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PubMed1989

[Clinical significance of right ventricular ejection fraction in cases with atrial septal defect].

Right ventricular ejection fraction (RVEF) assessed by cardiac radionuclide angiography has been applied to evaluate right ventricular function such as ischemic, valvular and congenital heart disease. Using this modality, previous reports also suggest that there is good correlation between RVEF and mean pulmonary arterial pressure (mPA) from catheterization findings in mitral valvular disease and chronic obstructive lung disease. In this study, cardiac RI angiography were performed on 33 adult patients with atrial septal defect (ASD), RVEF is not so good correlation (r = -0.42) with mPA, but in cases within pulmonary to systemic ratio (Qp/Qs) less than 2.0 limits, there is good correlation between RVEF and mPA (n = 9, r = -0.71). As a conclusion, in ASD, both afterload assessed by mPA and preload assessed by Qp/Qs decrease RVEF.

Adult↗
PubMed1982

Atrial refractoriness and spontaneous or induced atrial fibrillation.

Atrial refractoriness and vulnerability were studied in 10 patients with paroxysmal atrial fibrillation (PAF) and in 12 age-matched normal subjects (N). Effective and functional refractory periods were measured at three sites of the right atrium: high, middle and low in the lateral wall, both in sinus rhythm and during atrial pacing (120/min). Twice threshold stimuli were applied. Dispersion of refractoriness (D) was measured as the longest minus the shortest refractory period. Atrial fibrillation (AF) was induced in 5 of the PAF; in each of these 5 only one atrial site proved vulnerable (middle in one case, low in the other 4). In every case the shortest refractory period was located at the vulnerable atrial site. In vulnerable patients coupling intervals only slightly different from those which induced AF determined an abrupt change in the atrial electrogram recorded at the vulnerable site, suggesting a modified and in some way abnormal behaviour of the atrial activation wave. At the same time the interval between the beginning of the electrogram at the vulnerable site and of that obtained by the electrode positioned near the A-V node lengthened, suggesting a lower conduction velocity of the atrial activation wave. PAF evidenced significantly higher refractoriness and D than did N during sinus rhythm. Atrial pacing significantly reduced refractoriness but not D, which remained significantly higher than that of N at the same driven frequency. In conclusion, lower cycle length (paced rhythm), a short refractory period and the possibility of delivering extrastimulus at shorter coupling intervals seem conditions favourable to the induction of irregular activation of atrial myocardium. The increased D might be connected to the particular pathophysiological condition of our patients.

Adult↗
PubMed1996

Percutaneous venoarterial extracorporeal membrane oxygenation for emergency mechanical circulatory support.

In this retrospective study we report our initial experience with percutaneous venoarterial extracorporeal membrane oxygenation in the emergency treatment of intractable cardiogenic shock or pulseless electrical activity. Between January 1994 and July 1995, percutaneous venoarterial extracorporeal membrane oxygenation was attempted in seven patients (pulseless electrical activity, five patients; cardiogenic shock, two patients). In two of the seven patients, efforts at arterial cannulation resulted in cannula perforation at the level of the iliac artery. In the remaining five patients, percutaneous venoarterial extracorporeal membrane oxygenation could be established and was maintained for 3-84 h. Major bleeding remained a common complication during extracorporeal membrane oxygenation despite the use of heparin-coated bypass circuits and was responsible for death during extracorporeal membrane oxygenation in one patient. The remaining four patients could be weaned from mechanical circulatory support within 24 h, two after surgical interventions (resection of right atrial tumor, heart transplantation), one after thrombolytic therapy. In one patient, cardiac function recovered spontaneously after 6 h on venoarterial extracorporeal membrane oxygenation. Three patients were discharged from hospital, two of them made a full recovery, one sustained severe hypoxic brain injury. A few patients with intractable cardiogenic shock or pulseless electrical activity can be resuscitated with the help of emergency percutaneous venoarterial extracorporeal membrane oxygenation. Emergency venoarterial extracorporeal membrane oxygenation is associated with a high rate of complications and its use should therefore be limited to selected patients with a rapidly correctable underlying cardiopulmonary pathology (anatomic, metabolic or hypothermic) who do not respond to conventional advanced cardiac life support.

Emergencies↗
PubMed1985

Pre-operative sinus node function in adult patients with atrial septal defect (ostium secundum type).

The authors studied, pre-operatively, the sinus node function in adult patients with secundum atrial septal defect and large left-right shunts, using Holter ECG and electrophysiological tests. Sinus node electrophysiological tests were found abnormal in 17 out of 26 patients; on the contrary, Holter monitoring was always within normal limits. The authors believe that concealed sinus node dysfunction existing before surgical correction may be a cause of early, acute, and reversible, post-operative sick sinus syndrome.

Adolescent↗
PubMed1978

Serum levels and electrophysiological effects of N-acetlyprocainamide as compared with procainamide in the dog heart in situ.

The electrophysiological effects of procainamide and its major metabolite N-acetylprocainamide were tested and compared on the heart of the anaesthetized dog by means of His bundle electrography and programmed electrical stimulation. Both drugs exerted a negative chromotropic effect. They also increased intra-atrial and intraventricular conduction times; procainamide was, however, the more potent of the two drugs. In contrast to procainamide, N-caetylprocainamide did not increase His-Purkinje and atrioventricular nodal conduction times, and at the lowest dose employed, atrioventricular nodal conduction times were decreased during atrial pacing. Both drugs increased the functional and effective refractory period of the right atrium and ventricle. N-acetylprocainamide increased the functional refractory period of the atrioventricular node, but to a lesser extent than procainamide.

Animals↗
PubMed2005

Asymmetrical dimethylarginine in idiopathic pulmonary arterial hypertension.

OBJECTIVE: We explored the potential role of the endogenous NO synthase inhibitor asymmetrical dimethylarginine (ADMA) in patients with idiopathic pulmonary arterial hypertension (IPAH). Method and Results- We correlated plasma ADMA levels and cardiovascular indices from right heart catheterization in 57 patients with IPAH. Predictors of survival in patients with IPAH were studied. Furthermore, the effect of systemic ADMA infusion on pulmonary ventricular resistance and stroke volume was investigated in healthy volunteers using right heart catheterization. Mean plasma ADMA concentrations were significantly higher in patients with IPAH than in control subjects (0.53+/-0.15 versus 0.36+/-0.05 micromol/L; P<0.001). ADMA plasma concentrations correlated significantly with indices of right ventricular function, such as mixed-venous oxygen saturation (r=-0.49; P<0.0001), right atrial pressure (r=0.39; P<0.003), cardiac index (r=-0.35; P<0.008), as well as survival (r=-0.47; P<0.0001). Multiple regression analysis revealed that right atrial pressure (r=0.31; P<0.026) and ADMA (r=0.29; P<0.039) were independent predictors of mortality. Moreover, patients with supra-median plasma ADMA levels had significantly (P<0.021) worse survival than patients with infra-median ADMA values. ADMA infusion in healthy volunteers increased pulmonary vascular resistance (68.9+/-7.6 versus 95.6+/-6.3 dyne x s x cm(-5); P<0.05) and decreased stroke volume (101.1+/-6.7 mL versus 95.6+/-6.3 mL; P<0.05). CONCLUSIONS: Increased ADMA plasma levels are associated with unfavorable pulmonary hemodynamics and worse outcome in patients with IPAH.

Adult↗
PubMed1998

Varying types of circus movement re-entry with both normal and dissociated contralateral conduction causing different right and left atrial rhythms in canine atrial flutter.

The purpose of this study was to develop an animal model of atrial flutter (AFL) or fibrillation (AFB) and to determine precisely the pathway of atrial activation during arrhythmias induced by programmed stimulation. In 10 dogs, a shunt from the left subclavian artery to the left upper pulmonary vein was created to produce left atrial enlargement. Five months later, using programmed electrical stimulation, it was possible to induce 17 sustained atrial tachycardias in 9 of the 10 dogs, including 9 episodes of AFL caused by circus movement re-entry, 6 episodes of focal tachycardia, and 2 episodes of AFB. Short cycle length left atrial tachycardias caused by either circus movement or a focus did not propagate in a uniform 1:1 pattern to the right atrium (RA), resulting in RA dissociation. In these arrhythmias, complex wavefronts from both current and preceding left atrial cycles coexisted in the RA. Circus movement was associated with a spectrum of different re-entrant pathways with different path lengths. These differences in the path length were determined by various ways in which obstacles such as the superior vena cava and orifice of the right atrial appendage or pulmonary vein orifices were combined by contiguous areas of functional block.

Animals↗
PubMed1991

[A case of chronic constrictive pericarditis with rheumatic valvular heart disease successfully treated by surgery].

Chronic constrictive pericarditis and rheumatic valvular heart disease are common surgical conditions, but the simultaneous occurrence of both is extremely rare and poses problems in diagnosis and treatment. A 47-year-old male with constrictive pericarditis and rheumatic valvular heart disease was successfully treated with operation. The valvular dysfunction had included aortic, mitral and tricuspid regurgitations. He had also complicated severe hepatic dysfunction due to the cardiac constriction and the secondary tricuspid valve regurgitation. With the aid of cardiopulmonary bypass radical pericardiectomy was performed for almost all cardiac surfaces including that of both ventricles, the right atrium, and the venae cavae. After the pericardiectomy, aortic valvular replacement, mitral and tricuspid valvular annuloplasties were performed. Postoperative course was uneventful and the hemodynamic abnormalities (elevated right atrial and ventricular end diastolic pressures) as well as the depressed hepatic functions were dramatically improved postoperatively.

Chronic Disease↗
PubMed1987

[Testing the regulation mechanism in inserting an artificial heart by model simulation].

The problems of controlling the cardiac output and the balance of the blood volumes in the circulatory system were discussed for the natural heart as well as for an implanted artificial heart by means of a mathematical function model of the human organism. The control by the Starling mechanism (right atrial pressure) can adapt sufficiently the cardiac output according to the demands of the body, in case the loading steps do not exceed a fixed limit. The false regulation by a strong load of the organism is evidently caused by the limited capacity of the artificial heart and not by the strategy of the control.

Cardiac Output↗
PubMed1977

The significance of pulmonary changes associated with cerebral perfusion with hypoxic blood in monkeys.

Parameters of cerebral and pulmonary function were studied in ten animals whose brains were perfused with hypoxic right atrial blood according to the Moss method. All animals died as a result of cerebral hypoxia at about 95 minutes after the onset of perfusion. Gross pulmonary congestion, edema, and leukocyte plugs occurred in the seven animals breathing spontaneously, but positive pressure ventilation prevented these changes in three. The resumption of cerebral perfusion with oxygenated blood after 30 minutes of the Moss procedure did not prevent the pulmonary changes and, of more importance, did not prevent cerebral swelling and death at about the same time as that of all the other animals. There were no changes in oxygen uptake or in arterial oxygen tension to indicate that progressive pulmonary failure contributed to death. It is concluded that this model produces brain swelling and brain death with incidental pulmonary pathological changes indistinguishable from early findings in hemorrhagic shock models and that the cerebral hypoxic perfusion model in monkeys is not suitable for studying the effects of "shock lung" therapy.

Animals↗
PubMed1984

Incessant focal atrial tachycardia: a surgically remediable cause of cardiomyopathy.

Following electrophysiological study and intraoperative mapping, an 11-year-old girl with incessant automatic atrial tachycardia and clinical features of congestive cardiomyopathy underwent successful surgical excision of an ectopic focus localized to the right atrial appendage. Dramatic clinical improvement resulted, and echocardiographic indices of left ventricular function returned to normal over a 1 year follow-up period.

Cardiomyopathy, Dilated↗
PubMed1988

[Assessment of interaction between the left and right ventricles using pressure-volume loops in various heart diseases].

To assess the interaction and interdependence of left and right ventricular function, ECG-gated radionuclide angiocardiography was performed immediately after cardiac catheterization during right atrial pacing for 11 patients with old myocardial infarction (MI), two with non-obstructive hypertrophic cardiomyopathy, one with aortic stenosis (AS), two with pulmonary infarction (PI), and one with neurocirculatory asthenia (NCA). Absolute left ventricular (LV) volume curves were obtained by the count-based method with attenuation factor corrections. Biventricular pressure and volume curves were digitized and synchronized to end-diastole, and pressure-volume (P-V) loops were constructed throughout a cardiac cycle. The stroke work index (SWI), the work index per min (WI/M) and the contractility index (CNTI) were calculated from the P-V loops. In a patient with NCA, LV end-diastolic volume decreased during rapid pacing, but no significant change in the LV end-systolic P-V relation was recognized. However, the entire right ventricular (RV) P-V loop was shifted toward the left during rapid pacing. In a patient with AS, the LV P-V loop was markedly enlarged and every parameter of LV function was much greater than that of the right ventricle due to increased LV afterload. The areas of RV P-V loops in two patients with PI were larger than those of other patients, because RV pressure was relatively high, and RV volume was increased. It is suggested that RV pressure and volume overloads prevail in patients with PI. In four MI patients with three vessel disease and having collateral circulation, the LV end-systolic P-V relationship was shifted toward the lower right, and every parameter (SWI, WI/M, CNTI) of LV function decreased by rapid pacing. Myocardial ischemia may be induced by rapid pacing stress, causing decreased LV contractility. It was concluded that the P-V loops obtained by RNA and catheterization are clinically useful for estimating the interaction and interdependence between right and left ventricular hemodynamics.

Adult↗
PubMed1989

Additive effects of enoximone and nitroprusside in unstable chronic heart failure.

In the present study, the safety and efficacy of the combined administration of intravenous nitroprusside and oral enoximone, an experimental compound with phosphodiesterase inhibitory properties, were evaluated. Ten patients with unstable chronic heart failure maintained on digitalis and diuretics were selected to receive enoximone because of their poor response to intravenous nitroprusside. For a mean peak dose of 115 micrograms min-1 nitroprusside, cardiac index increased from 1.8 +/- 0.4 to 2.0 +/- 0.4 l min-1 m-2, while pulmonary artery diastolic pressure and mean right atrial pressure decreased from 29 +/- 6 to 24 +/- 5 and from 15 +/- 6 to 11 +/- 3 mmHg respectively; mean arterial pressure and heart rate were unchanged. The addition of 1.6 mg kg-1 oral enoximone t.i.d. to nitroprusside resulted in a substantial improvement of cardiac function: cardiac index increased further to 2.8 +/- 0.5 l min-1 m-2 (P less than 0.001), pulmonary artery diastolic pressure and right atrial pressure decreased to 18 +/- 5 and 7 +/- 3 mmHg (P less than 0.01), respectively, while mean arterial pressure rose from 90 +/- 11 mmHg to 95 +/- 0 mmHg (P less than 0.05); heart rate was unchanged. The salutary haemodynamic response to combined nitroprusside-enoximone therapy persisted for more than 32 h, and cardiac performance remained improved on enoximone for a further 8 h despite the discontinuation of nitroprusside. No serious side-effects or changes in the arrhythmia profile were observed. The addition of oral enoximone to nitroprusside has beneficial haemodynamic effects in unstable chronic heart failure.

Aged↗
PubMed1987

Selective ganglionic blockade of vagal inputs to sinoatrial and/or atrioventricular regions.

Vagal postganglionic neurons to sinoatrial (SAN) and atrioventricular (AVN) nodal regions of the canine heart have been localized surgically around the right pulmonary vein-atrial fat pad and in the fat pad overlying the epicardium at the inferior vena cava-inferior left atrial junction, respectively. Local ganglionic blocking doses (total of 5 mg per injection) of hexamethonium were injected into the pulmonary vein-atrial fat pad to block selectively right and left vagal inputs to the SAN region without interrupting vagal inputs to AVN. Conversely, hexamethonium injected into the inferior vena cava-inferior left atrial pad selectively blocked vagal control of arteriovenous conduction without interfering seriously with vagal control of SAN function. Vagal ganglia situated in pulmonary vein-atrial fat pad also exercise moderate but incomplete control of right atrial contractile force. Lesser vagal control of atrial inotropism is localized in the inferior vena cava-inferior left atrial fat pad. Ganglia situated in a large fat pad on the dorsal epicardial surface of the left atrium (left atrial fat pad) appear to play little or no role in SAN or AVN regulation, although some left preganglionic axons may pass through it en route to the AVN region. Vagal stimulation is associated with prompt and profoundly negative chronotropic and dromotropic responses, but in response to the same stimulation, a negative change in atrial contractile force is much slower in development and is much longer lasting. Such precise anatomical localization and differentiation of the intrinsic vagal regulation of SAN, AVN and contractile force opens new avenues of research on the neural regulation of cardiac performance.

Animals↗
PubMed2001

Echocardiographic evaluation of right ventricular systolic functions in pure mitral stenosis.

Detailed echocardiographic evaluation of right ventricular muscle thickness and systolic functions was performed in twenty two cases of isolated rheumatic mitral stenosis without clinical signs of systemic venous congestion, tricuspid regurgitation or atrial fibrillation. Twenty two age and sex matched normal persons formed the control group. Right ventricular thickness was significantly increased in the patients with mitral stenosis. End-diastolic and end-systolic long axis measurements and areas were significantly increased and fractional shortening of these parameters was significantly reduced in the patient group. Our results show that right ventricular systolic functions are significantly impaired even in absence of clinical signs of systemic venous congestion. This impairment of systolic function did not correlate with pulmonary flow acceleration time. Myocardial involvement in rheumatic process could be one possibility. Systolic movement of the Tricuspid annulus and right ventricular mid cavity short axis dimension were not sensitive in detecting right ventricular systolic dysfunction.

Female↗
PubMed2005

Cardiopulmonary bypass reduces atrial Na+-K+-ATPase expression in children.

Cardiopulmonary bypass (CPB) may induce serious side effects, potentially leading to myocardial failure. The Na(+)-K(+)-ATPase is a key component for myocardial function. Due to its developmental regulation, results from adult studies cannot be adopted to the situation in childhood. Right atrial myocardium from patients with left-to-right shunts at atrial level (VO, n=8) and those without (NO, n=8) was excised during heart surgery before and after CPB. Na(+)-K(+)-ATPase isoforms ATP1A1 (p=0.008) and ATP1A3 (p=0.038) decreased during CPB, which decrease was restricted to the VO group. This study highlights the importance of the underlying heart defect for susceptibility to the effects of CPB, showing a reduced Na(+)-K(+)-ATPase mRNA expression only in patients with left-to-right shunts on the atrial level. This seemed to be an early molecular event, as apart from one, none of the patients showed heart failure before or after surgery.

Adolescent↗
PubMed1991

Transesophageal echocardiography in renal cell carcinoma: an accurate diagnostic technique for intracaval neoplastic extension.

Between 4 and 10% of patients with renal cell carcinoma have tumor involving the inferior vena cava and many of these patients have suprahepatic extension. In patients with intracaval neoplastic extension precise definition of the superior aspect of the tumor thrombus is critical. Transabdominal ultrasonography, computerized tomography (CT), magnetic resonance imaging (MRI) and inferior venacavography are all currently used to evaluate the inferior vena cava in these patients. Intraoperative transesophageal echocardiography was used to image the inferior vena cava in 5 patients with renal cell carcinoma and intracaval neoplastic extension. In each patient transesophageal echocardiography correctly revealed the superior extent of tumor thrombus. In 3 patients tumor thrombus was found at a higher level by transesophageal echocardiography than by CT, MRI and inferior venacavography. In all patients tumor imaging by transesophageal echocardiography correlated well with the gross appearance and extent of tumor found at operation. Echocardiography also documented the absence of residual gross tumor after resection. Transesophageal echocardiography was also useful to assess left ventricular function. Although each of these patients had a pulmonary artery catheter as well transesophageal echocardiography can be useful in situations when right atrial tumor thrombus prevents right heart catheterization. This small series demonstrates that intraoperative transesophageal echocardiography can accurately evaluate the extent of tumor thrombus and provides a means to assess myocardial function complementary to the pulmonary artery catheter.

Carcinoma, Renal Cell↗