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PubMed1985

Venoarterial bypass: a technique for spinal cord protection.

In the present study, we examined the effects of various levels of oxygen tension on spinal cord blood flow while using somatosensory evoked potentials to monitor spinal cord sensory function during hypoxia. In this experiment, six adult, mongrel dogs were heparinized and placed on right atrial-femoral artery bypass with an oxygenator in the bypass circuit. The aorta was cross-clamped proximal to the left subclavian artery, and bypass flow and fluid balance were adjusted so as to maintain a distal aortic perfusion pressure of greater than 80 mm Hg. Oxygen flow to the oxygenator was lowered by graded decrements to provide decreasing levels of oxygen tension, which ultimately approached pure venoarterial bypass. Each successive oxygen level was maintained for 30 minutes. Spinal cord blood flow was measured with radioactive microspheres, and latency and amplitude of somatosomatic evolved potentials were continuously monitored. The somatosensory evolved potential signal was invariably present as long as the distal aortic pressure was greater than 80 mm Hg; there were several transient hypotensive episodes (less than 5 minutes), which were accompanied by reversible loss of somatosensory evolved potentials. The spinal cord blood flow increased from 13.6 to 119.7 ml/100 gm/min as the distal oxygen tension fell to a mean value of 30 mm Hg, while latency of somatosensory evolved potentials increased 19.3% and amplitude decreased 43.3%. These results suggest the following conclusions: (1) In response to hypoxia, spinal cord blood flow dramatically increases and somatosensory evolved potentials deteriorate (increase in latency and decrease in amplitude). (2) However, during prolonged hypoxia, spinal cord sensory function can be maintained by sufficiently high flow rates and perfusion pressures. (3) Somatosensory evolved potentials can be used to monitor continuously spinal cord sensory function under these conditions.

Animals↗
PubMed1992

[Two-stage Jatene procedure after Mustard or Senning operation].

We have successfully performed a two-stage Jatene procedure in four patients who showed severe anatomical right ventricular dysfunction after atrial switch (Mustard or Senning) operation for transposition of the great arteries. All four patients developed an adequate left ventricular pressure for the arterial switch operation by one or two-stage pulmonary artery banding. Left ventricular posterior wall thickness increased sufficiently enough after the banding although left ventricular ejection fraction showed significant decrease. After Jatene procedure left ventricular ejection fraction recovered, and RV end-diastolic volume which had been prominently enlarged preoperatively was dramatically normalized. Cardiac index increased from 3.6 +/- 1.6 l/min/m2 preoperatively to 5.3 +/- 6.1 l/min/m2 postoperatively with the decrease in left atrial pressure. Postoperative electrophysiological study revealed the recovery of sinus node function and atrial conduction by means of the take-down of atrial switch operation previously performed. We conclude that the Jatene procedure should be an ideal alternative in patients with right ventricular dysfunction after atrial switch operation. The left ventricle could be prepared by an effective pulmonary artery banding in most instances.

Cardiac Surgical Procedures↗
PubMed1979

Low output syndrome in right ventricular infarction.

In this paper we describe clinical and hemodynamic data in ten patients with right ventricular infarction and low output syndrome. Atrioventricular block and supraventricular arrhythmias were a common finding. All of them had a right atrial pressure disproportionately increased (average 16.3 +/- 5.2 mm. Hg) in relation to left ventricular filling pressure (average 15 +/- 4.5 mm. Hg), and a very low cardiac index (average 1.42 +/- 0.45 liters/min./m.2). The right atrial pulse tracings were similar to those of constrictive pericarditis, showing a deep "y" descent in every patient. We made the differential diagnosis between similar hemodynamic entities and constructed function curves of right and left ventricles. Right ventricular diastolic work index was always increased (average 6.26 +/- 3.63 gm./beat/M.2), being higher than net work index (average 3.28 +/- 1.87 gm./beat/M.2). While all function curves of the right ventricle were flat or depressed, those of the left ventricle were very different. Treatment consisted mainly of fluid overload and, in some cases, of vasodilators or dopamine. Mortality rate was 40%. We think that coexisting left ventricular damage may account in part for the bad prognosis of these patients.

Adult↗
PubMed2006

Determinants of the severity of functional tricuspid regurgitation.

We performed a prospective study of patients with chronic right ventricular (RV) dilation to determine the factors associated with the degree of functional tricuspid regurgitation (FTR). We prospectively enrolled 64 patients with chronic RV dilation and measured right atrial (RA) area, RV area and its fractional area change (RVFAC), tricuspid annular diameter and contraction, tricuspid valve (TV) tethering area, and systolic pulmonary artery pressure. We also measured the RV eccentricity index and the RV sphericity index for simple presentation of RV geometry. Regurgitant orifice area of FTR was obtained for the quantification of FTR. End-systolic RV eccentricity index (r=0.73), end-diastolic RV eccentricity index (r=0.56), RA area (r=0.49), TV tethering area (r=0.37), age (r=0.31), end-systolic (r=0.42) and end-diastolic (r=0.30) tricuspid annular diameters, and left ventricular ejection fraction (r=-0.37) were significantly related to the regurgitant orifice area of FTR in univariate analysis. However, RV area, RVFAC, and systolic pulmonary artery pressure were not. In multivariate analysis, the end-systolic RV eccentricity index (p<0.001), TV tethering area (p=0.003), and end-diastolic tricuspid annulus diameter (p=0.007) showed the independent associations with regurgitant orifice area of FTR. The sensitivities and specificities for predicting more than mild FTR were found to be 79% and 82% with an end-systolic RV eccentricity index>2.0, 69% and 73% with an end-systolic tethering area>1.0 cm2, and 64% and 59% for an end-systolic tricuspid annulus diameter>3.9 cm, respectively. FTR severity was found to show the best correlation with the end-systolic RV eccentricity index. In conclusion, these findings underscore the importance of eccentric RV dilation for determining FTR severity and should lead to the development of more rational surgical approaches to FTR beyond TV annuloplasty.

Echocardiography, Doppler↗
PubMed1995

Biventricular repair in cardiac isomerism. Report of seventeen cases.

Ninety-three patients with cardiac isomerism were treated surgically from July 1985 to June 1991. Among them, three patients with right and 14 with left isomerism underwent biventricular repair. Ages ranged from 4 months to 41 years (mean 4.8 years). Anatomic repair was accomplished in 15 patients and functional repair with the right ventricle used as the systemic ventricle in two patients. Methods of atrial septation to separate pulmonary venous flow from systemic venous flow included atrial partition with a straight patch in seven patients, intraatrial rerouting with a tailored baffle in five, and a Mustard-type atrial switch in five. One hospital death (5.8%) and two late deaths (12%) occurred. Two patients required reoperation (12%), one reconstruction of a stenotic systemic venous connection and one mitral valve replacement because of incompetence. Surgically induced complete atrioventricular block was not observed in any of the patients. Optimal atrial septation offers the possibility of biventricular repair for patients with acceptable intraventricular structure.

Abnormalities, Multiple↗
PubMed1988

Forward diastolic flow in pulmonary artery induced by right atrial contraction of pig hearts.

To study whether right atrial contraction can forward blood into the pulmonary artery during diastole, blood volume was expanded in anesthetized open-chest pigs until mean right atrial pressure was 13-20 mmHg (range). In the control situation, blood flow in the pulmonary artery was only observed during ventricular systole. Forward diastolic pulmonary artery flow, coinciding with right atrial contraction, was observed when diastolic pulmonary artery pressure was reduced during selectively increased left-side contractility, during bradycardia after propranolol injection (0.5 mg/kg body wt iv), and during the prolonged diastolic interval after spontaneously occurring atrial extrasystoles. The prolongation of the diastolic interval in all three series caused the diastolic pulmonary artery pressure to decline and the filling of the right atrium to increase, thus further stimulating the right atrial Frank-Starling mechanism. The diastolic blood flow in the pulmonary artery constituted 11% of the stroke volume during increased left-side inotropic stimulation, 8% during bradycardia, and 6% in beats preceded by a prolonged diastolic interval. Thus, in the normal heart, blood can be ejected into the pulmonary artery during right atrial contraction.

Animals↗
PubMed1984

Right heart function during left heart assist and the effects of volume loading in a canine preparation.

A significant fraction of patients in whom mechanical left ventricular assist devices are implanted for refractory cardiac failure after open heart surgery have had the complication of right heart failure. To evaluate the effects of left ventricular assistance and pressure unloading on right ventricular function, we performed experiments in the normal hearts of open-chest, anesthetized, large mongrel dogs. We compared right ventricular function before and after left ventricular-to-aortic bypass with a roller pump at right atrial pressure levels of 1, 3, 5, and 7 mm Hg produced by volume loading. No significant changes were found in cardiac output or stroke volume over this range of right atrial pressures when comparing that before to that during left ventricular bypass, which at a right atrial pressure of 1 mm Hg reduced peak left ventricular pressure from 96 +/- 6 to 15 +/- 9 mm Hg and at a right atrial pressure of 5 mm Hg reduced it from 113 +/- 3 to 29 +/- 12 mm Hg, while maintaining aortic pressure. There was no evidence of right ventricular failure under these conditions: (from before to during bypass) at a right atrial pressure of 1 mm Hg cardiac output was 3.4 +/- 0.4 to 3.7 +/- 0.6 liter/min and stroke volume was 28 +/- 5 to 33 +/- 6 ml; during volume loading at a right atrial pressure of 7 mm Hg cardiac output was 5.6 +/- 0.6 to 5.7 +/- 0.7 liter/min and stroke volume was 47 +/- 5 to 52 +/- 5 ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Effect of right ventricular anatomy on the cardiopulmonary response to exercise. Implications for the Fontan procedure.

Incorporation of the right ventricle (RV) into the pulmonary circulation of patients with tricuspid atresia undergoing a Fontan procedure has been advocated. The consequences of this approach on the exercise function of these patients was studied by examining the effects of progressive and steady-state bicycle exercise tests performed by 11 patients with right atrial (RA)-RV Fontan anastomoses, seven patients with RA-pulmonary artery (PA) Fontan anastomoses, 13 patients after repair of tetralogy of Fallot, and 34 normal control patients. All patients were in New York Heart Association class I. The exercise function of the patients undergoing RA-RV and RA-PA Fontan procedures were similar. The achieved peak work loads 60% and 67% of control and peak oxygen consumptions 60% and 64% of control, respectively. Both groups also displayed excessive ventilation, elevated dead space/tidal volume ratios, and depressed cardiac output during steady-state exercise. In contrast, tetralogy of Fallot patients achieved peak work loads and oxygen consumptions 83% of control and maintained normal cardiac outputs and dead space/tidal volume ratios during steady-state exercise. These results suggest that the presence of an RV within the pulmonary circulation of the Fontan patient does not result in improved exercise function. This may be due to the development of obstructive gradients across the RA-RV conduits during exercise or to the RV's negative effect on left ventricular compliance. Moreover, in contrast with the postoperative tetralogy of Fallot patient, the hypoplastic RV of tricuspid atresia may not have sufficient myocardium to assume the active pumping function required by exercise.

Adolescent↗
PubMed2003

[Angiosarcoma of the right atrium detected by transesophageal echocardiography. A case report].

Primary tumors of the heart are uncommon. 75% of these tumors in the adult are benign and 25% are malignant. Angiosarcoma was the most frequent malignant tumour. 75% occurred on the right side, especially in the right atrial. This tumour was generally discovered in post-mortem because the non specificity of functional symptomatology. Echocardiography is the first non invasive tool for diagnosis and evaluation of cardiac mass. Angiosarcoma was associated with an unfavourable outcome. We reported a case of an atrial angiosarcoma revealed by transoesophageal echocardiography in a 42 years old woman.

Adult↗
PubMed2005

[Intraoperative transesophageal echocardiography to guide removal of a hypernephroma with vena cava and right atrial extension].

We describe the case of a 70-year-old man who underwent resection of a right hypernephroma with vena caval and right atrial extension with continuous monitoring by transesophageal echocardiography. The monitoring technique brought important advantages, providing images that facilitated anatomical and functional evaluation of cardiac structures without obstructing the surgical field. Images of the heart and great vessels obtained in real time allowed the surgeon to make operative decisions based on accurate assessment of the cephalad extension of the tumor to the right chambers. Transesophageal echocardiography also allowed the anesthesiologist to monitor hemodynamic status throughout surgery and watch for tumoral emboli. The imaging technique proved to be highly useful for both anesthetic and surgical management of the patient.

Aged↗
PubMed1992

[Discovery of the electrical activity and conduction system of the heart].

Since our student days we have been accustomed to enumerating the individual elements of the heart's rhythmic centre and conduction system in accordance with the order of their functions, from cranial to caudal. We begin, therefore, with the sino-atrial node in the right atrium, after which comes the atrioventricular node, the bundle of His and, finally, Purkinje's fibres. The respective discoveries were made in precisely the opposite order, however. Purkinje's fibres were discovered in 1839, the bundle of His in 1893, the atrioventricular node was discovered by Aschoff and Tawara in 1905-1906 and the sinus node by Keith and Flack in 1906. The biographies of the respective discoverers and the circumstances surrounding their discoveries are dealt with briefly.

Animals↗
PubMed1986

[Corrected transposition of the great vessels in aged adults. Apropos of 2 patients aged 72 and 80].

The authors report two unusual new cases of corrected transposition of the great arteries diagnosed in patients 72 and 80 years of age respectively, presenting with symptoms of cardiac failure of recent onset. Both patients had mild or moderate regurgitation of the systemic atrio-ventricular valve, associated in one case with aortic regurgitation. This association would appear to be fortuitous although already reported in six occasions. The diagnosis was made by echocardiography and confirmed by catheterisation in one case, and by digitised intravenous angiography in the other. These cases are of interest for three reasons: They are very rare: there have been only 20 comparable cases reported in patients over 40 years of age, the eldest being 73. This is probably explained by the high frequency of associated malformations. They illustrate the decisive role of echocardiography in the diagnosis of congenital heart disease, even in the adult. They constitute a "natural experimental model" of a right ventricle submitted to systemic pressures and tend to show that, in the absence of other abnormalities giving rise to an additional pressure or volume overload, the right ventricle is capable of long term adaptation to this situation. These observations indicate a favourable long-term prognosis for children who have undergone "corrective" surgery at atrial level for simple transposition and in whom the right ventricle is required to assume the function of the systemic ventricle for the rest of their life.

Aged↗
PubMed1982

Leukotrienes C4, D4 and E4: effects on human and guinea-pig cardiac preparations in vitro.

The effects of leukotrienes C4, D4 and E4 (LT C4, D4 and E4) were studied in isolated preparations of guinea-pig and human myocardium in order to assess their contribution to cardiac dysfunction associated with systemic anaphylaxis. LT C4, D4 and E4 all caused long-lasting and dose-related decreases in the contractile force and coronary flow rate of the isolated guinea-pig heart. The rank order of potency was LT D4 greater than C4 greater than E4. The effects of LT C4 and D4 were antagonized by the anti-slow-reacting-substance compound FPL 55712. The negative inotropic effect of LT is unlikely to be secondary to the concomitant reduction in coronary flow because: 1) the same reduction in coronary flow by angiotensin II resulted in a negligible decrease in contractility and 2) the negative inotropic effect of LT also occurred in the electrically paced, noncoronary perfused left atrium and right ventricular papillary muscle of the guinea pig and in pectinate muscles obtained from surgical specimens of human right atrial appendage. LT D4 potentiated the positive chronotropic effect of histamine, supporting the concept that functional interactions occur between the various mediators of immediate hypersensitivity. The cardiac effects of pure synthetic LT are similar to those previously obtained with crude slow-reacting substance of anaphylaxis indicating that the prolonged contractile failure associated with systemic anaphylaxis largely could be due to the negative inotropic effect of LT. Because LT are released in a variety of immunological and inflammatory reactions, their potent myocardial depressant effects may play a role in cardiac dysfunction associated with these reactions.

Abdomen↗
PubMed1994

Hemodynamic effects of different modes of mechanical ventilation in acute cardiac and pulmonary failure: an experimental study.

OBJECTIVE: To determine the hemodynamic effects of four different modes of mechanical ventilation in an animal model of acute cardiac and pulmonary failure. DESIGN: Prospective, randomized, crossover design. SETTING: University research laboratory. SUBJECTS: Twelve piglets weighing 10 to 16 kg. INTERVENTIONS: The experimental protocol consisted of three stable 30-min periods: when ventricular and pulmonary functions were normal (control), after the induction of acute cardiac failure by the administration of a beta-adrenergic receptor blocker, and after pulmonary failure induced by repeated lung lavage. Modes of mechanical ventilation included controlled mechanical ventilation, high-frequency oscillation, synchronized high-frequency jet ventilation, and external negative pressure oscillation combined with pressure support ventilation. Each mode of respiratory support was randomly and sequentially applied to each animal with the assessment of cardiopulmonary function at the end of each period. MEASUREMENTS AND MAIN RESULTS: Continuous monitoring included electrocardiogram, right atrial, left ventricular end-diastolic, pulmonary arterial, intrathoracic aortic, arterial, esophageal, and transpulmonary pressures and arterial and mixed venous oxygen saturation measurements. In addition, cardiac output using the thermodilution technique was measured intermittently. Whereas in the control period cardiac index was significantly (p < .05) higher during synchronized high-frequency jet ventilation (193 +/- 19.3 mL/kg/min) than during controlled mechanical ventilation (151 +/- 12.1 mL/kg/min) and high-frequency oscillation (151 +/- 18.1 mL/kg/min), there was no significant hemodynamic difference between the four modes of mechanical ventilation in the cardiac and pulmonary failure periods. In the pulmonary failure period, transpulmonary pressure was significantly higher during high-frequency oscillation (7.1 +/- 1.6 mm Hg) than during controlled mechanical ventilation (5.6 +/- 0.6 mm Hg), high-frequency ventilation (4.1 +/- 0.4 mm Hg), and external negative pressure oscillation combined with pressure support ventilation (5.3 +/- 0.5 mm Hg). CONCLUSIONS: Synchronized high-frequency ventilation improves cardiac performance in control conditions. No hemodynamic difference is present between the four modes of mechanical ventilation in the cardiac and pulmonary failure periods. External negative pressure oscillation combined with pressure support ventilation has moderate hemodynamic advantages over controlled mechanical ventilation and high-frequency oscillation in different clinical settings, but it also results in a deterioration of pulmonary gas exchange during the pulmonary failure period.

Animals↗
PubMed1984

Aging and atrial electrophysiologic properties in man.

In order to assess the influence of age on atrial electrophysiologic properties, we studied 17 normal subjects, whose ages were homogeneously distributed between 17 and 78 years, measuring in each of them effective (ERP) and functional (FRP) refractory periods at 3 sites of the right atrium (high, middle and low in the lateral wall) at the same driven frequency (120/min). Twice threshold stimuli of 2 msec duration were applied. Dispersion of atrial refractoriness was measured as the longest minus the shortest refractory period. A significant direct correlation was observed between age and dispersion of atrial refractoriness (of ERP: r = 0.75, P less than 0.001; of FRP: r = 0.82, P less than 0.001). Moreover, age showed a significant direct correlation with refractoriness at high right atrium (ERP: r = 0.66, P less than 0.01; FRP: r = 0.76, P less than 0.001), but did not correlate with that at the other two sites. We suggest that ageing modifies atrial refractoriness in a non-uniform manner inducing a progressive increment of dispersion of atrial refractoriness. The impression is that a slow but continuous process takes place from juvenility to old age.

Adolescent↗
PubMed1989

Effects of a single dose of isosorbide-5-mononitrate on the left ventricular diastolic function in systemic hypertension.

The effect of a single dose of isosorbide-5-mononitrate on left ventricular (LV) diastolic function was assessed by radionuclide ventriculography in 18 hypertensive patients. The effect of the mononitrate on atrial filling also was assessed. As expected, there was a significant decrease in mean blood pressure (120 +/- 17 to 102 +/- 18 mm Hg, p less than 0.005). Global LV ejection fraction did not show a significant change, increasing slightly from 64 +/- 9 to 68 +/- 8% (difference not significant). The mononitrate prolonged the time to peak filling rate from 176 +/- 36 to 195 +/- 29 ms (p less than 0.0001). The percentage of time to peak filling rate from diastole also increased, from 46 to 53% (p less than 0.05), whereas the normalized peak filling rate did not change (2.36 +/- 0.6 to 2.31 +/- 0.6 end-diastolic volumes/s, difference not significant). This effect on LV diastolic function was closely related to a certain reduction in preload, as suggested by the reduction in mean left atrial filling (45 +/- 12 to 40 +/- 13 counts/s, p less than 0.005) and LV diastolic counts, suggesting that the "impairment" of diastolic function induced by nitrates is secondary to the reduction in venous return to the left atrium. The mononitrate did not affect the mean right atrial filling rate (50 +/- 12 to 52 +/- 13 counts/s) and the right ventricular end-diastolic counts, suggesting a primary vasodilatory effect of nitrates on the pulmonary vascular bed.

Adult↗
PubMed1993

Left ventricular diastolic dysfunction late after coarctation repair in childhood: influence of left ventricular hypertrophy.

OBJECTIVES: Left ventricular systolic and diastolic function were evaluated late after successful operation for aortic coarctation in childhood. BACKGROUND: Persistent arterial hypertension and left ventricular hypertrophy after coarctation repair might impair left ventricular function. METHODS: Biplane angiography and simultaneous high fidelity pressure measurements were performed in 12 patients 3 to 12 years postoperatively (residual pressure gradient 4 mm Hg). Eight patients were normotensive and four had borderline hypertension. Data at rest and after nitroprusside infusion (1.7 micrograms/kg per min) were evaluated and compared with data from 12 control subjects. RESULTS: Systolic left ventricular function (ejection fraction-end-systolic wall stress relation) was normal in all patients. However, left ventricular muscle mass (113 vs. 86 g/m2), right atrial pressure (5.2 vs. 1.9 mm Hg) and left ventricular end-diastolic pressure (16 vs. 11 mm Hg) were significantly higher in patients than in control subjects. There was a linear relation between muscle mass and left ventricular end-diastolic (r = 0.66, p < 0.001) or right atrial (r = 0.60, p < 0.01) pressure. Left ventricular relaxation and myocardial stiffness were normal. However, there was an upward shift of the diastolic pressure-volume curve when compared with control values, but this shift was reversed by the administration of nitroprusside. CONCLUSIONS: Systolic function is normal late after coarctation repair. However, diastolic function can be abnormal with an upward shift of the diastolic pressure-volume curve that is reversed by nitroprusside administration and is probably due to residual left ventricular hypertrophy.

Adolescent↗
PubMed2000

Atrial septal defect in adults. Thirty-eight-year follow-up of a surgically and a conservatively managed group.

This report describes the long-term (up to 38 years) outcome, in terms of mortality and cardiovascular morbidity, in a non-randomized clinical observation study of a surgically and a conservatively managed group of adult patients with shunt lesions at atrial level. Haemodynamic status was assessed at baseline and at repeat examination. Twelve patients underwent surgical repair of the lesion between these two heart catheterizations, resulting in a marked reduction in heart size and right ventricular systolic pressure. These changes were associated with improvement in functional class and a trend towards less risk of cerebrovascular incidents, but not atrial fibrillation, during follow-up. Among 12 patients not operated on between catheterizations, symptomatic deterioration was common, often necessitating later surgical repair. The results support the assumption that early surgery should be recommended for adults with a haemodynamically significant lesion, to reduce the risk of mortality and prevent symptomatic deterioration.

Adolescent↗