Heart Rate Adjustment of ST Segment Depression as a Myocardial Ischemia Index of Coronary Artery Disease

BACKGROUND: Exercise testing is an importnat diagnostic and prognostic procedure in the assessment of patients with ischemic heart disease. But standard ST-segment depression criteria was not high enough to estimate coronary srtery disease. Recently, the heart rate adjustment of ST segment depression, ST segment/heart rate slope and index, have been proposed as a more accurate criteria for diagnosing significant coronary artery disease. The objective of this study was to compare the discriminating power of proposed ST segment/heart rate slope and index with that of a standard method of assessing exercise-induced ST segment depression for estimating coronary artery disease. METHODS: Sixty nine patients with ischemic heart disease were studied with exercise treadmill testing and coronary angiography. Computer-measured ST-segment amplitudes were obtained and analysis of the heart rate-adjusted ST segment depression(ST/HR slope and big up tri, Delta ST/HR index) was done. The sensitivity, specificity, and extent of coronary artery disease on each criteria were compared. RESULTS: 1) The sensitivity of big up tri, Delta ST/HR index partition of 1.6uV/beats/min was slightly higher(83%) and the specificity of ST/HR slope partition of 2.4uV/beats/min was higher(87%) than the standard exercise electrocardiographic criteria. 2) Early onset of ischemic ST-segment depression, profound ST-segment depression(> or =2mm), and downsloping ST-segment were associated with more extensive coronary artery disease. 3) On ST/HR slope, no CAD was 1.7+/-0.26uV/beats/min, one vessel disease was 2.6+/-0.34 uV/beats/min, two vessel disease was 2.7+/-1.36uV/beats/min, one vessel disease was 2.8+/-0.35uV/beats/min, and on big up tri, Delta ST/HR index, no CAD was 1.8+/-0.38uV/beats/min, one vessel disease was 2.8+/-1.36uV/beats/min, two vessel disease 3.4+/-1.44uV/beats/min, and three vessel disease was 3.7+/-2.95uV/beats/min. The increment of ST/HR slope and big up tri, Delta ST/HR index were associated with the coronary artery disease and its severity, but the correlations were not high enough. CONCLUSION: The heart rate adjustment of ST segment depression was not high enough for improved detection of coronary artery disease, compared with standard ST-segment depression criteria. But these indexes can be improved the clinical usefulness of the treadmill exercise test for coronary aretry disease.

Significance of ST Changes after Urokinase Administration in Acute Myocardial Infarction

BACKGROUND: The effects of intravenous thrombolytic therapy depend on maintaining the patency of infarct-related artery in acute myocardial infarction. Thirty-two patients with acute myocardial infarction and ST segment elevation were studied to determine the usefulness of early resolution of ST segment elevation as an index of recanalization after intravenous urokinase administration. METHOD: 32 patients(male 24, female 8, mean age+/-standard deviation 62+/-11 years) were given intravenous urokinase therapy for acute myocardial infarction. Patients were classified into two groups according to changes of Summation operator ST segment elevation : early resolution(group I)=resolution to or =25% of peak value. The relationship between early changes in Summation operator ST segment elevation, time to peak creatinine kinase(CK), peak CK, changes of QRS score and & stenosis of infarct-related artery were investigated in both group. RESULTS: 1) The Summation operator ST segment elevation decreased by more than 75% of initial Summation operator ST within 12 hours after urokinase administration in 13 patients(40.6%). 2) The initial Summation operator ST segment was higher in the early resolution group than in the nonresolution group(26.0+/-4.2 vs 15.2+/-1.9mm, p<0.05). 3) The initial QRS score in both groups were not different significantly(7.2+/-0.9 vs 5.4+/-0.6 p<0.05), but QRS score decreased in the early resolution group and did not change in the no resolution group(-0.69+/-0.23 vs 0.63+/-0.16, p<0.05). 4) The early resolution group showed higher peak CK level(2409.2+/-347.7 vs 1445.2+/-280.4, p<0.05) and earlier peak time(10.6+/-1.0 vs 24.2+/-4.6, p<0.05). 5) There was no total occluded artery in both group, but the early resolution group tended to less stenosis in infarct related arteries(66.7+/-80 vs 86.7+/-3.3%, p=0.13) in predischarge coronary angiography. CONCLUSIONS: Early ST resolution after intravenous urokinase administration in acute myocardial infarction is an useful clinical index of recanalization or benefit induced by thrombolytic therapy.

The Effect of Left Ventricualr Mass on the Transmitral Blood Flow

Measurements of mitral flow velocity by pulsed Doppler echocardiography are very useful in evaluating left ventricular diastolic filling properties. In hypertensive patients, abnormalities of diastolic function may precede systolic abnormalities and may serve as a more sensitive marker of end organ damage. We estimated left ventricular nass by 2-D echo short axis area-length method and compared with peak mitral flow velocity in early diastole(PFVE)and during atrial systolic(PFVA). There was a significant increase of LV mass and LV mass indices in the hypertensive patients and PFVE/PFVA ratio was decreased in them. Aithough there was no relationship between blood pressure and PFVE/PFVA ratio, a significant relationship was demonstrated between LV mass index and PFVE/PFVA ratio in the hypertensive patients.

Significance of QRS Scoring System in the Acute Myocardial Infarction

Early and longterm prognosis depended on the extents of acute myocardial infarction and residual myocardial function. Many clinical methods have been evaluated to determine their ability to estimate the size of myocardial infarcts. But because of many disadvantages simplified QRS scoring system, used with standard 12-lead EKG, was developed, which is noninvasive, inexpensive and easily releatible. Therefore, the correlation between QRS and peak CK,killip classification were evaluated in 55 patients with initial acute myocardial infarction at the Chung-Ang University, Yong-San and Pil-Dong Hospital during the period from January 1983 to December, 1986. The results were as follows : 1) The average QRS score of the anterior wall infarction is 7.1 and that of the inferior wall infarction is 4.5 and there is a statistical significance(p<0.01). 2) In the acute myocardial infarction, the correlation coefficeient between the QRS score and the killip classification is 0.66(p<0.05). 3) In the acute myocardial infarction, the average QRS score is 6.3 and the correlation coefficient between the leak CK and the QRS score is 0.52(p<0.05). 4) In the anterior wall infarction, the average QRS score is 7.1 and the correlation coefficient between the peak Ck and QRS score is 0.48(p<0.05). 5) In the inferior wall infarction, the average QRS score is a 4.5 and the correlation coefficient between the leak CK and QRS score is 0.79(p<0.05).

Clinical Study of Atrial Fibrillation

Clinical study was done on 119 patients with atrial fibrillation in the aspect of underlying diseases, particulary. The results were as follow : 1) In the underlying diseases of atrial finbrillation, rheumatic heart disease, hepertension and ischemic heart disease were common, which occupied 27.8%, 22.7% and and 15.1%, respectly. No apparent underlying disease was found in 21.0%, but in the transient atrial fibrillation, no apparent underlying disease in 42.9%. 2) There were no significant correlations between the ventricular rate, amplitude of f wave and underlying diseases of atrial fibrillation. 3) Complications were found in 29.4% of all cases, such as congestive heart failure(22.7%), embolism(6.7%). Otherwise, atrial fibrillation without underying cardiovascular diseases, congestive heart failure was found only(7.7%).

Clinical Implications of Echocardiographic Findings in Bacterial Endocarditis

42 patients with the clinical evidences of endocarditis were examined by echocardiography. In 28 of 42 cases(66.7%) vegetation was present, whereas in 14(33.3%) vegetation was not visualized. Alpha-hemolytic streptococcus was the most common infecting organism(47.6%) and rheumatic heart disease was the most common predisposing heart disease(47.6%). Patients with echocardiographically demonstrable vegetation had a higher incidence of congestive heart failure compared to the patients without vegetation(75.0% vs. 21.4% p<0.05). But major embolism was not significantly different in the two groups. Mortality was higher in the patients with vegetation than in the patients without it(39.3% vs. 0%, p<0.05). Among vegetation positive patients, mortality was highest in aortic valve patients.(58.3%) So patietns with aortic valve vegetation should be regarded as high risk group and early surgical intervention should be considered if indicated. The causes of mortality were congestive heart failure(45.5%), cerebral embolism(36.4%), myocardial infarction(9.1%) and ventricular tachycardia(9.1%) in decreasing frequency.

A Case of Combined Double Chambered Right Ventricle and Discrete Subaortic Stenosis

Combined double chambered right ventricle(DCRV) and discrete subaortic stenosis(DSAS) is a rare entity on which only 12 cases have been reported in the literature. We presented a case of combined DCRV and DSAS in an 18 year old girl. She had type II(thin membranous type) DSAS and the peak systolic prssure gradient between aorta and left ventricle was 38 mmHg. Aberrant muscle bundle was found on the right ventriculography and the pressure gradient in the right ventricle was 35 mmHg. She also had aortic regurgitation, persistent left sided superior vena cava and extracardiac malformations such as kyphoscoliosis and congenital cloacal anomaly.

A Case of Takayasu's Arteritis Associated with Aortic Regurgitation and Coronary Artery Involvement

Takayasu's arteritis is an arteritis of undetermined etiology, which affects the aorta and the proximal portions of its major branches. But aortic regurgitation and coronary artery involvement were unusual manifestations in this disease. We experienced a patient of Takayasu's arteritis who represented these unusual manifestations. Aortogram revealed grade IV aortic regurgitation and proximal segment narrowing of left main coronary artery. A case of Takayasu's arteritis associated with aortic regurgitation and left main coronary artery involvement is reported with a review of literatures.