Transient but marked ST elevation in precordial leads caused by ischemia of the isolated right ventricular branch

The present case is a 64 year-old man in whom transient but marked ST elevation was confirmed in the contralateral precordial leads (V1-3) during percutaneous transluminal coronary angioplasty (PTCA) of the proximal right coronary artery, suggesting that the patient had anteroseptal ischemia. The ST elevation persisted even after the balloon was deflated, and no changes in the left coronary artery were detected. In addition, blood flow in the affected area of the right coronary artery was favorable and there was a transient delay only in the right ventricular branch. Once blood flow in the right ventricular branch improved, ST returned to baseline, and when the right ventricular branch was again occluded by the balloon, ST elevation occurred in a reproducible manner. Hence, the electrocardiographic changes in the precordial leads were caused by occlusion of the right ventricular branch. It is rare to observe ST elevation caused by isolated right ventricular branch ischemia.     

A common electrocardiographic finding in an uncommon presentation

Anterior ST-segment elevation is the hallmark electrocardiographic finding of acute anterior left ventricular infarction that is caused by occlusion in one of the branches of the left coronary artery. We report a case of marked ST-segment elevation in the precordial leads, with concomitant inferior ST-segment elevation that was caused by acute occlusion of the marginal branches of the right coronary artery (RCA) causing an isolated right ventricular myocardial infarction (RVMI) during coronary angioplasty. Isolated occlusion of the marginal branches of the RCA appears to be extremely rare. In the case presented, this was caused by an iatrogenic spiral dissection with subsequent stenting of the RCA. This case illustrates that diffuse ST-segment elevation in the precordial leads may occur due to the occlusion of the RCA or its branches. It is important to recognize this scenario, since the treatment of left ventricular myocardial infarction differs from that of RVMI, where maintaining adequate preload and avoiding vasodilators to preserve right ventricular stroke volume is crucial.     

Surface electrocardiogram in the detection of transmural myocardial ischemia during coronary artery occlusion

To examine whether coronary occlusion causing transmural ischemia was accurately reflected by ST-segment elevation on routine electrocardiograms, intracoronary and surface electrocardiograms were simultaneously recorded during percutaneous transluminal coronary angioplasty (PTCA). The study group consisted of 54 patients who had intracoronary ST-segment elevation during transient coronary occlusion (left anterior descending [LAD]: 25 patients, left circumflex [LC]: 19 patients, right coronary artery: 12 patients). Elevation of the ST segment on the surface electrocardiogram (greater than or equal to 0.1 mV) was recorded in 84% of patients during LAD dilatation, in 32% of patients during LC dilatation (p less than 0.01 vs LAD and right), and in 92% of patients during right coronary dilatation (not significant vs LAD). The magnitude of intracoronary ST elevation was 1.10 +/- 0.8, 1.68 +/- 1.2 and 0.8 +/- 0.6 mV for the LAD, LC and right occlusions, respectively (not significant). Thus, despite the comparable magnitude of intracoronary ST elevation, LC occlusion resulted in ST-segment elevation on the surface electrocardiogram in significantly fewer patients than did LAD or right occlusion. During LC occlusion, 9 patients had no electrocardiographic changes and 4 had only precordial ST depression. Thus, in patients with transmural ischemia during right or LAD occlusions, concordant ST elevation on the surface electrocardiogram is common. In contrast, ST-segment elevation is an insensitive marker of LC occlusion. In patients with ongoing ischemic symptoms and isolated precordial ST depression or no repolarization abnormalities, LC occlusion should be considered in the differential diagnosis.     

Primary angioplasty for isolated right ventricular infarction.

We describe a case of isolated right ventricular infarction that has rarely been diagnosed antemortem. Electrocardiogram showed ST segment elevation in left precordial chest, right precordial chest, and inferior leads, which mimicked those of anterior and inferior left ventricular infarction. Coronary angiography revealed that culprit lesion was totally occluded right coronary artery. Infarcted artery was nondominant right coronary artery with branches supplying only right ventricular wall. Restoration of coronary blood flow was obtained by primary stenting and resulted in prompt ST segment normalization in all leads. Despite extensive right ventricular wall motion abnormality, subsequent right ventricular dysfunction was not observed.     

Anterior ST-segment elevation with right coronary artery occlusion: a unique case of isolated right ventricular infarction

Anterior ST-segment elevation is the classic electrocardiographic feature of anterior left ventricular myocardial infarction due to occlusion of the left anterior descending artery. However, anterior ST-segment elevation has also been described in patients with right coronary artery occlusion, in whom concomitant inferior ST-segment elevation is also typically present. A case of proximal right coronary artery occlusion resulting in anterior ST-segment elevation without inferior ST-segment elevation is reported in this article. It is hypothesized that the inferior left ventricular wall was protected by left-to-right collaterals, as seen on coronary angiography, with resultant isolated right ventricular infarction upon proximal right coronary artery occlusion. In conclusion, this report presents a unique case of an isolated right ventricular infarction resulting in an electrocardiographic pattern mimicking anterior-wall left ventricular infarction.     

Massive ST-segment elevation in precordial and inferior leads in right ventricular myocardial infarction

This report describes a case of right ventricular infarction in which massive ST-segment elevation in the precordial and inferior leads was observed. The maximum magnitude of the ST-segment elevation in the precordial leads was 21 mm in lead V2 and that in the inferior leads was 10 mm in lead II. Angiography revealed a reduction of 90% in the diameter of the right coronary artery in its proximal portion and a normal left coronary system. Recent reports have shown that precordial ST-segment elevation may reflect right ventricular infarction. However, no previously reported instance except our case has shown massive ST-segment elevation in both the precordial and inferior leads. In right ventricular infarction, the current of injury is usually simultaneously present in the right ventricular free wall and left ventricular inferior wall, electrically opposed to each other. Thus, the diffuse and massive ST-segment elevation observed in this study seems to be a rare phenomenon.     

Marked ST-segment elevation in the precordial and inferior leads in right ventricular myocardial infarction: a case report

This is a report of right ventricular infarction complicated by inferior myocardial infarction in which marked ST-segment elevation was observed in the precordial and inferior leads. A 51-year-old man was admitted with chest pain of one-half hour duration. His admission ECG showed conspicuous ST-segment elevation in the precordial and inferior leads. The maximum magnitude of the ST-segment elevation in the precordial leads was 21 mm in lead V2 and 10 mm in lead II. Echocardiography showed akinesis of the right ventricular free wall and the posterior half of the left ventricle. Angiography revealed a 90% reduction in the diameter of the right coronary artery in its proximal portion, and a normal left coronary system. Recent reports have indicated that precordial ST-segment elevation may reflect right ventricular infarction. However, there has been no previous report of marked ST-segment elevation in the precordial and inferior leads. In right ventricular infarction, the currents of injury usually occur simultaneously in the right ventricular free wall and left ventricular inferior wall, and then are electrically opposed to each other. The diffuse and marked ST-segment elevation observed in this case is thus a rare phenomenon.     

Complications of emergency coronary angioplasty for acute myocardial infarction]

To assess the incidence and consequences of complications occurring during emergency percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI), we studied 347 patients who underwent PTCA within 24 hours after the onset of AMI. Acute occlusion occurred in 29 patients (8.4%), of whom 16 patients underwent successful repeat PTCA. All of them survived until hospital discharge. The in-hospital reocclusion rates of these 16 patients were comparable to those of patients who had not experienced acute occlusion (18.8 vs 12.8%, ns). In the remaining 13 patients, reperfusion were not successful after acute occlusion, and 6 died. Side branch occlusion occurred in 21 patients (6.1%). Left circumflex artery occlusion occurring during PTCA for the proximal left anterior descending artery was fatal in 3 patients. Right ventricular branch occlusion during PTCA for the middle of the right coronary artery resulted in intractable right ventricular infarction in one patient, and he died. Among 14 patients who underwent repeat angiography, 13 had a patent side branch which had been occluded during PTCA. One patient had coronary rupture and died. During PTCA of the proximal left anterior descending artery, acute occlusion of the artery without reperfusion or occlusion of the left circumflex artery was often fatal. However, the prognosis of acute occlusion was relatively good, if repeat PTCA was successful and most of the occluded side branches remained patent in the chronic state.     

Coronary angiography in patients with U wave inversion during coronary artery spasm

During ergonovine-induced vasospastic angina, U wave inversion without significant ST segment deviation on the precordial electrocardiograms was documented in four patients. Coronary angiography revealed incomplete spastic obstruction of the left anterior descending artery without delayed filling and runoff in three patients. In the remaining patient, the proximal left anterior descending artery was totally occluded and there were well-developed collaterals from the non-spastic artery. Thus, ergonovine-induced U wave inversion was related to the presence of coronary vasospasm, and angiography demonstrated less severe myocardial ischemia in such patients than in cases with ST segment elevation or depression, which is usually associated with subtotal or total obstruction of a major coronary artery without adequate collaterals. In their clinical courses, two patients had episodes of angina with ST segment elevations or depressions. It was suggested that vasospastic angina with U wave inversion alone is one aspect of a continuous spectrum of vasospastic myocardial ischemia.     

Ratio of ST-segment depression in lead V2 to ST-segment elevation in lead aVF in evolving inferior acute myocardial infarction: an aid to the early recognition of right ventricular ischemia

The potential value of the ratio of precordial ST-segment depression to inferior ST-segment elevation as a sign of concomitant right ventricular (RV) ischemia was examined. The study group consisted of 68 patients, admitted within 3 hours of the onset of inferior acute myocardial infarction (AMI), in whom there was no evidence of prior AMI. In 27 of the 34 patients in whom inferior AMI was the result of right coronary artery occlusion proximal to the RV branch, the magnitude of ST-segment depression in lead V2 was 50% or less of the magnitude of ST-segment elevation in lead aVF, whereas in only 3 of the 34 patients in whom the site of occlusion was either distal to the RV branch (n = 23) or in the left circumflex artery (n = 11) was this ratio 50%; in no patient was it less than 50% (p less than 0.001). All 34 patients with occlusion of the right coronary artery proximal to the RV branch also had regional or global ischemic RV dysfunction by radionuclide ventriculography, with a mean RV ejection fraction of 30 +/- 10% compared with 42 +/- 6% in patients with occlusion distal to the RV branch or in the left circumflex artery (p less than 0.001). In conclusion, in patients with evolving inferior AMI, ST-segment depression in lead V2 of 50% or less of the magnitude of ST-segment elevation in lead aVF may be a useful sign (sensitivity 79%, specificity 91%, positive predictive value 90% and negative predictive value 82%) for identifying patients with concomitant RV ischemia.     

Coronary collateral circulation

The occurrence and influence of coronary collateral circulation and obstruction of the supplying coronary arteries on left ventricular contractility, prevalence of myocardial infarction, and bicycle exercise ergometer test were studied in a random sample of 286 patients with angiographically documented coronary artery disease. Collaterals appeared increasingly in all three main coronary arteries with grade of obstruction. The highest prevalence of collaterals occurred in stenosis of the right coronary artery (60%), followed by the left descending artery (45%); they occurred least in the left circumflex artery (21%) (p less than 0.001). The frequency of intra-arterial collateral circulation was 42%, 11%, and 12%, respectively (p less than 0.001). With total occlusion of the left anterior descending coronary artery, 22% of the patients had normokinetic anterior and apical left ventricular wall when collaterals were present. More often, the inferior wall showed normal contraction with total occlusion of the right coronary artery and collaterals [52%, p less than 0.001 compared with left anterior descending artery (LAD)]. The prevalence of inferior myocardial infarction was 39%, with collateral circulation to the totally occluded right coronary artery. The respective prevalence of anterior infarction and total occlusion in the left coronary artery was 58% (p less than 0.02). The presence or absence of collaterals had no obvious influence on ST-segment response during bicycle ergometer test. In triple-vessel disease, peak work capacity was better when collaterals to LAD were not jeopardized (427 kpm) than when jeopardized (321 kpm) (p less than 0.02).     

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.     

Negative U wave during percutaneous transluminal coronary angioplasty

To clarify the clinical significance of the negative U wave during acute myocardial ischemia, the appearance of the U wave and ST-segment elevation on electrocardiography during percutaneous transluminal coronary angioplasty (PTCA) of the left anterior descending artery (LAD group: 11 patients) or right coronary artery (RCA group: 18 patients) was studied. During PTCA, U-wave inversion (newly developed negative U wave, and increased negativity of the pre-existing negative U wave) was observed in 37 (90%) of 41 patients in the LAD group and in 16 (89%) of 18 patients in the RCA group. The incidence of ST-segment elevation was similar to that of U-wave inversion; however, U-wave inversion appeared before detectable ST-segment elevation in 20 patients (49%) in the LAD group and in 4 patients (22%) in the RCA group. Moreover, U-wave inversion was observed frequently in a wider range of leads than ST-segment elevation. These results suggest that the U wave is a more sensitive indicator of myocardial ischemia than ST-segment elevation in some patients, and that a negative U wave may be produced by a different mechanism than that which produces ST-segment deviation, although both are related to myocardial ischemia.     

Value of lead V4R for recognition of the infarct coronary artery in acute inferior myocardial infarction

In 84 patients with an acute inferior wall myocardial infarction (MI) admitted within 10 hours after the onset of chest pain, a right precordial lead V4R electrocardiogram was recorded in addition to the standard 12-lead electrocardiogram. The presence or absence of ST-segment elevation in lead V4R was correlated with results of coronary angiography performed 2 to 26 weeks (mean 10) after MI. Patients were classified into 3 groups: (1) those with a critical stenosis or occlusion proximal to the first right ventricular (RV) branch (27 patients); (2) those with stenosis distal to the right ventricular branch of the right coronary artery (36 patients); and (3) those with stenosis in the left circumflex coronary artery (21 patients). The presence of ST-segment elevation greater than or equal to 1 mm in lead V4R has a sensitivity of 100% and a specificity of 87% for occlusion of the right coronary artery above the first RV branch; the predictive accuracy is 92%. Seven of 36 patients with a distal occlusion of the right coronary artery showed ST-segment elevation of 1 mm or more in lead V4R . The absence of ST-segment elevation greater than or equal to 1 mm in lead V4R excluded proximal occlusion of the right coronary artery. ST-segment elevation in lead V4R was not seen either in 29 of 36 patients with a distal occlusion of the right coronary artery or in all patients with an occlusion of the left circumflex artery. Recording of lead V4R within 10 hours after onset of acute inferior wall MI can give information rapidly about the vessel responsible for MI.(ABSTRACT TRUNCATED AT 250 WORDS)     

Precordial ST segment elevation in acute ischemia caused by right coronary artery occlusion.

The purpose of this study is to determine why precordial ST elevation (V1 lead) occurs during acute occlusion of the right coronary artery (RCA). Nineteen patients with vasospastic angina, in whom ergonovine administration into RCA provoked spasms, were divided into 2 groups by precordial ST change during spasms. Group I (n = 6) had precordial ST elevation; group II (n = 13) had no precordial ST elevation. A subgroup, IIA was comprised 6 patients in group II with spasms in the RCA proximal segment (segment number less than 2 of AHA coronary classification). None had left coronary dominancy. There was no difference in collateral flow during spasms. Location of spasms in group I was in the RCA proximal segment, and was significantly more proximal compared to group II. There was no difference in sigma ST in II, III, aVF between group I and II or IIA. Max ST elevation time by which duration of ischemia was estimated was significantly longer in group I than in group IIA. Three patients in group I displayed precordial ST depression before elevation, in all of whom in sigma ST in II, III, aVF was higher during precordial ST elevation than during depression. During acute occlusion in the RCA proximal segment, precordial ST elevation is caused by ischemia of the right ventricular anterior wall. Furthermore, precordial ST elevation can occur in a patient with RCA dominance, even if ischemic injury in the left ventricular infero-posterior wall increases progressively.     

Clinical implications of precordial ST-segment elevation in acute inferoposterior myocardial infarction caused by proximal right coronary artery occlusion

BACKGROUND: The clinical significance of inferior wall acute myocardial infarction (MI) with combined ST-segment elevation in both anterior and inferior leads, compared with inferior leads alone, is unknown. HYPOTHESIS: Despite having more leads with precordial ST-segment elevation, these patients may have a better outcome due to less posterior involvement, which tends to drag down the precordial ST-segment. METHODS: A total of 158 postinferior MI patients with documented proximal right coronary artery occlusion were retrospectively studied. They were divided into three subgroups according to the magnitude of concurrent ST-segment deviation in lead V2: Group A (n = 19) had ST-segment elevation >/= 2.0 mm; Group B (n = 74) had ST-segment lay between + 2.0 mm and - 2.0 mm; and Group C (n = 65) had ST-segment depression >/= 2.0 mm. The clinical and electrocardiographic characteristics were then compared among these threes subgroups. RESULTS: The baseline demography, prevalence of risk factors, and treatment received were of no difference among the subgroups. However, Group A patients had significantly lower peak creatinine phosphokinase level and more preserved left ventricular function than Group B and C. Moreover, they had lower total sum of inferior ST-segment magnitude, less ST-segment depression in V4-6, and more ST-segment elevation in V(4R) than Group C. Group C patients had highest in-hospital and one-year mortality although it did not reach statistical significance. CONCLUSIONS: Precordial ST-segment elevation in inferior wall acute MI was associated with smaller infarct size and better left ventricular function, probably secondary to occlusion of a less dominant RCA, which did not result in a significant posterior infarction.     

Protective role of collaterals in patients with coronary artery occlusion

We reviewed the clinical, hemodynamic and angiographic data of 105 patients with right coronary artery occlusion and of 82 patients with left anterior descending coronary artery occlusion, subdivided into 3 groups by the presence and quality of collaterals to the occluded coronary (absent, poor or good collaterals). We found that patients with right coronary artery occlusion and good collaterals had a lower frequency of diaphragmatic myocardial infarction (60%) than patients with absent collaterals (100%) (P < 0.01). In addition, in patients with old diaphragmatic myocardial infarction, both poor and good collaterals were associated with a lower frequency of severe asynergy of the diaphragmatic left ventricular segments at left ventriculography (54% and 14%, respectively), compared to patients with no collaterals to the right coronary artery (92%, P < 0.02 vs. poor collaterals, P < 0.001 vs. good collaterals). In contrast, in patients with left anterior descending coronary artery occlusion, the presence of either poor or good collaterals to the left anterior descending coronary artery was not associated with a lower frequency of old anterior myocardial infarction, or, in patients with old anterior myocardial infarction, with a less severe asynergy of the anterior left ventricular segments.Our results suggest that collaterals are effective in protecting the diaphragmatic left ventricular wall in patients with right coronary artery occlusion, but not the anterior left ventricular wall in patients with left anterior descending coronary artery occlusion.     

Clinical significance of ST-segment elevation in lead V1 in patients with acute inferior wall Q-wave myocardial infarction

BACKGROUND: This study was designed to determine the clinical significance of ST-segment elevation in the precordial leads (leads V1 and V2) in acute Q-wave inferior wall myocardial infarction. METHODS AND RESULTS: One hundred fifty-eight consecutive patients with acute Q-wave inferior wall myocardial infarction were classified into 3 groups on the basis of the initial ST-change in V1 (group 1 = 29 patients with ST elevation, group 2 = 97 patients with ST depression, and group 3 = 32 patients with no ST-segment change). The right coronary artery was the infarct-related artery in all the patients in group 1. Although there was no significant difference between groups 1 and 2, the number of left ventricular asynergic segments was larger and the incidence of major in-hospital arrhythmias was higher in groups 1 and 2 compared with group 3. Patients in group 1 had a significantly higher incidence of proximal lesion (86%) and right ventricular infarction (69%) than the other 2 groups did. When ST elevation in leads V1 and V2 was considered, 14 of 15 patients (93%) with ST elevation only in V1 had right ventricular infarction, whereas 6 of 14 patients (43%) with ST elevation in both V1 and V2 had right ventricular infarction (P =.011). CONCLUSIONS: ST-segment elevation in V1 on admission in patients with acute Q-wave inferior wall myocardial infarction indicates a right coronary artery lesion associated with a larger infarct size and a higher incidence of major in-hospital arrhythmias.