Structured optimization of QRS duration reduction post-Cardiac Resynchronization Therapy is feasible and shorter QRS duration is associated with better clinical outcome

Funding Acknowledgements

Type of funding sources: None.

Introduction

Cardiac resynchronization therapy (CRT) is an established treatment for heart failure in selected patients(1). A recently developed device-based algorithm for optimization of AV- and VV-timing (SyncAV) has shown promising acute hemodynamic improvement by tailoring the device settings for maximum reduction in QRS-duration(2). We aimed to evaluate if optimization by maximizing QRS reduction is feasible in an all-comer CRT population and if reduced QRS-duration is associated with a better clinical outcome.

Methods

Medical records of 254 consecutive patients with left bundle branch block receiving CRT implants during the period 2015-2020 were retrospectively evaluated. Implants from 2015-2017 were designated as control group. Typical programming in the control group included a short AV-time to ensure biventricular capture and synchronous pacing of the right and left ventricle, or in selected patients a slight preexitation (20-40 ms) of the left ventricle. Starting from 2018 and onwards, an active 12-lead electrogram (ECG) based optimization of QRS duration had been implemented and these patients were designated as the intervention group. QRS duration and morphology were evaluated in a structured way at various device settings, including use of specific device algorithms when applicable and manual modifications of AV- and VV-delays and LV only pacing when applicable, aiming to maximize reduction of QRS duration. Digital ECGs before and after CRT implantation were collected and QRS duration reduction was automatically analyzed. The primary endpoint was a composite of heart failure hospitalization or death from any cause.

Results

Patients were followed for up to 6 years (median 2.9 [1.8-4.1]), during which 82 patients (32%) reached the primary endpoint; 53 deaths (21%) and 58 (23%) heart failure hospitalizations. Median QRS duration pre-implant was 162ms [150-174] and post-implant 146ms [132-160]. Mean reduction in QRS duration was progressively larger for each year during the intervention period, changing from -9.5ms in the control group to -24 in the year 2020 (p=0.005). In Kaplan Meier analysis across all groups, QRS reduction >14ms (median value) was associated with lower risk of death or heart failure hospitalization (p=0.049). In a multivariate model the hazard ratio was 0.60 [0.38-0.96] (p=0.03).

Conclusion

Implementing a general strategy of CRT device-optimization by aiming for shorter QRS duration is feasible in a structured clinical setting, and results in larger reductions in QRS duration post-implant. In patients with larger QRS reduction, compared to those with smaller QRS reduction, there is an association with a better clinical outcome, including lower risk of mortality and heart failure hospitalization. If confirmed in prospective trials, this strategy may become useful for improving clinical outcome for CRT recipients, regardless of device-brand and underlying etiology.

Phenotypic and genotypic analysis of benzimidazole resistance in reciprocal genetic crosses of Haemonchus contortus

Haemonchus contortus is arguably one of the most economically important and ubiquitous parasites of livestock globally and commonly involved in cases of anthelmintic resistance. Here, we performed reciprocal genetic crosses using susceptible (MHco3(ISE)) and multiple anthelmintic resistant (MHco18(UGA2004)) H. contortus isolates. Resultant admixed populations were designated MHco3/18 or MHco18/3, where the lead isolate reflects the origin of the females. Three independent filial generations were generated for each cross, which were subjected to bioassays, molecular approaches and population genetic analyses to investigate the phenotypic and genotypic inheritance of benzimidazole (BZ) resistance at each stage. A panel of microsatellite markers confirmed the success of the genetic cross as markers from both parents were seen in the F1 crosses. Egg hatch tests revealed a stark difference between the two F1 crosses with ED50 estimates for MHco18/3 being 9 times greater than those for MHco3/18. Resistance factors based on ED50 estimates ranged from 6 to 57 fold in the filial progeny compared to MHco3(ISE) parents. Molecular analysis of the F167Y and F200Y SNP markers associated with BZ resistance were analysed by pyrosequencing and MiSeq deep amplicon sequencing, which showed that MHco3/18.F1 and MHco18/3.F1 both had similar frequencies of the F200Y resistant allele (45.3% and 44.3%, respectively), whereas for F167Y, MHco18/3.F1 had a two-fold greater frequency of the resistant-allele compared to MHco3/18.F1 (18.2% and 8.8%, respectively). Comparison between pyrosequencing and MiSeq amplicon sequencing revealed that the allele frequencies derived from both methods were concordant at codon 200 (rc = 0.97), but were less comparable for codon 167 (rc = 0.55). The use of controlled reciprocal genetic crosses have revealed a potential difference in BZ resistance phenotype dependent on whether the resistant allele is paternally or maternally inherited. These findings provide new insight and prompt further investigation into the inheritance of BZ resistance in H. contortus.

Paediatric dentistry in outreach settings: an essential part of undergraduate curricula?

INTRODUCTION

Although placements in primary care settings remote from dental schools are becoming a common feature of undergraduate dental curricula, little evidence is available regarding the experience of paediatric dentistry gained in this way.

MATERIALS AND METHODS

Treatment logs relating to salaried primary care placements undertaken by the Class of 2007 at Cardiff University School of Dentistry were examined, particular attention being paid to paediatric-specific procedures.

RESULTS

Forty-nine logs relating to placements undertaken in South East Wales and 51 relating to those in North Wales were retrieved. In South East Wales, 90% of students gained experience of primary tooth restoration, 61% carrying out primary endodontics. Sixty-three percent of students undertaking placements in South East Wales and 69% of those placed in North Wales gained experience of primary tooth extraction under local anaesthesia. All but three students gained experience of administering inhalation sedation.

DISCUSSION

The findings of this study should go some way towards reassuring those who have expressed concern that recruitment difficulties within dental schools inevitably lead to increasing numbers of students qualifying without clinical experience of paediatric dental procedures considered to be within the remit of a newly qualified dental practitioner. However, there remains wide variation in the breadth and depth of experience of individual students and it is still possible for some students to graduate without what might be considered core experience in paediatric dentistry.

CONCLUSION

Salaried primary care settings are ideally placed to provide students with experience of paediatric-specific procedures. Clinical education in paediatric dentistry should, therefore, incorporate the strengths of dental school and placement education.

Combined simultaneous endoscopic transsphenoidal and endoscopic transventricular resection of a giant pituitary macroadenoma

Intrasellar and sellar-suprasellar adenomas are generally removed through a transsphenoidal approach. Giant adenomas with significant suprasellar extension often require a craniotomy or combined "above and below" approach. The use of endoscopes has increased the visualization capacity of the transsphenoidal route and made these surgeries less invasive. In this report, we describe a novel combination of the endoscopic transsphenoidal approach with the endoscopic transventricular approach to remove a giant pituitary macroadenoma extending into the third and lateral ventricles. The tumor was initially removed via an endoscopic transnasal transsphenoidal, transtuberculum, transplanum approach. A second endoscope was then advanced into the lateral ventricle through a pre-coronal burr hole to assist in mobilizing the tumor and assure a complete resection. Multilayer closure and a ventriculo-peritoneal shunt were performed to insure a watertight seal of the skull base. Giant pituitary adenomas have traditionally been removed with staged or combined transsphenoidal and transcranial approaches. We describe the successful implementation of a minimal access endoscopic combined extended transsphenoidal and transventricular approach that avoids craniotomy and brain retraction.

Mutation patterns in gyrA and parC genes of ciprofloxacin resistant isolates of Neisseria gonorrhoeae from India

AIM

To analyse mutations in the gyrA and parC genes leading to possible increase in ciprofloxacin resistance (high MIC values for ciprofloxacin) in clinical isolates of Neisseria gonorrhoeae in Delhi, India.

METHOD

MIC of ciprofloxacin for 63 clinical isolates of N gonorrhoeae were examined by the Etest method. Subsequently, gyrA and parC genes of these isolates were amplified and sequenced for possible mutations.

RESULTS

Out of the 63 clinical isolates tested, only five (8%) isolates were found to be susceptible to ciprofloxacin (MIC <0.06 micro g/ml). DNA sequence analysis of the gyrA and the parC genes of all these isolates (n = 63) revealed that all isolates which were not susceptible to ciprofloxacin (n=58) had mutation(s) in gyrA and parC genes. 12 isolates (19%) exhibited high resistance with an MIC for ciprofloxacin of 32 micro g/ml. Two out of these 12 isolates (UD62 and UD63), harboured triple mutations (Ser-91 to Phe, Asp-95 to Asn and Val-120 to Leu) in the gyrA gene. The third mutation of Val-120 to Leu, lies downstream of the quinolone resistance determining region (QRDR) of the gyrA and has not been described before in gonococcus. In addition, both these isolates had a Phe-100 to Tyr substitution in the parC, a hitherto unknown mutation.

CONCLUSIONS

Emergence of ciprofloxacin resistance with high levels of MIC values (up to 32 micro g/ml) in India is alarming. Double and triple mutations in gyrA alone or together in gyrA and parC could be responsible for such a high resistance.

Selection of local therapy after neoadjuvant chemotherapy in patients with stage IIIA,B breast cancer

BACKGROUND

Stage IIIA,B breast cancer is commonly treated with neoadjuvant chemotherapy because of high objective response rates and improved operability. Criteria for subsequent selection of local therapy--mastectomy, radiotherapy, or both--are not well defined. We adopted a policy of selective local therapy based on rebiopsy of the breast and clinical axillary lymph node status at the time of best response to chemotherapy.

METHODS

Between 1980 and 1993, 126 patients with stage IIIA,B breast cancer were treated with neoadjuvant chemotherapy and definitive local therapy. The long-term incidence of locoregional failure (in-breast, chest wall, axilla, supraclavicular, neck), relapse-free survival, and overall survival was determined.

RESULTS

The overall clinical objective response rate to chemotherapy was 95.2%. Eighty-three patients underwent mastectomy, with negative margins achieved in 91.6%. Forty-two patients had breast preservation; the overall in-breast recurrence rate was 19.0% (8 of 42 patients). The overall locoregional recurrence rate by site was: chest wall-8.7% (11 of 126 patients), axilla-8.7% (11 of 126 patients), supraclavicular-5.6% (7 of 126 patients), and neck-4.0% (5 of 126 patients). The axillary recurrence rate was 6.6% (5 of 76 patients) for clinically negative axilla treated with radiotherapy only, and 12.0% (6 of 50 patients) for clinically positive axilla treated with surgery only. The overall long-term survival probabilities (6 years) according to stage were: stage IIIA-58.0%, stage IIIB(noninflam)-58.0%, stage IIIB(inflam)-36.0%.

CONCLUSIONS

These findings support a selective approach to local therapy in patients with stage IIIA,B breast cancer. This approach provides local control in most patients, and allows for breast preservation and elimination of axillary dissection in selected patients.

siaD PCR ELISA for confirmation and identification of serogroup Y and W135 meningococcal infections

Non-culture diagnosis and serogroup determination of meningococcal infection is important in contact management where vaccination may be possible. A serogroup B and C PCR ELISA assay for the non-culture diagnosis and serogroup determination has proved invaluable for enhanced epidemiological surveillance and contact management. A polymerase chain reaction assay, based on a restriction fragment length polymorphism in the meningococcal serogroup Y and W135 sialyltransferase (siaD) gene, was developed to enhance the range of non-culture diagnosis of meningococcal infection from clinical samples. The PCR assay was adapted to an ELISA format incorporating hybridisation with serogroup-specific Y and W135 oligonucleotide probes. The serogroup-specific W135 and Y PCR ELISA is a useful addition to currently available serogroup B and C assay for non-culture diagnosis of meningococcal infection and outbreak investigation.

Reabuse rates in a sample of children followed for 5 years after discharge from a child abuse inpatient assessment program

Efforts to accurately measure rates of reabuse have been elusive because of problems in definition and methodology. The present study examines reabuse rates across a 5-year follow-up period in a sample of children assessed for child abuse (October 1986-October 1987). Participants consisted of 304 children (7 months-15 years of age), systematically selected from a population of 1,100 children consecutively admitted to a hospital-based, interdisciplinary, child abuse assessment unit. Reabuse was determined by matching sample names against information in a centralized reporting system. Reabuse was studied across demographic and socioeconomic variables, vulnerability days, initial and subsequent type(s) of abuse, and other considerations. At the end of the 61-72 month follow-up period, the sample had a 16.8% incidence of reabuse. The greatest risk of reabuse occurred during the first 2 years following an initial discharge diagnosis of maltreatment. Although no particular initial maltreatment diagnosis was a statistically significant predictor of the likelihood or type of reabuse, neglect was shown to be the most frequent type of reabuse. Children experiencing reabuse were more likely to reside in public housing/apartments, have unmarried and/or unemployed parent(s), and be Medicaid recipients. Opportunities for secondary prevention initiatives and future research are discussed.

Transcutaneous oxygen and carbon dioxide monitoring in sick neonates using a combined sensor

Using a combined O2-CO2 sensor, we evaluated the effect of cathode size and membrane thickness and incorporation of correction factor upon transcutaneous O2-CO2 readings. The present studies were carried out in three phases in newborns less than a week of age. The data from these studies indicate that a combined O2-CO2 sensor with a smaller cathode, Teflon membrane and with a built-in correction factor can accurately reflect arterial O2 and CO2 tension and can replace the present two heated sensors.

Tissue pH monitoring by a disposable sensor in critically ill neonates

Using a new disposable polymer sensor, tissue pH was continuously monitored successfully in 33 critically ill neonates. Tissue pH correlated well with the arterial pH at wide pH ranges [n = 476; r = .84; y = 0.46 + (0.94)x]. Tissue pH changes accurately reflected the arterial pH during both respiratory and metabolic acidosis and alkalosis. During severe metabolic acidosis (arterial pH less than 7.10) tissue pH was lower than arterial pH. No complications were encountered during or after monitoring. Compared with earlier studies using a glass electrode, this electrode reflects a marked technologic improvement because of its ease of application, longevity of use, disposability, and decreased risk of complications in small preterm infants. Unlike transcutaneous oxygen and carbon dioxide sensors, this device is invasive but is not heated and does not require frequent site changes.