Electrocardiographic Diagnosis Of Myocardial Infarction Research Articles

Automated electrocardiographic diagnosis of myocardial infarction

In 2020, the Russian Society of Cardiology published the clinical guidelines for the diagnosis of acute coronary syndrome and acute myocardial infarction with the use of electrocardiography terms and symbols. Currently, a specialist in functional diagnostics often has questions when formulating an ECG diagnosis. The formulations accepted for describing ECG for coronary circulation disorders («focal myocardial changes»), and non-specifi c repolarization abnormalities stated («diff use myocardial changes») in the Russian methodology [1] are not always related to a coronary disease. The article presents an overview of currently existing ECG criteria of myocardial infraction to be used by a specialist in functional diagnostics in an automated workplace. It is suggested to prepare an ECG report for patients with acute coronary syndrome (particularly those with myocardial infarction) based on the presence of areas of myocardial ischemia, damage and necrosis.

Prehospital versus hospital fibrinolytic therapy using automated versus cardiologist electrocardiographic diagnosis of myocardial infarction: abortion of myocardial infarction and unjustified fibrinolytic therapy

Background This study investigated the incidence of abortion of myocardial infarction and of unjustified fibrinolysis by using automated versus cardiologist-assisted diagnosis of acute ST-elevation myocardial infarction. The results of prehospital diagnosis and treatment (2 cities in the Netherlands) were compared with those of inhospital treatment. Unjustified fibrinolysis must be differentiated from justified thrombolysis resulting in aborted myocardial infarction. Both have the absence of a significant rise in cardiac enzymes in common. In aborted myocardial infarction, this is a result of timely reperfusion; in unjustified thrombolysis, this is the result of an incorrect diagnosis. Methods In the city of Rotterdam, 118 patients were treated before hospitalization for myocardial infarction, diagnosed through the use of a mobile computer electrocardiogram; in the city of Nijmegen, 132 patients were treated before hospitalization with the use of transtelephonic transmission of the electrocardiogram to the coronary care unit and judged by a cardiologist. Their data were compared with those of 269 patients treated inhospital in the city of Arnhem, using the same electrocardiographic criteria. Abortion of myocardial infarction was diagnosed as the absence of a significant rise in cardiac enzymes and the presence of resolution of chest pain and 50% of ST-segment deviation within 2 hours after onset of therapy. Lacking these, the diagnosis of unjustified fibrinolytic therapy was made. Results Unjustified treatment occurred in 8 (3.2%) prehospital-treated patients (4 in Rotterdam and 4 in Nijmegen). Of the inhospital–treated patients in Arnhem, 5 (1.9%) were treated unjustifiably ( P = .49). Aborted myocardial infarction occurred in 15.3% and 18.2% in Rotterdam and Nijmegen, respectively, against 4.5% in inhospital treatment in Arnhem ( P < .001). Conclusions Abortion of myocardial infarction is associated with prehospital thrombolysis. Unjustified fibrinolysis for acute myocardial infarction occurs in prehospital fibrinolysis as frequently as in the inhospital setting. The use of different electrocardiographic methods for diagnosing acute myocardial infarction does not appear to make any difference.

Electrocardiographic diagnosis of myocardial infarction in patients with left bundle branch block

Study Objective: To validate ECG criteria previously proposed by Sgarbossa et al for the detection of myocardial infarction (MI) in patients with left bundle branch block (LBBB) and suspected ischemia. Methods: A retrospective cohort study was performed at an urban teaching hospital. All patients admitted with suspected ischemia and LBBB were eligible. MI was defined as an elevated creatine kinase (CK) isoenzyme MB (>14 IU/L) that was at least 5% of total CK level. ECGs were interpreted by 2 physicians blinded to patient outcome. Interpreters were asked to rate ECGs for the presence of each of the 3 criteria proposed by Sgarbossa et al: (1) ST-segment elevation greater than or equal to 1 mm concordant with the QRS complex; (2) ST-segment elevation greater than or equal to 5 mm discordant with the QRS complex; and (3) ST-segment depression in leads V1 through V3. Interobserver agreement was assessed. Results: Of 190 eligible patients, 25 (13%) had MI. Sensitivities of the 3 criteria varied from 0 to 16%, with specificities of 93% to 100%. Only the first criterion demonstrated a clinically useful likelihood ratio (positive likelihood ratio=16 [95% confidence interval 4 to >100]). Patients with new LBBB were more likely to have MI (relative risk=5.1 [95% confidence interval 2.6 to 10]). Interobserver agreement among ECG interpreters ranged from 93% to 98%. Conclusion: The criteria of Sgarbossa et al cannot be used to exclude MI in patients with LBBB because of low sensitivities and poor negative likelihood ratios. ST-segment elevation concordant with the QRS complex had a high positive likelihood ratio for identification of MI. Patients with new LBBB and suspected ischemia are 5 times more likely to have MI than patients with LBBB of chronic or unknown duration. [Li SF, Walden PL, Marcilla O, Gallagher EJ. Electrocardiographic diagnosis of myocardial infarction in patients with left bundle branch block. Ann Emerg Med. December 2000;36:561-565.]

Precision of electrocardiographic diagnosis of myocardial infarction in the ventricular septal area

Precision of electrocardiographic diagnosis of myocardial infarction in the ventricular septal area

Recent advances in the electrocardiographic diagnosis of myocardial infarction: left bundle branch block and pacing.

Recent advances in the electrocardiographic diagnosis of myocardial infarction: left bundle branch block and pacing.

DIAGNOSING MI IN PATIENTS WITH LEFT BUNDLE BRANCH BLOCK.

The electrocardiographic diagnosis of myocardial infarction is notoriously difficult in the presence of left bundle branch block (LBBB). These

Mitral Anular Calcification: An Age-Stratified Case-Control Study

Age-adjusted oods ratios, 95% confidence limits, χ 2 values, and power to detect relative risks≥1.5 were used to compare the features of 371 patients with MAC (cases) to 672 age-stratified patients without MAC (controls). The results show a strong association between MAC and chronic renal insufficiency (odds ratio 2.7; 95% confidence limits 1.83 and 3.99; χ 2 24.8; p>0.001). Disproportionately high odds ratios for MAC and chronic renal insufficiency were found for ages 40-49 years (odds ratio 24.00) and 50-59 years (odds ratio 13.80). No association was found between MAC and ischemic cerebral vascular accidents (odds ratio 0.93; 95% confidence limits 0.67 and 1.38; power 0.73) or transient ischemic attacks (odds ratio 0.76; 95% confidence limits 0.42 and 1.38; power 0.76). Similarly, no associations were found between MAC and electrocardiographic diagnosis of myocardial infarction (odds ratio 0.85; 95% confidence limits 0.62 and 1.16; power 0.75), echocardiographic evidence for regional wall motion abnormality (odds ratio 0.83; 95% confidence limits 0.57 and 1.20; power 0.81), or the clinical diagnosis of atherosclerotic peripheral vascular disease (odds ratio 1.40; 95% confidence limits 0.98 and 2.00; power 0.73)

Electrocardiographic diagnosis of myocardial infarction in the presence of complete left bundle branch block

Electrocardiographic diagnosis of myocardial infarction in the presence of complete left bundle branch block

Electrocardiographic diagnosis of myocardial infarction in the presence of complete left bundle branch block

Whether myocardial infarction (MI) can be diagnosed electrocardiographically in the presence of left bundle branch block (LBBB) is controversial. Our study sought to test the reliability of ECG criteria for diagnosing MI in patients with LBBB. Among 985 patients presenting within 18 hours of the onset of ischemic chest pain, 35 had complete LBBB. Acute MI was identified by serial MB-creatine kinase (CK) elevations and prior MI was determined by previously documented ECG and/or enzyme changes. Among those with LBBB, 24 patients had acute and/or prior MI, while 11 had neither. Eleven ECG criteria previously proposed for detecting MI in the presence of LBBB were evaluated. In patients presenting with ischemic chest pain and complete LBBB, presence of any one of the following ECG criteria was highly specific (90% to 100%) and predictive (85% to 100%) for acute or prior MI: Q waves in at least two of leads I, aV L, V 5, or V 6; R wave regression from V 1 to V 4; notching of the upstroke of the S wave in at least two of leads V 3, V 4, or V 5, and primary ST-T wave changes in two or more adjacent leads.

Electrocardiographic Diagnosis of Myocardial Infarction During Ventricular Pacing

The diagnosis of myocardial infarction during ventricular pacing can be made in a substantial number of patients, mostly by applying the diagnostic criteria that are useful in the presence of complete left bundle branch block. There are, however, important exceptions to this general rule during ventricular pacing, and normal depolarization patterns must be recognized to avoid the erroneous diagnosis of myocardial infarction.

Morphology of ventricular premature beats as an aid in the electrocardiographic diagnosis of myocardial infarction

To determine whether morphologic analysis of ventricular premature beats (VPBs) can aid in the electrocardiographic diagnosis of myocardial infarction (MI), 12-lead electrocardiograms were evaluated in 760 consecutive patients who underwent cardiac catheterization, and 2-minute multiple-lead rhythm strips were evaluated in 515 of these patients. VPBs occurred in 58 patients; 21 had prior MI diagnosed by regional akinesia or dyskinesia on left ventricular cineangiography. Standard criteria were used to diagnose prior MI from the sinus beats of the electrocardiogram. Infarction was diagnosed from the morphology of a VPB when it had a QR or QRS pattern with Q wave ≥ 0.04 second. Morphologic analysis of VPBs had a low sensitivity (29%) but high specificity (97%) and high predictive value (86%) for the diagnosis of Ml. Sinus beats diagnosed Ml with higher sensitivity (52%, and 69% if patients with left bundle branch block and left ventricular hypertrophy were excluded from analysis) than VPB morphologic analysis (p < 0.05), but with similar specificity (97%) and predictive value (92%). Two patients with angiographic Ml had no Ml according to standard electrocardiographic criteria, but did have an Ml manifest by VPB morphologic analysis. Despite low sensitivity, analysis of the morphology of VPBs may be useful for the diagnosis of Ml when the morphology of sinus beats is not diagnostic. Therefore, VPB analysis is complementary to the standard electrocardiographic diagnosis of MI.

The electrocardiographic diagnosis of myocardial infarction in the presence of ventricular conduction defects. A new attempt to solve an old problem

Ventricular conduction defect (VCD) in certain cases may obscure the electrocardiographic (ECG) signs of myocardial infarction (MI). While many previous studies have dealt with this problem, criteria derived from such studies have usually been limited in their clinical usefulness because their sensitivity and specificity were not indicated. Realizing the need for such information, we have gathered 816 records with VCD, and analyzed their Prank-lead ECGs to determine optimal diagnostic criteria for MI. The data used in the study were collected in a prospective fashion from six Veterans Administration Medical Centers, thereby including a fairly representative hospital population of adult males. Two thirds of these patients were white and one third black. Cases were randomly grouped into a training set of 547 and a test set of 269 subjects. The training set was analyzed first. In the presence of RVCD, 72% of cases with MI manifested a Q-wave abnormality in at least one lead. We defined a Q-wave abnormality as any one of the following: a Q/R amplitude ratio in lead x of more than 0.20, in lead y of greater than 0.22, and in lead z of less than 0.10. Among cases without MI, 29% met at least one of the same three criteria (false positives). We did not find R- or S- wave parameters useful to differentiate cases with MI from those without. In contrast to RVCD, a Q-wave abnormality in the presence of LVCD was significant for MI only when present in lead x or lead y. Forty-one percent of cases with MI had a Q/R amplitude ratio in lead x of more than 0.20, and/or a Q/R ratio in lead y exceeding 0.22. Only 11% of cases without MI manifested either one or both Q-wave abnormalities (false positives). A Q/R ratio in lead z of less than 0.10 did not differentiate between cases with MI and those without. In the absence of LVCD, this finding denotes loss of anterior forces, and thus probable anterior MI. Neither did we find unique R- or S- wave measurements to distinguish between LVCD cases with and without MI. There was good repeatability of results when the same criteria were applied to the 269 test cases. On this set, the three criteria for MI in the presence of RVCD had 79% sensitivity and 72% specificity; for MI in the presence of LVCD, sensitivity was 44% and specificity 91%.

Myocardial Infarction: Electrocardiographic Differential Diagnosis

The book is directed specifically to the physician who regularly reads and interprets electrocardiograms, and its main purpose is the refinement of electrocardiographic diagnosis of myocardial infarction. The nucleus of the book is devoted to the ECG Q wave. Wilson's cavity potential theory and the vectorial theory are reviewed in describing the genesis of Q waves. Those that occur as normal variants and with ventricular hypertrophy and altered ventricular conduction are discussed. The reader is reminded that reversal of the limb leads and the improper placement of electrodes produce spurious Q waves. Other common Q wave ECG patterns are discussed. The author correctly points out that considerable caution must be exercised in interpreting the ECG with a widened QRS duration, as altered ventricular conduction frequently produces pseudoinfarctional Q waves. The book is well illustrated with ECG examples that are displayed in close association with the descriptive text. Important points are

Primary ST and T wave abnormalities in the diagnosis of acute anterior myocardial infarction during permanent ventricular pacing

The electrocardiographic diagnosis of myocardial infarction in patients with ventricular pacemakers is often difficult. This report describes the electrocardiograms of two patients with permanent ventricular pacemakers in whom the diagnosis of acute anterior myocardial infarction could be made with confidence by observing the evolution of primary ST and T wave abnormalities in the absence of specific QRS changes.

TRANSIENT BUNDLE-BRANCH BLOCK.

Fourteen patients with transient bundle-branch block have been personally studied. All but one suffered from ischemic heart disease commonly accompanied by hypertension. The conduction defect was observed to appear during acute infarction, attacks of prolonged chest pain, and episodes of left ventricular failure. Not infrequently, however, the appearance and disappearance of bundle-branch block was unaccompanied by any recognizable change in the patient's physical condition. Bundle-branch block may revert to normal intraventricular conduction after many years. In one patient bundle-branch block disappeared on three separate occasions after having been present for over 12 months. Another patient is described in whom normal conduction returned after left bundle-branch block had been established for a record duration of 6 years. The etiology, prognosis, and pathogenesis of transient bundle-branch block have been discussed and the practical importance of this conduction defect in the electrocardiographic diagnosis of myocardial infarction is mentioned.

The difficult electrocardiographic diagnosis of myocardial infarction

A review of data on patients suffering from acute pancreatitis provides few instances wherein electrocardiographic evidence of acute myocardial injury or necrosis developed under circumstances in which concomitant coronary insufficiency was not a more likely cause of the myocardial damage. Experimentally induced acute pancreatitis and the intravenous injection of pancreatic enzymes were not attended by electrocardiographic changes of the kind associated with myocardial infarction. Therefore, if a patient suffering from acute pancreatitis develops electrocardiographic changes indicative of acute myocardial infarction, it is likely that a disparity between coronary flow and myocardial need has resulted in myocardial infarction. Intracranial hemorrhage or trauma commonly induces cardiac arrhythmias and changes in T waves, probably by increased vagal stimulation. However, the eletrocardiographic changes described in all except one of the reports reviewed supply only inferential evidence of myocardial injury. Unless other clinical evidence supports existence of myocardial infarction, that diagnosis rests insecurely. Electrocardiographic evidence of confluent myocardial scar rarely is encountered in patients having primary myocardial disease. This conclusion is consonant with the disseminated focal myocardial changes that characterize this type of myocardial disease morphologically. Segmental and T wave changes in acute pericarditis may mimic those of myocardial infarction; the presence of pathologic Q waves, however, is distinctive of infarction. Cor pulmonale, acute or chronic, may simulate posterior myocardial infarction, but only rarely in a degree sufficient to induce sustained justified confusion. A major acute myoccardial infarction may prove difficult of diagnosis when the infarct is transmural but of small circumference, when it is confined to subendocardium, or to the lateral or posterolateral wall of the left ventricle. The nature of electrocardiographic changes induced by such lesions and the basis for their peculiar features are reviewed. Healed myocardial infarcts frequently produce no electrocardiographic changes permitting recognition of the scar. Such scarring almost certainly is responsible for some instances of major shifts in mean electrical axis to the left (left-axis deviation of −30 to −90, S 2 S 3 pattern). However, review of two pathologic studies supports the judgment that uncomplicated left-axis deviation is a perilous sole criterion on which to rest a diagnosis of myocardial infarction.

Electrocardiographic diagnosis of myocardial infarction in the presence of bundle branch block (right and left), ventricular premature beats and wolff-parkinson-white syndrome

The diagnostic difficulties in the recognition of myocardial infarction in the presence of bundle branch block and the Wolff-Parkinson-White syndrome are discussed. However, through a “deductive” approach in the analysis of the electrocardiogram, such difficulties may be eliminated to a great extent. The knowledge of the sequence of cardiac activation in normal and abnormal circumstances as in bundle branch block, “pre-excitation syndrome”, and extrasystolia, is fundamental. To sum up, the “deductive” approach to clinical electrocardiography not only facilitates the general diagnosis but also indicates the limitations in arriving at a precise diagnosis of infarction.

Electrocardiographic diagnosis of myocardial infarction in cases of complete left bundle branch block

The electrocadiograms of 13 patients with myocardial infarction and left bundle branch block are analyzed. The diagnosis of the infarction was based on autopsy (6 cases), on typical electrocardiographic changes in some records without the disturbance in conduction (3 cases), and on the typical clinical syndrome and evolutive changes of the S-T segment and T wave (4 cases). The electrocardiographic changes were compared to those of 87 patients with complete left bundle branch block in whom there was no reason to suspect a myocardial infarction (autopsy in 20 cases), and also to those of 27 patients who were suffering from typical or probable angina pectoris. All the signs described in the literature as indicating a myocardial infarction in the presence of a left bundle branch block were considered. The conclusion is that only some changes in the S-T segment and the T wave (particularly if they are evolutive and not explained by the administration of digitalis) indicated with certainty a myocardial infarction. Most of the other signs described, especially those referring to the QRS complex, were found in the absence of a myocardial infarction and, therefore, were not diagnostic.

Electrocardiographic diagnosis of myocardial infarction in the presence of left bundle-branch block.

It is generally accepted that most myocardial infarctions are obscured on the electrocardiogram by left bundle-branch block. The number of published cases in which this could be evaluated, however, is small, and the case reports are scattered. We have studied 30 cases of myocardial infarction with left bundle-branch block in which the location of the infarction could be determined with certainty, by autopsy, or by a previous electrocardiogram with normal intraventricular conduction. Twenty such published cases have also been collected. Electrocardiographic abnormalities have been correlated with infarctions in different locations. The possible specificity of these abnormalities is discussed.

A study of unipolar left back leads and their application to posterior myocardial infarction.

The electrocardiographic diagnosis of myocardial infarction of the posterior wall is often missed because it is largely dependent on lead and because this electrode position often does not subtend the diseased myocardium. To remedy this defect, a new method is described—unipolar left back leads. The validity of this method in registering potential from the posterior left ventricular wall is discussed as well as its importance in the diagnosis of myocardial infarction of the posterior wall. Left back leads can illuminate the significance of questionable Q waves.