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Prevalence of cardiovascular autonomic dysfunction assessed by spectral analysis, vector analysis, and standard tests of heart rate variation and blood pressure responses at various stages of diabetic neuropathy.

To establish a test battery for the detection and characterization of cardiovascular autonomic neuropathy (CADN) and to evaluate its prevalence, a number of autonomic function tests based on spectral analysis, vector analysis, and standard tests of heart rate variation and blood pressure responses were performed in 261 diabetic patients aged 11-76 years with various stages of peripheral neuropathy. The percentages of abnormal results in the individual tests based on heart rate variation were 6-31% in 115 patients without peripheral neuropathy, 16-45% in 61 patients with subclinical neuropathy, 22-59% in 73 patients with symptomatic peripheral neuropathy, and 67-100% in 12 patients with the latter in conjunction with autonomic symptoms (p < 0.05). The most frequently abnormal indices, each representing a different physiological basis, were the coefficient of variation, low-frequency and mid-frequency power spectrum at rest, mean circular resultant, postural change in systolic blood pressure, and, in particular, the max/min 30:15 ratio and Valsalva ratio. CADN, defined as the presence of > or = 3 abnormalities among these seven parameters was detected in none of 120 control subjects, 13.0% of the patients without peripheral neuropathy, 34.4% of those with subclinical neuropathy, 49.3% of those with symptomatic peripheral neuropathy, and in 100% of the subjects with the latter and concomitant autonomic symptoms (p < 0.05). The overall prevalence of CADN in 103 patients completing all parameters was 46.6%. The corresponding rate of CADN defined as > or = 2 abnormalities among the five tests included in an optimized version of the battery proposed by Ewing and Clarke was 38.8%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Left ventricular function during exercise before and after bypass surgery.

Biplane left ventricular cineangiograms and pressure measurements were performed in 44 patients with coronary heart disease at rest and during submaximal or symptom-limited supine bicycle exercise before and 7 +/- 3 months after bypass surgery. Revascularization was complete in 12 (group I) and incomplete in 32 patients (group II). Preoperative left ventricular ejection fraction (EF) was within normal limits at rest and declined similarly during exercise in both groups (group I from 59 to 51%, p less than 0.01; group II from 61 to 48%, p less than 0.001). Postoperative EF at rest was nearly identical to preoperative EF in both groups (group I, 65%; group II, 58%) and remained unchanged during exercise (group I, 63%; group II, 56%). Peak systolic pressure to end-systolic volume index ratio (LVSP/ESVI in mm Hg/ml . m-2) also decreased during exercise in both groups preoperatively (group I from 3.7 to 3.2, NS; group II from 3.4 to 2.6, p less than 0.005). Postoperative LVSP/ESVI at rest was again unchanged as compared to preoperative LVSP/ESVI. During exercise, however, it increased in both groups reaching higher values in patients of group I than of group II (5.1 versus 3.7, p less than 0.05). Whereas both parameters indicate an improvement in global left ventricular function following surgery, LVSP/ESVI even suggests a more sizable recovery of function in patients with complete as compared to those with incomplete revascularization.

Adult↗

Detecting abnormalities in left ventricular function during exercise before angina and ST-segment depression.

To determine if abnormalities in left ventricular function precede angina pectoris and electrocardiographic evidence of myocardial ischemia, we used radionuclide angiocardiography to measure left ventricular ejection fraction, volumes, cardiac output and wall motion in 10 normal subjects and 25 patients with coronary artery disease at rest and during two levels of upright bicylce exercise. In the patients with coronary artery disease, the first radionuclide study during exercise was performed before and the second after the onset of ST-segment depression. In all normal subjects, the ejection fraction increased more than 5%, the end-diastolic volume increased less than 25% and the end-systolic volume decreased from rest to both levels of exercise. Wall motion was normal at rest and increased with exercise. No patient with coronary artery disease had chest pain or ST-segment depression during the first level of exercise. The ejection fraction either decreased or increased less than 5% in 18 patients, the end-diastolic volume increased more than 25% in nine, the end-systolic volume increased in 19 and a segmental contraction abnormality developed in 14. Hemodynamic and wall motion abnormalities occurred in all patients during the second level of exercise when ST-segment depression was present. During exercise in patients with coronary artery disease, abnormalities in left ventricular function frequently develop before angina pectoris and electrocardiographic evidence of myocardial ischemia.

Adult↗

Video-assisted sympathectomy for essential hyperhidrosis: effects on cardiopulmonary function.

BACKGROUND: Essential hyperhidrosis is characterized by overactivity of the sympathetic fibers passing through the upper-dorsal ganglia (second and third thoracic ganglia [D2-D3]), and the treatment of choice is video-assisted thoracoscopy sympathectomy. Alterations in cardiopulmonary function after treatment have been reported. STUDY OBJECTIVE: To evaluate cardiopulmonary function impairment after sympathectomy in patients with essential hyperhidrosis. DESIGN AND SETTING: Prospective controlled trial at a pulmonary function unit of a university hospital. PATIENTS: Twenty patients (2 men and 18 women) with essential hyperhidrosis. MEASUREMENTS AND RESULTS: Pulmonary function tests, including spirometry and thoracic gas volume, bronchial challenge with methacholine, and maximal exercise, were performed before and 3 months after D2-D3 sympathectomy. Video-assisted sympathectomy was performed using a one-stage bilateral procedure with electrocoagulation of D2-D3 ganglia. Pulmonary function values (spirometrics and volumes) were not statistically different in the two groups. The maximal midexpiratory flow was the only variable that showed significant changes, from 101% (SD, 26%) to 92% (SD, 27%) [p < 0.05]. Ten patients had positive bronchial challenge test results that remained positive 3 months after surgery, and 2 patients whose challenge test results were negative before surgery became positive after sympathectomy. Significant reductions in maximal heart rate (HR) and oxygen and carbon dioxide uptakes were observed during the maximal exercise test. CONCLUSIONS: Video-assisted thoracoscopy is a safe treatment, and the observed modifications in cardiopulmonary function only suggest a minimal small airway alterations in the presence of positive bronchial hyperresponsiveness and mild sympathetic blockade in HR. The clinical importance of these findings is not significant.

Adolescent↗

Effects of digoxin on left ventricular function in coronary artery disease patients.

To assess whether digitalis modifies or prevents the deterioration of the left ventricular ejection fraction and wall motion during acute ischemia, we performed gated blood pool radionuclide ventriculograms in 15 patients with angiographically documented coronary artery disease. All patients were studied in the resting state and during maximal supine bicycle exercise, both before and 1 hour after 1 mg intravenous digoxin. There was no significant difference, pre-digoxin vs post-digoxin, in exercise tolerance (415 +/- 84 vs 418 +/- 107 seconds), number of segments with abnormal resting wall motion (12 vs 11) or exercise wall motion (21 vs 19). Ten patients developed angina during the same exercise load, irrespective of digoxin administration. Twelve patients had subnormal left ventricular ejection fraction during exercise pre-digoxin, vs 13 patients post-digoxin (P = ns). In the resting state, the left ventricular ejection fraction was higher after digoxin (53 +/- 14% pre vs 58 +/- 14% post, P less than 0.05). During exercise, however, the left ventricular ejection fraction was not significantly improved after digoxin (50 +/- 16% pre vs 53 +/- 17% post, P = ns). These data indicate that although acute administration of digoxin improves the resting left ventricular function, it does not improve exercise tolerance to angina. Furthermore, intravenous digoxin does not appear to prevent the deterioration of left ventricular wall motion and ejection fraction during exercise induced ischemia.

Blood Pressure↗

[The cardiovascular reflex tests in autonomic cardiac neuropathy diagnosis].

Ewing's five standard cardiovascular reflex tests were used for the assessment of autonomic function. Changes in heart rate during deep inspiration and expiration, Valsalva manoeuvre or standing up evaluate parasympathetic innervation, whereas blood pressure fluctuations during standing up and handgrip evaluate sympathetic innervation. According to physiological principles we must remind that each test is useful predominantly but not exclusively to reveal the impairment of parasympathetic or sympathetic innervation. A total of 271 patients (247 with diabetes mellitus) were estimated for the diagnosis of autonomic neuropathy. Computed time domain analysis of the heart rate variability reveals 21% of the patients with autonomic neuropathy, but this method doesn't rich the performance of spectral analysis witch is x3 times greater. The deep inspiration and expiration remains the preferable test according to its sensibility, specificity and predictive value. I found that handgrip test has, beside the known limitations (arterial hypertension, heart failure, valvular disease, emphysema, advanced diabetic retinopathy, drugs like digitalis, beta-receptor blockers, antihypertensives, sedatives, etc.) one more linked by the hand muscular force. Orthostatic hypertension has too many false results so the interpretation must be done with much precaution.

Algorithms↗

[New method for estimating left ventricular myocardial elasticity by vibration analysis].

We solved numerical solutions of Advani-Lee's equation, which treats free vibrations of fluid-filled spherical shells, and forms the basis for non-invasive estimation of left ventricular myocardial elasticity. Numerical results showed that elasticity is approximated by E = 86.5.a2.f2 (E: elasticity (dyn/cm2), a: internal radius (cm), f: eigen-frequency (Hz)). To examine the accuracy of this theoretical equation in estimating elasticity, we made 7 spherical shells of silicone rubber, and compared the estimated elasticity by this equation with that by a standard stretch test. The elasticity calculated by Advani-Lee's equation and by stretch test proved to be nearly identical. Therefore, we concluded that we can estimate the elasticity of a spherical shell using this equation. We calculated the myocardial elasticity at the first heart sound emission in 25 normal persons with a simplified (approximated form of) Advani-Lee's equation. The mean elasticity in normal subjects was (7.04 +/- 2.46) x 10(5) dyn/cm2.

Elasticity↗

[Left ventricular function at rest and during dynamic load before and after aortocoronary bypass. Preliminary report].

17 patients with coronary artery disease were studied before and 10 +/- 3 months (mean +/- 1 SD) after aortocoronary bypass surgery. Left ventricular performance was analyzed at rest and in 12 cases during dynamic exercise (work load 59 +/- 22 watts) with tip manometer pressure measurements. The degree of coronary artery obstruction was estimated pre- and postoperatively by vascularization index (VaI). Patients were separated into 2 groups (group A: 8 patients with postoperatively improved VaI, and group B: 9 patients with unchanged or worsened VaI). Apart from a significant fall in LVEDP (p less than 0.025) in group A, there was no significant change in left ventricular dynamics in either group at rest, while a significant improvement in mean LVEDP (p less than 0.05), max dP/dt (p less than 0.05), Vpm (p less than 0.005) and Vmax (p less than 0.005) during dynamic exercise was observed in group A, but no significant change in these terms in group B, after surgery.

Coronary Artery Bypass↗