bundle pacing (HBP) or Left Bundle Branch Area Pacing (LBBAP) have been shown to generate comparatively narrower QRS complexes and thus mitigate this cardiomyopathy development [4,5].

The 2021 ESC guidelines have a class 2b indication for consideration of HBP as an alternative to RV pacing in those with AV block and left ventricular ejection fraction >40%, who are anticipated to have >20% ventricular pacing burden [6].

Purpose

To retrospectively identify ECG, echocardiographic, permanent pacemaker (PPM) setting and patient factors associated with high RV pacing burden that may aid selection of those who may benefit from conduction system pacing (CSP).

Methods

We retrospectively identified 300 consecutive patients who underwent cardiac implantable electronic device insertion in our Electrophysiology Lab from the years 2017–2018. We excluded patients who underwent generator replacements, in addition to those who had biventricular devices or implantable cardioverter defibrillators inserted. We collated ECG, echo, past medical history and pacing data for each patient over a three-year follow up period.

Data were analysed using SPSS v.26.

Results

160 patients met inclusion criteria. Those with an RV pacing burden >20% were categorised group one (n=85) and those with <20% in group two (n=75). Baseline characteristics of these two groups are compared in Table 1 and Table 2.

Our analysis showed that significant differences between these groups included a lower mean HR (Table 1) (55.1±17.8 vs 57.63±17.4) with a more prolonged PR interval (225.7ms ± 8.34 vs. 188.6ms ± 6.62) or atrial fibrillation/flutter (AF/AFL) on admission ECG. There were more males with a greater mean age (High Ventricular Paced (VP) = 76.6 years ± 8.4 vs Low VP = 71.23 years ± 12.3) in the higher VP group, and they demonstrated more incidence of dilated RA/RV on echo (Enlarged RA = 30.5%; Enlarged RV = 23.6% vs 10% and 8.4% respectively).

There were significant differences in PPM indications and setting between groups (Table 2), with the higher VP groups having PPM inserted for persistent high-grade AV block (CHB = 31.5% vs 4.9% and Mobitz 2 = 9.6% vs 0%) and had less MVP mode activated (Mode switch algorithm = 13.3% vs 71%).

Conclusion

Our data suggests that those with persistent high grade AV block such as Mobitz 2 or CHB should be considered for CSP. Other considerations include older age, male sex, dilated RV/RA, prolonged PR, lower intrinsic HR or AF/AFL on admission ECG. PPM mode switching settings to reduce RV pacing burden should be utilised where possible.

Funding Acknowledgement

Type of funding sources: None.

Protection of bone mineral density in heart failure patients:audit on current clinical practice in a busy tertiary care hospital cardiology department in Ireland

Background

The strong association between heart failure (HF) and osteoporosis is well recognised. Heart failure, due to its multiple risk factors and common pathogenesis with osteoporosis can lead to low bone mineral density (BMD) and increase the risk of fragility fractures. The mortality of HF patients following these fractures is high. Current National Osteoporosis Foundation Guidelines recommend that pharmacological therapy should be reserved for postmenopausal women and men aged 50 years or older who present with a hip or vertebral fracture, where the vertebral fractures may be clinical or identified on a radiograph alone.

Methods

Most HF patients have frequent chest radiographs over their course years. We aimed to audit the prevalence of osteoporosis and current practice of prescribing BMD-protection in patients attending the HF clinic in a busy tertiary care hospital in Ireland. 100 patients attending the clinic in the last one year were randomly selected and clinical, medication and chest radiograph information on this cohort was collected via the hospital electronic information system. All those patients with Radiologist confirmed vertebral compression fractures (VCF) on their plain chest radiographs were audited regarding osteoporosis screening and bone protection prescription.

Results

Due to limited penetration,18 out of 100 chest radiographs were inconclusive,reducing the sample size to 82. 9 out of the remaining 82 patients had radiologist confirmed VCF on their plain chest radiographs whereas 2 patients had VCF incidentally picked up on their lumbar spine x-rays. All patients were aged more than 50. 4 were female and 7 male. Median ejection fraction calculated was 35%. 3 out of 11 were smokers,8 had atrial fibrillation and were on anticoagulation,4 had DM-II and 2 had CKD. 10 were on loop diuretics. Of note,4 patients were on calcium and vitamin D supplements but only 1 patient was on antiresorptive therapy for osteoporosis.

Conclusion

Despite its strong association with heart failure,Osteoporosis remains undertreated in this patient cohort.Due to the significant mortality and morbidity associated with major osteoporotic fractures, doctors should carefully assess and screen heart failure patients for osteoporosis and initiate specific therapy where indicated.

Funding Acknowledgement

Type of funding sources: None.

Left atrial scar burden in sinus rhythm differs from atrial fibrillation using automated voltage analysis during radiofrequency ablation for atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Scar burden in atrial fibrillation (AF) can be overestimated due to many factors. Scar burden has prognostic value and substrates considered for ablation by some electrophysiologists. We compared left atrial (LA) scar voltage in AF to sinus rhythm (SR) using voltage histogram analysis (VHA) of those undergoing pulmonary vein isolation (PVI) for persistent AF (PeAF). We believe this is the first study analysing LA scar location in SR and AF using VHA.

Methods

We retrospectively analysed 120 anatomical segments (AS) and whole LA voltages (N= 10 patients, mean age 68 ± 7, 4 females) in SR and AF. Fast anatomical maps (FAM) were grouped into 6 AS in AF and SR: Anterior, Posterior, Roof, Floor, Septal and Lateral AS, which were analysed via VHA (Figure 1) in 10 voltage ranges between 0mV-0.5mV. Total LA area in each voltage aliquot was recorded in SR and AF, taking diseased LA as 0.2-0.5mV and dense LA scar as <0.2mV. The pulmonary veins, mitral annulus and trans-septal puncture sites were excluded from analyses. We included patients over age 18 with PeAF who had de novo PVI with no extra ablation lines, maps with >1000 voltage points in both rhythms and uniform procedure involving initial mapping in AF then remapping in SR after PVI. Statistical analyses conducted with IBM SPSS v.26.

Results

Total LA scar burden was greater in AF (Mean 142.76 mm², SD ± 138.78mm²) than SR (Mean 109mm², SD ± 107.8mm²), p= <0.0001, Table 1. Scar correlation in SR and AF had a good relationship, R = 0.416 (p= <0.001). Every 1mm² of scar identified during SR yielded a mean of 1.54mm² in AF, (p= <0.001).

Conclusions

AF was associated with higher scar burden in the Roof, Anterior, Lateral and Posterior AS. Dense LA scar (≤ 0.2mV) on the Posterior AS was significantly higher in AF, while in other AS was comparable to SR. Mapping substrate in AF, especially the posterior wall, may be misleading as scar burden may be overestimated when compared to SR. Table 1Voltage< 0.02 mV (mean area ± SD mm2)0.2-0.5mV (mean area mm2)RhythmSRAFp-valueSRAFp-valueEntire LA115.89 ± 113.61143.41 ± 144.230.02*105.78 ± 103.73144.00 ± 135.24<0.0001*Roof82.72 ± 117.3283.68 ± 113.560.95115 ± 77.14150.61 ± 93.170.01*Anterior131.8 ± 169.53126.5 ± 154.570.85158.53 ± 99.22220.87 ± 173.070.002*Lateral70.5 ± 80.0090.57 ± 117.990.3687.52 ± 66.82137.05 ± 104.990.0002*Septal80.99 ± 89.0380.99 ± 89.030.6899.123 ± 73.62115.37 ± 84.830.18Floor105.1 ± 134.91106.42 ± 148.670.96117.62 ± 85.41151.2 ± 110.070.052Posterior102.14 ± 157.47159.03 ± 194.650.02*138.27 ± 112.28234 ± 150.45<0.0001*LA scar distribution in SR and AF, *denotes significant results.Abstract Figure 1

Lipid profile analyses of patients with and without type-2 diabetes in a cardiac rehabilitation population

Funding Acknowledgements

Type of funding sources: None.

Introduction

Type 2 diabetes mellitus (T2DM) can double your risk of coronary artery disease (CAD). SGLT2 inhibitors reduce all-cause mortality for patients with T2DM and CAD, targeting metabolic syndrome components like HbA1c, blood pressure and weight. Lipid profiles are intrinsically linked to obesity however the secondary effects of SGLT2 inhibitors remain unclear, with studies showing a rise in HDLc and LDLc with these medications.

Propose

To compare the effect of cardiac rehabilitation and guideline directed statin therapy on lipid panels of those with diabetes to those without, and to conduct a sub-analysis on SGLT2 inhibited patients to assess for increased HDLc and LDLc.

Methods

We retrospectively reviewed our cardiac rehab records. Data was collected on sequential patients over age 18 who completed cardiac rehab, until 90 diabetics and 90 non-diabetics were identified. Statistical analyses performed using SPSS v.26.

Results

Diabetics had significantly lower total cholesterol, HDL and LDL prior to commencing rehab (Table 1). Diabetics also showed less reduction in total cholesterol and LDL than non-diabetics. Groups had similar follow-up time and anti-lipid therapy. N = 12 (13.3%) diabetics were on SGLT2 inhibitors. This group showed the greatest mean increase of HDL and lowest mean decrease of LDL levels, however, did start with the lowest initial lipid levels.

Conclusions

Diabetics had lower LDL and HDL prior to rehab, which may have led to reduced change in their profiles compared to non-diabetics. Interestingly however, patients on SGLT2 inhibitors showed a trend towards least reduction in mean LDL and the greatest increase in mean HDL compared to other diabetics.

Table 1 Category(Lipids in mmol/L) Non-Diabetics, n = 90 (Mean ± SD) Diabetics, n = 90 (Mean ± SD) p-value SGLT2 cohort, n = 12 (Mean ± SD) Age (Years) 66.1 ± 8.73 67.73 ± 8.88 0.21 66.41 ± 7.8 Max. statin (%) 92.2% 90% 0.16 100% Pre-Total Chol. 4.21 ± 1.29 3.57 ± 0.9 <0.01* 3.36 ± 0.62 Pre-Triglyceride 1.6 ± 0.85 1.87 ± 1.02 0.054 1.63 ± 0.6 Pre-HDL 1.33 ± 0.48 1.12±.029 <0.001* 1.03 ± 0.22 Pre-LDL 2.14 ± 1.03 1.68 ± 0.93 0.002* 1.60 ± 0.57 Change- Total Chol. -0.75 ± 1.13 -0.26 ± 0.09 0.9 -0.09 ± 0.45 Change-HDL -0.01 ± 0.42 +0.03 ± 0.19 0.33 +0.19 ± 0.13 Change- LDL -0.61 ± 0.96 -0.28 ± 0.75 0.01* -0.24 ± 0.63 Lipids rechecked (months) 8.4 ± 0.25 7.9 ± 0.26 0.14 8.25 ± 2.26 Pre-intervention lipid profiles, followed by change in levels over time. *Denotes significance.

Correlation of STOP-bang obstructive sleep apnoea screening tool to apnoea-hypopnea index in a general cardiology population

Funding Acknowledgements

Type of funding sources: None.

Introduction

The link between obstructive sleep apnoea (OSA) and cardiovascular disease is well known. Prevalence can be very high in this population, sharing many pathophysiological drivers in addition to being a risk factor. More concerning however is the increasing number of patients with undiagnosed OSA, who are at higher risk of long-term complications such as coronary artery disease, hypertension, atrial fibrillation, heart failure or stroke. There are several OSA screening tools available to clinicians, with variable sensitivities and specificities depending on patient demographics.

Predictive efficacy of the STOP-Bang screening tool in a general cardiology population with mixed cardiovascular disease has not been established.

Proposal

To identify the correlation between the STOP-Bang assessment score (1-8) and real-world Apnoea-Hypopnoea Index (AHI) in a general cardiology clinic population.

Methods

250 successive patients in a general cardiology clinic were asked to complete a STOP-Bang assessment. Of those, 50 patients with a variety of STOP-Bang scores were randomly selected to undergo sleep studies. A STOP-Bang value of ≥ 5 was taken as high-risk for moderate-severe OSA. Statistical linear regression analysis was performed in IBM SPSS version 26.

Results

Of n = 50 patients, mean STOP-Bang score =3.7 (SD +/-2.17) with mean AHI =15.8, (SD +/- 14.3). See Table 1 for categories 1-8. N = 44 (88%) had AHI ≥ 5 (At least mild OSA). N = 18 (36%) had an AHI ≥ 15 (Moderate-severe OSA). N = 29 (58%) had symptoms such as sleepiness, loud snoring or witnessed apnoea. Correlation between STOP-Bang score and AHI was high, with an  R value of 0.704, R2 = 0.496 (p < 0.01). A STOP-Bang score increase of 1 corresponded with a mean AHI rise of 4.648. When taking a STOP-Bang value of ≥ 5 as "positive", we demonstrated a sensitivity of 83.33% (95% C.I. 58.58-96.42) and specificity of 93.94% (95% C.I. 79.77-99.26%) for moderate-severe OSA (AHI ≥ 15). 

Conclusion

We discovered a very high number of patients with undiagnosed OSA of at least mild severity. We found a strong correlation between STOP-Bang score and real-world AHI in a general cardiology population with mixed cardiovascular disease with 5 as an acceptable screening score for moderate-severe OSA.

Table 1 STOP-Bang Value 1 2 3 4 5 6 7 8 Patients (N=) 12 5 7 9 5 5 5 2 AHI (Mean) 6.67 6.62 9.97 11.95 24.44 22.20 39.54 35.25 Standard Deviation (±) 3.29 2.74 3.45 4.63 12.87 5.69 27.2 6.72 Summary of mean apnoea-hypopnoea index and standard deviation for each STOP-Bang patient category.

Abstract Figure 1

Micromachined Fused Silica Liquid Core Waveguide Capillary Flow Cell

A planar, chip-based flow cell for UV-vis absorbance detection in HPLC is presented. The device features a microfabricated free-standing liquid core waveguide (LCW) capillary detection tube of long path length that is based on total internal reflection. We report on the linearity and calibration slope characteristics of lithographically produced LCWs with different interior/exterior geometries. 3D ray tracing was indispensable in modeling behavior in the more demanding geometries: multipath behavior may be intrinsic to these waveguides with consequent nonlinearity. Fortunately, nonlinearity in lithographically easy-to-produce waveguide geometries (such as with a flat, concave exterior and a round interior) is not as detrimental as might be initially expected. Experimental performance is predictably affected by the attainable surface quality of the LCW and efficient and reproducible coupling of the input light into the LCW.

Meaning in caring: reconceptualizing the nurse-family carer relationship in community practice

To date family caregiving studies have considered family caring in primarily practical terms such as 'how to do' and 'how to cope'. Research efforts have focused upon exploiting the productive elements of a certain conception of the essence of family caregiving. Thus despite a wealth of studies, the question of the nature of family caregiving is not well understood. This ontological-hermeneutic study highlights the importance of understanding the human experience of family caring at home. The study involved in-depth audio-taped interviews with seven family carers who care for an older relative at home. Thematic analysis of the transcribed interviews uncovered a number of common themes which highlighted unique and shared meanings family carers ascribed to their everyday existence as carers. The findings will challenge practitioners to reconceptualize the nurse-family carer relationship, to appreciate the many ways in which family members' involvement in care provides meaning and significance to their lives, and to understand family carers through a process of human relating which fosters families' meaningful involvement in caring at home.

Evaluation of a self-paced education package on violence against women for rural community-based health workers

There are no reported education programs specifically focusing on the needs of rural health workers in the area of violence against women. The most commonly reported contact sought by women experiencing injuries and health problems associated with violence and abuse is with health workers. Women report a failure by health workers to make direct enquires, which may be due to their lack of education and confidence in responding to these issues. A convenience sample of 60 community-based rural health workers from a range of occupations and settings within the Wide Bay Health Region, Queensland, participated in the evaluation of a self-paced, distance education package on violence against women. The package contained seven modules. These included written and audio tape material, and activities that together formed a community development approach to addressing the needs in the participants' local community. Participants were given a mentor and teleconference support during the 8 weeks allocated to complete the package. A pre- and post-course evaluation, containing quantitative and qualitative data, was completed. Analysis of the quantitative data identified significant changes in participants' knowledge, and the qualitative data highlighted an increased sense of confidence in assisting women, forming support networks and using resources more effectively. Participants reported the most useful aspects of the package were: (i) modular- and user-friendly format; (ii) flexible, practical, health-focused content; and (iii) real world examples.

The clinical relevance of hemoglobin, platelet, and serotonin changes in sequestered and circulating blood during cardiopulmonary bypass

OBJECTIVE

To determine how hemoglobin (Hb), platelet, and serotonin concentrations change during cardiopulmonary bypass (CPB) in sequestered blood from the pulmonary artery compared with circulating systemic blood; and to determine the correlation between platelet and serotonin variability at the two sites and clinical outcome measurements related to hemodynamics and blood loss.

DESIGN

A prospective clinical study.

SETTING

A university hospital.

PARTICIPANTS

Twenty patients undergoing elective aortocoronary bypass.

INTERVENTIONS

Measurements of Hb, platelet, and serotonin concentrations were performed before, during, and after CPB on paired blood samples from the pulmonary artery and the radial artery. Hemodynamic measurements were recorded before and after CPB and chest tube drainage was recorded postoperatively.

MEASUREMENTS AND MAIN RESULTS

The Hb, platelet, and serotonin concentrations were all significantly different between radial artery and pulmonary artery samples at the different measurement times (p < 0.001, analysis of variance [ANOVA] for repeated measures). Hb, platelet, and serotonin concentrations were all significantly increased in the pulmonary artery at the time of aortic cross-clamping compared with the corresponding radial artery blood samples (p < 0.0005, ANOVA). During the period of ischemic arrest, Hb was unchanged in the pulmonary artery and remained significantly increased compared with systemic blood (p < 0.0005, ANOVA). Serotonin concentrations in both systemic and sequestered pulmonary artery blood had significant correlation with cardiac index (CI), right ventricular ejection fraction (REF), and systemic vascular resistance index (SVRI; p < or = 0.006, least squares analysis). Postoperative chest tube drainage most closely correlated with the platelet counts measured in both the radial and pulmonary arteries at the start of CPB (p < 0.05, least squares analysis).

CONCLUSION

During CPB, there were significant differences in Hb, platelet, and serotonin concentrations in sequestered pulmonary artery blood compared with circulating systemic blood. The initial differences and subsequent changes were most likely attributable to decreased hemodilution and a different pattern of platelet activation in the pulmonary artery blood compared with the systemic blood. Despite the hematologic differences, serotonin concentration and platelet counts in the pulmonary artery blood had significant correlation to indices of cardiac function and postoperative chest tube drainage, respectively. Platelet and serotonin changes in sequestered pulmonary artery blood were also associated with some of the adverse consequences of CPB.

Community health workers' response to violence against women

This paper reports on a qualitative study of community health workers from a predominantly rural based region in Queensland. The purpose of this study was to determine the community health worker barriers to identification, assessment and intervention on the issue of violence against women. The qualitative research method comprised five structured focus group interviews with 28 community health workers using open-ended questions to explore their perceptions. Analysis of the focus group data revealed that community health workers expressed reluctance to become involved in cases of violence against women. The reasons they provided are grouped under three main themes: barriers to identification; barriers to assessment; and barriers to intervention. Training programs offered to rural community health workers need to be aware of the barriers to identifying, assessing and intervening in cases of violence against women that are highlighted by this study. Further studies are needed to assess the wider relevance of these findings to other groups of community health workers in rural and non-rural settings.

Amiodarone-related postoperative adult respiratory distress syndrome

Directed surgical intervention in patients with ventricular tachyarrhythmias who have experienced failure of amiodarone therapy is a common clinical scenario. Sixty-seven patients with malignant ventricular tachyarrhythmias received either an automatic implantable cardioverter-defibrillator (n = 43) or subendocardial resection (n = 24). Nineteen cardiothoracic procedures (automatic implantable cardioverter-defibrillator in six, endocardial resection in 13) were performed in 17 patients who received amiodarone before surgery. Eight received the drug acutely as a loading dose of 1,200 mg/day for 7-14 days; 11 patients were on chronic oral amiodarone at a mean dose of 362 +/- 74 mg/day. Eight patients were removed from amiodarone therapy a mean of 6.6 days before surgery. Adult respiratory distress syndrome (ARDS) developed after surgery in nine (50%) of 18 surgical survivors. ARDS was manifested by hypoxemia, pulmonary infiltrates, and prolonged intubation. Pulmonary capillary wedge pressure and cardiac output were measured before and after surgery and during ARDS. Pulmonary capillary wedge pressure and cardiac output remained constant after surgery at a time that the PaO2/FIO2 ratio fell significantly. By contrast, none of the remaining 44 patients who did not receive amiodarone developed ARDS despite similar preoperative and intraoperative clinical parameters. Patients with ventricular tachyarrhythmias who receive even a short course of amiodarone are at risk for postoperative ARDS.

Entrainment of hamster pup circadian rhythms by prenatal melatonin injections to the mother

A circadian pacemaker, thought to be within the suprachiasmatic nucleus (SCN) of the hypothalamus, begins to function before birth in rodents. Prenatal entrainment of the pacemaker appears to be mediated by signals regulated by the maternal SCN; ablation of the mother's SCN during gestation disrupts the normal phase of the pups' rhythms. The present paper presents an experimental approach for identifying candidate entraining signals and for testing when they are effective during development. The candidate signal examined in these experiments was the pineal gland hormone, melatonin. Female golden hamsters (Mesocricetus auratus) received SCN lesions on day 7 of gestation. During the last week of gestation, they were given two daily subcutaneous injections of oil 12 h apart. One of the injections each day contained melatonin (10, 50, or 100 micrograms). The phases of the pups' activity rhythms were measured at weaning and were found to be related to the timing of the daily injection that contained melatonin, demonstrating that the melatonin directly or indirectly set the phase of the pups' rhythms. Injections given over 4 days of gestation were found to be as effective as injections given over 7 days. Although a physiological role for melatonin as an entraining signal has not been demonstrated, the results show that exogenous, prenatal treatment can predictably set the phase of the offsprings' circadian rhythms.