Publications by authors named "Karen S Teo"

Article Synopsis
  • Methamphetamine-associated cardiomyopathy (MA-CMP) is a recognized cause of heart disease linked to significant methamphetamine use, and cardiovascular magnetic resonance (CMR) imaging is used to assess its features.
  • A study examined CMR scans of 30 MA-CMP patients between 2015 and 2020, revealing that most were middle-aged men with severe left and right ventricular dysfunction, as indicated by high levels of dilation and low ejection fractions.
  • Key CMR findings included late gadolinium enhancement in 73.3% of patients, often located in the interventricular septum, along with a notable occurrence of intracardiac thrombus in some patients, emphasizing the serious cardiac impacts of methamphetamine use
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A large body of evidence demonstrates an independent association between arterial stiffness and prospective risk of cardiovascular events. A reduction in coronary perfusion is presumed to underscore this association; however, studies confirming this are lacking. This study compared invasive measures of coronary blood flow (CBF) with cardiac magnetic resonance (CMR)-derived aortic distensibility (AD).

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Background And Aims: Echocardiographic studies have shown improvements in cardiac indices associated with renal sympathetic denervation (RDN), however, the benefits on myocardial perfusion have never been assessed. This trial was designed to study the effects of RDN on myocardial perfusion using cardiac magnetic resonance (CMR) imaging.

Methods: A total of 14 patients with resistant hypertension were recruited for RDN and myocardial perfusion, alongside other CMR indices, was assessed at baseline and at 6 months.

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Chest pain is an important presenting symptom. However, few cases of chest pain are diagnosed as acute coronary syndrome (ACS) in the acute setting. This results in frequent inappropriate discharge and major delay in treatment for patients with underlying ACS.

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Aim: Preclinical studies have demonstrated improvements in renal blood flow after renal sympathetic denervation (RSDN); however, such effects are yet to be confirmed in patients with resistant hypertension. Herein, we assessed the effects of RSDN on renal artery blood flow and diameter at multiple time points post-RSDN.

Methods And Results: Patients (n=11) with systolic blood pressures ≥160 mmHg despite taking three or more antihypertensive medications at maximum tolerated dose were recruited into this single-center, prospective, non-blinded study.

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Background: Imaging of the heart is important in the diagnosis and follow-up of a broad range of cardiac pathology. The authors discuss the growing role of cardiac magnetic resonance imaging (CMR) in cardiology practice and its relevance to primary healthcare.

Objective: In this article we discuss the advantages of CMR over other imaging modalities, and give a brief description of the common CMR techniques and cardiac pathologies where CMR is especially useful.

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Background: Cardiovascular magnetic resonance (CMR) advances in imaging techniques, permits the ability to accurately characterise tissue injury post myocardial infarction. Pre-contrast T1 mapping enables this through measurement of pre-contrast T1 relaxation times. We investigate the relationship between T1 characterisation of myocardial injury with global and regional diastolic function.

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Cardiovascular disease (CVD) is the leading cause of death in the western world and is becoming more important in the developing world. Recently, advances in monitoring, revascularisation and pharmacotherapy have resulted in a reduction in mortality. However, although mortality rates have declined, the burden of disease remains large resulting in high direct and indirect healthcare costs related to CVDs.

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Background: The high diagnostic accuracy of adenosine stress cardiac magnetic resonance (AS-CMR) for detecting coronary artery stenoses, with high sensitivity and specificity, is well documented. Prognostic data, particularly in non-low risk study populations and for greater than 12 months of follow up, is however lacking or variable in its findings. We present prognostic data, in an intermediate cardiovascular risk cohort undergoing adenosine stress perfusion CMR, over approximately 2 years of follow up.

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Background: Advances in the management of myocardial infarction have resulted in substantial reductions in morbidity and mortality.

Methods: However, after acute treatment a number of diagnostic and prognostic questions often remain to be answered, whereby cardiac imaging plays an essential role.

Results: For example, some patients will sustain early mechanical complications after infarction, while others may develop significant ventricular dysfunction.

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Background: ST-segment-resolution (STR) on surface electrocardiogram (ECG) is a good surrogate for myocardial reperfusion in patients with acute ST-segment-elevation-myocardial-infarction (STEMI). We sort to determine the optimal criteria of measuring STR on intracoronary-ECG (IC-ECG) for prediction of myocardial injury evaluated by cardiac MRI (CMR).

Methods: Measurements of IC-ECG ST-segments were performed at baseline, immediately after (early) and 15 min (late) after achieving TIMI-3 flow during primary-PCI.

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Microvascular obstruction (MVO) is a strong independent predictor of left ventricular remodelling and mortality following ST-segment elevation myocardial infarction (STEMI). Microvascular obstruction can be identified at angiography or with gadolinium-enhanced cardiac MRI (CMR). First-pass perfusion CMR also allows a novel quantitative evaluation of myocardial blood flow (MBF) that might provide superior predictive data in the assessment of MVO.

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Left ventricular noncompaction (LVNC) is a rare cardiomyopathy characterized by deep intertrabecular recesses communicating with the main ventricular chamber. Cardiac magnetic resonance offers high spatial resolution, and thereby substantial aptitude for the diagnosis of LVNC. Additional clinically relevant information, including thrombus and myocardial fibrosis evaluation, can be readily acquired.

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Background: Adenosine stress cardiovascular magnetic resonance (CMR) has been proven an effective tool in detection of reversible ischemia. Limited evidence is available regarding its accuracy in the setting of acute coronary syndromes, particularly in evaluating the significance of non-culprit vessel ischaemia. Adenosine stress CMR and recent advances in semi-quantitative image analysis may prove effective in this area.

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Introduction: Microvascular obstruction (MVO) following ST-segment elevation myocardial infarction (STEMI) is associated with larger infarct size and an increased mortality. Although angiographic predictors of MVO in primary percutaneous coronary intervention (primary-PCI) setting have been identified, an earlier and objective "in-lab" predictor may be beneficial, in order to potentially influence therapies administered during primary-PCI. We hypothesised that intracoronary-electrocardiogram (IC-ECG) is a simple, objective and accurate predictor of MVO evaluated by cardiac magnetic resonance (CMR) and is comparable to myocardial blush grade (MBG) and TIMI myocardial perfusion grade (TMPG).

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Background: Many adult patients with secundum-type atrial septal defects (ASDs) are able to have these defects fixed percutaneously. Traditionally, this has involved an assessment of ASD size, geometry and atrial septal margins by transoesophageal echocardiography (TOE) prior to percutaneous closure. This is a semi-invasive technique, and all of the information obtained could potentially be obtained by non-invasive cardiovascular magnetic resonance (CMR).

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Background: Percutaneous closure of atrial septal defects (ASDs) should potentially reduce right heart volumes by removing left-to-right shunting. Due to ventricular interdependence, this may be associated with impaired left ventricular filling and potentially function. Furthermore, atrial changes post-ASD closure have been poorly understood and may be important for understanding risk of atrial arrhythmia post-ASD closure.

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Background: There is a paucity of published experience investigating novel treatment strategies in preclinical and clinical studies of nonischemic cardiomyopathy. We set out to validate an ovine model of doxorubicin-induced cardiomyopathy, using cardiac magnetic resonance (CMR) to assess cardiac function.

Methods And Results: Ten Merino sheep (51 +/- 8 kg) underwent intracoronary infusions of doxorubicin (1 mg/kg dose) every 2 weeks.

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