Biventricular Function is Impaired in Right Ventricular Septal Pacing-A Prospective Study Using Myocardial Strain Imaging

BACKGROUND

Left ventricular (LV) dysfunction is known to occur after right ventricular (RV) pacing; the effect on RV function is less well studied. The aim of this study was to assess the impact of RV mid-septal pacing upon RV function using the novel parameters of speckle-tracking derived RV global longitudinal strain (RV GLS) and RV free wall strain (RV FWS), as well as the conventional parameters RV fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), and tricuspid annular systolic velocity (RV S').

METHODS

Thirty-two (32) consecutive patients with normal baseline LV and RV function requiring permanent pacemaker insertion (for high-grade AV block or sinus node dysfunction) were prospectively recruited. Echocardiography was performed prior to implantation, at 1 day, 1 month and 1 year after implantation, with 29 patients completing follow-up.

RESULTS

After 1 year, three patients (10%) with otherwise normal RV parameters developed abnormal RV strain patterns. Compared to 1 day after implantation, at 1 year significant reductions were observed in mean RV GLS (-24.8 to -21.8%) RV S' (15.1 to 12.2 cm/s), TAPSE (24.2 to 21.9 mm), RV GLS (-24.8 to -21.8%), left ventricular ejection fraction (LVEF) (66.0 to 57.9%), LV GLS (-19.9 to 17.0), all p<0.01. There was a non-significant reduction for RV FWS (-29.0 to -26.7%, p=0.06) and there was no change in RV FAC (49.1 to 46.9%, p=0.24).

CONCLUSION

We report abnormalities of RV strain developing 1 year after pacemaker insertion. Measurement of myocardial strain is emerging as an additional method to detect patients at risk of RV dysfunction in those who have undergone pacemaker implantation.

Late recurrence of atrial fibrillation and flutter in patients referred for elective electrical cardioversion

Aim    The primary aim was to ascertain long-term rates of atrial fibrillation (AF) recurrence in this all-comer patient population undergoing elective electrical cardioversion (DCR). Secondary aims included procedural DCR success, clinical predictors of long-term maintenance of sinus rhythm (SR) and AF related hospitalizations.Material and Methods    A retrospective cohort study was conducted. Consecutive patients (n=316) undergoing elective DCR were included.Results    Successful immediate reversion to SR was attained in 266 (84 %) of patients. 224 (84 %) patients were followed up for a median period of 3.5 years (IQR 2.7-4.3). Most patients (150 [67 %]) had recurrence of AF / flutter at a median time of 240 days. Clinical predictors of AF recurrence included a history of AF (HR 0.63, p=0.038) and a dilated left atrium (HR 4.13, p=0.048). Maintenance of SR was associated with fewer unplanned hospitalizations for AF (HR 3.25, p&lt;0.01).Conclusion    There was high procedural success post DCR. However, long-term rates of AF recurrence were high, and AF recurrences were associated with increased hospitalizations. These findings underscore the importance of clinical vigilance and multi-modal management as part of a comprehensive and effective rhythm control strategy.

Safety and Long-Term Clinical Outcomes of Fractional Flow Reserve Guided Coronary Revascularisation

BACKGROUND

Increasingly, fractional flow reserve (FFR) is employed to assess coronary artery stenoses although there is limited real world long-term outcome data with a recent report questioning its safety. This study aimed to assess the in-hospital complications and clinical outcomes up to 10 years after FFR-guided revascularisation at a tertiary Australian hospital.

METHODS

The cohort comprised 274 consecutive patients undergoing FFR from 2010 to 2015 with follow-up to 2020. In-hospital complications and long-term outcomes were compared between patients with FFR≤0.80 and FFR>0.80. Major adverse cardiac events (MACE) comprised cardiac death, myocardial infarction (MI) and target vessel revascularisation (TVR).

RESULTS

The FFR was ≤0.80 in 166 and >0.80 in 108 patients. Stable coronary disease was present in 95%. Revascularisation was undertaken in 86.7% of the FFR≤0.80 group and in 2.8% of the group with an FFR>0.80. In-hospital adverse events were 3.3% with no pressure wire-related coronary dissection, stroke or death. At median follow-up of 5 years, patients with FFR≤0.80 and FFR>0.80 had a similar rate of cardiac death (2.6% versus 5.0%, p=0.335) and MI (2.6% versus 6.9%, p=0.154). In the FFR>0.80 group, MACE (17.8% v 7.9%; p=0.018) and TVR (12.9% v 5.3%; p=0.033) were significantly higher.

CONCLUSION

This observational study highlights the safety and long-term effectiveness of FFR-guided coronary revascularisation in patients with predominantly stable disease.

Accuracy of wrist-worn heart rate monitors for rate control assessment in atrial fibrillation

BACKGROUND

Wrist-worn heart rate (HR) monitors are increasingly popular. A paucity of data exists on their accuracy in atrial fibrillation (AF) in ambulatory patients. We sought to assess the HR accuracy of two commercially available smart watches [SW] (Fitbit Charge HR [FB] and Apple Watch Series 3 [AW]) compared with Holter monitoring in an ambulant patient cohort.

METHODS

Thirty-two participants ≥18 years referred for 24-hour Holter monitoring were prospectively recruited. Each participant was randomly allocated to wear either a FB or AW along with their Holter monitor.

RESULTS

Across all devices, 53,288 heart rate values were analysed from 32 participants. Twenty wore the AW (17 had persistent AF and 3 had sinus rhythm [SR]) while 12 participants wore the FB (9 in persistent AF and 3 in SR). Participants in SR demonstrated strong agreement compared to Holter monitoring (bias <1 beat, limits of agreement [LoA] -11 to 11 beats). In AF, both devices underestimated HR measurements (bias -9 beats, LoA -41 to 23). The degree of underestimation was more pronounced when HR > 100 bpm (bias of -28 beats for HR range 100-120 bpm, -48 for 120-140 bpm, and -69 for >140 bpm) compared to a slower HR (bias of -6 for HR range 80-100 bpm, <1 for 60-80 bpm, and -1 for <60 bpm).

CONCLUSION

In ambulatory patients, smartwatches underestimated HR in AF particularly at HR ranges >100 bpm. Further improvements in device technology are needed before integrating them into the clinical management of rate control in AF.

P574Accuracy of wrist-worn heart rate monitors for chronotropic assessment in atrial fibrillation

Introduction

Wrist-worn fitness and heart rate (HR) monitors are increasingly popular. Previous studies in healthy participants with sinus rhythm (SR) have yielded variable results depending on HR, activity levels and device tested. A paucity of data exists on their accuracy in atrial fibrillation (AF) in ambulatory patients.

Purpose

We sought to assess the HR accuracy of 2 commercially available smart watches (Fitbit Charge HR [FB] and Apple Watch Series 3 [AW]) compared with Holter monitoring in an ambulant patient cohort.

Methods

Patients aged >18 years referred for 24-hour Holter monitoring were prospectively recruited. The Holter monitor was the criterion measure. Each patient was randomly allocated to either a FB or AW along with their Holter monitor. The study protocol was approved by the institutional review board.

Statistical analysis: Pearson (r) correlation coefficients and Bland-Altman comparison with 95% limits of agreement (LoA) were evaluated to assess criterion validity and agreement between the smart watch and Holter ECG-HR. Bias was the calculated mean difference between the smart watch and ECG-HR. A ± 10-beat different between Holter-HR and SW-HR was used as a clinically relevant range to establish the accuracy of HR estimation by SW.

Results

Across all devices, 53,288 hear rate values were recorded from 32 patients. Twenty six patients were in persistent AF and six were in SR. Twelve patients wore the FB while 20 wore the AW. In the FB arm, nice patient were in persistent AF and three in SR. In the AW arm, persistent AF was the rhythm in seventeen and SR in three. Patients in SR demonstrated overall strong agreement compared to Holter monitoring (Mean Bias <1 beat, LoA −11 to 11 beats) and a correlation coefficient of 0.87 (p<0.001). In AF, both devices underestimated HR measurements (Overall Bias −9 beats, LoA −41 to 23, r=0.60, p<0.001). The AW had lower bias and narrower LoA compared to FB (−5 beats vs −13 beats, LoA −31 to 21 beats vs −50 to 22 beats). Using a ± 10-beat range against ECG-HR for clinical accuracy, both the AW and FB performed satisfactorily in SR with 95.2% of AW and 92.2% of FB HR readings considered valid. In AF, however, the AW-HR readings were within the ± 10-beat threshold in 76.5% of the time compared with only 56.1% of FB readings.

Conclusion

In ambulatory patients, smart watches were accurate in HR estimation when compared to Holter monitor in SR; however tended to underestimate HR in AF. Further improvements in device technology are needed before the widespread consumer adoption of this nascent technology for chronotropic assessment in arrhythmias.

Electrical remodelling and response following cardiac resynchronization therapy: A novel analysis of intracardiac electrogram using a quadripolar lead

BACKGROUND

Cardiac resynchronization therapy (CRT) improves morbidity and mortality in patients with heart failure. Although structural remodelling correlates with improved long-term outcomes, the role of electrical remodelling is poorly understood. This study aimed to evaluate electrical remodelling following CRT using a quadripolar left ventricular (LV) lead and to correlate this with structural remodelling.

METHODS

Consecutive patients undergoing initial CRT implantation using a quadripolar LV lead were enrolled. Patients were followed up for 12 months. Twelve lead ECG, transthoracic echocardiogram, and evaluation of intracardiac electrograms (EGM) were performed. Measures included right and left ventricular lead intrinsic delay, RV-pacing to LV-sensing (RVp-LVs) delay, and LV-pacing to RV-sensing (LVp-RVs) delay. The electrical changes were then correlated with echocardiographic response to CRT, defined by ≥15% relative reduction in LVESV and ≥ 5% absolute improvement in EF on TTE. Activation sequence was determined using the quadripolar lead.

RESULTS

Forty patients were enrolled. Mean intrinsic RV-LV EGM values decreased from 121.9 ± 14.7 ms to 109.1 ± 15.0 ms (P < .01), mean RVp-LVs EGM values from 146.7 ± 16.7 ms to 135.1 ± 13.1 ms, (P < .01), and mean LVp-RVs EGM values from 155.7 ± 18.1 ms to 144.2 ± 17.1 ms (P < .01). The improvement in intrinsic RV-LV EGM was 14.9 ± 8.5 ms in responders vs 8.9 ± 7.9 ms in nonresponders to CRT (P < .05). Changes in activation sequence did not correlate with CRT response.

CONCLUSIONS

This novel study used EGMs from a quadripolar LV lead to demonstrate electrical remodelling occurs following CRT. A nonsignificant trend suggests that electrical remodelling in CRT is greater in responders compared to nonresponders, although further study is needed.

Staphylococcus aureus urinary tract bacteriuria: single-institutional antibiotic susceptibility trends over a decade

Objectives: Methicillin resistant Staphylococcus aureus (MRSA) is a troublesome pathogen which is difficult for clinicians to treat. The purpose of this surveillance program is to assess the prevalence of MRSA urinary tract infections and determine risk factors for methicillin resistance in adults amongst urinary isolates of SA and to describe the antibiotic susceptibilities to guide empirical therapy.Methods: From 2005 through to 2014, we retrospectively reviewed urine cultures recorded in a laboratory database at a university hospital in Cambridge, UK. Susceptibility testing was performed by BSAC (British Society of Antimicrobial Chemotherapy) disc diffusion testing and reported for fluoroquinolones, gentamicin, nitrofurantoin, linezolid, trimethoprim and vancomycin. Samples were denoted “MRSA” if they were resistant to oxacillin or cefoxitin.Results: In total, 690 cultures were positive for SA, of which 293 (42.5%) were methicillin resistant. The number of SA bacteriuria decreased from around 100 per year to 40 per year. The proportion demonstrating methicillin resistance decreased from around 60% to around 20%. Both methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA isolates were susceptible to vancomycin and nitrofurantoin. MRSA isolates demonstrated some increased resistance to trimethoprim and gentamicin and greatly increased resistance to fluoroquinolones. Urinary catheterization and increasing age were risk factors for methicillin resistance.Conclusion: The incidence of SA and MRSA bacteriuria decreased during the study period. A high degree of resistance to fluoroquinolones was observed in MRSA compared to MSSA. Analysis of antibiotic susceptibility profiles suggests nitrofurantoin and trimethoprim may be useful in treating uncomplicated MSSA and MRSA urinary tract infections without concurrent bacteremia.

Candida growth in urine cultures: a contemporary analysis of species and antifungal susceptibility profiles

BACKGROUND

Recent publications suggest the distribution of Candida species causing candiduria may vary geographically, which has implications for the continued efficacy of antifungal therapy and emerging resistance.

AIM

To investigate the incidence of Candiduria at a university hospital in the UK. Further, to assess the distribution of species and the accompanying antifungal susceptibility profile, in order to monitor the clinical utility of current antifungal treatment guidelines for candiduria so that patients receive the best possible outcomes from the most up to date care.

DESIGN

Retrospective audit.

METHODS

From 1st January 2005 to 31st October 2014, we retrospectively reviewed 37 538 positive urine cultures recorded in a computerized laboratory results database. Identification and susceptibility testing was performed using the VITEK® 2 fungal susceptibility card (bioMérieux, Marcy d'Etoile, France).

RESULTS

In total, 96 cultures were positive for Candida species, of which 69 (72%) were C.albicans, which translates to a prevalence of 2.6 per 1000 positive urine cultures. Candiduria was more common in younger patients, males and catheterized females. We report 94 and 73% of isolates of C.albicans and other non-C.albicans Candida species were susceptible to fluconazole. All isolates were susceptible to amphotericin B.

CONCLUSIONS

Our results add weight to the evidence supporting current European and North American guidelines recommending fluconazole or amphotericin B for treatment of candiduria, if antifungal treatment is clinically indicated.

Vancomycin resistant enterococci in urine cultures: Antibiotic susceptibility trends over a decade at a tertiary hospital in the United Kingdom

Purpose

Enterococci are a common cause of urinary tract infection and vancomycin-resistant strains are more difficult to treat. The purpose of this surveillance program was to assess the prevalence of and determine the risk factors for vancomycin resistance in adults among urinary isolates of Enterococcus sp. and to detail the antibiotic susceptibility profile, which can be used to guide empirical treatment.

Materials and Methods

From 2005 to 2014 we retrospectively reviewed 5,528 positive Enterococcus sp. urine cultures recorded in a computerized laboratory results database at a tertiary teaching hospital in Cambridge, United Kingdom.

Results

Of these cultures, 542 (9.8%) were vancomycin resistant. No longitudinal trend was observed in the proportion of vancomycin-resistant strains over the course of the study. We observed emerging resistance to nitrofurantoin with rates climbing from near zero to 40%. Ampicillin resistance fluctuated between 50% and 90%. Low resistance was observed for linezolid and quinupristin/dalfopristin. Female sex and inpatient status were identified as risk factors for vancomycin resistance.

Conclusions

The incidence of vancomycin resistance among urinary isolates was stable over the last decade. Although resistance to nitrofurantoin has increased, it still serves as an appropriate first choice in uncomplicated urinary tract infection caused by vancomycin-resistant Enterococcus sp.

Prevention of sepsis prior to prostate biopsy

Purpose

Urosepsis is the most feared complication of transrectal prostate biopsy. The incidence may be increasing from <1% to 2%–3% in contemporary series. Historically, fluoroquinolones have been effective antibiotic prophylaxis to prevent infective complications but antibiotic resistance is increasing. The increase in antibiotic resistance may contribute to reported increases in urosepsis and hospitalization after transrectal biopsy. This article will review other methods clinicians may employ to reduce the incidence of infective complications after prostate biopsy.

Materials and Methods

A systematic review of the literature was conducted using literature databases PubMed and Ovid MEDLINE in August 2015 in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) criteria.

Results

Effective strategies to reduce infective complications after transrectal prostate biopsy include augmented prophylaxis with other antibiotics, rectal swab culture directed antibiotic prophylaxis or a transperineal biopsy approach. Needle disinfection, minimizing the number of biopsy needles and rectal disinfectants may also be of use. These methods may be of particular utility in patients with risk factors for developing urosepsis such as recent antibiotic use and overseas travel.

Conclusions

The scientific literature describes various techniques designed to reduce infective complications caused by prostate biopsy. Clinicians should consider incorporating these novel techniques into their contemporary practice.

Magnetic resonance imaging for prostate cancer: Comparative studies including radical prostatectomy specimens and template transperineal biopsy

Purpose

Multiparametric magnetic resonance imaging (mpMRI) is an emerging technique aiming to improve upon the diagnostic sensitivity of prostate biopsy. Because of variance in interpretation and application of techniques, results may vary. There is likely a learning curve to establish consistent reporting of mpMRI. This study aims to review current literature supporting the diagnostic utility of mpMRI when compared with radical prostatectomy (RP) and template transperineal biopsy (TTPB) specimens.

Methods

MEDLINE and PubMed database searches were conducted identifying relevant literature related to comparison of mpMRI with RP or TTPB histology.

Results

Data suggest that compared with RP and TTPB specimens, the sensitivity of mpMRI for prostate cancer (PCa) detection is 80–90% and the specificity for suspicious lesions is between 50% and 90%.

Conclusions

mpMRI has an increasing role for PCa diagnosis, staging, and directing management toward improving patient outcomes. Its sensitivity and specificity when compared with RP and TTPB specimens are less than what some expect, possibly reflecting a learning curve for the technique of mpMRI.

Current role of multiparametric magnetic resonance imaging in the management of prostate cancer

The purpose of this review was to evaluate the current role of multiparametric magnetic resonance imaging (mp-MRI) in the management of prostate cancer (PC). The diagnosis of PC remains controversial owing to overdetection of indolent disease, which leads to overtreatment and subsequent patient harm. mp-MRI has the potential to equilibrate the imbalance between detection and treatment. The limitation of the data for analysis with this new technology is problematic, however. This issue has been compounded by a paradigm shift in clinical practice aimed at utilizing this modality, which has been rolled out in an ad hoc fashion often with commercial motivation. Despite a growing body of literature, pertinent clinical questions remain. For example, can mp-MRI be calibrated to reliably detect biologically significant disease? As with any new technology, objective evaluation of the clinical applications of mp-MRI is essential. The focus of this review was on the evaluation of mp-MRI of the prostate with respect to clinical utility.

Collaboration and research as key elements for strengthening blood donation in developing nations: the case of Grenada, West Indies

OBJECTIVE

The purpose of the study was to identify ways to strengthen the collaboration between the Grenadian Blood Bank, the St George's University (SGU) chapter of the American Medical Students Association, and St George's University Health Clinic in order to improve the promotion of blood drives and increase the number of volunteer donors.

METHODS

The study had two phases. Phase 1: an assessment of the strengths and needs of the collaborators and of the blood drives. Phase 2 consisted of three student assessments: a cross-sectional survey of second year medical students, a cross-sectional survey of students in the School of Arts and Sciences and a case-control study of factors affecting student donation on the day of blood drives. Embedded within both phases were service-learning opportunities for students. Both phases received approval from SGU's Institutional Review Board.

RESULTS

Preliminary achievements included a transient increase in blood donation of twenty per cent during five months though advertising of blood drives remains inadequate. Assessments reveal that most students lack knowledge about the drives, and time (medical students) and fear of needles and infection (Arts and Science students) are potential hindrances to blood donation.

CONCLUSIONS

The Blood Bank needs to increase its profile on the university campus and develop a more effective promotion of the blood drives addressing the concerns of students. St George's University needs to continue supporting student involvement in health promotion activities and identify ways to ensure the sustainability and continuity of these activities. Collaboration and research are useful and effective means to promote blood donation. College students are potentially an excellent source of collaborators and donors if provided with the promotion skills and participation is made convenient.