Brugada-like electrocardiographic pattern induced by an episode of anemia

Summary The mechanisms responsible for the undulating pattern of ST-segment elevations in the Brugada syndrome are still a matter of discussion. This report describes a young man with a Brugada-like electrocardiographic pattern. The specific ST-segment elevations were unmasked during an episode of anemia due to a duodenal ulcer.     

Precordial ST-segment mapping 5. Analysis of maps and standard electrocardiograms in patients with inferior myocardial infarction

Measured and derived electrocardiographic parameters pertaining to ST-segment elevations, R and Q wave amplitudes from standard electrocardiograms, and 49-lead precordial maps from ten patients with acute inferior transmural myocardial infarction were analyzed. Sums of ST-segment elevations correlated well with corresponding values derived from various combinations of standard leads expressing inferior ischemic injury. Derived ECG R and Q wave data from maps did not correlate with corresponding parameters from the standard ECGs. Stability of parameters derived from ST-segment elevations over the course of the study and lack of correlation with data expressing changes in the R and Q waves were noted. An analytical pattern such as the one utilized in this study can be used for assessment of therapeutic interventions in the Coronary Care Unit.     

Effect of diltiazem on silent myocardial ischemia]

Thirty-four patients with coronary heart disease who had silent myocardiac ischemic episodes as evidenced by long-term ECG monitoring were examined. Silent ST-segment elevations and depressions were encountered 2.7- and 4.9-fold as compared to manifest ones. The fact that the CHD patients had silent ST-segment depressions and/or prolonged high-amplitude silent ST-segment elevations suggests a grave severity of abnormal myocardial processes. There was a reduction in the number, duration of silent ST-segment elevations and depression episodes and in the amplitude of silent ST-segment depressions. This may indirectly indicate that the agent affects predominantly coronary blood flow and coronary vascular tone.     

Precordial ST-segment mapping: 6. Evaluation of serial changes in ST-segment elevations and QRS complexes of precordial maps and standard ECGs in patients with acute myocardial infarction

A total of 21 patients, 10 with anterior and 11 with inferior myocardial infarction (MI) had serial precordial 49-lead ECG maps or standard ECGs on admission, and 2, 6, 12, 24 hours, and 7 days thereafter, to evaluate the natural course of ST-segment elevation (index of ischemic injury) and QRS changes (index of necrosis), and their relationship. ECG parameters used included the sum of ST-segment elevations, number of sites showing such changes, the sum of R waves from all leads with ST-segment elevations, and a QRS score of all leads showing ischemic injury on admission. Sums of ST-segment elevations either did not show statistically significant change throughout the study or showed unexplained re-elevation (anterior MI), or completed their downward course in 6 hours (inferior MI). The number of sites showing ST-segment elevations either remained unchanged (inferior MI), or declined at 2 hours without further change. However changes in the sum of R waves or QRS scores were gradual and completed most of their overall course within 24 hours. Decline of sums of R waves correlated well with sums of ST-segment elevations on admission (inferior MI), and the number of sites showing changes (anterior MI). The course of changes in QRS complexes is more reliable than the alterations of ST-segment elevations for the monitoring of evolution of MI. The former, assessed frequently in the first 24 hours, should be useful in the evaluation of therapies for patients with MI.     

Use of precordial ST-segment mapping

Serial precordial ST-segment ECG mapping with a grid consisting of 49 recording marks made on the anterior thorax of patients with acute anterior transmural myocardial infarction has been applied in the study of usefulness of this technique. It has been found that a pattern of variable devolution of the magnitude of ST-segment elevations is seen in uncomplicated myocardial infarction. Extension of the infarct has been characterized by re-elevation of ST-segments. Beneficial therapeutic interventions have resulted in reduction of the magnitude of ST-segment elevation. However, the technique cannot be applied in patients with inferior transmural myocardial infarction or in patients with functioning pacemakers, bundle branch blocks, or pericarditis. The significance of adherence to strict guidelines in performing ST-segment mapping and the analysis of mapping data in the light of the total clinical picture at the time of recordings is emphasized.     

Precordial ST-segment elevation in acute occlusion of the proximal right coronary artery

Isolated right ventricular myocardial infarction (RVMI) rarely occurs and accounts for only 3% of all myocardial infarction cases. In the literature, there are several reported isolated RVMI cases with precordial ST-segment elevation. We describe a 45-year-old man with marked ST-segment elevations in leads V1 through V4 accompanied by slight ST-segment elevations in the inferior leads (III, aVF) caused by acute occlusion of a nondominant small right coronary artery proximal to the conus branch causing isolated RVMI.     

Complete sustained reversal of cyclic ST-segment elevation (coronary cyclic flow variations) by low-dose intravenous nitroglycerin during acute coronary syndrome

Background

Recurrent ST-segment elevations in acute coronary syndromes have been attributed to coronary cyclic flow variations (CCFVs) possibly due to coronary vasospasm and unstable platelet aggregation in partially occluded arteries.

Methods

We describe the case of a patient with an acute myocardial infarction, recurrent ST-segment elevations and diffuse disease of the left anterior descending artery.

Results

The post-angiography 12-lead continuous ECG monitoring revealed cyclic anterior ST-segment elevations that were completely abolished with continuous intravenous infusion of low-dose isosorbide-dinitrate.

Conclusion

The complete and sustained response to low-dose nitrate suggests that vasoconstriction plays a crucial role to provoke CCFVs. This case underlines the importance of continuous 12-lead ECG monitoring with ST-segment trend analysis in the CCU.     

Effects of nicardipine in silent myocardial ischemia

201Tl myocardial scintigraphy was performed in 29 patients with coronary heart diseases and silent myocardial ischemic episodes revealed during a long-term monitoring of ST segment. The painless ST segment depression episodes and long high-amplitude painless ST segment elevations were found to be indicative of a significant severity of pathological processes in the myocardium. A 12-day nicardipine monotherapy produced antianginal and hypotensive effects and contributed to decrease in the frequency, duration, and amplitude of silent ST-segment depressions and in the duration of silent ST-segment elevations.     

ST elevations in leads V1 to V5 may be caused by right coronary artery occlusion and acute right ventricular infarction

In 5 of 69 patients (7%) undergoing intracoronary or intravenous streptokinase treatment, the ST-segment elevations in leads V₁ to V₅ were caused by occlusion of the right rather than the left anterior descending coronary artery and by myocardial infarction (MI) of the right ventricular (RV) wall rather than the anterior left ventricular (LV) wall or the ventricular septum. RV involvement was documented by technetium pyrophosphate uptake, hypokinesia, dilatation and depressed RV ejection fraction. The left anterior descending artery was patent and the anterior LV wall had normal thallium-201 uptake, no technetium uptake and normal wall motion. ST-segment elevation was highest in lead V₁ or V₂ and decreased toward lead V₅; in patients with anterior LV MI, the ST-segment elevations are usually lowest in lead V₁ and increase toward the V₅ lead. In contrast to anterior LV infarcts, the R waves in leads V₁ to V₅ did not decrease and Q waves did not evolve with progression of the MI.The ST-segment elevations in leads V₁ to V₅ in our patients were associated with small or absent ST-segment elevations in leads, II, III and aVF, suggesting that in other cases of RV infarction, the appearance of ST-segment elevations in leads V₁ to V₅ is blocked by the dominant electrical forces of the LV inferior MI. This suggestion was confirmed in a canine model. Recognition of the presence of RV infarction may be therapeutically important.     

Coronary Angioscopy Revealing Ruptured Plaque and Thrombus Causing Acute Anterior Myocardial Infarction With a Subsequent Acute Inferior Myocardial Infarction — A Case Report

We report a unique case that suggests that a thrombotic coronary occlusion was caused by local plaque rupture in the left anterior descending coronary artery (LAD), with subsequent thrombotic occlusion in the right coronary artery (RCA), and presented with simultaneous double coronary artery occlusions. ST-segment elevations in the precordial leads and cardiac tamponade were observed first, followed by ST-segment elevations in the inferior leads. Emergency coronary intervention for the RCA lesion resulted in further ST-segment elevation, suggesting an acute inferior infarction. A left ventricular rupture was found in the anterolateral wall, consistent with acute anterior infarction. Angioscopy one month later revealed the presence of ruptured plaque with thrombus, in both the LAD and the RCA. Yuji Okuyama and Masaya Usami, contributed equally to this report     

Racial and sexual differences in the standard electrocardiogram of black vs white adolescents.

Standard 12-lead electrocardiograms were recorded in 114 healthy adolescents to substantiate possible influences of race and sex on the "juvenile pattern" (increased precordial voltages of QRS complex, precordial T wave inversions, and ST-segment elevations considered pathologic in adults) in this age group. Black male subjects had the highest precordial QRS amplitudes and the highest incidence of biphasic or negative precordial T waves and ST-segment deviations. In white male subjects, these findings were less pronounced but were more evident than in black or white female subjects. Results indicate the following: (1) race-specific and sex-specific normal electrocardiographic standards should be developed in adolescents; (2) criteria for left ventricular hypertrophy are race-specific and sex-specific and should be tested against independent anatomic or physiologic information in adolescents with left ventricular overload; and (3) the "juvenile pattern" may be viewed as a predictable continuum of age-related changes starting in childhood and progressing through adolescence on to later life.     

Stress-induced ST-segment elevation following myocardial infarction and its role in wall motion abnormality, myocardial ischemia and viability: comparison of response to exercise, dobutamine and dipyridamole.

Stress-induced ST-segment elevation following myocardial infarction (MI) has been correlated with myocardial ischemia, viability and wall motion abnormality, but its mechanism is still unclear, so the present study compared ST-segment elevation and wall motion response during exercise, dobutamine and dipyridamole stresses. Twenty-five patients with their first anterior MI underwent exercise, dobutamine and dipyridamole echocardiography on different days 4-6 weeks after MI. Left ventricular wall motion was analyzed using 5-grade/16-segment model and myocardial ischemia was considered as a worsening of the wall motion score index (WMSI) during the stress test; myocardial viability was defined as a reduction of WMSI during low dose dobutamine. Dyskinesis formation was defined by visual analysis as akinesis that became dyskinetic or if the dyskinesis worsened. Both exercise and dobutamine induced ST-segment elevation, but dipyridamole did not. There was no significant difference in the degree of ST-segment elevation between the patients with and without myocardial ischemia or dyskinesis formation. Exercise induced a higher ST-segment elevation in patients with myocardial viability than those without (0.17+/-0.09 mV vs 0.09+/-0.07 mV, p<0.05). Exercise-induced ST-segment elevations correlated with dobutamine-induced ST-segment elevations (p<0.01), changes in heart rate (p<0.05) and systolic blood pressure (p<0.05). In conclusions, stress-induced ST-segment elevation does not correlate with either myocardial ischemia or stress-induced dyskinesis, but may be associated with myocardial viability.     

Diagnosis of acute myocardial infarction in angiographically documented occluded infarct vessel : limitations of ST-segment elevation in standard and extended ECG leads.

STUDY OBJECTIVES: The majority of thrombolysis studies require defined ST-segment elevations as an inclusion criterion for the diagnosis of acute myocardial infarction (AMI). However, depending on the occluded infarct vessel and the criteria applied, the ECG diagnosis of AMI can be difficult to establish. Accordingly, this study was performed to evaluate the sensitivity of ST-segment elevation of standard and extended ECG leads in a cohort of patients with angiographically confirmed diagnosis of AMI. PATIENTS AND METHODS: In 418 patients (mean +/- SD age, 60 +/- 13 years) with AMI (pain onset, 4.8 +/- 3.0 h), coronary angiography with percutaneous transluminal coronary angioplasty/stenting of the culprit lesion was performed. The diagnosis of AMI was confirmed by emergency coronary angiography and laboratory analyses. ST-segment elevation (in two contiguous leads) of 1 mm in standard lead I through aVF and ST-segment elevations of 2 mm (or 1 mm, corresponding values presented in parentheses) in V(1) through V(6) were considered significant. In a subset of 102 AMI patients, additional right precordial leads V(3)R through V(6)R for evaluation of right ventricular infarction and additional chest leads V(7) through V(9) for evaluation of posterior infarction were recorded. ST-segment elevations of 1 mm in the right precordial leads and 1 mm or 0.5 mm in the posterior leads were considered significant. RESULTS: Standard leads I through V(6) showed ST-segment elevation in 85% (96%) of patients with left anterior descending artery occlusion, in 46% (61%) of patients with left circumflex coronary artery (CX) occlusion, and in 85% (90%) of patients with right coronary artery occlusion. On consideration of additional ECG tracings in the subgroup of 102 patients (V(3)R through V(6)R and V(7) through V(9)), the respective numbers increased by 2 to 8% depending on different criteria for ST-segment elevation; in patients with CX occlusion, the increase amounted to 6 to 14%. There was a trend toward an extended infarct size (maximum creatine kinase [CK] values) with concomitant ST-segment elevation in additional ECG leads as assessed by maximum CK levels. CONCLUSIONS: The sensitivity of the ECG diagnosis of AMI is only marginally increased by extended precordial chest leads. There is a trend toward an extended infarct size in those patients with concomitant ST-segment elevation in additional ECG leads.     

Precordial ST-segment mapping 4. Experience with mapping of ST-segment depression in anterior transmural myocardial infarction

In order to assess the relative significance of precordial ST-segment elevations and depressions, 32 patients with anterior transmural myocardial infarction were studied utilizing serial 49-lead precordial maps. Theoretically, zones of ST-segment depression adjacent to major zones of ST-segment elevation might represent border areas of mild ischemia, and hence could be more readily amenable to intervention therapy. As expected, an extensive zone of ST-segment elevation was observed precordially in each of these patients. However, zones of ST-segment depression in adjacent areas were noted to occur inconsistently, were limited in distribution and magnitude, and bore no fixed relationship to zones of ST-segment elevation. Thus, mapping of precordial ST-segment depression in anterior transmural infarction probably has a limited role in assessing evolution of ischemic injury or therapy in these patients. This finding does not, however, vitiate the significance of ST-segment depressions in angina, intermediate coronary syndrome, or non-transmural infarction, conditions which may deserve further study using mapping techniques.     

Persistent ST-segment elevation and left ventricular wall abnormalities: A 2-dimensional echocardiographic study

Twenty-three patients with an anterior wall myocardial infarction (MI) and persistent ST-segment elevations (Group I) were examined for wall motion abnormalities using 2-dimensional (2-D) echocardiography. Twenty-two (96%) had dyskinetic wall motion of the infarcted area and 10 (43%) had a left ventricular aneurysm. Among 15 patients who had a chronic anterior wall MI without ST-segment elevation (Group II), 13 (86%) had akinesia of the infarcted segment. To document that dyskinetic wall motion caused the persistent electrocardiographic ST-segment elevations, 15 patients with an acute anterior wall MI (Group III) were followed by serial 2-D echocardiography for 2 to 24 months (mean 8). Of the 10 patients who had dyskinetic wall motion abnormalities on their initial 2-D echocardiogram, persistent ST-segment elevation developed in 9. All 5 patients with akinetic or severely hypokinetic wall motion abnormalities on their first 2-D echocardiogram did not show ST-segment elevation on late follow-up surface electrocardiograms. Infarct size as determined by peak creatine kinase levels for the former subgroup was greater than that for the latter subgroup (2243 ± 429 vs 899 ± 320 IU, respectively, p < 0.01). In conclusion, persistent ST-segment elevation after an acute anterior wall MI is indicative of dyskinetic wall motion rather than aneurysm formation. Dyskinesia precedes the appearance of ST-segment elevation and is probably responsible for these changes on the surface electrocardiogram. Infarct size is larger in persons in whom dyskinetic wall motion abnormalities are likely to develop.     

Phonocardiographic timing of third and fourth heart sounds during acute myocardial infarction

A 47-year-old diabetic woman was referred for diagnostic coronary angiography as part of an evaluation before renal transplantation. During attempts to cannulate the left coronary artery, the patient developed severe dyspnea and new ST-segment elevations in the anterior leads. Left coronary angiography showed acute occlusion of the proximal left anterior descending (LAD) coronary artery. She then underwent emergent percutaneous intervention of the occluded vessel. Continuous electrocardiographic and phonocardiographic recordings were obtained during the procedure that documented the timing and appearance of ST-segment elevations and the onset of third and fourth heart sounds. In this report, the sequence of these events is discussed, and the literature is reviewed.     

Clinical characteristics and prognosis of patients with postinfarction angina caused by coronary artery spasm

Clinical features and the course of 15 patients with postinfarction angina caused by coronary artery spasm are described. Episodes of postinfarction angina in the patients recurred at rest in the early recovery phase and were accompanied by transient ST-segment elevation. The area where ST-segment elevations were demonstrated on a 12-lead ECG always included the leads with newly developed abnormal Q waves. Pain resolved spontaneously or after sublingual nitroglycerin in several minutes. Holter ECGs during a 24-h period demonstrated frequent episodes of ST-segment elevation that were not always associated with chest pain. Treatment with calcium antagonist and/or nitrates effectively suppressed angina, and only one patient developed reinfarction. The patient's subjective symptoms were abolished by diltiazem and isosorbide dinitrate. A Holter ECG of the patient revealed silent ST-segment elevations before and after the reinfarction and an increase of the drugs completely suppressed the recurrence of silent ischemic ECG changes. Coronary arteriograms were obtained from 8 patients, which demonstrated more than 75% segmental stenosis on one coronary artery in 5 patients and no significant obstruction in the remaining 3. All patients performed a treadmill exercise stress test before discharge and most demonstrated excellent tolerance. All patients experienced no form of chest pain for an average of 25 months follow-up under medication. We conclude that among patients with postinfarction angina, those cases caused by coronary artery spasm have a relatively good prognosis.     

ST segment changes in long-term ECG in healthy heart probands

100 healthy medical students were studied with 24-h Holter monitoring for ST-segment evaluation. Six recordings (1.8% of males and 11.6% of females) contained at least one episode of horizontal or downsloping ST-segment depression of at least 0.1 mV or more and 1 min duration in the V-5-like lead. Since ST-segment elevations (in 73% of the recordings in the V-5-like lead, and in 40% in the V-2-like lead) and discordant (negative) T-waves associated with ST-segment depressions (in 31% of the recordings in the V-2-like lead) were commonly seen, these ECG findings have to be considered as nonspecific. During exercise tests using a protocol of maximal work load, not one of these healthy individuals displayed typical ST-segment depressions indicative of myocardial ischemia. Therefore, typical documented ST-segment alterations in Holter-ECG recordings should be used with caution when observed in individuals with suspected coronary heart disease, particularly when they are female.     

Left spontaneous pneumothorax presenting with ST-segment elevations: a case report and review of the literature

Common electrocardiogram (ECG) changes associated with left-sided pneumothorax include right axis deviation, reduced R-wave amplitude in precordial leads, QRS alterations (amplitude changes), and T-wave inversions. Few reports exist of ST-segment elevations or changes suggestive of acute myocardial infarction (AMI), and these involve older patients with tension pneumothorax and previous coronary heart disease. We report on a young man with no significant medical history, presenting with left-sided spontaneous pneumothorax and ECG changes that included ST-segment elevations and T-wave inversions in the precordial leads, reminiscent of AMI. All changes resolved after decompression of the pneumothorax. On the basis of the patient’s presenting symptoms, response to therapy, and our review of the literature, we propose a number of possible mechanisms explaining his electrocardiographic findings.     

Validation of trend-supported ST segment analysis of long-term ECG recordings

Trend recordings of relative ST-segment deviations represent a useful tool for the identification of ischemia-like episodes during Holter monitoring. For the generation of trend recordings beat-to-beat data are filtered. The influence of the time constant of the filter on the sensitivity and the specificity for the detection of ischemia-like ECG changes is unknown, however. Ischemia-like episodes were, therefore, simulated and recorded by a frequency modulated Holter recorder and by a conventional six-channel ECG system. Relative ST-segment deviations were filtered using a time constant of 8, 16, 32 or 64 s, or an arithmetic averaging over 9 s for the generation of ST-segment trends. The magnitude of short-lasting ST-segment deviations was underestimated, when beat-to-beat data were filtered using time constants of greater than or equal to 32 s. The influence of posture-related ECG changes on the ST-segment trends was investigated by recording lead CM5 in 14 consecutive patients in different positions by a conventional ECG system. Four out of the 14 patients developed ST-segment elevations greater than or equal to 0.1 mV during leftsided position. Only in these four patients were ST-segment deviations of similar magnitude recorded during the following Holter monitoring. The posture-related ST-segment changes were characterized by an abrupt onset and an abrupt end, resulting in a box-like shape which enabled their correct identification in the ST-segment trend analysis. In order to determine the relative frequency of posture-related ST-segment changes, 35 patients with coronary artery disease (CAD) and 35 patients without underwent Holter monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)