The Effectiveness for Vagal Stimulation by Ice Water Application to Face during Controlled Respiration and Mechanism of Individual Variability of Responsiveness to Vagal Stimulation (Power Spectral Analysis of Heart Rate Variability)

BACKGROUND: The effectiveness for vagal stimulation by ice water aplication to face during metronome-controlled respiration of 15 breaths/minute was examed. The importance of basal vagal tone and sympathovagal interaction in the individual variability of responsiveness to the vagal stimulation was investigated. METHOD: Fifty three 12~13 year old healthy volunteers were included. Vagal tone and sympathovagal interaction before and after application of ice water to the face were assessed by power spectral analysis of RR interval(heart rate) variability. RESULT: Basal heart rate, high frequency power, and low to high frequency power ratio were 81+/-13(58~110 beats/min), 791+/-1061(56~4161 msec2) and 1.08+/-1.22(0.04~4.85) during controlled respiration. After ice water application twenty three children developed 5 more nodal escape beats due to severe bradycardia. Minimum heart rate, high frequency power and low to high power ratio changed to 42+/-12(19~72/min), 1890+/-1882(221~7258msec2) and 0.64+/-0.43(0.12~1.46). The increased ratio of high frequency power, maximum heart rate decrement and its percent after stimulation were 5.44+/-5.62(0.63~24.26), 39+/-14(10~81/min) and 47+/-15(16~81%) respectively. The increased ratio of high frequency power was correlated with basal logarithmic high frequency power(r=-0.60, p=0.0004). Maximum heart rate decrement was correlated with basal logarithmic high frequency power(r=-0.41, p=0.0018) and low to high frequency power ratio(r=0.27, p=0.04). CONCLUSION: Application of ice water to the face during controlled respiration produces powerful vagal stimulation and bradycardia, however, there is a wide individual variability of responsiveness to it. The absolute basal vagal tone contribute to this individual variability.

(99m)Tc-MIBI SPECT Findings in Diabetics with Coronary Artery Disease

BACKGROUND: Evaluation of coronary artery disease(CAD) by radionuclide myocardial perfusion scintigraphy is safe, convenient and informative for diagnosis of CAD & assessment of functional significance of stenotic lesions. We tried to evaluate the characteristics of CAD in dibetics by intravenous dipyridamloe (99m)Tc-MIBI(methoxy isobutyl isonitrile) SPECT(Single Photon Emission Computed Tomography). METHOD: (99m)Tc-MIBI SPECT and coronary arteriography(CAG) were performed simultaneously in less than 2 week interval in 41 diabetics(diabetic group) and 103 non-diabetics(non-diabetic group) with clinical suspicion of CAD. The sensitivity and specificity of (99m)Tc-MIBI SPECT for detection of CAD were compared between two groups. The site and number of involved vessels, the extent of perfusion defect and redistribution pattern were compared between two groups. RESULT: 1) The sensitivity and specificity of (99m)Tc-MIBI SPECT for detection of CAD were 97% and 80% in diabetics, these were comparable to those in non-diabetics(97% and 78%). 2) Three vessel disease were common(p<0.01)in diabetics(SPECT 28.1%, CAG 32.3%) than in non-diabetics(SPECT 11.4%, CAG 7.5%). Distal lesions were also more common(p<0.005) in diabetics(CAG 40.3%) than in non-diabetics(CAG 15.7%). 3) On stress SPECT, the extent of perfusion defect was not different in individual vessel areas between diabetics and non-diabetics. However the perfusion defect of left ventricle as a whole was significantly higher(p<0.05) in diabetics(35.2+/-16.2%) than in non-diabetics(26.4+/-15.5%). 4) On rest SPECT, the percent redistribution was significantly lower in diabetics than in non-diabetics(left anterior descending artery area ; diabetic group 31.1+/-22.5% vs non-diabetic group ; 49+/-28.5%, p<0.05, left ventricle as a whole ; diabetic group 30.6+/-21.2% vs non-diabetic group 48.2+/-27.6%, p<0.02). CONCLUSION: Quantitative (99m)Tc-MIBI SPECT provided high sensitivity and specificity for detection of CAD in diabetics. Multiple vessel disease, distal lesion and fixed lesions were more common in diabetics than in non-diabetics, (99m)Tc-MIBI SPECT is useful noninvasive test for diagnosis of CAD & important prognostic implications.

The Novel Low Frequency Oscillation in Pulmonary Artery Pressure

BACKGROUND: It is well known that systemic blood pressure oscillates with low(0.04~0.1Hz), mid(0.1~0.15Hz), and high(respiratory) frequency range. But there has been no study about oscillation of pulmonary artery pressure(PAP). METHOD: We measured PAP for 5 minutes in 32 patients of ventricular septal defect and stored them to computer files. Power spectral density curve was obtained. Low, mid, respiratory frequency power were measured by integrating the area within each frequency range below the power density curve. RESULT: The incidence of significant low frequency power(more than 5% of total power) were higher in patients of high PAP and hign Rp/Rs than those of low PAP and Rp/Rs(p<0.01 and p<0.005 respectively). The low frequency power positively correlates with PAP and Rp/Rs(r=0.62, p<0.0005 and r=0.61, p=0.0005 respectively). CONCLUSION: It can be said conclusively that as PAP and pulmonary vascular resistance elevates, the PAP tends to definitively oscillate in low frequency range.

The Onset of Coronary Artery Aneurysm and Changes of T Cell Subsets and the Effect of High Dose Gammaglobulin Therapy in Mucocutanenous Lymph Node Syndrome

We studied the onset of coronary artery aneurysm formation in 42 patients of Mucocutaneous lymph node syndrome (MCLS), the serial changes of T cell subsets, and serum immunoglobulin levels including lgG, lgA, lgM, in 13 patients among them during acute (before high dose gamma-globulin therapy ) and subacute phase (after gamma-globulin therapy) to evaluate the role of the immunoregulatory abnormalities in coronary artery aneurysm formation. The following results are obtainded : 1) The coronary artery aneurysm was found in 16 patients (38%). They were detected in between 6th and 13th day of illness with the mean of 8.8+/-2.1 day. 2) The total T lymphocyte (T1), helper T lymphocyte (T4), and helper/supperessor ratio (T4/T8) decreased during acute phase. 3) Following gamma-globulin therapy it showed a increase in T4,T8, and all immunoglobulines. Above results showed that the most of aneurysms developed during acute phase and suppressed, rather than enhanced, T cell function significantly contributed to aneurysm formation, whereas high dose gamma-globulin retarded or reversed this suppression which would be one of mechanism of beneficial effort of gamma-globulin in MCLS.

A Study of Individual Variation of Responsiveness to Vagal Stimulation in Children (Nonspectral Analysis)

BACKGROUND: It is well known that there is wide individual variation of responsiveness when parasympathetic nervous system is stimulated physiologically, pathologically, and therapeutically. But no appropriate explanation is present for that yet. So the purpose of this study is to verify individual diversity of vagal tone during resting state and after vagal stimulation and to find factor that may significantly contribute to it. METHOD: We serially measured variation of heart period(VHP : sec) which had been known to be an accurate index of cardiac parasympathetic tone during resting state(VHPb) and after vagal stimulation by ice water application to face(VHPv). And we analyzed correlation between VHPb, VHPv and ratio of VHPv to VHPb(ratio). RESULT: There was wide variation of vagal tone both in resting state (VHPb : 0.025-0.161) and after vagal stimulation (VHPv : 0.087-0.661). VHPb could be classified into 3 groups according to stem and leaf distribution(group A : VHPb could be classified into 3 groups according to stem and leaf distribution(group A : VHPb0.1). The low VHPb group A showed dramatic increase in vagal tone after vagal stimulation (ratio 2.21-20.24 mean 7.7), on the other hand high VHPb group C did not (ratio 0.80-2.55 mean 1.39). There ws also a significant negative correlation between VHPb and ratio (r=0.69, p<0.001). CONCLUSION: These results suggest that there is wide individual diversity of responsiveness to vagal stimulation and magnitude of vagal tone in resting state is an important factor to determine the responsiveness to vagal stimulation.

Office Blood Pressure is Higher than Home Blood Pressure, and Digital Electronic Sphygmomanometer is Useful for Self-Monitoring of Blood Pressure in Hypertensive Patients

BACKGROUND: To investigate the possibie difference, if any, between office blood pressure(BP) and home BP may be important in the diagnosis and treatment of hypersensive patients. This report deails the difference between the two BP's and the usefulness of digital electronic sphygmomanometer(DES) for self-monitoring of home BP. METHODS: The BP's of 14 patients with essential hypertension were measured with mercury sphygmomanometers at outpatient department by physician and with DES at home(twice a day) by the patients. Patients were followed up every 2 weeks for 4 weeks and previous 2 weeks' average home BP's were compared with the office BP's of each 2 weeks' end. RESULTS: There was a significant difference between office and home BP(both systolic and diastolic) ; office average BP(151/95mmHg) was higher than home average BP(136/86mmHg). CONCLUSION: Caution may be needed in the interpretation of office BP unless it is measured several times after adequate rest.

Clinical Significance of Myocardial Perfusion Imaging Using Oral Dipyridamole Thallium-201 SPECT in Coronary Artery Disease

The clinical utility of thallium-201 SPECT combined dwith pharmacologic vasodilation induced by oral dipyridamole as an alternatiove to intravenous dipyridamole was incestigated in 21 patients who had concomitant coronary arteriography. Tomographic images were assessed visually. Sensitivity & specificity for overall detection of coronary artery disease were 93.7% and 80% respectively. Sensitivity & specificity for identification of indevidual diseased vessels were 84.6% and 87.5% for the left anterior descending artery, 75% and 84.6% for the right coronary artery, 60% and 100% for the left circumflex artery, respecitively. Of the 26 patients unergoing thallium scintigraphy 11 patients(42.3%) had some adverse effects between 20 and 50 minutes after oral dipyrdamole ingestion, including headache(26.9%), chest pain(26.9%), electrocardiographic changes(19.2%), and nausea(11.5%). Intravenous aminophylline was used to resolve these adverse effects in 8 patients & most of the adverse effects were subsided within 10 minutes. There was no ventricular arrhythmias, myocardial infarctions or deaths. In conclusion, oral dipyridamole thallium-201 SPECT is safe and accurate test for the overall detection of coranary artery disease and identification of disease in individual arteries. Furthermore it is useful for determining the necessities of coronary reperfusion and prognstically stratiofying the patients with coronary artery disease.

Assessment of Rapid Atrial Pacing in the Diagnosis of Coronary Artery Disease

The sensitivity and specificity of ST segment change on ECG for detection of coronary artery disease(CAD) by pacing stress test were assessed. Among 28 cases with chest pain(mean age 52, M/F : 21/7), 10 patients had normal coronary angiographic finding(Group I), and 18 had coronary artery disease(Group II). Pacing stress test showed high specificity(100%), but low sensitivity(61%) for the diagnosis of CAD. Especially in patients with 1 vessel disease, the sensitivity was only 50%, and positive results were not attained unless there was at least 90% or more stenosis in any of the major branches(LAD, RCA or LCX). But in patients with multivessel disease, the sensitivity was much higher(83%). Lateral(V4-6) or inferior leads(2, 3, aVF) showed ischemic ST segment depression most commonly. Therefore one of the inferior lead and V5 may be a minimum requirement for monitoring pacing-induced ST segment changes. Time constant during isovolumic relaxation showed statistically significant prolongation after pacing only in CAD patient group, suggesting pacing-induced impairment of early left ventricular relaxation.

Changes of Doppler Echocardiographic Findings After Mitral Valve Operation

Pulsed Doppler echocardiography was performed before and five to fifteen days (mean, 9.3 days) after mitral valve surgery to evaluate the change of pulmonary arterial pressure in 80 patients (29 males and 51 females) with mitral valve disease by preejection period (PEP)/acceleration time (AT) ratio at the right ventricular outflow tract. In 13 patients with pulmonary hypertension (mean pulmonary arterial pressure equal to or greater than 20mmHg), Doppler echocardiography was followed three to twelve months after operation. In 76 patients with a mitral valve prosthesis (15 patients with the Bjork-Shiley valve, 28 patients with the Ionescu-Shiley valve, and 33 patients with the St. Jude valve), mean transmitral pressure gradient and pressure-half time were estimated by continuous wave Doppler echocardiography five to fifteen days after operation. 1) PEP/AT Ratio by pulsed Doppler echocardiography correlated well with the mean pulmonary arterial pressure gradient by cardiac catheterization (r=0.83, p<0.001). 2) After mitral valve surgery, PEP/AT ratio decreased significantly (p<0.001). In group with mean pulmonary arterial pressure equal to or greater than 40mmHg, immmediate postoperative PEP/AT ratio was greater (P<0.05) than that in group with mean pulmonary arterial pressure less than 20 mmHg, but, difference between the preoperative and postoperative PEP/AT ratio was much greater (P<0.001) than that in group with mean pulmonary arterial pressure between 20 and 39 mmHg. 3) In 13 patients, on whom repeated Doppler echocardiography performed, PEP/AT ratio decreased immediately after mitral valve surgery (p<0.001). After then, it decreased further, but, the amount of the decrease was much smaller than immediate one (p<0.001). 4) There was no significant difference in postoperative PEP/AT ratio among the different prosthesis. Mean transmitral pressure gradient and pressure half-time of the Bjork-Shiley, Ionescu-Shiley, and St, jude valves were 3.1 mmhg and 67.3 msec, 2.9 mmHg and 65.3 msec, and 2.7 mmhg and 60.2 msec, repectively. The St.Jude valve had somewhat smaller mean transmitral pressure gradient and pressure half-time, but there was no statistical significance. In conclusion, elevated pulmonary arterial pressure in patients with mitral valve disease decreased greatly within 15 days after operation, and Doppler echocardiography was a useful method in the follow-up of prosthetic mitral valve function.

A Case of Pulmonary Vein Aneurysm Simulating Lung Tumor

A case of pulmonary vein aneurysm is presented. Chest X-ray revealed round density along the right cardiac border in right lower lung field. The round density was suspected as solid tumor initially, but the angiocardiogram showed dealyed opacification of right inferior pulmonary vein. So it was confirmed as pulmonary vein aneurysm. This patient took mitral valve replacement because of mitral and aortic regurgitation. Pulmonary vein aneurysm is considered as congenital in origin and pulmonary venous hypertension has its pathogenetic role in enlarging the varix. Pulmonary vein aneurysm probably has little clinical significance although cases of spontaneous rupture have been reported. There are a few reported cases in the literature, but the actual incidence probably is much higher than reported. This is the first to be reported in Korean literature.

Clinical Observation of Cardiac Myxoma

Cardiac myxoma is rare and has protean clinical manifestations mimicking various disease. Unless clinician has a high index of suspicion, the diagnosis can be easil missed. However diagnosis is all the more important since surgery can be dramatically successful, where as untreated myxoma invariably leads to death. Cardiac myxoma accounts for 50% of primary cardiac tumor and mainly originates in left atrium.(75%). The features of myxoma can be described under the three headings : Constitutional, obstructive, and embolic. From 1977 to 1985, the authors have experienced 30 cases of cardiac myxoma, one of which recurred. Of 29 patients, 8 were male and 21 were female. Their ages ranged from 11 to 55 years with average of 39.8 years. Constitutional manifestation was found in 25 of the 27 patients, obstructive manifestation in 27, and embolic phenomenon in 5. The diagnosis of myxoma was made on the basis of 2-D echocardiography. The sensitivity was 100%. Except 1 case who refused operation, all received surgical treatment. Immediate postoperative complication occurred in 6 patients(23%). Among them serious complication could be found only in 2 cases(7.7%). During long term follow up there was one recurrence and one patient with right ventricular myxoma has tricuspid regurgitation. In other cases, we could not found any problems.