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Cardiopulmonary measurements in dogs undergoing gastropexy without gastrectomy for correction of gastric dilatation-volvulus.

OBJECTIVE: To measure cardiopulmonary variables, including cardiac index, in dogs with naturally acquired gastric dilatation-volvulus (GDV). DESIGN: Prospective clinical study. ANIMALS: 6 dogs with GDV. PROCEDURE: In addition to typical medical and surgical management of GDV, the dorsal metatarsal and pulmonary arteries and right atrium of the dogs were catheterized to obtain cardiopulmonary measurements before and during anesthesia and surgery. RESULTS: All dogs underwent gastropexy but none required gastrectomy. Mean cardiac index and mean arterial blood pressure for this small population of dogs with GDV were not significantly different from those reported for clinically normal awake or anesthetized dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs with naturally acquired GDV without gastric necrosis may not have the classic characteristics, including decreased cardiac index and hypotension, of hypovolemic circulatory shock.

Animals↗

[Comparative value of 24-hour ECG monitoring and standardized maneuvers in the detection and exploration of cardiac autonomic neuropathy in diabetics].

24-hour continuous electrocardiographic ECG monitoring and standardized tests were performed to detect cardiac autonomic neuropathy in diabetic patients. Thirty-eight patients, with a mean duration of diabetes of 10 years, twenty-five IDDM and thirteen NIDDM, and thirty-two controls, with no illness or treatment which could alter the heart rate (HR), were studied. Five standardized tests were performed. Three tests investigated parasympathetic function: variations of HR during Valsalva manoeuvre, deep breathing and standing. The other two tests investigated sympathetic function: detection of orthostatic hypotension and blood pressure response to sustained handgrip. Parasympathetic HR control was impaired in twenty-nine patients, together with impaired sympathetic cardiovascular control in seven. According to the 6 indices studied, 24-hour ECG monitoring detected abnormalities in only eight patients. Mean minimum 24-hour HR and mean sleeping HR were elevated in the group of patients whose five standardized tests were normal and in the group of patients with impairment of both parasympathetic and sympathetic cardiovascular control, but not in the group of patients with only impaired parasympathetic HR control. This study suggests that 24-hour ECG monitoring is a less sensitive test of cardiac autonomic neuropathy than standardized tests. Moreover, it shows HR abnormalities that are not specific to cardiac autonomic neuropathy.

Adult↗

[Cardiopulmonary exercise test for evaluating cardiac reserve in chronic congestive heart failure].

To evaluate whether maximal oxygen consumption (VO2 max) measured by cardiopulmonary exercise test (CAR-PET) reflects cardiac reserve in patients with congestive heart failure (CHF), supine bicycle CAR-PET and exercise hemodynamic measurements were performed simultaneously in 12 patients with CHF of NYHA II-IV. With increasing workload, VO2 and cardiac output elevated gradually, then plateaued, demonstrating that patients with CHF could reach VO2max. According to VO2max, patients were divided into 4 classes: including 2 patients of class A (VO2max: 24.5 +/- 2.29 ml.min-1/kg, mean +/- s mean), 3 of B (17.6 +/- 1.37 ml.min-1/kg), 5 of C (13.6 +/- 0.66 ml.min-1/kg) and 2 of D (6.5 +/- 1.64 ml.min-1/kg). Maximal cardiac indices were 8.79 +/- 2.35 L.min-1/m2 in class A, 5.82 +/- 0.97 L.min-1/m2 in B, 3.53 +/- 0.95 L.min-1/m2 in C and 2.21 +/- 1.56 L.min-1/m2 in D. No significant correlation between supine resting hemodynamic parameters and VO2max/kg was found, suggesting that exercise tolerance could not be predicted by the measurement of resting cardiac performance. Furthermore, VO2max correlated poorly with NYHA classification in these patients. However, cardiac output correlated linearly with VO2 during exercise, suggesting that VO2 max/kg is a good predictor for cardiac reserve in CHF(CI = 0.6809 +/- 0.2748 VO2/kg, n = 40, r = 0.84, P < 0.0001; CO = 1.1618 +/- 7.9065 VO2, n = 40, r = 0.84, P < 0.0001). The results also showed that VO2max/kg did not correlate with the changes of pulmonary capillary wedge pressure (PCWP), indicating that exercise tolerance in CHF depends more on cardiac output than on ventilatory consequence of pulmonary congestion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Diagnostic techniques in cardiac disorders: Part II.

Advances in technology over the past 15 years have given birth to a new field of multidisciplinary cardiovascular care and research, that of perinatal cardiology. Today's neonatal nurse must become familiar with the battery of tools that may be enlisted to assist in the assessment, diagnosis, intervention, and evaluation of cardiac disorders and therapeutic maneuvers in the neonate. In the first part of this two-part article, the standard initial examination of the history and physical, the chest x-ray, and the electrocardiogram were reviewed. This second part discusses the role of both invasive and noninvasive "high-tech" diagnostic techniques commonly used in today's management of neonatal cardiac disease.

Angiocardiography↗

Effects of in vivo gene transfer of fibroblast growth factor-2 on cardiac function and collateral vessel formation in the microembolized rabbit heart.

The effects of gene transfer of the secreted form of fibroblast growth factor-2 (FGF-2) were tested using an adenovirus vector in the microembolized rabbit heart. Japanese white rabbits underwent an intracoronary injection of 25-microm microspheres followed by recombinant adenovirus vectors encoding a secreted form of FGF-2 (FGF group), LacZ (LacZ group), or saline (saline group). Left ventricular (LV) systolic function was serially assessed by echocardiography. Vascular density was measured at 14 days with Azan and CD31 staining. The development of collateral vessels was assessed by measuring myocardial blood flow before and after the occlusion of the left anterior descending coronary artery. Percent fractional shortening (%FS) decreased after the microembolization, and improved gradually for 14 days in the FGF group only (41+/-1% (FGF) vs 32+/-1% (LacZ), 31+/-1% (saline), p<0.01). The vascular density and myocardial collateral blood flow were significantly higher in the FGF group in comparison with other groups. Transcoronary arterial gene transfer of the secreted form of FGF-2 was beneficial for the recovery of LV systolic function and development of collateral vessels in the microembolized rabbit heart.

Animals↗

Evaluation of left ventricular performance in coronary heart disease: use of isometric handgrip stress test.

The usefulness of isometric handgrip exercise in the assessment of left ventricular function was studied in 27 patients, all of whom had angiographically documented coronary artery disease. The effect of extensiveness of coronary disease and presence or absence of collaterals (both delineated by coronary arteriography) on the response to handgrip stress was also evaluated. Of 11 patients with a normal handgrip response, 4 exhibited a normal left ventriculogram and 7 were abnormal. Of these 7, 6 had inferior hypokinesis. Conversely, of 16 patients with an abnormal response to handgrip, 15 had abnormal ventriculograms. Of these, 9 had anterior akinesis. Of patients with a normal handgrip response 82% had two- or three-vessel coronary disease, and 94% with an abnormal response exhibited two- or three-vessel obstruction. There was no observed correlation between the presence or absence of collaterals and the response to handgrip. This study indicates that (1) handgrip stress, when combined with left ventriculography, often yields important additional information regarding the effect of localized contraction abnormalities on overall left ventricular performance; (2) the extent of coronary obstructive disease or the presence of collaterals per se do not appear to be the primary determinants of left ventricular performance; (3) it is possible that the location as well as severity and extent of left ventricular contraction abnormality may play an important role in determining overall left ventricular performance.

Adult↗

A database obtained from in vitro function testing of mechanical heart valves.

The in vitro function of the CarboMedics, Medtronic Hall, Omniscience, Starr-Edwards, St. Jude and Sorin (formerly Shiley) Monostrut heart valves have been compared using a pulsatile flow model left heart and load system. A wide range of flows and heart rates were used. The above valves in all sizes and in both aortic and mitral positions were tested. Results for transvalvular pressure, regurgitation and effective orifice area are presented. The small size St. Jude valves showed the least transvalvular pressure and largest effective orifice area. For large valves, the least regurgitation was exhibited by the Starr-Edwards valve. The data provides a reference for the range of normal performance that can be expected of mechanical prosthetic heart valves.

Aortic Valve↗

Beneficial effect of long-term PGE1-treatment in left ventricular heart failure.

Five male patients aged 34-47 years with congestive heart failure showed an improvement of left ventricular ejection fraction (LVEF) at rather low PGE1-doses (10-30 ng/kg/min) without affecting blood pressure or heart rate. LVEF was estimated by means of radionuclide ventriculography (RNV) prior to and during i.v.-infusion of PGE1 at increasing dose rates (10-100 ng/kg/min). Therefore, we administered to these responders PGE1 at a rate of 20 ng/kg/min i.v. continuously on a long-term basis by means of a portable infusion pump. Until up to 4 months the remarkable benefit in LVEF induced by PGE1 was still present to a comparable extent in all the patients. No rebound desensitization phenomenon occurred either on platelet activity or on LVEF. PGE1, via a more practical route of application or by a stable analogue, may be a promising therapy at this stage of cardiomyopathy (CMP).

Adult↗

Increased high-frequency heart rate variability during insulin-induced hypoglycaemia in healthy humans.

Despite causing sympathetic activation, prolonged hypoglycaemia produces little change in HR (heart rate) in healthy young adults. One explanation could be concurrent parasympathetic activation, resulting in unchanged net effects of autonomic influences. In the present study, hypoglycaemic (2.7 mmol/l) and normoglycaemic (4.7 mmol/l) hyperinsulinaemic clamp studies were performed after normoglycaemic baseline clamp periods with 15 healthy volunteers (seven male; mean age, 27 years) on two occasions in a randomized single-blind cross-over design. Non-invasive indices of cardiac autonomic activity and hormones were measured at baseline and 1 h after the beginning of hypoglycaemia or control normoglycaemia. Plasma insulin levels and mean HR were similar during both conditions. During hypoglycaemia, there was a 485% increase in plasma adrenaline (epinephrine). A shortening of the pre-ejection period by 45% suggested strong sympathetic cardiac activation. High-frequency (0.15-0.45 Hz) HRV (HR variability) increased, indicating a concomitant increase in parasympathetic tone. Thus, during hypoglycaemia-induced sympathetic cardiac activation in healthy adults, parasympathetic mechanisms are involved in stabilizing mean HR.

Adult↗