Thomas R Burchell

Acute myocarditis presenting as acute coronary syndrome: role of early cardiac magnetic resonance in its diagnosis

Background In patients presenting with acute cardiac symptoms, abnormal ECG and raised troponin, myocarditis may be suspected after normal angiography. Aims To analyse cardiac magnetic resonance (CMR) findings in patients with a provisional diagnosis of acute coronary syndrome (ACS) in whom acute myocarditis was subsequently considered more likely. Methods and results 79 patients referred for CMR following an admission with presumed ACS and raised serum troponin in whom no culprit lesion was detected were studied. 13% had unrecognised myocardial infarction and 6% takotsubo cardiomyopathy. The remainder (81%) were diagnosed with myocarditis. Mean age was 45±15 years and 70% were male. Left ventricular ejection fraction (EF) was 58±10%; myocardial oedema was detected in 58%. A myocarditic pattern of late gadolinium enhancement (LGE) was detected in 92%. Abnormalities were detected more frequently in scans performed within 2 weeks of symptom onset: oedema in 81% vs 11% (p<0.0005), and LGE in 100% vs 76% (p<0.005). In 20 patients with both an acute (<2 weeks) and convalescent scan (>3 weeks), oedema decreased from 84% to 39% (p<0.01) and LGE from 5.6 to 3.0 segments (p=0.005). Three patients presented with sustained ventricular tachycardia, another died suddenly 4 days after admission and one resuscitated 7 weeks following presentation. All 5 patients had preserved EF. Conclusions Our study emphasises the importance of access to CMR for heart attack centres. If myocarditis is suspected, CMR scanning should be performed within 14 days. Myocarditis should not be regarded as benign, even when EF is preserved.

Characterisation of myocardial structure and function in adult-onset growth hormone deficiency using cardiac magnetic resonance

Growth hormone (GH) can profoundly influence cardiac function. While GH excess causes well-defined cardiac pathology, fewer data are available regarding the more subtle cardiac changes seen in GH deficiency (GHD). This preliminary study uses cardiac magnetic resonance imaging (CMR) to assess myocardial structure and function in GHD. Ten adult-onset GHD patients underwent CMR, before and after 6 and 12 months of GH replacement. They were compared to 10 age-matched healthy controls and sex-matched healthy controls. Left ventricular (LV) mass index (LVMi) increased with 1 year of GH replacement (53.8 vs. 57.0 vs. 57.3 g/m2, analysis of variance p = 0.0229). Compared to controls, patients showed a trend towards reduced LVMi at baseline (51.4 vs. 60.0 g/m2, p = 0.0615); this difference was lost by 1 year of GH treatment (57.3 vs. 59.9 g/m2, p = 0.666). Significantly reduced aortic area was observed in GHD (13.2 vs. 19.0 cm2/m2, p = 0.001). This did not change with GH treatment. There were no differences in other LV parameters including end-diastolic volume index (EDVi), end-systolic volume index, stroke volume index (SVi), cardiac index and ejection fraction. There was a trend towards reduced baseline right ventricular (RV)SVi (44.1 vs. 49.1 ml/m2, p = 0.0793) and increased RVEDVi over 1 year (70.3 vs. 74.3 vs. 73.8 ml/m2, p = 0.062). Two patients demonstrated interstitial expansion, for example with fibrosis, and three myocardial ischaemia as assessed by late gadolinium enhancement and stress perfusion. The increased sensitivity of CMR to subtle cardiac changes demonstrates that adult-onset GHD patients have reduced aortic area and LVMi increases after 1 year of GH treatment. These early data should be studied in larger studies in the future.

Cardiovascular changes in patients with acromegaly assessed by CMR

Summary The study describes cardiovascular changes in patients with acromegaly before and one year after treatment. Background Acromegaly causes a distinct cardiomyopathy, which remains poorly understood, because cardiac changes typically appear before the development of hypertension or diabetes. The aim of the study was to describe cardiovascular changes in patients with acromegaly before and one year after treatment. Methods Thirteen patients with acromegaly and age- and sexmatched controls (n=13) underwent CMR. Patients underwent scans before disease treatment and at twelve months after treatment. Cardiac parameters were calculated and indexed to body surface area (BSA). The comparison between groups was done using Mann-UWhitney test and within the group using Wilcoxon test. Results In patients with acromegaly left ventricular (LV) mass index (LVMi) was increased (65.7 vs. 45.8 g/m2, p=0.0021) and was observed in both females (58.8 v. 40.9 g/m2, p=0.0028) and males (71.1 vs. 56.7 g/m2, p=0.0286) compared to matched controls. The LVMi did not correlate with the serum insulin growth factor (IGF) activity (r=0.099, p=0.745) or age (r=-0.08, p=0.175). Patients with acromegaly had significantly higher cardiac index (CI; 3.7 vs. 3.0 l/min/m2, p=0.021) However, there were no differences between end diastolic volume index (EDVi; 86.9 vs. 75.4 ml/m2, p=0.0649), end systolic volume index (ESVi; 35.1 vs. 29.3 ml/m2, p=0.1662) and ejection fraction (EF; 60 vs. 59 %, p=0.327) in acromegaly group and controls. There were no differences between right ventricular (RV) RVEDVi (81.3 vs. 72.5 ml/m2, p=0.2382), RVESVi (32.7 vs. 29.1, p=0.6816) and RVEF (61 vs. 59 %, p=0.4407) in the acromegaly group and controls. At one year, patients with acromegaly demonstrated a significant fall in IGF with treatment (with somatostatin analogues or transphenoidal surgery) from baseline median IGF-I SDS +10.58 (range 1.19 to 6.52) to +0.40 (range -1.93 to 3.02) at one year (p=0.0042). CMR parameters of the LV did not change after 1 year of therapy: LVMi 65.7 vs. 61.0 g/m2, p=0.0547; EDVi 89.5 vs. 85.8 ml/m2, p=0.1641; ESVi 33.7 vs. 30.1 ml/m2, p=0.6523; EF 60 vs. 66 %, p=0.7792; CI 3.7 vs. 3.4 l/min/m2, p=0.4961.

Renin-Angiotensin System Blockade Improves Cardiac Indices in Acromegaly Patients

Blockade of the angiotensin-renin system, with angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs), has been shown to improve cardiac outcomes following myocardial infarction and delay progression of heart failure. Acromegaly is associated with a disease-specific cardiomyopathy, the pathogenesis of which is poorly understood.The cardiac indices of patients with active acromegaly with no hypertension (Group A, n=4), established hypertension not taking ACEi/ARBs (Group B, n=4) and established hypertension taking ACEi/ARBs (Group C, n=4) were compared using cardiac magnetic imaging.Patients taking ACEi/ARBs had lower end diastolic volume index (EDVi) and end systolic volume index (ESVi) than the other 2 groups ([C] 73.24 vs. [A] 97.92 vs. [B] 101.03 ml/m2, ANOVA p=0.034, B vs. C p<0.01). Groups A and B had EDVi and ESVi values at the top of published reference range values; Group C had values in the middle of the range.Acromegaly patients on ACEi/ARBs for hypertension demonstrate improved cardiac indices compared to acromegaly patients with hypertension not taking these medications. Further studies are needed to determine if these drugs have a beneficial cardiac effect in acromegaly in the absence of demonstrable hypertension.

Cardiovascular changes in patients with adult-onset growth hormone deficiency assessed by CMR

Summary The study investigated cardiovascular changes in adultonset growth hormone deficiency (GHD) and showed that patients with adult-onset GHD have a left ventricular mass index (LVMi) at or below the lower limit of normal, which improves with one year of growth hormone replacement. Background GHD causes cardiovascular problems, with loss of cardiac response to exercise and increased cardiac mortality, however the underlying processes are poorly understood. Methods Ten patients with adult-onset GHD and age- and sexmatched controls (n=10) underwent CMR. Patients underwent scans before disease treatment and at twelve months after treatment. Cardiac parameters were calculated and indexed to body surface area (BSA). The comparison between groups was done using Mann-UWhitney test and within the group using Wilcoxon test. The data are presented as median values. Results Patients with GHD did not have significantly different left ventricle (LV) mass or volumetric parameters from controls: LV mass index (LVMi) 55.0 vs. 56.6 g/m 2 , p=0.315; end diastolic volume index (EDVi) 69.2 vs. 76.3 ml/m 2 , p=0.1655; end systolic volume index (ESVi) 24.8 vs. 28.3 ml/m 2 , p=0.3527 and ejection fraction (EF) 64 vs. 63 %, p=0.8197. However, patients had an LVMi beneath the lower limit of normal when compared to published normal ranges (55.4 - 74.0 g/m 2 ). There were no differences between right ventricular (RV) EDVi (68.0 vs. 80.8 ml/m 2 , p=0.393), ESVi (26.2 vs. 27.5, p=0.7394) and EF (63 vs. 61 %, p=0.9696) in the GHD group and controls. Patients with GHD on GH treatment for 1 year showed an increase in median insulin-like growth factor I (IGF-I) SDS from -1.83 to +0.40 (p=0.0068). There was no correlation between LVMi and IGF-I SDS (r=0.164, p=0.657). At one year the median LVMi moved into the previously published normal range (55.0 to 63.0 g/m 2 , normal range 55.4 - 74.0) achieving statistical significance compared to pre-treatment values (p=0.0156). Conclusions Patients with adult-onset GHD have an LVMi at or below the lower limit of normal, which improves with one year of growth hormone replacement.

The natural time course of myocardial oedema in the 12 months post ST-elevation MI in patients treated with primary angioplasty

Background Myocardial oedema, myocardial salvage and myocardial salvage index, have been described as markers of prognosis and surrogate markers for clinical trials. The timecourse of oedema following revascularised MI has been described in the first 6 months following PPCI but there is wide disagreement on the time to complete resolution. We therefore aimed to determine the time-course of post infarct myocardial oedema using serial T2weighted CMR imaging for the first year following MI. Methods 16 patients with acute ST-elevation MI who underwent primary PCI with stent implantation within 12 hours of symptom onset were recruited. Patients were scanned on days 1, 3, 10, 20, 96 and 384 days following their PPCI with a 1.5T Philips Achieva (Philips Medical Systems). Images were obtained as continuous short-axis stacks covering the left ventricle with a slice thickness of 8mm and gap of 2mm. Myocardial oedema was assessed at all time points using T2-weighted triple inversion turbo spin echo STIR imaging (TE 80, TR 1667). Image analysis was performed using dedicated software, CMR42 (Circle CVI, Calgary, Canada). Scar and oedema volumes were calculated by manually drawing endocardial and epicardial contours followed by semi-automated selection of normal remote myocardium per slice. The oedema was described as >2SD in signal intensity from remote normal myocardium. Values are expressed as a percentage of the LV mass (% LVM). Results

Acute myocarditis presenting as acute coronary syndrome: clinical utility of cardiac magnetic resonance imaging

Results The mean age was 47 ± 15 years (range 21-79) and 25% were female. Serum troponin (Tn) was available in 46 (84%) and was elevated in 39 (85%). Urgent angiography was performed in 75% in whom 90% had unobstructed arteries. In the patients with abnormal angiography, epicardial or midwall focal fibrosis (FF) was detected in LV segments unrelated to the stenosed artery. The median interval from admission to CMR was 24 days (range 1685). LV systolic function was normal in 47% and preserved with regional hypokinesia in 27%. LV impairment (LVI) was mild in 13%, moderate in 13% and severe in none. FF was detected in 78%, and was subepicardial, mid-wall or patchy in all. T2 weighted oedema imaging was obtained in 27 (49%), and was abnormal in 48%. LVI was reported in 2/7 (29%) Tn-ve patients and 8/39 (21%) Tn+ve patients, FF was detected in 4/7 (57%) and 31/39 (79%) patients respectively (p = ns). Myocardial oedema was demonstrated in 12/22 (55%) Tn+ve patients and in no (0/3) Tn-ve patient (ns). In Tn+ve patients, oedema was demonstrated in 11/12 if the scan was performed < 2 weeks of symptom onset, and 1/7 if performed later (p < 0.005). Four patients were admitted with sustained (7%) and another patient died in hospital (2%); the LV dysfunction was mild in 4 and moderate in one.

Prognosis in patients with normal cardiac perfusion scans

Methods We identified 100 consecutive patients who underwent stress perfusion cardiac magnetic resonance scans between March 2008 and November 2008 and were reported as having normal perfusion scans. Patients were contacted via telephone to determine the endpoints of an adverse cardiac event identified as a composite of death from coronary heart disease or hospital admission with an acute coronary syndrome. Case notes were checked to confirm the endpoint when it occurred.

Further refining stress perfusion imaging: the initial clinical impact of a 32 channel surface coil

Introduction Adenosine stress cardiac magnetic resonance (CMR) is widely accepted as a safe, reliable and reproducible investigation to identify areas of inducible ischaemia. Optimal images depend on sequence parameters, including a large field of view (FOV) coverage, a high signal to noise ratio (SNR) and minimal artefact. 32-channel surface coils may provide a higher SNR over a larger FOV compared to standard 5-channel coils.