Improved detection of acute myocardial infarction in patients with chest pain and significant left main stem coronary stenosis.

BACKGROUND: Non-invasive diagnosis of acute myocardial infarction (AMI) associated with significant left main stem (LMS) stenosis remains challenging. METHODS: Consecutive patients presenting with acute ischaemic-type chest pain from 2000 to 2010 were analysed. Entry criteria: 12-lead ECG and Body Surface Potential Map (BSPM) at presentation, cardiac troponin T (cTnT) ≥12 h and coronary angiography during admission. cTnT ≥0.03 µg/l defined AMI. ECG abnormalities assessed: STEMI by Minnesota criteria; ST elevation (STE) aVR ≥0.5 mm; ST depression (STD) ≥0.5 mm in ≥2 contiguous leads (CL); T-wave inversion (TWI) ≥1 mm in ≥2 CL. BSPM STE was ≥2 mm in anterior, ≥1 mm in lateral, inferior, right ventricular or high right anterior and ≥0.5 mm in posterior territories. Significant LMS stenosis was ≥70%. RESULTS: Enrolled were 2810 patients (aged 60 ± 12 years; 71% male). Of these, 116 (4.1%) had significant LMS stenosis with AMI occurring in 92 (79%). STEMI by Minnesota criteria occurred in 13 (11%) (sensitivity 12%, specificity 92%), STE in lead aVR in 23 (20%) (sensitivity 23%, specificity 92%), TWI in 38 (33%) (sensitivity 34%, specificity 71%) and STD in 51 (44%) (sensitivity 49%, specificity 75%). BSPM STE occurred in 85 (73%): sensitivity 88%, specificity 83%, positive predictive value 95% and negative predictive value 65%. Of those with AMI, 74% had STE in either the high right anterior or right ventricular territories not identified by the 12-lead ECG. C-Statistic for AMI diagnosis using BSPM STE was 0.800 (P < 0.001). CONCLUSION: In patients with significant LMS stenosis presenting with chest pain, BSPM STE has improved sensitivity (88%), with specificity 83%, over 12-lead ECG in the diagnosis of AMI.

Investigation of a multimarker approach to the initial assessment of patients with acute chest pain.

Early identification of acute coronary syndrome (ACS) is important to guide therapy at a time when it is most likely to be of value. In addition, predicting future risk helps identify those most likely to benefit from ongoing therapy. Cardiac troponin T (cTnT) is useful for both purposes although cannot reliably rule out ACS until 12 hours after pain onset and does not fully define future risk. In this review article we summarize our previously published research, which assessed the value of myocyte injury, vascular inflammation, hemostatic, and neurohormonal markers in the early diagnosis of ACS and risk stratification of patients with ACS. In addition to cTnT, we measured heart fatty acid binding protein (H-FABP), glycogen phosphorylase-BB, high-sensitivity C-reactive protein, myeloperoxidase, matrix metalloproteinase 9, pregnancy-associated plasma protein-A, D-dimer, soluble CD40 ligand, and N-terminal pro-brain natriuretic peptide (NT-proBNP). Of the 664 patients enrolled, 415 met inclusion criteria for the early diagnosis of acute myocardial infarction (MI) analysis; 555 were included in the risk stratification analysis and were followed for 1 year from admission. In patients presenting <4 hours from pain onset, initial H-FABP had higher sensitivity for acute MI than cTnT (73% vs. 55%; P=0.043) but was of no benefit beyond 4 hours when compared to cTnT. On multivariate analysis, H-FABP, NT-proBNP, and peak cTnT were independent predictors of 1-year death/MI. Our research demonstrated that, in patients presenting within 4 hours from pain onset, H-FABP may improve detection of ACS. Measuring H-FABP and proBNP may help improve long-term risk stratification.

The effect of internal DC shocks on the atrial fibrillation frequency.

The objective of this study, was to investigate the effect of internal DC shocks on the atrial fibrillation frequency (AFF). AFF has previously been shown to predict the success and energy requirements in patients undergoing internal cardioversion (IC) of atrial fibrillation (AF). However the possibility that unsuccessful shocks during IC may influence the AFF has not been before studied. Thirty eight patients with AF, suggested for DC cardioversion at the Royal Victoria Hospital in Belfast, were included in our study. Two catheters were positioned in the right atrial appendage (RAA) and the coronary sinus (CS), to deliver a biphasic shock waveform, synchronized with the R wave of the electrocardiogram (ECG) signal. A voltage step-up protocol (50-300 V) was used for patient cardioversion. The ECG was analyzed for a mean of 52,8+/-10.1 seconds (corresponding to segments before and after nonsuccessful shocks). Atrial fibrillatory activity was extracted by means of bandpass filtering and ventricular activity (QRST) cancellation. QRST complexes were cancelled using a recursive least squared (RLS) adaptive filter. FFT was applied to the residual atrial fibrillatory signal. AFF was estimated from the dominant frequency within the 3-12 Hz band of the power spectrum. R-R intervals during the segments were also analyzed. A total of 26 patients were successfully cardioverted, employing 167 shocks (141 nonsuccessful). AFF, computed with 10 s of signal, showed significant reduction (mean 0.3052 +/- 1.1055 Hz, P=0.028) comparing segments immediately before and after shocks, and AFF significantly increases (mean 0.2582 +/- 0.609 Hz, P=0.007) between segments immediately after shocks and those 35 s after. AFF showed distinct behavior according to the energy level of the shocks. In conclusion, intracardiac electric shocks could cause transitory changes in the AFF of patients with atrial fibrillation.

Diabetic patients with acute coronary syndromes in the UK: high risk and under treated. Results from the prospective registry of acute ischaemic syndromes in the UK (PRAIS-UK).

OBJECTIVES: Short-term randomised trials suggest that patients with diabetes mellitus (DM), admitted with acute coronary syndromes (ACS) are at increased risk of subsequent adverse events. We tested whether this hypothesis was true for an unselected population of ACS patients with and without DM admitted with non-ST elevation MI or unstable angina, in a non-trial setting over a longer term of follow-up. METHODS: Prospective, centrally, coordinated multicenter registry involving 56 centers throughout the UK (half having angiographic facilities). Consecutive patients admitted with ACS without ST elevation on the presenting ECG were followed up to 6 months. A sub-group of patients were flagged with the UK Office for National Statistics and followed-up for death over 4 years. RESULTS: Data were collected on 1046 ACS patients of whom 170 (16%) had a prior diagnosis of DM. DM patients had higher baseline co-morbidities and unadjusted mortality rates at 6 months (11.8% vs. 6.4%, p=0.01). After correcting for clinical variables such as age, gender, smoking status and chest pain/ischaemic ECG changes on admission, prior history of any of myocardial infarction, heart failure, hypertension, hypercholesterolemia (on treatment), stroke or coronary revascularisation (PTCA or CABG), mortality rates for DM patients were no longer significantly raised (hazard ratio 1.35, 95% CI: 0.79-2.30; p=0.27 at 6 months and 1.15, 95% CI 0.72-1.83 at 4 years). 30% of diabetics were dead after 4 years of follow-up. Patients with DM were more likely to have been revascularised at 6 months and were more likely to receive ACE inhibitors. Based on the rate of recruitment and the population covered in the study, about 21,000 patients with DM will be admitted with non-ST elevation ACS each year in the UK. CONCLUSIONS: DM is common amongst patients admitted with ACS without ST elevation and is associated with significant morbidity and mortality: approximately 1 in 8 will not survive up to 6 months and 1 in 3 to 4 years. DM patients should be managed aggressively to reduce their risk of future complications.

Ectopic right coronary artery to pulmonary artery fistula masquerading as patent arterial duct.

A patient is described in whom communication between an ectopic right coronary artery and the main pulmonary artery presented with clinical features of a patent arterial duct. Full clinical data documented by Doppler echocardiography, cardiac catheterisation and intra-operative findings are described.