Jim Newton

Guidance for accurate and consistent tissue Doppler velocity measurement: comparison of echocardiographic methods using a simple vendor-independent method for local validation.

BACKGROUNDnVariability has been described between different echo machines and different modalities when measuring tissue velocities. We assessed the consistency of tissue velocity measurements across different modalities and different manufacturers in an in vitro model and in patients. Furthermore, we present freely available software tools to repeat these evaluations.nnnMETHODS AND RESULTSnWe constructed a simple setup to generate reproducible motion and used it to compare velocities measured using three echocardiographic modalities: M-mode, speckle tracking, and tissue Doppler, with a straightforward, non-ultrasound, optical gold standard. In the clinical phase, 25 patients underwent M-mode, speckle tracking, and tissue Doppler measurements of s, e, and a velocities. In vitro, the M-mode and speckle tracking velocities agreed with optical assessment. Of the three possible tissue Doppler measurement conventions (outer, middle, and inner edge) only the middle agreed with optical assessment (discrepancy -0.20 (95% CI -0.44 to 0.03) cm/s, P = 0.11, outer +5.19 (4.65 to 5.73) cm/s, P < 0.0001, inner -6.26 (-6.87 to -5.65) cm/s, P < 0.0001). A similar pattern occurred across all four studied manufacturers. M-mode was therefore chosen as the in vivo gold standard. Clinical measurements of s velocities by speckle tracking and the middle line of the tissue Doppler showed concordance with M-mode, while the outer line overestimated significantly (+1.27(0.96 to 1.59) cm/s, P < 0.0001) and the inner line underestimated (-1.82 (-2.11 to -1.52) cm/s, P < 0.0001).nnnCONCLUSIONSnEchocardiographic velocity measurements can be more consistent than previously suspected. The statistically modal velocity, found at the centre of the spectral pulsed wave tissue Doppler envelope, most closely represents true tissue velocity. This article includes downloadable, vendor-independent software enabling calibration of echocardiographic machines using a simple, inexpensive in vitro setup.

121 High Diagnostic Yield in Patients Presenting with Acute Chest Pain, Positive Troponins but non-obstructive Coronaries by Cardiovascular Magnetic Resonance imaging with Conventional and Novel T1 Mapping Techniques

Introduction Up to 10% of patients presenting with chest pain and elevated troponin levels demonstrate non-obstructive coronary arteries on angiography, posing a clinical challenge in diagnosis, prognosis and management. The final diagnosis has important implications for the patient, including prescription for treatment and fitness for permissible activities, occupation and medical insurance. Cardiovascular magnetic resonance (CMR) is superior to other cardiac imaging modalities in tissue characterisation. We hypothesised that CMR, when performed early using conventional and novel tissue characterisation techniques, can determine the cause of acute myocardial injury in these patients and provide a diagnosis. Methods One hundred and twenty (n = 120) patients (mean age 50 ± 17 yrs; 50% female) presenting with chest pain, positive troponin I (normal <0.04, median 3.99, range 0.07 to >60 μg/L) and non-obstructive coronaries were prospectively recruited.Early CMR at 1.5T (median 3 days, IQR 1–6 days) included cine, T2W (dark-blood STIR), T1-mapping (ShMOLLI) and LGE imaging. Findings were compared to 50 controls matched for age and gender distributions.Image analysis included: the detection of oedema comparing T2 signal intensity of myocardium to skeletal muscle (>2.0) or remote myocardium (>2 SD); myocardial T1 times (areas of injury defined as an area of ≥40 mm2 with T1 >990 ms as validated for detecting oedema); and presence of LGE. Results When CMR was performed early using only conventional techniques (cine, T2W and LGE), there was a high diagnostic yield of 95%. Oedema was detected in 79% and LGE in 61% of patients.Based on CMR findings, including the type, pattern and regional distribution of injury, the commonest diagnosis was myocarditis (37%), followed by Takotsubo cardiomyopathy (23%), myocardial infarction (18%), acute regional stunning (9%; wall motion abnormality with oedema but no LGE), dilated cardiomyopathy (4%), hypertrophic cardiomyopathy (3%), and missed pulmonary embolism (1%). In 11/21 (52%) of patients with MI, a patent foramen ovale (PFO) was demonstrated on echocardiography with agitated saline contrast, suggesting these patients may have suffered a paradoxical coronary embolism. The remaining 5.0% (n = 6) of patients had no findings on T2W and LGE imaging. However, T1 mapping localised areas of injury in 4 out of the remaining 6 patients, improving the detection rate to 98%. Conclusions Early CMR using conventional and novel T1-mapping techniques has a high diagnostic yield in patients presenting with acute chest pain, positive troponins but non-obstructive coronaries. T1 mapping detected additional areas of abnormality when conventional CMR was “normal”, improving the detection rate to 98%. Early multiparametric CMR is able to localise areas of affected myocardium and is useful in the further management or diagnostic workup in this patient cohort.

Cardiovascular magnetic resonance using T1-mapping, T2-weighted and late gadolinium enhancement imaging provides a high diagnostic yield in patients presenting with acute chest pain, positive troponin and non-obstructive coronary arteries

Cardiovascular magnetic resonance using T1-mapping, T2-weighted and late gadolinium enhancement imaging provides a high diagnostic yield in patients presenting with acute chest pain, positive troponin and non-obstructive coronary arteries Vanessa M Ferreira, Erica Dall’Armellina, Stefan K Piechnik, Theodoros D Karamitsos, Jane M Francis, Robin Choudhury, Keith Channon, Rajesh Kharbanda, Colin Forfar, Oliver Ormerod, Bernard D Prendergast, Attila Kardos, Jim Newton, Matthias G Friedrich, Matthew D Robson, Stefan Neubauer

087 THE USEFULNESS OF EARLY CARDIOVASCULAR MAGNETIC RESONANCE IN PATIENTS PRESENTING WITH ACUTE CHEST PAIN, POSITIVE TROPONIN AND NON-OBSTRUCTIVE CORONARY ARTERIES

Introduction Patients presenting with chest pain, raised troponin but non-obstructive coronary arteries pose a clinical challenge in diagnosis, prognosis and management. We hypothesised that early cardiovascular magnetic resonance (CMR) imaging can provide a diagnosis and comprehensive characterisation for acute myocardial injury of indeterminate aetiology. Methods and results 120 patients presenting with chest pain, positive troponin (TnI>0.04u2005µg/l) and non-obstructive coronary arteries prospectively underwent early CMR (median 3u2005days, range 0–14u2005days) at 1.5u2005T, including cine imaging for function, T2-weighted imaging for oedema and late gadolinium enhancement (LGE) imaging for myocardial necrosis/scarring. The mean age=50±17u2005years (50% female); median TnI=3.99 ug/l (0.07–60u2005µg/l); mean left ventricular ejection fraction=64±12%. There was a high CMR diagnostic yield of 95%. Significant oedema was detected in 79% and LGE in 61%. The commonest diagnosis was myocarditis (37.5%), followed by Takotsubo cardiomyopathy (22.5%), myocardial infarction (17.5%), acute regional stunning (9.2%; wall motion abnormality with oedema but no LGE), dilated cardiomyopathy (4.2%), hypertrophic cardiomyopathy (3.3%), and missed pulmonary embolism (0.8%). Eleven of the 21 patients with MI (52%) had a patent foramen ovale (PFO) demonstrated on transthoracic echocardiography with agitated saline contrast and presumably suffered a paradoxical embolism to a coronary artery. The remaining 5.0% of patients had no clear diagnosis identified. Conclusions CMR has a high diagnostic yield (95%) in patients presenting with troponin-positive chest pain but non-obstructive coronary arteries when performed early (median 3u2005days). This study highlights the importance and usefulness of early access to CMR in this group of patients. When no apparent cause is identified, early conventional CMR was able to exclude myocardial infarction, wall motion abnormality, significant oedema or scarring.