Diagnostic performance of a device for acoustic heart sound analysis in patients with suspected myocardial infarction

BACKGROUND

As only a small proportion of patients with chest pain suffers from myocardial infarction (MI), safe rule-out of MI is of immense importance. Recently an ultrasensitive microphone performing diastolic heart sound analysis (CADScorSystem) for rule-out of coronary artery disease (CAD) has emerged. In this explorational study, we aimed to evaluate the feasibility of the CADScorSystem for diagnosis of MI in the setting of a large emergency department.

METHODS

Patients presenting to the emergency department with suspected MI were included. Acoustic heart sound analysis was performed in all patients and automated CAD-score values were calculated via a device-embedded algorithm, which also requires inclusion of three clinical variables: age, sex and presence of hypertension. Patients additionally received serial high-sensitive troponin T measurement measurements to assess the final diagnosis according to third Universal Definition of Myocardial Infarction applying the European Society of Cardiology 0 hour/3 hours algorithm. Diagnostic parameters for MI, considering different CAD-score cut-offs, were computed.

RESULTS

Of 167 patients, CAD-scores were available in 61.1%. A total of eight patients were diagnosed with MI. At a cut-off value of <20, CAD-score had a negative predictive value (NPV) of 90.7 (78.4-96.3). The corresponding positive predictive value (PPV) was 6.8 (2.7-16.2). For the adjusted CAD-score (age, sex, hypertension), at a cut-off value of <20, NPV was 90.0 (59.6-99.5) with a PPV of 10.8 (5.3-20.6).

CONCLUSION

In this explorative analysis, a transcutaneous ultrasensitive microphone for heart sound analysis resulted in a high NPV analogous to the findings in rule-out of stable CAD in elective patients yet inferior to serial high-sensitivity cardiac troponin measurements and does not seem feasible for application in an emergency setting for rule-out of MI.

TRIAL REGISTRATION NUMBER

NCT02355457.

SYNTAX score-0 patients: risk stratification in nonobstructive coronary artery disease

BACKGROUND

The complexity of coronary artery disease (CAD) is a predictor of cardiovascular events in patients with >50 % diameter stenosis as determined by SYNTAX score. Here, we compare the Gensini score to SYNTAX in patients with CAD as well as apply the Gensini score in patients with nonobstructive CAD (NOB-CAD), defined by ≤50 % diameter stenosis, were the SYNTAX score cannot be utilized to define future risk.

METHODS

The AtheroGene study enrolled 2316 patients [861/37.2 % with acute cardiovascular syndrome (ACS) and 1500/62.8 % with stable CAD (SCAD)]. Of these, 1966 had obstructive CAD (OB-CAD) with SYNTAX and Gensini scores available and 291 events with either cardiovascular mortality or non-fatal myocardial infarction were recorded. Furthermore, 350 patients had NOB-CAD with only Gensini score and 36 events. Median follow-up time was 4.9 years.

RESULTS

In the OB-CAD cohort the SYNTAX and the Gensini score predicted outcome. Kaplan-Meier curve analysis with the dichotomized Gensini score showed a significant result (p = 0.04) in the NOB-CAD cohort. Cox Regression analysis after adjustment showed a hazard ratio (HR) of 1.33 and p = 0.04 for the Gensini score in the NOB-CAD cohort. Receiver operating characteristic curve (ROC) analysis provided the highest area under the curve (AUC) regarding the outcome for the Gensini score with 0.65 (p = 0.004). Comparing the SYNTAX and Gensini score in this cohort showed improved discrimination of patients with events by the Gensini score (p = 0.02).

CONCLUSION

The Gensini score predicted events in patients with ≤50 % diameter lesions. Utilization of this score is useful to define risk in NOB-CAD patients.

Revascularisation versus medical treatment in patients with stable coronary artery disease: network meta-analysis

OBJECTIVE

To investigate whether revascularisation improves prognosis compared with medical treatment among patients with stable coronary artery disease.

DESIGN

Bayesian network meta-analyses to combine direct within trial comparisons between treatments with indirect evidence from other trials while maintaining randomisation.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

A strategy of initial medical treatment compared with revascularisation by coronary artery bypass grafting or Food and Drug Administration approved techniques for percutaneous revascularization: balloon angioplasty, bare metal stent, early generation paclitaxel eluting stent, sirolimus eluting stent, and zotarolimus eluting (Endeavor) stent, and new generation everolimus eluting stent, and zotarolimus eluting (Resolute) stent among patients with stable coronary artery disease.

DATA SOURCES

Medline and Embase from 1980 to 2013 for randomised trials comparing medical treatment with revascularisation.

MAIN OUTCOME MEASURE

All cause mortality.

RESULTS

100 trials in 93,553 patients with 262,090 patient years of follow-up were included. Coronary artery bypass grafting was associated with a survival benefit (rate ratio 0.80, 95% credibility interval 0.70 to 0.91) compared with medical treatment. New generation drug eluting stents (everolimus: 0.75, 0.59 to 0.96; zotarolimus (Resolute): 0.65, 0.42 to 1.00) but not balloon angioplasty (0.85, 0.68 to 1.04), bare metal stents (0.92, 0.79 to 1.05), or early generation drug eluting stents (paclitaxel: 0.92, 0.75 to 1.12; sirolimus: 0.91, 0.75 to 1.10; zotarolimus (Endeavor): 0.88, 0.69 to 1.10) were associated with improved survival compared with medical treatment. Coronary artery bypass grafting reduced the risk of myocardial infarction compared with medical treatment (0.79, 0.63 to 0.99), and everolimus eluting stents showed a trend towards a reduced risk of myocardial infarction (0.75, 0.55 to 1.01). The risk of subsequent revascularisation was noticeably reduced by coronary artery bypass grafting (0.16, 0.13 to 0.20) followed by new generation drug eluting stents (zotarolimus (Resolute): 0.26, 0.17 to 0.40; everolimus: 0.27, 0.21 to 0.35), early generation drug eluting stents (zotarolimus (Endeavor): 0.37, 0.28 to 0.50; sirolimus: 0.29, 0.24 to 0.36; paclitaxel: 0.44, 0.35 to 0.54), and bare metal stents (0.69, 0.59 to 0.81) compared with medical treatment.

CONCLUSION

Among patients with stable coronary artery disease, coronary artery bypass grafting reduces the risk of death, myocardial infarction, and subsequent revascularisation compared with medical treatment. All stent based coronary revascularisation technologies reduce the need for revascularisation to a variable degree. Our results provide evidence for improved survival with new generation drug eluting stents but no other percutaneous revascularisation technology compared with medical treatment.

Influence of ST-segment recovery on infarct size and ejection fraction in patients with ST-segment elevation myocardial infarction receiving primary percutaneous coronary intervention

In patients with ST-segment elevation myocardial infarction treated with fibrinolytics, electrocardiogram-derived measures of ST-segment recovery guide therapy decisions and predict infarct size. The comprehension of these relationships in patients undergoing mechanical reperfusion is limited. We studied 144 patients treated with primary percutaneous coronary intervention. We aimed to define the association between infarct size as determined by cardiac magnetic resonance imaging and different metrics of ST-segment recovery. Electrocardiograms were assessed at baseline and 90 minutes after primary percutaneous coronary intervention. Three methods for calculating and categorizing ST-segment recovery were used: (1) summed ST-segment deviation (STD) resolution analyzed in 3 categories (> or = 70%, > or = 30% to <70%, and <30%); (2) single-lead STD resolution analyzed in the same 3 categories; (3) worst-lead residual STD analyzed in 3 categories (<1 mm, 1 to <2 mm, and > or = 2 mm). Infarct size and ejection fraction were assessed at 4 months by cardiac magnetic resonance imaging. All 3 ST-segment recovery algorithms predicted the final infarct size and cardiac function. Worst-lead residual STD performed the same as, or better than, the more complex methods and identified large subgroups at either end of the risk spectrum (median infarct size from the lowest to highest risk category (percentage of left ventricle: 7.7% [interquartile range 10.8], 13.1% [interquartile range 13.6]; 24.6% [interquartile range 21.1]); with adjusted odds ratios for infarct size greater than the median (reference <1 mm): 1 to <2 mm, odds ratio 2.3 (95% confidence interval 0.8 to 5.9); > or = 2 mm, odds ratio 6.3 (95% confidence interval 1.7 to 23.7; c-index 0.781). In conclusion, an electrocardiogram obtained early after primary percutaneous coronary intervention analyzed by a simple algorithm provided prognostic information on the final infarct size and cardiac function.

Effect of intravenous FX06 as an adjunct to primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction results of the F.I.R.E. (Efficacy of FX06 in the Prevention of Myocardial Reperfusion Injury) trial

OBJECTIVES

The purpose of this study was to investigate whether FX06 would limit infarct size when given as an adjunct to percutaneous coronary intervention.

BACKGROUND

FX06, a naturally occurring peptide derived from human fibrin, has been shown to reduce myocardial infarct size in animal models by mitigating reperfusion injury.

METHODS

In all, 234 patients presenting with acute ST-segment elevation myocardial infarction were randomized in 26 centers. FX06 or matching placebo was given as intravenous bolus at reperfusion. Infarct size was assessed 5 days after myocardial infarction by late gadolinium enhanced cardiac magnetic resonance imaging. Secondary outcomes included size of necrotic core zone and microvascular obstruction at 5 days, infarct size at 4 months, left ventricular function, troponin I levels, and safety.

RESULTS

There were no baseline differences between groups. On day 5, there was no significant difference in total late gadolinium enhanced zone in the FX06 group compared with placebo (reduction by 21%; p = 0.207). The necrotic core zone, however, was significantly reduced by 58% (median 1.77 g [interquartile range 0.0, 9.09 g] vs. 4.20 g [interquartile range 0.3, 9.93 g]; p < 0.025). There were no significant differences in troponin I levels (at 48 h, -17% in the FX06 group). After 4 months, there were no longer significant differences in scar size. There were numerically fewer serious cardiac events in the FX06-treated group, and no differences in adverse events.

CONCLUSIONS

In this proof-of-concept trial, FX06 reduced the necrotic core zone as one measure of infarct size on magnetic resonance imaging, while total late enhancement was not significantly different between groups. The drug appears safe and well tolerated. (Efficacy of FX06 in the Prevention of Myocardial Reperfusion Injury [F.I.R.E.]; NCT00326976).

The relative accuracies of ECG precordial lead waveforms derived from EASI leads and those acquired from paramedic applied standard leads

Accurate precordial electrode placement can be difficult in emergency situations leading either to loss of time or diminished accuracy. A possible solution is the quasi-orthogonal EASI lead system, with only five electrodes and easily defined landmarks to provide a derived 12-lead electrocardiogram (ECG). The purpose of this study was to test the hypothesis that precordial waveforms in EASI-derived ECGs have no greater deviation from those in gold standard ECGs, than do the precordial waveforms in paramedic acquired standard ECGs. Twenty paramedics applied the standard precordial electrodes employing the routine procedure. A certified ECG technician applied the 6 standard precordial electrodes in their correct gold standard positions, and the EASI electrodes. 12-lead ECGs were obtained from the paramedics' standard leads, and derived from the EASI leads, for comparison with the gold standard ECG. In each precordial lead recording, 6 computer-measured QRS-T waveform parameters were considered. Differences between deltaEASI-gold standard versus deltaparamedic-gold standard were calculated for every waveform in every lead resulting in 720 comparisons. EASI and paramedic results were "equally accurate" in 47%, the paramedic was more accurate in 31%, and EASI was more accurate in the remaining 22%. The differences from gold standard recording of precordial waveforms in ECGs derived from the EASI leads and those acquired via paramedic-applied standard electrodes are similar. The results suggest that the EASI lead system may provide an alternative to the standard ECG precordial leads to facilitate data acquisition and possibly save valuable time in emergency situations.

Platelet serotonin transporter in stroke patients

OBJECTIVES

Post-stroke depression can be treated with serotonin transport inhibitors suggesting a role for the serotonin system in these patients. The number of platelet serotonin transporters in stroke patients and in control subjects have been measured in this study.

MATERIAL AND METHODS

Newly admitted stroke patients who did develop or who did not develop a post-stroke depression, non-acute patients who previously had had a stroke and control subjects were compared. The number of platelet serotonin transporters was analysed by ligand binding methodology.

RESULTS

The number of platelet serotonin transporters was low shortly after a stroke compared with normal subjects; no difference was found between the stroke patients who developed a post-stroke depression and those who did not.

CONCLUSION

A low number of platelet serotonin transporters may be a non-specific state marker for a condition as acute stroke.

Early reperfusion assessment and repeated thrombolysis in acute myocardial infarction estimated by repeated standard electrocardiography. A randomised, double-blind, placebo-controlled pilot study

Thrombolytic therapy with streptokinase (SK) in acute myocardial infarction (AMI) does not result in early reperfusion in approximately 25% of patients. We hypothesized that early repeated thrombolysis with rt-PA in patients with early failed reperfusion would result in myocardial reperfusion. Fifty-nine AMI patients with a symptom delay of <6 h, treated with SK were included. ECG was taken on admission and after 90 and 180 min. An ST recovery of > or =25% at 90 min was interpreted as successful reperfusion. Sixteen patients had failed reperfusion at 90 min and were randomized to repeated thrombolysis with rt-PA or placebo. At 180 min from SK start, ST recovery was higher in the placebo group than in the rt-PA group (71 vs. 40%, p = 0.05). No serious bleeding complications were observed. Due to the limited sample size it was not possible to draw prominent conclusions.

[Clinical studies on glycoprotein IIb/IIIa receptor antagonist]

Platelet activation plays a major role in the pathophysiology of acute coronary syndromes (ACS), and inhibition of platelet function is the basic pharmacological treatment of ACS. Platelet membrane glycoprotein IIb/IIIa inhibitors, a new class of potent antiplatelet agents, have been used in the treatment of ACS, as well as in the prevention of complications after percutaneous coronary interventions. The aim of this article is to describe the potential possibilities of platelet inhibition and to review the pharmacology of glycoprotein IIb/IIIa inhibitors, the results of the clinical trials with these agents, and their current use in the pharmacological treatment of ACS and in relation to percutaneous coronary intervention.

[Prognosis of acute myocardial infarction after introduction of thrombolytic therapy]

The present study describes the use of intravenous thrombolytic therapy, the in-hospital and the long-term mortality in a cohort of 1881 consecutive patients with confirmed myocardial infarction. Thirty-two percent received thrombolytic therapy. Common reasons for not administering thrombolytic therapy were contraindications, diagnostic problems and late hospital admission. The total in-hospital mortality was 14% among patients treated with, and 27% among those treated without thrombolytic therapy (p < 0.001). The mortality among all patients after 48 months of follow-up was 50%. Advanced age, previous myocardial infarction and a higher Killip class on admission were independent predictors of an adverse outcome. In conclusion, in an unselected population with confirmed myocardial infarction the long-term prognosis continues to be dubious, despite the advances in coronary care including intravenous thrombolytic therapy.

[Serum myoglobin as a non-invasive marker of coronary reperfusion after intravenous thrombolytic therapy in patients with acute myocardial infarction]

Non-invasive methods for evaluation of intravenous thrombolytic treatment in patients with acute myocardial infarction (AMI) are needed, since approximately 30% of the patients never obtain coronary reperfusion. These patients could be candidates for additional thrombolytic treatment or acute PTCA. This study included 63 AMI patients. Intravenous and/or intracoronary thrombolysis was given to 52 patients, and 11 patients received conservative treatment (placebo). Serum myoglobin was measured every 15 min. Acute coronary angiography showed a patent coronary artery in 49 patients ("Reperfusion" group), and 14 patients had no coronary reperfusion ("No-Reperfusion" group). Mean time to peak serum myoglobin was 149 (57-194) minutes in the "Reperfusion" group and 476 (330-660) minutes in the "No-Reperfusion" group, p < 0.0001. An observed peak serum myoglobin < 5 hrs. after initiation of intravenous thrombolysis would indicate coronary reperfusion with sensitivity = 0.94; specificity = 0.79; predictive values of positive and negative test: 0.94 and 0.79, respectively. It is concluded that an peak serum myoglobin < five hrs. after start of thrombolysis predicts reperfusion status with a high level of accuracy.

[The effect of thrombolytic therapy on the outcome of early exercise test in patients with acute myocardial infarction]

Exercise test variables, such as an impaired heart rate response, are known to be related to left ventricular function and patient prognosis following acute myocardial infarction. The present study was performed to compare exercise test variables in acute myocardial infarct patients following either intravenous thrombolysis or placebo. Symptom-limited bicycle ergometer tests, carried out one to two weeks from the infarction, were performed in 85 patients randomized to intravenous streptokinase (n = 41) or placebo (n = 44) given within 12 hours from onset of symptoms. Resting heart rate, systolic blood pressure and rate-pressure product were similar in the two groups. At maximum workload the streptokinase treated patients had a significantly higher median maximal heart rate than controls (136 vs. 126 min-1; p < 0.01) but only a trend towards higher systolic blood pressure was seen (175 vs. 163 mmHg; p = 0.09). Rate-pressure product at maximal exercise was 23.620 vs. 20.100 mmHg x min-1; p < 0.01). A significantly smaller number of patients in the streptokinase group had exercise capacity below 50 W (0% vs. 15.9%; p < 0.01).

IN CONCLUSION

patients treated with intravenous streptokinase for acute myocardial infarction reach both higher heart rates and rate-pressure products at maximum workload than their controls thus indicating that the beneficial effects of thrombolysis after acute myocardial infarction are reflected in an improved heart rate response during exercise.

[Diagnosis of long QT syndrome with the help of atropine provoked ventricular tachycardia]

A 49-year-old woman was admitted because of several syncopes during sports activity. She was appeared well, and the physical examination revealed no pathological findings, particularly no heart murmurs. The electrocardiogram had a normal PQ, QRS and the corrected QT (QTc)interval was 0.44 s. During the exercise test no arrhythmias were seen and the QTc was unchanged of 0.44 s, but 0.6 mg atropine injected intravenously provoked prolonged QTc = 0.49 s followed by nonsustained ventricular tachycardia. Electrophysiological examination and coronary arteriography showed no inducible arrhythmias and no presence of coronary artery disease. Beta-blocker treatment was started. During one year of observation she presented no syncope, and was still active in sports. It is concluded that patients presenting with syncope and an ECG with borderline QT prolongation should undergo several provocation trials, if simple stress test is initially negative, because undiagnosed patients without prophylactic treatment have a high mortality.

[Serum creatine kinase isoenzyme MB and myoglobin in patients with acute myocardial infarction and coronary reperfusion]

Thrombolytic therapy in patients with acute myocardial infarction (AMI) changes the time-concentration curve of serum creatine kinase isoenzyme MB (CK-MB) and serum myoglobin. In this study, 60 AMI patients received thrombolytic therapy and acute coronary arteriography, or conservative treatment. Group one (n = 32) demonstrated a patent infarct-related artery after intravenous thrombolytic therapy; group two (n = 17) had an initially occluded coronary artery which became patent during catheterisation; group three (n = 11) did not receive thrombolytic therapy. Frequent serum CK-MB and myoglobin measurements showed that patients with acute coronary reperfusion had a rapid increase, an earlier peak value and less total release of both CK-MB and myoglobin to blood compared to AMI patients treated conservatively. The changes in serum myoglobin compared to CK-MB demonstrated an even more rapid, more uniform, and relatively greater increase. Measurements of serum myoglobin may be a useful non-invasive method for evaluation of thrombolytic therapy in AMI patients.

Precordial ST segment depression predicts a worse prognosis in inferior infarction despite reperfusion therapy. The Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) Study Group

The impact of associated precordial ST segment depression in inferior myocardial infarction on angiographic and clinical outcomes after thrombolytic therapy and selective coronary angioplasty was studied in 583 patients with acute myocardial infarction. Anterior infarction (Group I), inferior infarction with precordial ST segment depression (Group II) and inferior infarction without precordial ST segment depression (Group III) were present in 289, 135 and 159 patients, respectively. Precordial ST segment depression was more frequent in circumflex than right coronary infarct-related arteries (44 [71%] of 62 versus 91 [40%] of 230; p = 0.000). Although acute patency rates were not statistically different, there was a trend toward different patency rates at day 7 (Group I 88%, Group II 84%, Group III 80%; p = 0.089) partly because of insignificantly higher reocclusion rates in inferior infarction without precordial ST segment depression (Group I 11%, Group II 10%, Group III 18%, p = 0.104). Infarct zone regional wall motion (standard deviations/chord) in inferior infarction was lower with precordial ST segment depression, both acutely (Group I -2.8 +/- 0.9, Group II -2.5 +/- 1.2, Group III 2.0 +/- 1.1; p = 0.000) and at day 7 (Group I -2.2 +/- 1.1, Group II -2.3 +/- 1.1, Group III -1.9 +/- 1.3; p = 0.011). Precordial ST segment depression was associated with a lower ejection fraction in inferior infarction both acutely (Group I 47 +/- 11%, Group II 53 +/- 11%, Group III 58 +/- 9%; p = 0.000) and at day 7 (Group I 49 +/- 12%, Group II 53 +/- 10%, Group III 58 +/- 8%; p = 0.000). Complication rates tended to be higher in inferior infarction when precordial ST segment depression was present. Mortality rates for Groups I, II and III were 8%, 6% and 5%, respectively. These results suggest that precordial ST segment depression in inferior infarction predicts a worse ventriculographic and clinical outcome despite reperfusion therapy.