Determinants of exercise capacity in hypertrophic cardiomyopathy.

Exercise capacity in hypertrophic cardiomyopathy is thought to relate to elevated left atrial pressure as a consequence of impaired diastolic function, but this assumption has not previously been evaluated. Twenty-three patients with hypertrophic cardiomyopathy underwent hemodynamic assessment during symptom-limited maximal exercise with objective measurement of exercise capacity by respiratory gas analysis. Maximal oxygen consumption and anaerobic threshold were 28.1 +/- 7.5 and 21.5 +/- 6.1 ml/kg per min, respectively (the lower limit of reference range in our laboratory is 39 and 27 ml/kg per min, respectively). Maximal oxygen consumption was reduced in 11 of 13 patients who were in New York Heart Association functional class I and who denied limitation of exercise capacity and in all 10 patients who were in functional class II or III. Maximal oxygen consumption and anaerobic threshold were related to peak cardiac index (r = 0.650, p less than 0.001 and r = 0.459, p = 0.03, respectively) and to the increase in cardiac index on exercise (r = 0.677, p less than 0.001 and r = 0.509, p = 0.016, respectively), but not to cardiac index at rest, peak and rest pulmonary capillary wedge pressure, pulmonary capillary wedge pressure at an oxygen consumption of 15 ml/kg per min or the rise in pulmonary capillary wedge pressure on exercise. These findings are not consistent with the hypothesis that elevated left atrial pressure is the major determinant of exercise capacity in patients with hypertrophic cardiomyopathy and they suggest that, as in patients with chronic cardiac failure, other mechanisms should be considered.

Echocardiographic and histologic evaluation of the right ventricle in ventricular tachycardias of left bundle branch block morphology without overt cardiac abnormality.

The right ventricle was investigated by multiple biopsies and detailed echocardiographic evaluation, including measurement of cavity dimensions at the level of the inflow, body and outflow tract, in 27 patients with right ventricular tachycardia who had no clinical evidence of an underlying morphologic abnormality. Nine (33%) patients had abnormal biopsy results, with a quantifiable increase in interstitial fibrosis. Abnormal echocardiograms, defined as an increase in greater than or equal to 2 dimensions of the right ventricular cavity or wall motion abnormalities or both, were seen in 9 patients. There was a strong association between abnormal myocardial histologies and abnormal right ventricular echocardiograms (p less than 0.001). An abnormal echocardiogram was 94% specific and 80% sensitive for an abnormal biopsy. The findings of echocardiography and biopsy were correlated with the electrocardiographic features of the tachycardia. Evidence of right ventricular disease was seen in all 6 patients with superior frontal plane axis of clinical tachycardia as compared with 4 of 21 with inferior axis (p less than 0.001). Thus, 2-dimensional echocardiography is a sensitive means of diagnosing right ventricular disease in patients with nonischemic tachycardias of left bundle branch block morphology. A superior frontal plane axis of ventricular tachycardia in this group strongly suggests right ventricular disease, whereas an inferior frontal plane axis is frequently not associated with any morphologic or histologic abnormality of the right ventricle.

Congenital coronary arteriovenous fistula associated with dilated cardiomyopathy.

A 59-year-old housewife with heart failure was found to have dilated cardiomyopathy associated with bilateral coronary artery fistula to the pulmonary artery. Coexistence of coronary arteriovenous fistula and dilated cardiomyopathy has not been reported and seems to be a casual association.

Ring-calcification of coronary artery aneurysms in an adolescent.

A 17-year-old asymptomatic boy with a history of Kawasaki disease in infancy was found to have an abnormal ring-calcification as seen in the chest roentgenogram and the electrocardiographic evidence of anteroseptal myocardial infarction. Coronary angiogram revealed aneurysms associated with ring-calcifications in the right coronary artery and subtotal obstruction of the left anterior descending coronary artery. A plain chest roentgenogram may, at times, be useful for identifying coronary aneurysms in patients with a possible history of Kawasaki disease.

[Significance of diffuse slow washout in dipyridamole loading thallium-201 myocardial perfusion scintigraphy].

To assess the significance of diffuse slow washout (DSW) in dipyridamole loading thallium-201 myocardial perfusion scintigraphy, 382 patients were studied. DSW were observed in 69 (24%) of 285 patients with perfusion defects, 5 (5%) of 97 patients without perfusion defects. There was significant relation between DSW and perfusion defects (p less than 0.01). Coronary angiography showed multivessel disease in 84% single vessel disease in 12% of patients with DSW and multivessel disease in 28%, single vessel disease in 50% of patients without DSW. During a mean follow up period of 29 months, initial CABG or PTCA were done in 41%, cardiac death occurred in 12%, nonfatal cardiac events occurred in 7% of patients with DSW and perfusion defects. In patients without DSW, initial CABG or PTCA were done in 11%, cardiac death occurred in 7%, nonfatal cardiac events occurred in 5%. Patients without perfusion defects had good prognosis regardless of the presence or absence of DSW. In conclusion, DSW indicates serious cardiac ischemia in patients with perfusion defects. DSW does not indicate cardiac ischemia in patients without perfusion defects.

[Clinical significance of negative dipyridamole perfusion scintigram].

Six hundred seventy-one patients who had dipyridamole perfusion scintigraphy were classified into two groups; ie, 242 patients without perfusion defect (Group A) and 429 patients with perfusion defect (Group B). Clinical significance of negative scintigram was then assessed and correlated with coronary angiographic findings and prevalence of cardiac events. 1) Significant coronary artery disease (greater than 50% luminar narrowing) was present in 7 of 92 patients (8%) in Group A and in 235 of 285 patients (82%) in Group B. Multi-vessel coronary artery disease was found only in 2 patients (2%) in Group A and in 119 patients (42%) in Group B. 2) During a mean follow-up period of 29 months, 48 cardiac death (8%) and 19 nonfatal cardiac events (3%) occurred in 619 medically treated patients. These cardiac complications were observed in 7 of 242 patients (3%) in Group A and in 60 of 377 patients (16%) in Group B, including 4 (2%) and 44 (12%) cardiac deaths, respectively. In conclusion, it is rare to see severe organic coronary artery disease and future cardiac event in patients with negative dipyridamole perfusion scintigram. It may be, therefore, stated that it is unnecessary to perform coronary angiography in these patients, unless they have symptoms which cannot be controlled medically.

[Blood pressure and diastolic function in the elderly].

To evaluate the relation between blood pressure and diastolic function in the elderly, 28 apparently healthy volunteers underwent blood pressure measurements, echocardiographic examinations, and radionuclide angiography acquired in list mode. Casual blood pressure did not correlate with diastolic indices measured either by echocardiography or by a radionuclide method, except for peak filling rate during atrial contraction assessed by radionuclide angiography (r = 0.39, p < 0.05). Ambulatory blood pressure monitoring revealed significant correlations between peak filling rate during atrial contraction assessed by radionuclide angiography and blood pressure measured over 24 hours, while awake and during sleep. The time to peak filling rate and the velocity of early diastolic filling were found to correlate with blood pressure, but the best correlation was between blood pressure during sleep and peak filling rate during atrial contraction (r = 0.53, p < 0.005). These results show a direct relation between blood pressure and diastolic function in the elderly, which is stronger during sleep than during wakefulness.

[Clinical pictures and prognosis of mitral valve prolapse in the middle-aged and old-aged patients].

The age as an important factor influencing the prognosis of mitral valve prolapse (MVP) was assessed by comparing two age groups; 26 cases whose ages were younger than 49 years, and 27 cases more than 50 years. 1. The aged group had higher incidence of dyspnea and enlarged heart most probably due to insidious heart failure. 2. The aged group frequently had an apical pansystolic murmur and enlarged left atrium, indicating the progress of mitral regurgitation. These observations suggest that the careful follow-up observation is mandatory for patients with MVP of advanced age.

[Coronary artery disease detected noninvasively by dipyridamole-loading 201T1 myocardial scintigraphy in elderly patients].

To evaluate the usefulness in diagnosing coronary artery disease (CAD), dipyridamole-loading 201T1 myocardial scintigraphy was performed for 52 elderly patients (65-92 years, mean: 72 years), and the results were compared with data from the treadmill exercise tests. Thirty-five patients could not tolerate adequate exercise tests. Seven of them had reversible defects; six, fixed (irreversible) ones. Dipyridamole scintigraphy is therefore applicable in detecting CAD among patients with suspected CAD who are unable to perform adequate exercise tests. Four of 16 patients with positive exercise tests had no reversible defects; the exercise results in three were regarded as false positives. Seventeen patients experienced chest pain; 12 had ST depression during dipyridamole loading. There were no serious complications, but seven patients required aminophylline. We demonstrated previously that the sensitivity and specificity of dipyridamole scintigraphy in detecting CAD were 90% and 92%, respectively, in patients with chest pain undergoing coronary angiography. These results were superior to those of conventional exercise myocardial scintigraphy. Therefore, dipyridamole scintigraphy is regarded as a safe and useful method for detecting CAD, particularly in elderly patients who have ST and T wave abnormalities but cannot tolerate exercise test adequately.

[Accuracy of the Master's exercise test in detecting significant coronary artery disease].

To assess the significance and accuracy of noninvasive tests in detecting significant coronary artery disease (CAD; greater than 50% stenosis), the Master's exercise test, treadmill exercise test and dipyridamole-loading myocardial perfusion scintigraphy were performed and their results were compared with coronary angiographic findings in 60 patients with angina but without myocardial infarction. Among these, 27 patients had significant CAD. The Master's test performed in outpatient clinics had an 85% sensitivity and a 76% specificity in detecting significant CAD, when the degree of ST depression was equal to or exceeded 1 mm. The sensitivity further improved to 96% by adding chest pain to the criteria; then all patients with multivessel disease or critical ischemia were identified by the Master's test. Treadmill tests performed after admission had a 78% sensitivity and a 67% specificity. When the severity of ischemia was judged either by exercise capacity or the degree of ST depression or the coronary T wave, the treadmill test was superior to the Master's test. Although patients without significant CAD had longer exercise capacity and the higher maximum heart rate in the treadmill test than did those in the Master's test, these trends were similar but less marked in patients with significant CAD. Dipyridamole-loading myocardial perfusion scintigraphy showed an excellent sensitivity and specificity; 96% and 94%, respectively, in detecting significant CAD. It was particularly useful in distinguishing false positive exercise results due to left ventricular hypertrophy and coronary spasm and that in women, from true positive results. In conclusion, the Master's test is a simple and useful method for screening CAD in community hospitals and in outpatient clinics.

[Angina with long-standing coronary T waves].

The clinical significance of long-standing (greater than or equal to 24 hours) coronary T waves without abnormal Q waves was evaluated in 24 patients with angina. They were categorized in two groups; 11 with ST elevation followed by coronary T waves (Group A), and 13 with coronary T waves alone (Group B). 1. The patients had long-standing or repetitive episodes of rest angina, with clinical features of unstable angina in all but one. Fifty-five % of patients in Group A and 85% in Group B had histories of effort angina. 2. Significant (greater than or equal to twice the upper normal) elevation of serum CPK value was observed in 36% of patients in Group A and in 46% in Group B. There was no correlation between the maximum CPK value and the number of leads with the coronary T wave. 3. Coronary angiography demonstrated significant (greater than 50%) coronary artery stenosis in 27% of patients in Group A and in 77% in Group B. The incidence of severe stenosis was greater in Group B than in Group A. Angioplasty was performed in 9% of patients in Group A and in 38% in Group B. 4. During the average follow-up period of 27 months, there was one cardiac event (unstable angina) in Group A, two events (one sudden death and one unstable angina) in Group B. Each cardiac event occurred after the patients themselves discontinued their medications. This was not related to the severity of coronary artery stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)