Publications by authors named "Ji-Jian Chow"

8 Publications

  • Page 1 of 1

The Impact of the Covid-19 Pandemic on Uptake of Influenza Vaccine: A UK-Wide Observational Study.

JMIR Public Health Surveill 2021 Feb 18. Epub 2021 Feb 18.

National Heart & Lung Institute, Imperial College London, Hammersmith Hospital CampusDu Cane Road, London, GB.

Background: In the face of the Covid-19 pandemic, the UK National Health Service (NHS) flu vaccination eligibility is extended this season to ~32.4 million (48.8%) of the population. Knowing intended uptake will inform supply and public health messaging to maximise vaccination.

Objective: The objective of this study was to measure the impact of the Covid-19 pandemic on acceptance of flu vaccination in the 2020-21 season, specifically focusing on those previously eligible who routinely decline vaccination and the newly eligible.

Methods: Intention to receive influenza vaccine in 2020-21 was asked of all registrants of the NHS's largest electronic personal health record by online questionnaire on 31st July 2020. Of those who were either newly or previously eligible but had not previously received influenza vaccination, multivariable logistic regression and network diagrams were used to examine reasons to have or decline vaccination.

Results: Among 6,641 respondents, 945 (14.2%) were previously eligible but not vaccinated, of whom 536 (56.7%) intended to receive flu vaccination in 2020/21, as did 466 (68.6%) of the newly eligible. Intention to receive the flu vaccine was associated with increased age, index of multiple deprivation (IMD) quintile, and considering oneself at high risk from Covid-19. Among those eligible but intending not to be vaccinated in 2020/21, 164 (30.2%) gave misinformed reasons. 47 (49.9%) of previously unvaccinated healthcare workers would decline vaccination in 2020/21.

Conclusions: In this sample, Covid-19 has increased acceptance of flu vaccination in those previously eligible but unvaccinated and motivates substantial uptake in the newly eligible. This study is essential for informing resource planning and the need for effective messaging campaigns to address negative misconceptions, also necessary for Covid-19 vaccination programmes.

Clinicaltrial: Not applicable.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2196/26734DOI Listing
February 2021

Electrocardiographic predictors of successful resynchronization of left bundle branch block by His bundle pacing.

J Cardiovasc Electrophysiol 2021 Feb 4;32(2):428-438. Epub 2021 Jan 4.

National Heart and Lung Institute, Imperial College London, Hammersmith Hospital, London, UK.

Background: His bundle pacing (HBP) is an alternative to biventricular pacing (BVP) for delivering cardiac resynchronization therapy (CRT) in patients with heart failure and left bundle branch block (LBBB). It is not known whether ventricular activation times and patterns achieved by HBP are equivalent to intact conduction systems and not all patients with LBBB are resynchronized by HBP.

Objective: To compare activation times and patterns of His-CRT with BVP-CRT, LBBB and intact conduction systems.

Methods: In patients with LBBB, noninvasive epicardial mapping (ECG imaging) was performed during BVP and temporary HBP. Intrinsic activation was mapped in all subjects. Left ventricular activation times (LVAT) were measured and epicardial propagation mapping (EPM) was performed, to visualize epicardial wavefronts. Normal activation pattern and a normal LVAT range were determined from normal subjects.

Results: Forty-five patients were included, 24 with LBBB and LV impairment, and 21 with normal 12-lead ECG and LV function. In 87.5% of patients with LBBB, His-CRT successfully shortened LVAT by ≥10 ms. In 33.3%, His-CRT resulted in complete ventricular resynchronization, with activation times and patterns indistinguishable from normal subjects. EPM identified propagation discontinuity artifacts in 83% of patients with LBBB. This was the best predictor of whether successful resynchronization was achieved by HBP (logarithmic odds ratio, 2.19; 95% confidence interval, 0.07-4.31; p = .04).

Conclusion: Noninvasive electrocardiographic mapping appears to identify patients whose LBBB can be resynchronized by HBP. In contrast to BVP, His-CRT may deliver the maximum potential ventricular resynchronization, returning activation times, and patterns to those seen in normal hearts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jce.14845DOI Listing
February 2021

Development of a pro-arrhythmic ex vivo intact human and porcine model: cardiac electrophysiological changes associated with cellular uncoupling.

Pflugers Arch 2020 10 1;472(10):1435-1446. Epub 2020 Sep 1.

Faculty of Medicine, National Heart and Lung Institute, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.

We describe a human and large animal Langendorff experimental apparatus for live electrophysiological studies and measure the electrophysiological changes due to gap junction uncoupling in human and porcine hearts. The resultant ex vivo intact human and porcine model can bridge the translational gap between smaller simple laboratory models and clinical research. In particular, electrophysiological models would benefit from the greater myocardial mass of a large heart due to its effects on far-field signal, electrode contact issues and motion artefacts, consequently more closely mimicking the clinical setting. Porcine (n = 9) and human (n = 4) donor hearts were perfused on a custom-designed Langendorff apparatus. Epicardial electrograms were collected at 16 sites across the left atrium and left ventricle. A total of 1 mM of carbenoxolone was administered at 5 ml/min to induce cellular uncoupling, and then recordings were repeated at the same sites. Changes in electrogram characteristics were analysed. We demonstrate the viability of a controlled ex vivo model of intact porcine and human hearts for electrophysiology with pharmacological modulation. Carbenoxolone reduces cellular coupling and changes contact electrogram features. The time from stimulus artefact to (-dV/dt) increased between baseline and carbenoxolone (47.9 ± 4.1-67.2 ± 2.7 ms) indicating conduction slowing. The features with the largest percentage change between baseline and carbenoxolone were fractionation + 185.3%, endpoint amplitude - 106.9%, S-endpoint gradient + 54.9%, S point - 39.4%, RS ratio + 38.6% and (-dV/dt) - 20.9%. The physiological relevance of this methodological tool is that it provides a model to further investigate pharmacologically induced pro-arrhythmic substrates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00424-020-02446-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7476990PMC
October 2020

Computer programming for clinicians: five steps to your new favourite skill. Part 2.

Authors:
Ji-Jian Chow

Heart 2020 Nov 27;106(22):1777. Epub 2020 Aug 27.

Cardiology, Imperial College Healthcare NHS Trust, London W12 0HS, UK

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/heartjnl-2020-317808DOI Listing
November 2020

Computer programming for clinicians: five steps to your new favourite skill. Part 1.

Authors:
Ji-Jian Chow

Heart 2020 Nov 14;106(21):1700-1701. Epub 2020 Jul 14.

Cardiology Department, Imperial College Healthcare NHS Trust, London, UK

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/heartjnl-2020-317344DOI Listing
November 2020

Prevalence of spontaneous type I ECG pattern, syncope, and other risk markers in sudden cardiac arrest survivors with Brugada syndrome.

Pacing Clin Electrophysiol 2019 02 6;42(2):257-264. Epub 2019 Jan 6.

Imperial College Healthcare NHS Trust, London, UK.

Introduction: A spontaneous type I electrocardiogram (ECG) pattern and/or unheralded syncope are conventionally used as risk markers for primary prevention of sudden cardiac arrest/death (SCA/SCD) in Brugada syndrome (BrS). In this study, we determine the prevalence of conventional and newer markers of risk in those with and without previous aborted SCA events.

Methods: All patients with BrS were identified at our institute. History of symptoms was obtained from medical tests or from interviews. Other markers of risk were also obtained, such as presence of (1) spontaneous type I pattern, (2) fractionated QRS (fQRS), (3) early repolarization (ER) pattern, (4) late potentials on signal-averaged ECG (SAECG), and (5) response to programmed electrical stimulation.

Results: In 133 patients with Bars, 10 (7%) patients (mean age = 39 ± 11 years; nine males) were identified with a previous ventricular fibrillation/ventricular tachycardia episode (n = 8) or requiring cardio-pulmonary resuscitation (n = 2). None of these patients had a prior history of syncope before their SCA event. Only two (20%) patients reported a history of palpitations or dizziness. None had apneic breathing and three (30%) patients had a family history of SCA. From their ECGs, a spontaneous pattern was only found in one (10%) of these patients. Further, 10% of patients had fQRS, 17% had late potentials on SAECG, 20% had deep S waves in lead I, and 10% had an ER pattern in the peripheral leads. No significant differences were observed in the non-SCA group.

Conclusion: The majority of BrS patients with previous aborted SCA events did not have a spontaneous type I and/or prior history of syncope. Conventional and newer markers of risk appear to only have limited ability to predict SCA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pace.13587DOI Listing
February 2019

Comparison of the Prognostic Usefulness of the European Society of Cardiology and American Heart Association/American College of Cardiology Foundation Risk Stratification Systems for Patients With Hypertrophic Cardiomyopathy.

Am J Cardiol 2018 02 7;121(3):349-355. Epub 2017 Nov 7.

Imperial College Healthcare NHS Trust, London, United Kingdom. Electronic address:

Implantable cardiodefibrillators (ICDs) have proven benefit in preventing sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HC), making risk stratification essential. Data on the predictive accuracy on the European Society of Cardiology (ESC) risk scoring system have been conflicting. We independently evaluated the ESC risk scoring system in our cohort of patients with HC from a large tertiary center and compared this with previous guidance by the American College of Cardiology Foundation and Heart Association (ACCF/AHA). Risk factor profiles, 5-year SCD risk estimates, and ICD recommendations, as defined by the ACCF/AHA and ESC guidelines, were retrospectively ascertained for 288 HC patients with and without SCD or equivalent events at our center. In the SCD group (n = 14), a significantly higher proportion of patients would not have met the criteria for an ICD implant using the ESC scoring algorithm compared with ACCF/AHA guidance (43% vs 7%, p = 0.029). In those without SCD events (n = 274), a larger proportion of individuals not requiring an ICD was identified using the ESC risk score model compared with the ACCF/AHA model (82% vs 57%; p < 0.0001). Based on risk stratification criteria alone, 5 more individuals with a previously aborted SCD event would not have received an ICD with the ESC risk model compared with the ACCF/AHA risk model. In conclusion, we found that the current ESC scoring system potentially leaves more high-risk patients unprotected from sudden death in our cohort of patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.amjcard.2017.10.027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5812921PMC
February 2018

Solitary renal fossa recurrence of renal cell carcinoma after nephrectomy.

Rev Urol 2014 ;16(2):76-82

Department of Urology, Medway Maritime Hospital, Kent, UK.

Renal cell carcinoma without metastasis responds well to surgical excision but is known to recur postnephrectomy. In a small but significant number of patients this recurrence is not accompanied by metastasis, which is important as these people benefit from further surgery. We examined 20 articles from the current literature to ascertain how best to treat this condition. Surgical management renders better results than conservative or medical therapies. Readily available investigations such as blood tests and computed tomography can help determine the right patients for surgery in an evidence-based fashion. Current findings have allowed us to suggest a protocol for the treatment of solitary renal fossa recurrence of postnephrectomy renal cell carcinoma. There are further opportunities for study in validating our protocol, and in novel renal cell carcinoma treatment strategies that have not been tested on solitary renal fossa recurrences.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4080852PMC
July 2014