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Biomedical subjects

H Nonogi

Publications and source records attributed to H Nonogi.

151 records · Page 9Linked to original sources
PubMed1982

Assessment of left ventricular function using an angiographic method.

Angiographic methods are by far the most frequently used for calculation of left ventricular volume, mass, forces acting within the ventricular wall or for analysis of contractile performance and diastolic property of the overall ventricle, as well as regional myocardial function in the presence of ischemia. A critical review of the theoretical basis and practical methods of calculation of these variables is presented. The left ventricular pressure-volume diagram is constructed which allows for an assessment of the inotropic state of the ventricle from the similar tension-length framework as obtained in the isolated papillary muscle. Computer technology of digital filtering and subtraction provides for an enhancement of the contrast of the ventricular image obtained with minimal doses of contrast medium. On-line methods for edge tracing and subsequent data processing are alleviating much of the tedious and laborious work of manual analysis of angiograms and accuracy of the calculation has been enhanced. Left ventriculography is most useful in diagnosing the presence of abnormal wall motion. Methods of assessing the magnitude and extent of the relative area of localized myocardial dysfunction are discussed. Quantitative information is crucial for evaluating prognosis and determining the application of therapeutic interventions.

Angiocardiography↗
PubMed1982

Effect of the vasodilator therapy in regurgitant valvular disease.

The hemodynamic response to afterload reduction by sodium nitroprusside was assessed in 5 patients with mitral regurgitation and in 7 with aortic regurgitation. The drug significantly lowered left ventricular systolic pressure, end-diastolic pressure and end-diastolic volume. In patients with mitral regurgitation, significant decreases in regurgitant volume (74 +/- 10 to 44 +/- 7 ml) and regurgitant fraction (60 +/- 4 to 41 +/- 5%) were associated with substantial increases in cardiac output (4.18 +/- 1.18 to 5.43 +/- 1.18 L/min) and forward stroke volume (49 +/- 10 to 64 +/- 9 ml). In patients with aortic regurgitation, vasodilator therapy was effective in increasing forward output only in 2 patients who had an initially elevated end-diastolic pressure which was reduced only to levels slightly above normal with nitroprusside. In patients with a lower level of end-diastolic pressure, further reduction in the filling pressure resulted in no benefit or rather a fall in forward stroke volume, despite a significant increase in pump function (ejection fraction being augmented from 55 +/- 4 to 61 +/- 5%). Experiments in dogs confirmed that nitroprusside reduced the amount of mitral regurgitation by virtue of diminishing the regurgitant orifice size, as a result of the reduction in size of the left heart chamber. These observations also support the concept that it is ultimately important to maintain filling pressure at an optimal level during administration of a vasodilating agent, otherwise effects due to afterload reduction tend to be offset.

Adult↗
PubMed1981

Automated method for left ventricular volume measurement by cineventriculography with minimal doses of contrast medium.

Cineventriculography is of considerable value in the dimensional analysis of the left ventricular cavity, but conventional methods necessitate injection of large amounts of contrast medium. In this study, small dose left ventriculography, using only 5 ml of dye, was performed in order to minimize the untoward effects of contrast medium. A computer-aided image processing system was also developed to enhance the contrast of the ventricular image by subtracting the reference image to eliminate irrelevant background. The boundary of the left ventricular cavity was automatically determined to calculate the instantaneous volume change throughout the cardiac cycle. With use of this small dose of dye, the elevation of left ventricular end-diastolic pressure that consistently occurred 1 to 3 minutes after injection of conventional large doses could be avoided. (End-diastolic pressure at 1 minute after dye injection averaged 11.8 +/- 4.9 [mean +/- standard deviation] for small dose and 19.1 +/- 6.1 mm Hg for large dose injection.) Values for end-diastolic volume, end-systolic volume and ejection fraction calculated from the two consecutive small and large dose left ventriculograms in 16 patients were similar. Thus, minimal doses of contrast medium permit accurate measurement of left ventricular dimension and function without significant hemodynamic derangement. The optimal projection for regional wall motion analysis can easily be selected by this method with repeated exposure at various degrees of obliquity. With this technique, even noninvasive measurement of left ventricular volume can be provided by intravenous injection of small doses of contrast agent.

Angiocardiography↗
PubMedDate not supplied

Intracoronary thrombolysis in evolving isolated right ventricular infarction.

In a 52-year-old man with severe chest pain of 3 hours duration and ST-segment elevation in leads V1 and V2, a nondominant right coronary artery was recanalized by an intracoronary infusion of urokinase. Coronary cineangiography revealed a total occlusion of the nondominant right coronary artery and no significant narrowing of the left coronary artery. Hemodynamic studies during the acute phase of myocardial infarction demonstrated an increase of right atrial mean pressure in association with normal pulmonary capillary wedge pressure. Following the recanalization, chest pain disappeared and hemodynamic alterations were corrected. The purpose of this report is to document a case of isolated right ventricular infarction due to a nondominant right coronary artery occlusion.

Coronary Disease↗
PubMedDate not supplied

Transient increase of plasma lipoprotein(a) in patients with unstable angina pectoris. Does lipoprotein(a) alter fibrinolysis?

It has been shown that lipoprotein(a) (Lp[a]) may interfere with the fibrinolytic system and that the Lp(a) level in an individual remains constant. To evaluate the effects of Lp(a) on the fibrinolytic system in patients with unstable angina, we measured plasma levels of Lp(a), the alpha 2-plasmin inhibitor-plasmin complex, and the thrombin-antithrombin III complex. The latter is a marker of thrombin generation, and the alpha 2-plasmin inhibitor-plasmin complex is an indicator of plasminogen activation. Venous plasma samples were taken from 18 patients with unstable angina and 18 patients with stable exertional angina who had been matched for clinical variables. On admission, plasma levels of Lp(a) were significantly higher in patients with unstable angina than in those with stable exertional angina (319 +/- 193 mg/l versus 191 +/- 141 mg/l, respectively; p less than 0.05). On admission, plasma levels of the alpha 2-plasmin inhibitor-plasmin complex and of the thrombin-antithrombin III complex were also significantly higher in patients with unstable angina than in those with stable exertional angina (0.78 +/- 0.42 micrograms/ml and 3.6 +/- 1.3 ng/ml versus 0.41 +/- 0.13 micrograms/ml and 1.9 +/- 0.5 ng/ml, respectively; p less than 0.01). In nine of the 18 patients with unstable angina, serial changes of plasma levels of Lp(a), the alpha 2-plasmin inhibitor-plasmin complex, the thrombin-antithrombin III complex, and the acute-phase proteins C-reactive protein and alpha 1-antitrypsin were examined for 3 weeks after admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Restenosis after percutaneous transluminal coronary angioplasty in patients with non-insulin-dependent diabetes mellitus (NIDDM).

BACKGROUND: The effect of glycemic control on the incidence of restenosis after percutaneous transluminal coronary angioplasty (PTCA) in non-insulin-dependent diabetes mellitus (NIDDM) has not been well analysed. METHODS: Out of 1282 consecutive patients who had undergone elective and successful PTCA over 8 years, 86 known to have NIDDM and 117 non-diabetic cases were analysed for restenosis following PTCA. Definition of restenosis is an increase from 50% to 75% diameter stenosis at the same lesion within 1 year after angioplasty. Those with familial hypercholesterolemia, renal failure, unstable angina pectoris, bypass graft surgery within 1 month were excluded. Blood pressure, body mass index, history of smoking, fasting blood glucose, post-prandial glucose, HbA1c, cholesterol, triglycerides, number of stenotic vessels, restenosis rate were studied - 6 months before PTCA and 1, 3, 6 and 12 months after PTCA. RESULTS: The frequency of restenosis within 1 year of PTCA was significantly greater in poorly controlled NIDDM (75%) than in well or moderately controlled NIDDM (30-40%) or non-diabetic subjects (33%). Multivariate analysis showed that the degree of control of diabetes was significantly correlated with restenosis. CONCLUSION: Restenosis following elective and successive PTCA was significantly more frequent in poorly controlled NIDDM compared with moderately or well-controlled NIDDM or non-diabetic subjects. Multivariate analysis also showed the significant correlation between restenosis and glycemic control. These findings indicate that control of diabetes plays an important role in reducing restenosis after PTCA.

Aged↗