Value of electrocardiogram in diagnosing right ventricular involvement in patients with an acute inferior wall myocardial infarction

To study the value of the electrocardiogram in diagnosing right ventricular involvement in acute inferior wall myocardial infarction, the electrocardiographic findings were analysed in 67 patients who had had scintigraphy to pin-point the infarct. All 67 patients were consecutively admitted because of an acute inferior wall infarction. A 12 lead electrocardiogram with four additional right precordial leads (V3R, V4R, V5R, and V6R) was routinely recorded on admission and every eight hours thereafter for three consecutive days. Thirty-six to 72 hours after the onset of chest pain a 99mtechnetium pyrophosphate scintigraphy and a dynamic flow study were performed to detect right ventricular involvement, which was found in 29 of the 67 patients (43%). ST segment elevation greater than or equal to 1 mm in leads V3R, V4R, V5R, and V6R is a reliable sign of right ventricular involvement. ST segment elevation greater than or equal to 1 mm in lead V4R was found to have the greatest sensitivity (93%) and predictive accuracy (93%). The diagnostic value of a QS pattern in lead V3R and V4R or ST elevation greater than or equal to 1 mm in lead V1 was much lower. ST segment elevation in the right precordial leads was short lived, having disappeared within 10 hours after the onset of chest pain in half of our patients with right ventricular involvement. When electrocardiograms are recorded in patients with an acute inferior wall infarction within 10 hours after the onset of chest pain, additional right ventricular infarction can easily be diagnosed by recording lead V4R.     

Risk factors, echocardiographic patterns, and outcomes in patients with acute ventricular septal rupture during myocardial infarction

Ventricular septal rupture (VSR), which can complicate an acute myocardial infarction (MI), carries a high mortality rate. Because precordial and transesophageal echocardiography can identify the type of rupture and assess right ventricular (RV) function at the patient's bedside, we examined the prognostic significance of echocardiographic patterns in postinfarct VSR by postulating that complex rupture and RV involvement carry a worse prognosis. Seventeen patients (10 men; mean age 66 years) who had confirmed postinfarct VSR underwent precordial and transesophageal echocardiography followed by coronary angiography. Serial 12-lead and right precordial leads were also available. Type of septal rupture was classified as simple or complex based on autopsy-proved echocardiographic criteria. Three patients had inferior wall MI and 14 had anterior wall MI. ST-segment elevation persisted >72 hours in all 3 patients who had inferior wall MI and in 12 who had anterior wall MI. Segmental wall motion abnormalities helped in detecting the left ventricular entry site, and use of unconventional views superimposed with color flow Doppler provided the RV exit site. RV function was better appreciated with transesophageal echocardiography. Two patients who had inferior wall MI and 7 who had anterior wall MI had complex ruptures. All 3 patients who had inferior wall MI and 7 who had anterior wall MI had electrocardiographic and echocardiographic evidence of RV involvement. Mortality rate was higher in patients who had complex rupture (78% vs 38%, p <0.001) and in those who had RV extension (71% vs 29%, p <0.001). In conclusion, persistent ST elevation is a common finding in patients who have postinfarct VSR. Complex VSR and RV involvement are significant determinants of clinical outcome.     

Value of electrocardiogram in diagnosing right ventricular involvement in patients with an acute inferior wall myocardial infarction.

To study the value of the electrocardiogram in diagnosing right ventricular involvement in acute inferior wall myocardial infarction, the electrocardiographic findings were analysed in 67 patients who had had scintigraphy to pin-point the infarct. All 67 patients were consecutively admitted because of an acute inferior wall infarction. A 12 lead electrocardiogram with four additional right precordial leads (V3R, V4R, V5R, and V6R) was routinely recorded on admission and every eight hours thereafter for three consecutive days. Thirty-six to 72 hours after the onset of chest pain a 99mtechnetium pyrophosphate scintigraphy and a dynamic flow study were performed to detect right ventricular involvement, which was found in 29 of the 67 patients (43%). ST segment elevation greater than or equal to 1 mm in leads V3R, V4R, V5R, and V6R is a reliable sign of right ventricular involvement. ST segment elevation greater than or equal to 1 mm in lead V4R was found to have the greatest sensitivity (93%) and predictive accuracy (93%). The diagnostic value of a QS pattern in lead V3R and V4R or ST elevation greater than or equal to 1 mm in lead V1 was much lower. ST segment elevation in the right precordial leads was short lived, having disappeared within 10 hours after the onset of chest pain in half of our patients with right ventricular involvement. When electrocardiograms are recorded in patients with an acute inferior wall infarction within 10 hours after the onset of chest pain, additional right ventricular infarction can easily be diagnosed by recording lead V4R.     

Early diagnosis of right ventricular or posterior infarction associated with inferior wall left ventricular acute myocardial infarction

Right ventricular (RV) or posterior infarction associated with inferior wall left ventricular acute myocardial infarction (AMI) has important therapeutic and prognostic implications. However, RV and posterior chest leads in addition to the 12-lead electrocardiogram are required for accurate detection. Body surface mapping (BSM) has greater spatial sampling and may further improve inferior wall AMI classification. Consecutive patients with chest pain lasting <12 hours were assessed to identify those with AMI and > or =0.1 mV ST elevation in > or =2 contiguous inferior leads of the 12-lead electrocardiogram (bundle branch block or left ventricular hypertrophy excluded). A 12-lead electrocardiogram, RV leads (V(2)R, V(4)R), posterior chest leads (V(7), V(9)), and a BSM were recorded. From each BSM, the 12 electrodes overlying the RV region (regional RV map) and 10 electrodes overlying the posterior wall (regional posterior map) were assessed for ST elevation. Infarct size was estimated by serial cardiac enzymes. AMI occurred in 173 of 479 patients. Of the 62 patients with inferior wall AMI, ST elevation > or =0.1 mV occurred in 26 patients (42 in V(2)R or V(4)R compared with 36 patients (58%) in > or =1 electrode on the regional RV map (p = 0.0019). ST elevation > or =0.1 mV occurred in 1 patient (2%) in V(7) or V(9) compared with 17 patients (27%) in > or =1 electrode on the regional posterior map (p = 0.00003). ST elevation > or =0.05 mV occurred in 6 patients (10%) in V(7) or V(9) compared with 22 patients (36%) in > or =1 electrode on the regional posterior map (p = 0.00003). Patients with ST elevation on regional RV and/or posterior maps had a trend toward larger infarct size (mean peak creatine kinase 1,789+/-226 vs. 1,546+/-392 mmol/L; p = NS). Thus, BSM, when compared with RV or posterior chest leads, provides improved classification of patients with inferior wall AMI and RV or posterior wall involvement.     

Right ventricular infarction: relationships between ST segment elevation in V4R and hemodynamic, scintigraphic, and echocardiographic findings in patients with acute inferior myocardial infarction

The relationship between ST segment elevation on the right precordial lead V4R and the hemodynamic, echocardiographic, and myocardial scintigrapic signs suggestive of right ventricular (RV) infarction was studied in 42 patients with acute inferior myocardial infarction. Twenty-two patients had ST segment elevation in V4R. Among these patients, a significant correlation was demonstrated between V4R ST segment elevation and the hemodynamic (p less than 0.001), scintigraphic (p less than 0.001), and echographic (p less than 0.02) criteria for acute RV infarction. These results support the validity of this new electrocardiographic sign as a practical means in aiding the clinical detection of RV involvement with acute transmural inferior myocardial infarction.     

Electrocardiographic diagnosis of right ventricular infarction

The electrocardiographic findings in 11 cases of acute right ventricular infarction associated with acute left ventricular inferior wall myocardial infarction are described. The diagnosis of right ventricular infarction was proved by autopsy findings in five cases and supported by hemodynamic data in the other six. Ten of the 11 patients had typical electrocardiographic changes of acute inferior myocardial infarction and one had that of inferior wall injury. Transient S-T segment elevation was present in one (lead V₁) or more of the right precordial leads in eight cases. In the absence of other explanations for the S-T segment elevation, acute right ventricular infarction was most likely the cause. Therefore, when acute inferior myocardial infarction is accompanied by S-T segment elevation in the right precordial leads, the coexistence of right ventricular infarction should be suspected. The sensitivity and specificity of this electrocardiographic sign are yet to be determined.     

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.     

Right ventricular infarction mimicking anterior infarction: A case report

Right ventricular infarction usually occurs in association with inferior infarction, with no remarkable electrocardiographic signs in conventional leads. This report describes a patient with a previous inferior acute myocardial infarction who developed right ventricular infarction with significant anterior lead ST segment elevation (V1-V4) caused by the loss of two large right ventricular branches during a coronary angioplasty of the right coronary artery. The case is discussed and the literature is reviewed.     

Diagnostic criteria for computer-aided electrocardiographic 15-lead system. Evaluation using 12 leads and Frank orthogonal leads with vector display.

The criteria for the diagnosis of myocardial infarction and ischaemic heart disease by an automated 15-lead computer-aided electrocardiographic system were examined using electrocardiograms of 543 patients. Errors in the electrocardiographic diagnosis were evaluated for each lead system (Frank orthogonal 3-lead, 12-lead, and hybrid 15-lead) using clinical and catheterization data for definitive diagnosis before review of the electrocardiograms and their reports. The effects of combinations of these diagnoses and additional ventricular conduction defects were also studied. Myocardial infarction and left ventricular hypertrophy were more reliably diagnosed using 3-lead and 12-lead systems together than with either system alone. The most sensitive criteria for anterior infarction were a Q/R ratio in Z less than 0-1 and loss of the first 20 ms of anterior forces in the horizontal and sagittal planes of the vectorcardiogram. However, false positive results were frequent, particularly in association with left ventricular hypertrophy, non-specific intraventricular conduction defects, and left bundle branch system block. Our V lead criteria were more specific whether or not these associated conditions were present. No single criterion with an acceptable false positive rate could be found to be sensitive for inferior infarction in all situations. Our most sensitive criteria were those based on the limb leads, and the presence of superior forces for the first 30 ms in the frontal plane of the vectorcardiogram, but these were better in combination. Limb lead criteria were the most specific. False positive results for inferior infarction were more frequent in the presence of left ventricular hypertrophy or ventricular conduction defects other than left anterior hemiblock. ST and T wave abnormalities were more apparent in the 12 leads than in the orthogonal leads. Specificity and sensitivity of criteria were poor, and specificity was decreased and sensitivity was not significantly improved by combining 3-lead with 12-lead criteria. Because of frequent measurement errors of ST, T, and also Q waves by the computer programme, in practice we have achieved increased sensitivity in the diagnosis of ischaemia and infarction with the combination of 3-lead and 12-lead systems. It is concluded that errors of diagnosis by a computer-aided system can be reduced by using multiple leads and that both 12-lead and orthogonal 3-lead systems are necessary for optimal computer diagnosis of left ventricular hypertrophy, myocardial infarction, and ischaemia.     

Right ventricular function in patients with first inferior myocardial infarction: assessment by tricuspid annular motion and tricuspid annular velocity

BACKGROUND: Unlike left ventricular function, right ventricular (RV) function has not been widely studied after a myocardial infarction (MI). The current study describes RV function determined by tricuspid annular motion and tricuspid annular velocity after MI. METHODS AND RESULTS: Thirty-eight patients with a first acute inferior MI were prospectively compared with 33 patients with a first anterior MI and 24 age-matched healthy individuals. Association of RV infarction in inferior MI was defined as the presence of >/=1-mm ST-segment elevation at the right precordial lead, V(4)R, of the electrocardiograms. From the echocardiographic apical 4-chamber views, the systolic motion of the tricuspid annulus was recorded at the RV free wall with the use of 2-dimensional guided M-mode recordings. Peak systolic and peak early and late diastolic velocities of the tricuspid annulus at the RV free wall also were recorded with the use of pulsed-wave Doppler tissue imaging. The tricuspid annular motion was reduced in inferior MI compared with that in healthy individuals (20.5 and 25 mm, P <.001). The peak systolic velocity of the tricuspid annulus was significantly reduced in inferior MI compared with that in healthy individuals (12 vs 14.5 cm/s, P <.001) and patients with anterior MI (12 and 14.5 cm/s, P <.001). Patients with inferior MI were divided into 2 subgroups: those with and those without electrocardiographic signs of RV infarction. The tricuspid annular motion was significantly lower in patients with RV infarction than in patients without RV infarction (17 and 22.7 mm, P <.001). In addition, compared with patients without electrocardiographic signs of RV infarction, patients with RV infarction also had a significantly decreased peak systolic tricuspid annular velocity (13.3 and 10.3 cm/s, P <.001) and peak early diastolic velocity (13 and 8.2 cm/s, P <.001). CONCLUSIONS: These results suggest that tricuspid annular motion and tricuspid annular velocity can be used to assess RV function in association with inferior MI.     

Right ventricular infarction caused by isolated right ventricular branch occlusion: a case report

It is rare to observe right ventricular infarction caused by isolated right ventricular branch occlusion. Isolated right ventricular infarction accounts for less than three percent of all cases of infarction. Generally, it is associated with occlusion of a non dominant right coronary artery or of a right ventricular branch. ECG can be misleading with ST segment elevation in anterior leads. We describe a patient admitted for chest pain with ST segment elevation in leads V1 to V3 associated with ST segment elevation in leads V3R and V4R. Coronary angiography demonstrated isolated total occlusion of the right ventricular branch. Thus, right precordial leads need to be done in every patient presenting with ST segment elevation in precordial leads V1 to V3 and not only in inferior myocardial infarction.     

ST segment elevation in anterior precordial leads and right ventricular infarction. Apropos of 6 cases]

ST segment elevation in the anterior precordial chest leads may be observed in some cases of right ventricular infarction alone or associated with left ventricular inferior wall infarction. Six out of 700 patients admitted to our Coronary Care Unit over a 2 year period had right ventricular infarction with these electrocardiographic changes. In three cases, isolated right ventricular infarction was due to occlusion of a right marginal artery (N = 2) or of a small right coronary artery (N = 1) which only vascularised the right ventricle. In 2 cases, right ventricular infarction was associated with a recent or chronic left ventricular inferior wall infarct. This type of ST segment elevation may suggest a left ventricular anterior wall infarct especially when there are no changes in the inferior leads, as was the case in our first patient. However, the dome-like appearance of the ST segment, the reduction in amplitude of ST elevation from V2 to V5, the progressive regression of the ST changes without the appearance of Q waves, are more suggestive of the diagnosis of right ventricular infarction. In addition, normal left ventricular dilatation on echocardiographic examination rapidly confirms the diagnosis.     

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.     

Distance correction for precordial electrocardiographic voltage in estimating left ventricular mass: an echocardiographic study.

This study was undertaken to assess both the relation between echocardiographic measurement of left ventricular (LV) mass and commonly used electrocardiographic criteria for LV hypertrophy and the effect of the distance from the center of LV mass to the anterior chest wall on precordial voltage. Echocardiograms and standard 12-lead electrocardiograms were obtained on 100 persons, ages 3 to 79. The correlation coefficients of echocardiographically determined LV mass with ECG precordial voltage (SV1 + RV5 or V6), the Estes point score system, and a VL4 wave voltage were .686, .721, and .531, respectively. Extrapolating from the dipole nature of the heart, the precrodial voltage was multiplied by the square of the chest wall to mid-LV distance to correct for the loss of energy across the distance from LV to recording electrode. Utilizing this correction, a much improved precordial voltage estimation of LV mass (r = .846) was obtained. We conclude that the distance of the center of LV mass from the chest wall influences the amplitude of recorded precordial voltage and that correction for this influence improved the correlation of precordial voltage with LV mass.     

Comparison of diagnostic accuracy, time dependency, and prognostic impact of abnormal Q waves, combined electrocardiographic criteria, and ST segment abnormalities in right ventricular infarction.

OBJECTIVE--To determine the diagnostic and prognostic impact of abnormal Q waves in comparison to or in combination with ST segment abnormalities in the right precordial and inferior leads as indicators of right ventricular infarction during the acute phase of inferior myocardial infarction. DESIGN--Prospective study of a consecutive series of 200 patients with acute inferior myocardial infarction with and without right ventricular infarction. SETTING--Department of internal medicine, university clinic. RESULTS--Right ventricular infarction was diagnosed in 106 (57%) out of 187 patients from the results of coronary angiography, technetium pyrophosphate scanning, and measurement of haemodynamic variables or at necropsy, or both. In the acute phase of inferior infarction ST segment elevation > or = 0.1 mV in any of the right precordial leads V4-6R was the most reliable criterion for right ventricular infarction (sensitivity, 89%; specificity, 83%). Abnormal Q waves in the right precordial leads, the most specific criterion (91%) for right ventricular infarction, were superior to ST segment elevation in patients admitted > 12 hours after the onset of symptoms. Both ST segment elevation in leads V4-6R (increase in in hospital mortality, 6.2-times; P < 0.001; major complications, 2.3-times; P < 0.01) and abnormal Q waves (2.3-times, P < 0.05; 1.8-times, P < 0.05) on admission were highly predictive of a worse outcome during the in hospital period. In the presence of inferior myocardial infarction previously proposed combined electrocardiographic criteria were not better diagnostically or prognostically than ST segment abnormalities and abnormal Q waves alone. CONCLUSIONS--During the first 24 hours of inferior myocardial infarction ST segment elevation and abnormal Q waves derived from the right precordial leads are complementary rather than competitive criteria for reliably diagnosing right ventricular infarction, both indicating a worse in hospital course for the patient. In this they are better than any other previously proposed combined electrocardiographic criteria in diagnosing right ventricular infarction. Right precordial leads should be routinely monitored in acute inferior myocardial infarction.     

Unusual electrocardiographic presentation of an isolated right ventricular myocardial infarction secondary to thrombotic occlusion of a non-dominant right coronary artery--a case report and brief review of literature

Isolated right ventricular infarction is an extremely rare phenomenon. Its electrocardiographic (ECG) features may be misinterpreted or even missed if not suspected. A case of an isolated right ventricular myocardial infarction is presented, recognized by ST-segment elevation in a single precordial lead, such as V1, aided thereafter by right precordial ECG changes. Immediate coronary angiography revealed proximal occlusion of a small non-dominant right coronary artery. Coronary intervention as well as infusion of intravenous normal saline solution and pressor agent for hypotension provided symptomatic relief, and subsequent recovery from this potentially life-threatening, but rare condition. Routine 12-lead ECG done approximately 12 hours after the admission showed extension of ST segment elevation from V1 trough V3 without any ST-segment elevation in inferior leads. This case demonstrates that there might be a very unusual ECG appearance in the setting of an isolated right ventricular myocardial infarction and can be missed if not immediately suspected. Isolated right ventricular myocardial infarction may be difficult to recognize, requiring both a high index of clinical suspicion for its presence, as well as careful evaluation of unusual ECG features of the disease entity.     

Implications of precordial ST segment depression during acute inferior myocardial infarction. Arteriographic and ventriculographic correlations during the acute phase.

Thirty two patients presenting with acute transmural inferior wall myocardial infarction underwent cardiac catheterisation and angiography within 12 hours of the onset symptoms. Twelve lead electrocardiograms performed within one hour of catheterisation showed ST segment depression in the anterior precordial leads in addition to inferior wall changes in 17 patients and no ST segment changes in the anterior leads in 15. When the clinical, arteriographic, and ventriculographic variables were compared between the two groups no significant differences were noted with regard to age, sex, risk factors for coronary disease, duration of symptoms before angiography, Killip class, number of inferior leads with ST segment elevation, or initial serum creatine kinase activity. The extent of coronary artery disease as well as the prevalence of severe disease in the left anterior descending artery were similar for both groups. Biplane left ventriculography showed no significant differences between the two groups with regard to global ejection fraction or to the prevalence of posterolateral or anterior segmental wall motion abnormalities.     

Isolated right ventricular infarction presenting as anterior wall myocardial infarction on electrocardiography

Isolated right ventricle infarction is extremely rare, and its electrocardiographic (ECG) signs may be misinterpreted or even missed, especially when a typical clinical picture is lacking. This paper describes a case of isolated right ventricle infarction, recognized only by echocardiography. The patient presented with ST-segment elevation in left precordial leads together with minimal ST-segment elevation in inferior leads on a 12-lead ECG. Angiography revealed the culprit right coronary artery, which was small and non-dominant. No significant obstructions were found in the left anterior descending artery. This case demonstrates that the ECG appearance of isolated right ventricle infarction may mimic anterior wall infarction and can be easily missed if not suspected.