Diagnosis Of Inferior Myocardial Infarction Research Articles

Apical thrombus mimicking ventricular septal rupture.

A 51-year-old man with chest pain was admitted to the emergency department. The patient was taken to the coronary angiography lab with a diagnosis of inferior myocardial infarction.

Detection of inferior myocardial infarction based on densely connected convolutional neural network

Inferior myocardial infarction is an acute ischemic heart disease with high mortality, which is easy to induce life-threatening complications such as arrhythmia, heart failure and cardiogenic shock. Therefore, it is of great clinical value to carry out accurate and efficient early diagnosis of inferior myocardial infarction. Electrocardiogram is the most sensitive means for early diagnosis of inferior myocardial infarction. This paper proposes a method for detecting inferior myocardial infarction based on densely connected convolutional neural network. The method uses the original electrocardiogram (ECG) signals of serially connected Ⅱ, Ⅲ and aVF leads as the input of the model and extracts the robust features of the ECG signals by using the scale invariance of the convolutional layers. The characteristic transmission of ECG signals is enhanced by the dense connectivity between different layers, so that the network can automatically learn the effective features with strong robustness and high recognition, so as to achieve accurate detection of inferior myocardial infarction. The Physikalisch Technische Bundesanstalt diagnosis public ECG database was used for verification. The accuracy, sensitivity and specificity of the model reached 99.95%, 100% and 99.90%, respectively. The accuracy, sensitivity and specificity of the model are also over 99% even though the noise exists. Based on the results of this study, it is expected that the method can be introduced in the clinical environment to help doctors quickly diagnose inferior myocardial infarction in the future.

Quetiapine induced acute coronary syndrome: Possible Kounis syndrome.

There are a lot of reasons for the chest pain and acute coronary syndrome. The acute coronary syndrome occurs by a coronary vasospasm with an allergic reaction which is defined as Kounis Syndrome (KS). A 28 year old male patient was consulted to the emergency department with dyspnea resembling asthma, rare urticarial rashes, and violent chest pain. In the electrocardiogram, there was ST segment elevation at the D2-D3-AvF derivations. An urgent coronary angiography was performed resulting in the diagnosis of inferior myocardial infarction. A Normal coronary anatomy was detected. By the detailed history, we got that the patient was a smoker and the patient had taken 200 mg of Quetiapine to sleep. Only dyspnea and minimal rashes were detected for the allergic symptoms. With these signs and symptoms, the diagnosis was thought to be Quetiapine-induced Kounis Syndrome. In Kounis syndrome, the major pathophysiological mechanism of the coronary spasm is an allergic reaction took place due to the inflammatory mediators which discharged during a hypersensitivity reaction triggered by food, insect bites or drugs. Here, we report a case of coronary spasm due to the allergic reaction followed by the intake of Quetiapine.

Does Intravenous Administration of Recombinant Tissue Plasminogen Activator for Ischemic Stroke can Cause Inferior Myocardial Infarction?

Recombinant tissue plasminogen activator (rTPA) is one of the main portions of acute ischemic stroke management, but unfortunately has some complications. Myocardial infarction (MI) is a hazardous complication of administration of intravenous rTPA that has been reported recently. A 78-year-old lady was admitted for elective coronary artery bypass graft surgery. On the second day of admission, she developed acute left hemiparesis and intravenous rTPA was administered within 120 minutes. Three hours later, she has had chest pain. Rescue percutaneous coronary intervention was performed on right coronary artery due to diagnosis of inferior MI, and the symptoms were resolved.

Rheumatic Heart Disease Predisposing to Embolic Myocardial Infarction: A Multimodality Imaging Approach

We report a clinical case of a 45-year-old male with a diagnosis of inferior myocardial infarction and previous history of rheumatic fever during his childhood. Coronary angiography demonstrated normal coronary arteries. Transthoracic echocardiogram showed hypokinetic left ventricular inferolateral wall and mitral stenosis; furthermore, speckle tracking analysis revealed reduction of global longitudinal strain involving the inferior wall. A three-dimensional transesophaegeal echocardiography, performed to better characterize the anatomy of the valve and to find possible source of embolic infarct in an enlarged left atrium, showed rheumatic valvular involvement. Cardiac magnetic resonance confirmed the ischemic damage and also provided prognostic information. A multimodality imaging approach should be mandatory in patients with acute myocardial infarction and normal coronary angiography, to define possible sources of embolic infarction and to quantify myocardial damage.

DeBakey type 1 acute aortic dissection presenting as inferior myocardial infarction: A case report and review of literature

Acute dissection of the aorta is one of the most dramatic presentation of cardiovascular emergencies. It has a varying presentation and it is described as deceptive and dangerous. It is reported as rare, and most cases are discovered during autopsies. Prompt recognition and appropriate intervention is crucial. However, not all aortic dissections (AoD) present with classic symptoms of abrupt chest, back, or abdominal pain, and the diagnosis may be missed. We have reported here a 68-year-old man who presented with 18 hours of severe chest pain radiating to the left shoulder and was associated with shortness of breath, palpitations, sweating, and feeling of an impending doom. A diagnosis of inferior myocardial infarction was made based on ST-Segment elevation >2 mm in the Leads II, III and aVF on electrocardiogram (ECG). However, further evaluation with computed tomographic angiogram done revealed DeBakey's type 1 or Stanford type A AoD. He was later referred to a cardiothoracic centre, where he had an aortic root and valve replacement 2 months after the first presentation. He is currently doing fine at 2-year follow-up. Although, AoD is a rare entity and can masquerade in different forms, a high index of suspicion will enhance diagnosis and prompt appropriate intervention.

Diagnosis of inferior myocardial infarction based on the paced QRS complex

A 58-year-old man who sustained an inferolateral myocardial infarction (MI) with possible posterior involvement presented with syncope 3 years later (Fig. 1). An electrophysiologic study was performed. The apex of the right ventricle was paced at a rate faster than the sinus rate to provide a base paced ventricular rate (120 ppm) for the introduction of programmed ventricular stimulation (Fig. 2).

Right bundle branch block as a cause of false-negative ECG classification of inferior myocardial infarction

It is generally accepted in clinical electrocardiography that a right bundle branch block (RBBB) does not interfere with the electrocardiographic (ECG) diagnosis of myocardial infarction (MI). The basic assumption is that the initial excitation wavefronts are relatively unchanged in RBBB. This study compared serial changes in Q wave duration in inferior leads II, III, and aVF in 9 patients who developed RBBB within 3 weeks after myocardial revascularization procedure (RBBB group) and in 41 revascularized patients without RBBB in the same observation period (control group). Q wave durations in the electrocardiograms obtained before the patients' procedures were not significantly different between the study and control groups. However, Q wave durations shortened significantly more in the RBBB group than in the control group. The most pronounced Q wave duration shortening took place in lead aVF, −18.2 ms in the RBBB group versus −3.8 ms in the control group ( P = .0001). The shortening was less pronounced, although significant, in leads II and III: II, −7.6 ± −10.9 ms in the RBBB group vs −2.3 ± −3.5 ms in the control group ( P = .01); III, −11.3 ± −10.5 ms vs −2.6 ± −6.5 ms ( P = .002); aVF, −18.2 ± −13.5 ms vs −3.8 ± −5.3 ms ( P < .0001). It is concluded that incident RBBB complicating revascularization procedures may cause significant alterations in spatial orientation of the initial excitation wavefronts. This may be a potential source of false-negative ECG diagnosis of inferior MI, particularly in clinical trials where serial ECG analysis is an important part in MI classification.

New Criteria for the Diagnosis of Healed Inferior Wall Myocardial Infarction in Patients With Left Bundle Branch Block

The diagnosis of healed inferior myocardial infarction (MI) in patients with left bundle branch block (LBBB) is difficult because there are no established criteria. To develop criteria, we retrospectively examined the electrocardiograms of 166 patients with complete LBBB who had either normal images (normals) or an isolated, unequivocal inferior MI on delayed stress thallium imaging. Diagnostic Q waves were defined as a significant Q or QS of at least 30-ms duration. Diagnostic T-wave inversion was defined as complete T inversion or biphasic waves with initial, predominantly negative deflection. The most useful diagnostic findings were in lead aVF, where a Q wave was present in 10 of 35 patients in the MI group compared with only 4 of 131 patients in the normal group (p < 0.00001). Diagnostic T-wave inversion was noted in 23 of 35 patients in the MI group compared with 8 of 131 patients in the normal group (p < 0.00001). The presence in lead aVF of either a diagnostic Q-wave or T-wave inversion was seen in 30 of 35 patients with inferior MI (sensitivity of 86%) compared with only 12 of 131 patients with uncomplicated LBBB (specificity 91%). Thus, these criteria are potentially useful for the diagnosis of inferior MI in patients with LBBB.

Artificial neural networks for the electrocardiographic diagnosis of healed myocardial infarction

Artificial neural networks are computer-based expert systems that learn by example, in contrast to the currently used rule-based electrocardiographic interpretation programs. For the purpose of this study, 1,107 electrocardiograms (ECGs) from parents who had undergone cardiac catheterization were used to train and test neural networks for the diagnosis of myocardial infarction. Different combinations of QRS and ST-T measurements were used as input to the neural networks. In a learning process, the networks automatically adjusted their characteristics to correctly diagnose anterior or inferior wall myocardial infarction from the ECG. Two thirds of the ECGs were used in this process. Thereafter, the performance of the networks was studied in a separate test set, using the remaining third of the ECGs. The results from the networks were also compared with that of conventional electrocardiographic criteria. The sensitivity for the diagnosis of anterior myocardial infarction was 81% for the best network and 68% for the conventional criteria (p <0.01), both having a specificity of 97.5%. The corresponding sensitivities of the network and the criteria for the diagnosis of inferior myocardial infarction were 78% and 65.5% (p <0.01), respectively, compared at a specificity of 95%. The results indicate that artificial neural networks may be of interest in the attempt to improve computer-based electrocardiographic interpretation programs.

Smoothing techniques for improving the repeatability of the automated diagnosis of inferior myocardial infarction

This study describes the implementation of novel techniques that have been designed with the aim of improving the repeatability of the diagnostic section of the Glasgow electrocardiographic (ECG) analysis program. Specific reference is made to the agreement in consecutive computer-assisted diagnoses of inferior myocardial infarction (IMI). Inherent repeat variation was estimated in ECG parameters of interest and used in conjunction with smoothing methods to produce a continuous Q-wave index ranging from 0 (no IMI) to 1 (IMI). A decision as to the presence or absence of IMI was then made on the basis of this smooth index. The sensitivity and specificity of the new approach remain unchanged from the conventional procedure when analyzing single ECGs. However, consistency in interpretation of day-to-day and minute-to-minute ECG interpretations was enhanced. Specific reference is made to the agreement between consecutive pairs of computer-assisted diagnoses of ECGs from the same patient in which one or both interpretations was that of IMI.

Use of artificial neural networks within deterministic logic for the computer ECG diagnosis of inferior myocardial infarction

An investigation into the use of software-based artificial neural networks for the electrocardiographic (ECG) detection of inferior myocardial infarction was made. A total of 592 clinically validated subjects, including 208 with inferior myocardial infarction, 300 normal subjects, and 84 left ventricular hypertrophy cases, were used in this study. A total of 200 ECGs (100 from patients with inferior myocardial infarction and 100 from normal subjects) were fed to 66 supervised feedforward neural networks for training using a back-propagation algorithm. QRS and ST-T wave measurements were used as the input parameters for the neural networks. The best performing network using QRS measurements only and the best using QRS and ST-T data were selected by assessing a test set of 292 ECGs (108 from patients with inferior myocardial infarction, 84 from patients with left ventricular hypertrophy, and 100 from normal subjects). These two networks were then implanted separately into the deterministic Glasgow program for further study. After the implementation, it was found necessary to include a small inferior Q criterion to improve the specificity of reporting inferior myocardial infarction, thereby producing a small loss of sensitivity as compared with use of the network alone. The use of an artificial neural network within the deterministic logic performed better than either alone in the diagnosis of inferior myocardial infarction, producing a 20% gain in sensitivity with 2% loss in overall specificity compared with the original deterministic logic.

Isolated left posterior fascicular block: a reliable marker for inferior myocardial infarction and associated severe coronary artery disease.

The electrocardiographic (ECG) pattern of isolated left posterior fascicular block (LPFB) is a rare condition. It seems that true LPFB is often not recognized, whereas in cases of simple QRS axis of +60 degrees to +100 degrees in the frontal plane, the diagnosis of LPFB is made erroneously. Both facts rely on controversial and partially misleading opinions in the literature. Therefore, a retrospective and prospective study was performed in order to determine the prevalence of LPFB and to correlate its presence to the underlying disease. Retrospective study: Of a cohort of 830 patients referred in 1988 to a cardiologic laboratory for invasive investigation of certain or suspected coronary artery disease (CAD), 163 patients had an old inferior myocardial infarction (IMI). Nine patients (5.5%) showed the typical pattern of LPFB; eight of these had three-vessel disease. The diagnosis of IMI had been made only in one case before entry of the patient into the hospital, since LPFB generally masks IMI. Prospective study: 2502 ECGs were investigated, 1710 from a department of cardiology and 792 from two departments of internal medicine. Six LPFBs were detected (0.24%), all associated with IMI and four of them with three-vessel CAD. It is concluded that LPFB is a rare but clinically important intraventricular conduction disturbance. Its appearance is reliably connected with IMI and generally reflects severe three-vessel CAD, requiring invasive investigation.

Vectorcardiogram more sensitive than 12‐lead ECG in the detection of inferior myocardial infarction

The vectorcardiogram (VCG) is commonly stated to be more sensitive than the 12-lead electrocardiogram (ECG) for the diagnosis of inferior myocardial infarction. However, a recent study indicated that VCG is not superior to ECG for this diagnosis. The purpose of this study was to compare the performance of VCG and ECG criteria and to indicate possible explanations for the disagreement between earlier studies. Accordingly, we studied 65 patients with inferior myocardial infarction verified by left ventriculography or 201-TI myocardial scintigraphy and 351 normal subjects. Sensitivity was 69% (45/65) and 43% (28/65) for the VCG and ECG criteria, respectively. This difference was highly significant (P less than 0.001). Among the normal subjects there were only three with false positive ECG. We conclude that both VCG and ECG criteria for the diagnosis of inferior myocardial infarction are highly specific and that VCG criteria have greater sensitivity than ECG criteria.

Decision rules for the ECG diagnosis of inferior myocardial infarction

ECG measurements from 341 patients with inferior myocardial infarction (IMI) and 327 normal subjects were used to develop and test decision rules for the ECG diagnosis of IMI. Recursive partitioning provided a simple decision rule with 75% sensitivity and 97% specificity, using Q amplitude and Q duration in aVF, Q duration in III, and T-wave axis in the frontal plane as decision variables. Dropping T-wave axis from the decision rule led to a 10% decrease in sensitivity. Multiple logistic regression provided sensitivities and specificities which were similar to those for recursive partitioning. Both methods outperformed traditional noncontour criteria for IMI.

Improved ECG interpretation using synthesized VCG for the diagnosis of inferior myocardial infarction

Electrocardiographic (ECG) criteria for the diagnosis of inferior myocardial infarction (IMI) have high specificity but low sensitivity. Vectorcardiographic IMI criteria attain higher sensitivity without sacrificing specificity. One approach to improving ECG interpretation is to synthesize VCG loops from the 12-lead ECG. The performance of synthesized VCG (SVCG) was assessed, using the Frank VCG criterion of Starr et al. ECGs and SVCGs from 351 normal subjects and 65 patients with IMI verified by myocardial scintigraphy or angiocardiography were studied. The sensitivity was 14 percentage points higher for SVCG than for ECG (72% vs. 58%).

Vectorcardiogram versus Thallium-201 Planar Scintigram and Single-Photon Emission Computed Tomogram in the Diagnosis of Inferior Myocardial Infarction

This study describes the correlation between vectorcardiography, planar thallium-201 scintigraphy and SPECT in the diagnosis of inferior myocardial infarction

Importance of the terminal portion of the QRS in the electrocardiographic diagnosis of inferior myocardial infarction

The scalar electrocardiograms of 64 patients with inferior wall myocardial infarction (MI) and 87 normal subjects were quantitatively analyzed to determine the respective contributions of the initial and terminal portions of the QRS to the diagnosis of inferior Ml. Of the 10 best individual electrocardiographic criteria for inferior MI, 7 were Q-wave criteria and 3 were criteria that consisted of delayed termination of the QRS in leads II or III. Combining the best terminal QRS criterion (the QRS in lead III ending at least 20 ms later than the QRS in lead I) with the 7 best Q-wave criteria and the best Q-wave criterion (Q wave 40 ms or longer in lead aVF) with the 3 best terminal QRS criteria, resulted in criteria with better sensitivities and overall diagnostic performances than those of the individual criteria. Analyzing the vectorcardiograms that were also available in 26 of the patients with inferior MI and 34 of the normal subjects showed that the delayed inscription of the end of the QRS in leads II and III in patients with inferior MI is due to redirection of the terminal forces of ventricular depolarization. The terminal portions of the QRS complexes in the limb leads, considered both alone and in conjunction with traditional measurements of Q waves, contain information that is useful for diagnosing inferior MI.

Ranking of Fuzzy Alternatives in Electrocardiography

A system for computerized electrocardiography, where the final classification of the ECG is obtained through a fuzzy decision, is briefly described. The arising problem of ranking fuzzy utilities is explored. Different methods for ordering fuzzy quantities are applied to the simulation of a diagnosis of inferior myocardial infarction, in order to test the validity of the results. It is concluded that in general all methods are comparable, possibly with a slight preference in this practical context for the “center of gravity” suggested by Yager.

Electrocardiographic criteria for the diagnosis of combined inferior myocardial infarction and left anterior hemiblock

New electrocardiographic (ECG) criteria for diagnosing the combination of inferior myocardial infarction and left anterior hemiblock are proposed. The proposed criteria are based upon the relations between portions of the vectorcardiographic QRS loop in the frontal plane and the corresponding portions of the QRS complexes recorded by the limb leads. The application of the proposed criteria requires that the tracings be obtained with 3-channel ECG machines. The proposed criteria for the diagnosis of inferior myocardial infarction and left anterior hemiblock are as follows: (1) leads aVR and aVL both end in R waves, with the peak of the terminal R wave in lead aVR occurring later than the peak of the terminal R wave in lead aVL, and (2) a Q wave of any magnitude is present in lead II. The performance of the proposed criteria was superior to that of 10 combinations of traditional ECG criteria for inferior myocardial infarction and left anterior hemiblock.