Myocardial bridging of the left anterior descending coronary artery in acute inferior wall myocardial infarction

BACKGROUND

We observed marked myocardial bridging of the left anterior descending coronary artery (LAD) in the acute stages of inferior wall myocardial infarction (MI) in a group of patients who developed shock despite successful reperfusion of the infarct-related lesion (IRL).

HYPOTHESIS

The purpose of this study was to elucidate the clinical significance of myocardial bridging in patients with inferior wall MI and shock.

METHODS

The study group consisted of 53 patients with single-vessel disease of the right coronary artery, who underwent coronary angiography for acute inferior wall MI. Clinical characteristics, coronary angiographic findings, and left ventricular function during the chronic phase were compared between the patients who developed shock (the shock group) and those who did not (the non-shock group). In addition, a multiple logistic analysis was performed to identify independent predictors of shock in patients with acute inferior wall MI.

RESULTS

Reperfusion of the IRL was obtained in all 53 patients. The incidence of myocardial bridging of the LAD, the incidence of right ventricular MI, the peak creatine phosphokinase (CPK-MB). the pulmonary capillary wedge pressure, and the prevalence of pulmonary congestion seen on chest roentgenogram were significantly higher in the shock group than in the non-shock group. Myocardial bridging (p = 0.0018), right ventricular MI (p = 0.0374), and peak CPK-MB (p = 0.0189) were identified as independent predictors of shock in acute inferior wall MI.

CONCLUSION

This study suggests that myocardial bridging plays a role in left ventricular function in the acute stage of inferior wall MI.

Severity of residual stenosis of infarct-related lesion and left ventricular function after single-vessel anterior wall myocardial infarction: implication of ST-segment elevation in lead aVL of the admission electrocardiograms

BACKGROUND

The relationship between the severity of chronic-phase stenosis of infarct-related lesions (IRLs) and chronic left ventricular function in anterior acute myocardial infarctions (AMI) has not been adequately investigated.

HYPOTHESIS

This study investigated whether ST elevation in lead aVL of admission electrocardiogram (ECG) would be a determinant factor of the relationship between the severity of stenosis of the IRL and chronic left ventricular function after anterior wall AMI.

METHODS

One month after AMI, the IRL was evaluated by coronary angiography in 98 patients with anterior AMI, and left ventricular ejection fraction (LVEF) was determined using multigated radionuclide angiocardiography. Patients were classified according to the severity of the IRL: patients with 100% occlusion (Group O), patients with 90 to 99% stenosis (Group H), and patients with < or =75% stenosis (Group L). Patients with ST elevation > or =0.1 mV in the aVL lead on their admission ECG were included in the ST-elevation group, and those with ST elevation <0.1 mV were included in the non-ST-elevation group.

RESULTS

The LVEF was greater in the non-ST-elevation group than in the ST-elevation group (p<0.0001), and the LVEF in a whole group as follows: Group L LVEF>Group H LVEF>Group O LVEF (p = 0.0160). In the ST-elevation group, LVEF was higher in Group L than in the other groups (p = 0.0251). There were three independent predictors of a reduced LVEF: ST-elevation in aVL [odds ratio (OR): 3.38, p = 0.0044], IRL stenosis > or =90% (OR: 2.90, p = 0.0044), and the IRL occurring in the left anterior descending artery proximal to the first diagonal branch (OR: 6.31, p = 0.0024).

CONCLUSION

Left ventricular function was preserved, regardless of the severity of residual stenosis, in patients without ST elevation in aVL if the IRL was not totally occluded. In patients with ST elevation in aVL, LVEF was lower in patients with more severe stenosis, even if the IRL was patent.

Effect of the stenosis location and severity on left ventricular function after single-vessel anterior wall myocardial infarction

BACKGROUND

The purpose of the current study was to determine how the location of the infarct-related lesion (IRL) and the degree of stenosis during the acute and chronic phases of infarction might affect left ventricular (LV) function in patients with acute anterior wall myocardial infarction.

METHODS

Ninety consecutive patients with a first single-vessel anterior wall myocardial infarction (male/female ratio 75:15, mean age 60+/-9 years) underwent coronary angiography (CAG) immediately and 1 month after infarction. Patients were grouped according to IRL location (proximal [Coronary Artery Surgery Study (CASS) No. 12] or distal [CASS No. 13] to the first diagonal branch of the left anterior descending artery) and according to the severity of stenosis at 1 month (severe stenosis [IRL >75%] and mild stenosis [IRL < or =75%]). At the time of infarction and 1 month and 1 year after infarction, total wall motion index (TWMI), left ventricular end-diastolic dimension (LVDd), left ventricular end-systolic dimension (LVDs), and fractional shortening (FS) were determined.

RESULTS

TWMI was greater and FS was lower for CASS No. 12 lesions than for CASS No. 13 lesions. CASS No. 12 lesions were associated with a greater LVDd at 1 year and a greater LVDs throughout 1 year of observation. The patients with mild stenoses had significant improvements in TWMI and FS over time, whereas those with severe stenoses showed no improvement. Multivariate analysis showed that the independent factors predicting left ventricular function were IRL location at CASS No. 12, initial TIMI 0-1 flow in the IRL at emergency coronary artery graft, and the presence of a severe stenosis at 1 month.

CONCLUSIONS

In patients with severe stenoses at 1 month at CASS No. 12, left ventricular functional recovery is delayed and the left ventricular chamber is enlarged. In patients with CASS No. 13 lesions, left ventricular function is preserved well, regardless of the severity of residual stenosis.

Transition from classic aortic dissection to aortic intramural hemorrhage--a case report

A 64-year-old man was hospitalized with chief complaints of chest and back pain. A diagnosis of Stanford type A aortic dissection with a false lumen extending from the ascending to the descending aorta was made based on the results of computed tomography (CT). A CT obtained the following day showed resolution of the false lumen and increased brightness of the aortic wall, typical of aortic dissection with intramural hemorrhage. Although previous studies have described a gradual transition from aortic intramural hemorrhage to aortic dissection with a false lumen, there are no reports of the transition from an aortic dissection with a false lumen to the intramural hemorrhage type of aortic dissection. This patient is of interest when considering the pathogenesis of aortic dissection with intramural hemorrhage and the relationship between the intramural hemorrhage and false-lumen types of aortic dissection.

Cardiac rupture and admission electrocardiography in acute anterior myocardial infarction: implication of ST elevation in aVL

This study determines the usefulness of electrocardiography in the emergency room for assessing the risk of cardiac rupture after acute anterior myocardial infarction (MI). The presence of ST segment elevation on the admission 12-lead electrocardiography was evaluated in 325 consecutive anterior MI patients. A forward-stepwise logistic regression analysis for cardiac rupture was performed with the covariates of age, gender, hypertension, history of MI, reperfusion therapy by coronary angioplasty, and ST segment elevations in leads I, aVL, V1-V6. Cardiac rupture occurred in 16 patients, including 7 with left ventricular free wall rupture (FWR) and 9 with ventricular septal perforation (VSP). For FWR, ST elevation in lead aVL was the only independent predictor (odds ratio = 12.1, P = .0215). For VSP, female gender (odds ratio = 5.32, P = .0201) was the independent predictor. In conclusion, in patients with acute anterior MI, ST segment elevation in lead aVL on the admission electrocardiography is a significant risk factor for left ventricular FWR.

ST-segment elevation in leads I and aVL predicts short-term prognosis in acute anterior wall myocardial infarction

Our study demonstrates that ST-segment elevation in both leads I and aVL noted on admission for an anterior acute myocardial infarction does portend a worse short-term survival. Independent predictors of short-term prognosis in an anterior acute myocardial infarction include ST elevation in both leads I and aVL, advanced age, female gender, left ventricular failure, and malignant arrhythmias.

Sequential changes in cardiac structure and function in patients with Duchenne type muscular dystrophy: a two-dimensional echocardiographic study

BACKGROUND

Most patients with progressive muscular dystrophy of the Duchenne type (DMD) die of respiratory failure at approximately 20 years of age. However, some patients with DMD die of heart failure in relatively short periods of time. We investigated the long-term progression of cardiac impairment in patients with DMD by two-dimensional echocardiography.

METHODS

We monitored 74 patients for 4 years with two-dimensional echocardiography. Patients were classified into four groups according to the 8-grade Swinyard-Dever system. We also evaluated the echocardiographic features of 22 other patients with DMD with studies performed within 1 year before their deaths.

RESULTS

During the 4-year follow-up the left ventricle expanded, and regional left ventricular wall motion abnormalities developed in the posterior wall and apex. Almost all patients had myocardial dysfunction that progressed in parallel with their Swinyard-Dever stage. However, in a few patients who died of congestive heart failure, left ventricular dilation and circumferential left ventricular wall motion were severely impaired.

CONCLUSIONS

Myocardial impairment is accelerated in patients with DMD who died of heart failure. Two-dimensional echocardiography is a useful tool for the early diagnosis of left ventricular dysfunction and provides useful information for the treatment of patients with DMD.

ST-segment elevation in right precordial leads implies depressed right ventricular function after acute inferior myocardial infarction

BACKGROUND

The prognosis of acute inferior myocardial infarction is worse when it is complicated by right ventricular infarction. ST elevation in the right precordial leads is one of the reliable methods for detecting acute right ventricular infarction. The purpose of the study was to examine the relation between ST elevation in the right precordial electrocardiographic leads during acute inferior infarction and the severity of right ventricular systolic dysfunction.

METHODS

This study analyzed the relation between ST elevation > or = 0.1 mV in V4R and the severity of right ventricular systolic dysfunction in 43 consecutive patients (men/women: 35/8; average age 62+/-9 years) with acute inferior myocardial infarction with a rapid-response Swan-Ganz catheter to measure the right ventricular ejection fraction (RVEF).

RESULTS

RVEF was significantly lower in patients with ST elevation (n = 18) than in those without (n = 25) (33%+/-6% vs 40%+/-9%, p = 0.010). If the infarct-related lesion was located in the proximal right coronary artery, RVEF tended to be lower than if the lesion was located in the distal right coronary artery or the left circumflex coronary artery (33%+/-10% vs 37%+/-9% vs 42%+/-9%, p = 0.101). Logistic regression analysis demonstrated that ST elevation in V4R was the only independent predictor of depressed RVEF (odds ratio = 5.31, 95% confidence interval = 1.28 to 22.1, p = 0.022).

CONCLUSION

ST elevation in lead V4R during acute inferior myocardial infarction predicts right ventricular systolic dysfunction.

Asynergy of the noninfarcted left ventricular inferior wall in anterior wall acute myocardial infarction secondary to isolated occlusion of the left anterior descending artery

There are patients in whom left ventricular (LV) wall motion decreases in the noninfarcted region and LV systolic function declines globally despite the presence of a localized myocardial infarct attributable to narrowing or occlusion of a single coronary artery. This study examines angiographic characteristics of patients with chronic hypokinesia of noninfarcted myocardium after anterior wall acute myocardial infarction (AMI) due to narrowing of a single coronary artery, namely, the left anterior descending (LAD) artery. The LV ejection fraction, abnormalities in the motion of the noninfarcted LV inferior wall (SD/chord value by Sheehan's technique), the angiographic characteristics of the infarct-related coronary artery, the effect of acute reperfusion therapy, and presence of coronary risk factors were examined in 85 consecutive patients. The SD/chord value in the noninfarcted region showed a positive correlation with the LV ejection fraction (r = 0.505, p <0.0001). By multivariate analysis, hypertension (odds ratio = 0.53, 95% confidence interval [CI] 0.36 to 0.80), an infarct-related narrowing proximal to the origin of the first diagonal branch (odds ratio = 0.56, 95% CI 0.38 to 0.84), and patency of the infarct-related lesion during AMI (odds ratio = 1.56, 95% CI 1.03 to 2.30) were independent predictors of wall motion in the noninfarct region. In some patients with single-vessel anterior wall AMI, the motion of the noninfarcted inferior LV wall decreases during the chronic stage and cardiac function declines severely. In most of these patients, the infarct-related narrowing or occlusion is proximal to the origin of the first diagonal branch of the LAD artery.

Directed proximal magnetic resonance coronary angiography compared with conventional contrast coronary angiography

Magnetic resonance coronary angiography in 36 patients with proximal 1-vessel disease within 1 week of contrast coronary angiography was performed and the time required to complete the study was 13.4 +/- 4.2 min 13.2 +/- 8.1 minutes for the right and left coronary arteries, respectively. The sensitivity, specificity, positive and negative predictive values, and accuracy of magnetic resonance coronary angiography were 100% for right cronary artery disease, and 83%, 98%, 94%, 94%, and 94%, respectively, for left coronary artery disease.

Circadian rhythm and variability of heart rate in Duchenne-type progressive muscular dystrophy

Using 24-hour Holter monitoring and time domain and power spectral measurements, we evaluated the variability of the heart rate and its circadian rhythm in 55 male patients with Duchenne-type progressive muscular dystrophy (DMD) to characterize their autonomic function versus findings in 20 normal controls. Comparisons were also made in patients with mild, moderate, and severe stages of DMD. The percent difference between successive RR intervals that exceeded 50 ms, a measure of parasympathetic tone, was significantly lower even in patients with early stage of DMD than in controls (p < 0.01). This trend became marked with disease progression. Power in the high-frequency (HF) range (0.15 to 0.40 Hz), a measure of parasympathetic tone, was lower (p < 0.01), and the ratio of the power in the low-frequency (LF) range (0.04 to 0.15 Hz) and that of HF range (LF/HF ratio), a measure of sympathetic tone, was higher in DMD patients versus controls (p < 0.01). This trend was also marked with disease progression. Patients with mild or moderate disease had a slight circadian alteration in HF and LF/HF ratio. Patients with severe disease had virtually no circadian rhythm in HF. Their LF/HF ratio was higher at night (p < 0.01), lower in the morning (p < 0.01), and still lower during the day (p < 0.01), the opposite of control findings. The autonomic abnormalities in DMD were thus characterized by a significant increase in sympathetic activity and a significant decrease in parasympathetic activity. Thus, heart rate variability and circadian rhythm were useful in assessing autonomic dysfunction in DMD.