Publications by authors named "Kristopher Knott"

Rationale: Unrecognised coronary artery disease (CAD) may contribute to adverse outcomes in chronic obstructive pulmonary disease (COPD). Improved identification of at-risk groups could inform better preventative care. We aimed to evaluate the burden and relationships of radiologically detectable CAD in COPD, establish frequency of occult disease, and examine potential cardiovascular screening methods.

View Article and Find Full Text PDF

Metformin is an antihyperglycemic used to treat type 2 diabetes mellitus (T2DM). Patients with T2DM are at increased risk of cardiovascular disease. We explored the association between metformin use and cardiovascular magnetic resonance (CMR) derived stress myocardial blood flow (MBF), myocardial perfusion reserve (MPR) and major adverse cardiovascular events (MACE; all cause death, MI, stroke, heart failure hospitalisation and coronary revascularisation) in patients with T2DM.

View Article and Find Full Text PDF

To review the utility of cardiovascular magnetic resonance (CMR) in the management of hospital inpatients, we performed a retrospective review of all inpatient CMR scans performed over a six-month period at a tertiary referral cardiology centre. Patient demographics, indication for CMR imaging, results of the CMR scans and whether the results changed patient management were recorded. Change in management included medication changes, subsequent invasive procedures, or avoidance of such, and hospital discharge.

View Article and Find Full Text PDF
Article Synopsis
  • Bariatric surgery may improve coronary microvascular function and metabolic health in patients with obesity, reducing risks of heart dysfunction and heart failure.
  • A study showed significant decreases in obesity-related metabolic markers and an increase in myocardial blood flow and perfusion reserve 6 months after surgery.
  • Improvements in blood flow were linked to reductions in fasting insulin levels, but those with pre-existing type 2 diabetes saw less improvement.
View Article and Find Full Text PDF

Aims: Typical electrocardiogram (ECG) features of apical hypertrophic cardiomyopathy (ApHCM) include tall R waves and deep or giant T-wave inversion in the precordial leads, but these features are not always present. The ECG is used as the gatekeeper to cardiac imaging for diagnosis. We tested whether explainable advanced ECG (A-ECG) could accurately diagnose ApHCM.

View Article and Find Full Text PDF
Article Synopsis
  • Acute myocarditis involves inflammation of the heart muscle that can be triggered by infections or non-infectious factors, leading to a wide range of symptoms from mild discomfort to severe heart failure needing urgent care.
  • This condition's development is influenced by both the triggering factors and the body's immune response, with common causes including viruses, autoimmune reactions, and certain medications.
  • Diagnosing myocarditis is challenging due to its varied symptoms; thus, a thorough approach using clinical evaluations, imaging, and biopsies is necessary, while management typically focuses on supportive care with limited specific treatments.
View Article and Find Full Text PDF

Background: Late gadolinium enhancement (LGE) of the myocardium has significant diagnostic and prognostic implications, with even small areas of enhancement being important. Distinguishing between definitely normal and definitely abnormal LGE images is usually straightforward, but diagnostic uncertainty arises when reporters are not sure whether the observed LGE is genuine or not. This uncertainty might be resolved by repetition (to remove artifact) or further acquisition of intersecting images, but this must take place before the scan finishes.

View Article and Find Full Text PDF
Article Synopsis
  • Cardiac involvement is crucial in systemic amyloidosis outcomes, with this study investigating how myocardial ischaemia affects cellular damage using advanced imaging and tissue analysis.
  • The study involved 93 patients with cardiac amyloidosis and 97 controls, revealing that those with amyloidosis had significantly lower myocardial blood flow during stress tests compared to other groups.
  • Histopathological analysis showed vascular abnormalities and reduced capillary density in cardiac tissue from amyloid patients, highlighting a complex relationship between amyloid infiltration and ischaemia.
View Article and Find Full Text PDF

Background: Apical hypertrophic cardiomyopathy (ApHCM) accounts for ≈10% of hypertrophic cardiomyopathy cases and is characterized by apical hypertrophy, apical cavity obliteration, and tall ECG R waves with ischemic-looking deep T-wave inversion. These may be present even with <15 mm apical hypertrophy (relative ApHCM). Microvascular dysfunction is well described in hypertrophic cardiomyopathy.

View Article and Find Full Text PDF

A man in his 40s who was previously well had an out-of-hospital cardiac arrest. Postresuscitation ECG showed ST-elevation myocardial infarction (MI). Emergency coronary angiogram revealed MI with non-obstructive coronary arteries (MINOCA) with evidence of spasm in the right coronary artery.

View Article and Find Full Text PDF
Article Synopsis
  • Researchers aimed to establish normal values for myocardial blood flow (MBF) during stress and rest in healthy individuals, focusing on differences by sex and age, using advanced cardiovascular magnetic resonance (CMR) mapping techniques.
  • A study with 151 healthy volunteers found that females generally had higher MBF at rest and during stress compared to males, and both stress MBF and myocardial perfusion reserve (MPR) decreased with age.
  • The study concluded that automated CMR myocardial perfusion mapping yields normal values consistent with existing literature and highlights the importance of sex- and age-specific reference ranges for accurate disease detection.
View Article and Find Full Text PDF

Aims: The 2016 European Society of Cardiology Heart Failure Guidelines defined a new category: heart failure with mid-range ejection fraction (HFmrEF) of 40-49%. This new category was highlighted as having limited evidence and research was advocated into underlying characteristics, pathophysiology, and diagnosis. We used multi-parametric cardiovascular magnetic resonance (CMR) to define the cardiac phenotype of presumed non-ischaemic HFmrEF.

View Article and Find Full Text PDF

Background: To assess the feasibility of biventricular SAPPHIRE T mapping in vivo across field strengths using diastolic, systolic and dark-blood (DB) approaches.

Methods: 10 healthy volunteers underwent same-day non-contrast cardiovascular magnetic resonance at 1.5 Tesla (T) and 3 T.

View Article and Find Full Text PDF

Background: Patients with previous coronary artery bypass graft (CABG) surgery typically have complex coronary disease and remain at high risk of adverse events. Quantitative myocardial perfusion indices predict outcomes in native vessel disease, but their prognostic performance in patients with prior CABG is unknown.

Objectives: In this study, we sought to evaluate whether global stress myocardial blood flow (MBF) and perfusion reserve (MPR) derived from perfusion mapping cardiac magnetic resonance (CMR) independently predict adverse outcomes in patients with prior CABG.

View Article and Find Full Text PDF
Article Synopsis
  • * Non-invasive ischaemia testing is important for guiding decisions about further procedures, but it can be difficult to conduct and interpret in post-CABG patients due to various complexities in their condition.
  • * Advances in cardiac imaging technology, such as improved image quality and the use of artificial intelligence, present new opportunities to enhance ischaemia testing and understand the underlying health processes affecting CABG patients.
View Article and Find Full Text PDF

Aims: Differentiating exudative from transudative effusions is clinically important and is currently performed via biochemical analysis of invasively obtained samples using Light's criteria. Diagnostic performance is however limited. Biochemical composition can be measured with T1 mapping using cardiovascular magnetic resonance (CMR) and hence may offer diagnostic utility for assessment of effusions.

View Article and Find Full Text PDF

Background Impaired myocardial blood flow (MBF) in the absence of epicardial coronary disease is a feature of hypertrophic cardiomyopathy (HCM). Although most evident in hypertrophied or scarred segments, reduced MBF can occur in apparently normal segments. We hypothesized that impaired MBF and myocardial perfusion reserve, quantified using perfusion mapping cardiac magnetic resonance, might occur in the absence of overt left ventricular hypertrophy (LVH) and late gadolinium enhancement, in mutation carriers without LVH criteria for HCM (genotype-positive, left ventricular hypertrophy-negative).

View Article and Find Full Text PDF

Aims: Remodelling of the cardiovascular system (including heart and vasculature) is a dynamic process influenced by multiple physiological and pathological factors. We sought to understand whether remodelling in response to a stimulus, exercise training, altered with healthy ageing.

Methods: A total of 237 untrained healthy male and female subjects volunteering for their first time marathon were recruited.

View Article and Find Full Text PDF

Background: Quantitative myocardial perfusion mapping using cardiovascular magnetic resonance (CMR) is validated for myocardial blood flow (MBF) estimation in native vessel coronary artery disease (CAD). Following coronary artery bypass graft (CABG) surgery, perfusion defects are often detected in territories supplied by the left internal mammary artery (LIMA) graft, but their interpretation and subsequent clinical management is variable.

Methods: We assessed myocardial perfusion using quantitative CMR perfusion mapping in 38 patients with prior CABG surgery, all with angiographically-proven patent LIMA grafts to the left anterior descending coronary artery (LAD) and no prior infarction in the LAD territory.

View Article and Find Full Text PDF

Objectives: The purpose of this study was to explore the prognostic significance of PTT and PBVi using an automated, inline method of estimation using CMR.

Background: Pulmonary transit time (PTT) and pulmonary blood volume index (PBVi) (the product of PTT and cardiac index), are quantitative biomarkers of cardiopulmonary status. The development of cardiovascular magnetic resonance (CMR) quantitative perfusion mapping permits their automated derivation, facilitating clinical adoption.

View Article and Find Full Text PDF