Shinichi Okubo

Relation of phasic coronary flow velocity profile to clinical and hemodynamic characteristics of patients with aortic valve disease.

BACKGROUND Our objective was to assess phasic coronary blood flow and velocity characteristics of the proximal portion of the left anterior descending artery and to evaluate their relation to the clinical and hemodynamic manifestations in patients with aortic valve disease. METHODS AND RESULTS We examined 26 patients with chronic aortic regurgitation (AR), 12 patients with predominant aortic stenosis (AS), and 11 control subjects using an intravascular Doppler catheter with spectral analysis. Angiographic assessment of AR identified 10 patients with mild regurgitation and 16 with severe regurgitation. The resting systolic coronary flow velocity-time integral (VTI) was significantly higher and the diastolic VTI was slightly but significantly higher in patients with severe regurgitation than in those with mild regurgitation (11.8 +/- 4.2 vs 4.1 +/- 1.1 cm, P < .001; 18.5 +/- 5.8 vs 13.2 +/- 3.2 cm, P < .05) and control subjects (4.0 +/- 1.0 cm, P < .001 and 13.3 +/- 3.6 cm, P < .05), respectively. Patients with AS had a slightly lower resting systolic VTI (3.8 +/- 1.4 cm) and a higher diastolic VTI (14.6 +/- 3.7 cm) than control subjects. Resting coronary blood flow was greater in patients with aortic valve disease than in control subjects. There was a significant correlation between the ratio of the resting systolic to diastolic VTI (S/D ratio) and the ratio of the aortic systolic to diastolic pressure (r = .75, P < .001) in patients with AR. The S/D ratio was inversely correlated with left ventricular systolic pressure (r = -.92, P < .001) and positively correlated with the ratio of the aortic systolic to diastolic pressure (r = .68, P < .05) in patients with AS. CONCLUSIONS Our results indicate that hemodynamic changes related to aortic valve disease contribute to alterations in the resting phasic coronary blood flow and velocity profiles observed in these patients.

Effects of heart rate on phasic coronary blood flow pattern and flow reserve in patients with normal coronary arteries : a study with an intravascular Doppler catheter and spectral analysis

To assess the effects of pacing-induced tachycardia on phasic coronary blood flow pattern and flow reserve of left anterior descending artery, we examined 16 patients with chest pain and angiographically normal coronary arteries by using an intravascular Doppler catheter with spectral analysis of the velocity signal. The heart rate was increased from a mean of 68 +/- 11 beats/min during sinus rhythm to 100 beats/min and again to 120 beats/min. Cross-sectional area of the epicardial artery and resting systolic and diastolic coronary blood flows increased progressively, resulting in an elevation of total coronary flow from 142 +/- 54 ml/min during sinus rhythm to 190 +/- 66 ml/min at 100 beats/min (p < 0.05) and to 219 +/- 69 ml/min at 120 beats/min (p < 0.01). During maximal hyperemia with intracoronary injection of 10 to 12 mg of papaverine, there was an increase in the systolic coronary blood flow with a decrease in the diastolic flow, resulting in no significant change in the total flow. These alterations led to progressive reductions in coronary flow reserve from 3.9 +/- 0.7 during sinus rhythm to 2.9 +/- 0.9 at 100 beats/min (p < 0.01) and to 2.3 +/- 0.3 at 120 beats/min (p < 0.001). Thus careful consideration should be given to the effects of heart rate when phasic coronary blood flow pattern and flow reserve are assessed.

Early identification of amyloid heart disease by technetium-99m-pyrophosphate scintigraphy: A study with familial amyloid polyneuropathy

To determine whether technetium-99m-pyrophosphate (Tc-99m-PYP) scanning or two-dimensional echocardiography can detect amyloid heart disease in an earlier stage of familial amyloid polyneuropathy, 15 patients were examined. Although 10 of the 15 patients had no clinical evidence of congestive heart failure, as well as normal ventricular wall thickness and normal values for left ventricular systolic function, five (50%) of them showed mild or moderate myocardial uptake. On the other hand, none had characteristic highly refractile myocardial echoes on the two-dimensional echocardiographic images (p less than 0.01), and values for diastolic function were reduced in four of the five and normal in the remaining one. In 85 control subjects, diffuse positive pyrophosphate scans of the heart were found in four (5%) of them (three with dilated cardiomyopathy and one with sarcoidosis), and highly refractile granular sparkling echoes were observed in nine (11%) (five with hypertrophic cardiomyopathy, three with aortic stenosis, and one with hypereosinophilic syndrome). We conclude that Tc-99m-PYP scanning is a more sensitive and specific method and may have the potential ability to detect amyloid heart disease in the earlier stage of familial amyloid polyneuropathy than two-dimensional echocardiography.

Radionuclide angiographic assessment of left ventricular diastolic filling in amyloid heart disease: A study of patients with familial amyloid polyneuropathy

To assess left ventricular diastolic filling in amyloid heart disease, 17 patients with familial amyloid polyneuropathy and 20 normal subjects were examined by radionuclide angiography. None of the patients showed clinical evidence of restrictive cardiomyopathy. All but two patients had normal left ventricular ejection fraction. Peak filling rate was significantly lower and time to peak filling rate was significantly greater in patients than in normal subjects (2.60 +/- 0.52 versus 3.10 +/- 0.44 EDV/s, p less than 0.001, and 215 +/- 53 versus 147 +/- 18 ms, p less than 0.001, respectively). The mean left ventricular filling volume during rapid diastolic filling and atrial systole in patients was 54.5 +/- 19.5% and 44.2 +/- 21.6% of the stroke volume, respectively, compared with 83.8 +/- 6.6% (p less than 0.001) and 20.0 +/- 6.0% (p less than 0.001), respectively, in normal subjects. Although 10 of the 14 patients without clinical evidence of overt heart disease had normal ventricular wall thickness as well as normal ejection fraction, 8 of the 10 showed abnormal diastolic filling. In patients with familial amyloid polyneuropathy, indexes of diastolic filling were significantly related to ventricular wall thickness alone. The incidence and magnitude of abnormalities in time to peak filling rate and contribution of rapid filling as well as atrial systole to ventricular filling increased with age and duration of illness. Thus, abnormal diastolic filling can be seen even in the early stage of familial amyloid polyneuropathy and may be related to myocardial amyloid deposition as well as to fibrosis. Careful consideration should be given to age and duration of illness when diastolic filling is assessed in this disorder.

New tetrapolar circuit method using magnetic field for measurement of local impedance change in biological substances

A tetrapolar circuit and method using a magnetic field is proposed for measuring the local electric impedance change in living tissue. On the basis of this method, the authors designed an apparatus that can detect impedance changes in two closely situated parts of living tissue, simultaneously and independently. Using this apparatus, they showed the effectiveness of the proposed method by an in vitro experiment and by an in vivo measurement of pulsatile waveforms in the forearm arteries. The detection sensitivity for a local impedance change was confirmed to be higher than that of the conventional tetrapolar method. Pulsatile impedance waveforms measured in the radial and the ulnar parts of the forearm were consistent with those estimated from the anatomical structure.<<ETX>>

Estimation of pulmonary hypertension by perfusion lung scintigraphy: gravitational effect of postural changes between the lateral decubitus positions.

To estimate pulmonary hypertension in patients with various heart diseases, we devised a new method using perfuison lung scintigraphy with technetium-99m-labelled macroaggregated albumin. In this method, changes in the distribution of pulmonary perfusion caused by gravitational effects, namely, changes in the total count ratios of the right lung against the left lung between right and left lateral decubitus positions (rt/lt), were assessed in 62 patients and in 10 normal subjects. The rt/lt ratios were calculated as indices of the above changes. They correlated significantly with mean pulmonary arterial pressure (mPAP) (γ= −0.62,P < 0.001), pulmonary capillary wedge pressure (γ = −0.63,P < 0.001) and pulmonary arteriolar resistance (γ = 0.50,P < 0.001) in all subjects. In 17 patients with valvular heart diseases, the ratio correlated significantly with mPAP (γ = − 0.84,P < 0.001). In 10 patients with various heart diseases, the U/S ratio, i.e. the index of changes in the count ratios of the upper field against the lower field for the right lung following postural change from the upright to the supine position, was also obtained as well as the rt/lt ratio. The latter evidenced a better correlation with mPAP (γ = −0.90,P < 0.001) than the former (γ=−0.64,P < 0.05). We conclude that this method is valuable as a noninvasive approach for the estimation of pulmonary hypertension.

Comparison of patients with single, double and triple coronary arterial spasm

Abstract It is generally accepted that coronary arterial spasm plays an important role in ischemic heart disease. Some investigators described a case report showing spontaneous 3-vessel coronary vasospasm. 1 The other pointed out that multivessel coronary vasospasm is not rare. 2 The purpose of this report is to compare patients with 1-, 2- and 3-vessel coronary arterial spasm without significant organic stenosis and to elucidate the clinical characteristics and risk factors of them.

Development of High-Grade Ventricular Arrhythmias in Familial Amyloid Polyneuropathy

To determine which subsets of patients with amyloid heart disease are particularly susceptible to the development of clinically significant ventricular arrhythmias, 16 patients with familial amyloid polyneuropathy (FAP) were studied by serial 24-hour electrocardiographic monitorings and echocardiography. During a mean follow-up period of 26.6 months, seven patients (44%) developed repetitive premature ventricular complexes (PVCs), including ventricular couplets in four and ventricular tachycardia in three. One of them showed syncope at the time when the arrhythmia was identified. Although there were no significant differences in the mean age, duration of the illness before the beginning of the study, and the initial echocardiographic results, the mean follow-up periods were more prolonged and neurologic disabilities were more advanced in patients with repetitive PVCs compared with those without any significant arrhythmias. In addition, patients who developed repetitive PVCs showed significantly greater percent changes in ventricular wall thickness with resultant wall hypertrophy than those who did not. One of the three patients who died within one year of the final study experienced sudden cardiac death and had showed frequent episodes of ventricular tachycardia at the final study. We conclude that (1) high-grade ventricular arrhythmias develop frequently in patients with FAP in the far-advanced stage in whom progressive and marked myocardial amyloid infiltration occurs and (2) identification of subsets of patients with repetitive PVCs may be helpful for the treatment as well as management of amyloid heart disease.

Noninvasive Evaluation of Left Ventricular Systolic and Diastolic Time Intervals in Familial Amyloid Polyneuropathy

To determine left ventricular (LV) systolic and diastolic properties in patients with familial amyloid polyneuropathy (FAP), we analyzed simultaneous recordings of the electrocardiogram, phonocardiogram, carotid arterial pulse, and apex cardiogram (ACG) in 13 patients and 20 normal subjects. The following variables were measured: (1) LV systolic time intervals = iso-volumic contraction time (ICT), corrected preejection period (PEPi), corrected ejection time (ETi), corrected Q-I interval (Q-Ii), corrected Q-II interval (Q-IIi), PEP/ET, and ICT/ETi; (2) 1EA-O interval (IIA-O) = the time interval from the onset of the aortic component of the second heart sound to the 0 point on the ACG; (3) ΔT = the time interval from the onset of the aortic component of the second heart sound to the point on the ACG down-stroke where the curve falls to 50% of the total height of the diastolic deflection; and (4) ΔT/IIA-O. Patients with FAP had significantly greater Q-Ii, PEPi, Q-IIi, and PEP/ET than normal subjects, whereas there were no differences in the ETi, ICT, and ICT/ETi. Patients with FAP also showed slightly greater IIA-O than normal subjects but the difference was not significant. In addition, AT and AT/IIA-0 were significantly greater in patients with FAP than in normal subjects. We conclude that in patients with FAP, LV relaxation is impaired, especialy in early diastole, whereas systolic function is generally preserved, and that electromechanical delay is markedly increased.

Impaired Left Ventricular Diastolic Properties in Patients with Familial Amyloid Polyneuropathy : A Study by Computerized M-Mode Echocardiography

To determine left ventricular (LV) diastolic properties in patients with familial amyloid polyneuropathy (FAP), we examined 17 patients by means of computerized M-mode echocardiography and compared the results with 25 normal subjects. Patients with FAP showed a significantly lower peak rate of diastolic LV internal dimension (dD/dt) as well as a lower peak rate of diastolic thinning of the LV posterior wall (dW/dt) than normal subjects, whereas LV systolic parameters, including cardiac index, ejection fraction, and ejection time, were nearly identical. Furthermore, although eight of the 17 patients had normal LV posterior wall thickness, they had a significantly lower dD/dt, as well as a lower dW/dt, than normal subjects. We conclude that in patients with FAP LV diastolic properties are changed, whereas systolic function is almost preserved, and diastolic abnormalities can be seen even in the absence of LV hypertrophy.