Browsing by Author "Exner, Derek V."

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    Electrocardiographic Parameters in the Assessment of Myocardial Fibrosis and Left Ventricular Systolic Function
    (2016) Narous, Mariam; Exner, Derek V.; Anderson, Todd J.; Fine, Nowell M.; White, James A.
    Assessment of cardiac structure and function is central to the care of patients with heart disease. Cardiac magnetic resonance (CMR) is the gold standard for such assessment, however it is expensive and oftentimes not readily accessible. We sought to evaluate the utility of electrocardiographic (ECG) and impedance-based parameters in estimating the amount of myocardial scar, left ventricular (LV) systolic function and myocardial deformation. Consecutive patients (n = 241; 42% female; mean age 55 years) undergoing clinical CMR and ECG assessments were recruited. ECG analysis was performed manually, using both the Modified Selvester Score (MSS) and the presence of fractionated QRS (fQRS) signals, and impedance testing using the Non-Invasive Cardiac System (NICaS). While MCS was of value, neither fQRS nor NICaS meaningfully predicted scar extent, LV systolic function. Or the amount of myocardial deformation. These results support additional investigation of the utility of the MSS in estimating cardiac structure and function among patients in whom cardiac imaging is clinically indicated.
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    Quality of Life and Psychological Wellbeing in Patients with Vasovagal Syncope
    (2019-02-22) Ng, Jessica; Raj, Satish R.; Exner, Derek V.; Sheldon, Robert Stanley; Sears, Samuel F.
    Background: Vasovagal syncope (VVS) is the most common form of syncope. Previous findings have indicated that VVS patients experience a poor health-related quality of life (HRQoL) and considerable psychological distress. However, there is limited data comparing both outcomes between VVS patients and closely-matched healthy individuals, as well as identifying specific factors that affect changes in QoL over time. Aims: We aimed to identify the differences in HRQoL and psychological profile between VVS patients and a contemporary group of non-fainting healthy individuals. We also aimed to examine the change in HRQoL over time in VVS patients, as well as explore whether change differed with treatment or fainting during study follow up. Methods: The RAND 36-Item Health Survey (RAND36) or Short Form Health Survey (SF36), global health visual analogue scale (VAS), Hospital Anxiety and Depression Scale, Anxiety Sensitivity Index, and Positive and Negative Affect Schedule – Expanded Form were completed by healthy individuals, and by VVS patients at baseline, 6 months, and 12 months. Results: At baseline, VVS patients reported poorer HRQoL on all scales of the RAND36 and the VAS compared to healthy participants. VVS patients had significantly greater anxiety, depression, and anxiety sensitivity, as well as more negative affect and less positive affect. Over a 1-year period, patients reported improvement in all SF36 dimensions except for bodily pain. Post hoc analyses indicated that differences first occurred between baseline and 6 months for all but general health. Additionally, recent faints experienced during follow up or study drug randomization did not alter the improvements. Conclusions: The results from this thesis further support a negative relationship between VVS and a patient’s quality of life and psychological profile. Patients may benefit from a more comprehensive assessment and treatment of HRQoL, anxiety, and depression during presentation and subsequent follow up visits. Moreover, while HRQoL improves in VVS patients over time, future initiatives could identify alternative factors that may contribute to these changes.
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    The economic burden of cardiac implantable electronic device infections in Alberta, Canada: a population-based study using validated administrative data
    (2023-12-05) Rennert-May, Elissa; Chew, Derek; Cannon, Kristine; Zhang, Zuying; Smith, Stephanie; King, Teagan; Exner, Derek V.; Larios, Oscar E.; Leal, Jenine
    Abstract Background Cardiac implantable electronic devices (CIED) are being inserted with increasing frequency. Severe surgical site infections (SSI) that occur after device implantation substantially impact patient morbidity and mortality and can result in multiple hospital admissions and repeat surgeries. It is important to understand the costs associated with these infections as well as healthcare utilization. Therefore, we conducted a population-based study in the province of Alberta, Canada to understand the economic burden of these infections. Methods A cohort of adult patients in Alberta who had CIEDs inserted or generators replaced between January 1, 2011 and December 31, 2019 was used. A validated algorithm of International Classification of Diseases (ICD) codes to identify complex (deep/organ space) SSIs that occurred within the subsequent year was applied to the cohort. The overall mean 12-month inpatient and outpatient costs for the infection and non-infection groups were assessed. In order to control for variables that may influence costs, propensity score matching was completed and incremental costs between those with and without infection were calculated. As secondary outcomes, number of outpatient visits, hospitalizations and length of stay were assessed. Results There were 26,049 procedures performed during our study period, of which 320 (1.23%) resulted in SSIs. In both unadjusted costs and propensity score matched costs the infection group was associated with increased costs. Overall mean cost was $145,312 in the infection group versus $34,264 in the non-infection group. The incremental difference in those with infection versus those without in the propensity score match was $90,620 (Standard deviation $190,185). Approximately 70% of costs were driven by inpatient hospitalizations. Inpatients hospitalizations, length of stay and outpatient visits were all increased in the infection group. Conclusions CIED infections are associated with increased costs and are a burden to the healthcare system. This highlights a need to recognize increasing SSI rates and implement measures to minimize infection risk. Further studies should endeavor to apply this work to full economic evaluations to better understand and identify cost-effective infection mitigation strategies.
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    The Impact and Treatment of Postural Orthostatic Tachycardia Syndrome
    (2024-04-24) Bourne, Kate; Raj, Satish Ramnarayan; Sheldon, Robert Stanley; Exner, Derek V.; Ahmed, Sofia B.; Mak, Susanna
    Background: Postural orthostatic tachycardia syndrome (POTS) is a debilitating cardiovascular autonomic nervous system disorder. Patients with POTS experience a high symptom burden and significant reductions in quality of life, but the full impacts of POTS were previously not fully understood. There are no approved medications for treating POTS, and evidence for off-label medication use and non-pharmacological treatments is of poor quality. Aims: The two aims of this program of research were to (1) investigate the multi-factorial impacts of POTS, and (2) evaluate compression garments as a potential non-pharmacological treatment. Methods: Aim 1 consisted of two studies: A large survey used to evaluate the economic and employment impacts of POTS, the role of sex differences in POTS, and the impact of pregnancy on POTS symptoms, and a survey of patients at a specialist autonomic centre to evaluate long-term outcomes of POTS. Aim 2 consisted of three studies: an in lab clinical trial of a proof-of-concept compression garment, an at home clinical trial using “real-world” compression garments, and a qualitative interview project evaluating the patient experience with compression garments. Results: Aim 1: Patients with POTS experience significant employment and economic impacts. Female patients with POTS experienced longer diagnostic delays and were more likely to be told their POTS was all in their head compared to male patients. Most patients who had been pregnant experienced a worsening of POTS symptoms during pregnancy. Over the long term, most patients with POTS continue to experience POTS symptoms. Aim 2: Body compression of the abdomen and legs reduces heart rate and improves symptoms by increasing stroke volume. Patients reported benefits from compression garments, as well as limitations; it is important for clinicians to be aware of this. Conclusions: Patients with POTS experience significant impacts including economic and employment loss, female patients with POTS experience a longer diagnostic delay than male patients, and most patients experience worse POTS symptoms during pregnancy. Compression garments are a cost-effective treatment that should be recommended for patients with POTS. Easy to implement treatments like compression garments may help to reduce symptom burden and negative impacts of POTS.