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PubMed1977

Lung mechanics in congenital heart disease with increased and decreased pulmonary blood flow.

Respiratory rate, tidal volume, dynamic lung compliance, functional residual capacity, and pulmonary resistance were measured withim 24 hours of cardiac catheterization in 25 infants, 12 of whom had increased pulmonary blood flow and 13 of whom had decreased PBF. There were no differences in the two groups of patients with respect to VT and FRC. Respiratory rate and pulmonary resistance were higher in infants with increased PBF. Lung compliance was significantly lower in infants with increased PBF (4.9 ml/cm H2O) than in those with decreased PBF (8.9 ml/cm H2O) (P less than 0.01). The decrease in CL in infants with increased PBF significantly correlated with mean pulmonary artery pressure (r = 0.798). No correaltion was found between CL and left atrial pressure or magnitude of the left-to-right shunt. Compliance was normal in patients with increased PBF and normal PAP, suggesting that PAP and not PBF is the primary factor that affects CL in patients with intracardiac left-to-right shunts.

Airway Resistance↗
PubMed1982

[Atrial refractoriness and its dispersion in different physiopathologic conditions].

Previous studies have demonstrated a prolonged and non-uniform atrial refractoriness in patients with both sinus node dysfunction and supraventricular tachyarrhythmias. However, they have not been able to define separately the influence on atrial electrophysiologic properties of isolated "bradycardia", of sinus node dysfunction and of supraventricular tachyarrhythmias. Therefore we have measured the effective and functional refractory periods at three different sites of the right atrium (high, middle and low lateral wall) in 16 normal subjects (N), in 9 patients with chronic asymptomatic sinus bradycardia (AB), in 9 patients with sinus node dysfunction but without evidence of supraventricular tachyarrhythmias (SSS) and in 10 patients with paroxismal atrial fibrillation (PAF). The study was performed both in sinus rhythm and during atrial pacing (120 beats/min) utilizing twice threshold stimuli. Dispersion of atrial refractoriness (D) was determined from the range of refractory periods measured at the three different atrial sites as the longest minus the shortest refractory period. Refractoriness at the high site of the lateral wall (parasinusal zone), mean values of the refractory periods obtained at the three atrial sites, and dispersion were compared among the three groups. Refractoriness at the two rates (sinus rhythm and 120 beats/min) was also compared. During sinus rhythm SSS, AB and PAF showed a significantly higher refractoriness than N, while only SSS and PAF showed increased D. Atrial pacing reduced refractoriness but not D in all groups. At the same driven frequency refractoriness of SSS and AB, and D of SSS and PAF were still significantly higher than those of N. Finally, it is noteworthy that during paced rhythm, single values of mean refractoriness of SSS did not correspond with those of N. In conclusion, our data suggest that: 1) sinus node dysfunction and supraventricular tachyarrhythmias exert an independent influence on atrial electrophysiologic properties; 2) the presence of a less homogeneous recovery of atrial excitability should be considered as a possible concause in the genesis of atrial fibrillation; 3) chronic isolated sinus bradycardia seems to be characterized by a longer atrial refractoriness and not by an increased D; 4) contrary to results obtained in animal subjects, there does not seem to be a relation between D and cycle length in man.

Adult↗
PubMed2001

[Processes of left atrial remodeling in myocardial infarction survivors as shown by esophageal rheography].

To study the condition of the left atrium (LA) in patients with myocardial infarction (MI), 112 MI patients were compared to 24 healthy controls by the data obtained at ultrasonic investigation of the heart and esophageal rheography. 73.2% of the patients early after MI showed dilated LA. There were also changes in the ascending part of the rheographic atrial wave at its registration from the esophagus. Its marked prolongation (> 40% of the duration of the whole LA systole) is associated with alterations in the myocardial wall tonicity. If the above value was less, the number of supraventricular extrasystoles significantly increased, episodes of cardiac fibrillation occurred. Changed tonicity of the LA wall was accompanied also with prominent prolongation of the electrophysiological parameters of transesophageal pacing characterizing pacemaker's function and atrioventricular conduction. This suggests involvement not only left but also right atrium. Conclusion is that LA tonicity in MI is damaged and can be studied with esophageal rheography.

Adult↗
PubMed2006

Atrial septal defect in adults: the influence of age and haemodynamic parameters on the results of surgical repair.

INTRODUCTION: Indications for closure of atrial septal defect (ASD) are well established in children but still unclear in adult patients. There is also a discrepancy regarding the natural history of the defect and benefits of ASD closure and long-term prognosis. AIM: The aim of the study was to evaluate the outcome of surgical closure of atrial septal defect (ASD) with respect to age and selected haemodynamic parameters. METHODS: The study involved 52 patients with ASD, aged 38.6+/-15 years. All patients had a clinical examination, echocardiography, Holter ECG monitoring and cardiopulmonary exercise test (CPX) prior to and at least one year after the surgery. The results were analysed for the entire group of patients and then for the following subgroups of pts.: aged <40 and ł40 years; with right ventricular systolic blood pressure (RVSP) < or =30 and >30 mmHg; and with shunt volume ratio (Qp/Qs) <2.5 and > or =2.5. RESULTS: After repair of ASD, a significant improvement of the clinical status, as defined by NYHA class, was observed. At the same time, a constant or even increased incidence of arrhythmias was found. Repair of the defect resulted in a significant reduction of the right ventricular diameters in all studied subgroups. Among all evaluated parameters, only age at time of the operation was significantly associated with right ventricular diameter after surgery (b=0.598; p <0.001). Exercise capacity was found to have significantly increased after surgery, regardless of age, RVSP and Qp/Qs, but it remained significantly reduced in patients with pulmonary arterial hypertension compared to subjects with normal RVSP before ASD repair. A significant correlation was shown between peak oxygen consumption and RVSP both before (r=-0.68; p <0.001) and after (r=-0.38; p=0.01) surgery. CONCLUSIONS: Patients benefit from surgical closure of ASD regardless of age and previous RVSP and Qp/Qs. Age at the time of surgery and pulmonary arterial pressure determine long-term results and improvement of echocardiographic and ETT parameters.

Adult↗
PubMed2002

Analysis of atrioventricular plane movements by Doppler tissue imaging and M-mode in children with atrial septal defects before and after surgical and device closure.

Our objective was to compare the effects of surgical and device closure of atrial septal defects (ASDs) on atrioventricular plane function. In healthy individuals, both short- and long-axis motion contribute to ventricular pump function. Short-axis function (i.e., the amplitude and velocity of atrioventricular plane movements) may be evaluated by M-mode and Doppler tissue imaging. The study group consisted of 19 children with ASD of the secundum type before and after surgical (n = 12) or device (n = 7) closure and 10 healthy controls. Surgical and device closures were uncomplicated and all defects were completely closed. Registrations of atrioventricular plane systolic and diastolic amplitude and velocity were made from the tricuspid and the mitral annulus and from the septum in the apical four-chamber view. Comparisons were made between examinations before and after closure, between the two subgroups of patients treated by surgical and device closure, respectively, and between the patient group and the control groups. Before ASD closure, all measurements were normal or near normal. After surgery, systolic amplitudes and velocities of the tricuspid annulus and in the septum decreased significantly, whereas no changes were seen in the device group. Less marked changes were seen in diastolic measurements. However, in the surgical group significant decrease to subnormal values were found in the tricuspid annulus and in the septum, which may indicate a decreased diastolic function postoperatively. Mitral valve annulus amplitude and velocity were not affected by the treatment. Atrioventricular function is normal in children with right ventricular volume overload. The decrease to subnormal values after open-heart surgery is not seen after device closure of the ASD, indicating that surgery affects right ventricular function.

Adolescent↗
PubMed1991

[Right heart function and endotoxemia in animals].

We used a chronic instrumented ovine model to investigate right heart function following an endotoxin bolus. Primary aim of the experiments was to elucidate the influence of the right heart on the cardiopulmonary system. Furthermore, we tried a thromboxane synthetase inhibitor as a therapeutical approach. At least we investigated the IR-ANF release, as the endocrinal function of the right heart, in this model. Following the endotoxin administration we observed a massive increase of the pulmonary arterial pressure. As a result of the increased right ventricular afterload right ventricular ejection fraction decreased and end-systolic volume increased. Impaired right heart function could not be compensated sufficiently using Frank Starling mechanism. Consequently, decreased left ventricular preload, stroke volume and cardiac output followed. Pretreatment with OKY-046, a selective thromboxane synthase inhibitor, attenuated the increase in pulmonary arterial pressure and prevented the early right heart failure including the drop of cardiac output. Furthermore, OKY-046 changed the thromboxane-prostacyclin relationship. Therefore we consider the cardiopulmonary reactions following pretreatment with OKY-046 as a result of the attenuated right ventricular afterload as well as of the increased prostacyclin concentration. Endotoxin induced hypoxaemia could not be prevented by pretreatment with OKY-046 and might be caused by interstitial edema following endothelial leakage. IR-ANF release in our model, accompanied by polyuria and natriuresis, seemed to be independent of right heart dysfunction and increase of right atrial pressure. We suggest endotoxin or a endotoxin induced mediator as a trigger of IR-ANF release.

Animals↗
PubMed1995

The forgotten chamber: the importance of the right ventricle.

Historically, the right heart was viewed as less important than the left heart in the maintenance of normal overall hemodynamic performance. However, there is now considerable evidence that emphasizes the significance of intact right ventricular (RV) function. The RV's anatomy and physiology are reviewed in order to provide insight into how changes in volume can be accommodated within a low-pressure environment and how this contributes to hemodynamic stability. The interdependent relationship between the right and left ventricles is also explored. The contribution of RV performance to overall hemodynamics is best exemplified when the RV becomes diseased. RV infarction, atrial septal defect, and cor pulmonale are used as examples to illustrate the dramatic sequelae associated with RV dysfunction, as well as to identify the RV's specific adaptive mechanisms.

Heart Septal Defects, Atrial↗
PubMed2002

Right ventricular cardiomyopathy in beta-thalassaemia major.

AIMS: To evaluate right ventricular function in patients with beta-thalassaemia major and congestive heart failure. Background In patients with beta-thalassaemia major a high incidence of cardiac involvement still exists despite improved prognosis with chelation therapy. Development of severe right heart failure is common and has been attributed to pulmonary hypertension secondary to lung haemochromatosis. However, the possibility of direct right ventricular myocardial involvement in the absence of significant pulmonary hypertension has not been adequately investigated. METHODS: Twenty-nine consecutively screened patients with beta-thalassaemia major and congestive heart failure were investigated by Doppler echocardiography, right ventricular first-pass radionuclide examination and cardiac catheterization. Haemodynamic data were obtained both before and after volume loading. A control group of 39 patients with beta-thalassaemia major, free from cardiac disease, and matched for age, gender, body surface area and heart rate was used for comparison. A subset of the control thalassaemic group (n=15) underwent both radionuclide and haemodynamic assessment. RESULTS: The majority of patients were on non-optimal chelation therapy. Only two of 29 patients were found to have cor pulmonale. One other patient suffered from constrictive pericarditis. A restrictive filling pattern in both ventricles and left ventricular systolic dysfunction were evident in the other 26 patients. Pulmonary artery pressure (systolic, 33+/-8 vs 27+/-5 mmHg, P<0.05) and pulmonary vascular resistance (114+/-56 vs 65+/-29 dynes. s. cm(-5), P<0.01) were only mildly elevated in the heart failure group. After volume challenge, cardiac output remained unchanged although the increments of ventricular filling pressures were significant (Deltaright atrial: 4.8+/-2.2 mmHg, P<0.05; Deltapulmonary capillary wedge: 5.6+/-2.9 mmHg, P<0.05) and correlated with each other (r=0.69;P<0.001) in heart failure patients, suggesting pericardial constraint and ventricular interaction. In these patients compared with the control thalassaemic group, a lower right ventricular ejection fraction (29%+/-9 vs 59%+/-6, P<0.0001) without correlation with pulmonary artery pressures was found. Haemodynamically significant right ventricular dysfunction defined as mean right atrial pressure >10 mmHg and ratio of mean right atrial-to-capillary wedge pressure >0.8 was evident in 15 of the 26 patients (58%), all with severe symptoms, representing three fourths of the patients in functional class III and IV. Simultaneous pressure recordings in six of these 15 patients showed equalization of ventricular end-diastolic pressures within 5 mmHg. CONCLUSION: The majority of patients with beta-thalassaemia major and severe congestive heart failure demonstrated a unique haemodynamic pattern similar to that described in predominant right ventricular infarction, indicating severe right ventricular cardiomyopathy in addition to left ventricular dysfunction. The incidence of cor pulmonale as a cause of right heart failure seems to be much lower than previously hypothesized.

Adult↗
PubMed1994

Molecular and physiological alterations in murine ventricular dysfunction.

The present study reports the development and characterization of a murine model of right ventricular dysfunction following graded constriction in the pulmonary artery via microsurgical approaches. To analyze in vivo ventricular function, a technique of x-ray contrast microangiography was developed to allow the quantitative analysis of ventricular volumes and of ejection fraction in normal and pressure-overloaded right ventricle. Severe, chronic pulmonary arterial banding for 14 days resulted in right ventricular dilatation and dysfunction, associated with right atrial enlargement, and angiographic evidence of tricuspid regurgitation. These effects were dependent on the extent of hemodynamic overload, since more moderate pulmonary arterial constriction resulted in hypertrophy with maintenance of right ventricular function. With severe pulmonary artery constriction, the murine right ventricle displays a failing heart phenotype including chamber dilation with reduced function that resembles right ventricular dysfunction in man during chronic pulmonary arterial hypertension. Northern and immunoblot analyses demonstrate a marked down-regulation of phospholamban mRNA and its corresponding protein with both levels of constriction, while a less pronounced but significant depression of sarcoplasmic reticulum Ca(2+)-ATPase protein was observed with severe overload, suggesting that this pattern is an early genetic marker of ventricular dysfunction. By coupling mouse genetics with this murine model and the ability to assess cardiac function in vivo, one should be able to test the role of the down-regulation of phospholamban and other defined alterations in the cardiac muscle gene program in the onset of the failing heart phenotype.

Adenosine Triphosphatases↗
PubMed1988

[Respiratory changes of superior vena cava flow velocity in old myocardial infarction with severe left ventricular dysfunction].

The clinical significance of the flow velocity of the superior vena cava (SVC) in old myocardial infarction (OMI) with severe left ventricular dysfunction were evaluated using pulsed Doppler echocardiography. The subjects consisted of 10 patients with OMI (averaged left ventricular ejection fraction: 0.37 +/- 0.11) and 10 age-matched normal controls. Among the patients, eight had extensive anterior infarction and two had both anterior and inferior infarctions. During normal respiration, the peak SVC flow velocities in systole (S) and diastole (D), and the D/S ratio were measured. To evaluate right ventricular diastolic function, we measured the peak velocity across the tricuspid orifice in early diastole (rapid inflow: T-R) and the atrial contraction phase (T-A), and the ratio T-A/T-R during quiet expiration. In the normal controls, S was greater than D, both during expiration and inspiration. During inspiration, S, D and the D/S in the normal controls increased, with a greater increase in D than in S. In the patients, however, D and the D/S did not increase during inspiration. T-R was less and the T-A/T-R was greater in the patients with OMI than in the normal controls. These findings of tricuspid flow velocity revealed impaired diastolic filling of the right ventricle in patients with OMI. In conclusion, the impaired diastolic filling of the right ventricle in patients with OMI might be one of the causes of the abnormal response of the SVC flow velocity during normal spontaneous respiration.

Blood Flow Velocity↗
PubMedDate not supplied

Echocardiographic profile of the transplanted human heart in clinically well recipients.

Thirty-four clinically well heart transplant recipients, aged 21 to 60 years, were selected for echocardiographic study at 12 +/- 2 months after transplantation. All had normal findings at stress thallium scintigraphy and at radionuclide left ventriculography, and no endomyocardial biopsy evidence of rejection was found within 36 hours of study. Multiple echocardiographic measurements were compared with those from two control groups. The first control group consisted of 15 normal subjects of similar ages as the donors, and the second group consisted of 15 normal subjects of similar ages as the recipients. Left ventricular mass (193 +/- 55 gm) was significantly increased in the transplant recipients compared with both control groups (p less than 0.001). Left ventricular volumes and ejection fractions of the transplanted heart, however, were normal. Right ventricular diastolic wall thickness (0.6 +/- 0.1 cm) and chamber area in both diastole (23.3 +/- 3 cm2) and systole (15.7 +/- 4 cm2) were significantly increased in the transplant patients (p less than 0.001), but fractional area change was similar to that of the normal group. Both left atrial area (26.9 +/- 4 cm2) and right atrial area (20.7 +/- 4 cm2) were significantly increased in the transplant recipients (p less than 0.001). One year after transplantation, clinically well recipients are characterized by increased left ventricular mass, but normal volumes and ejection fraction, increased right ventricular wall thickness and cavity size, but normal right ventricular systolic function, and markedly dilated atria.

Atrial Function↗
PubMed2006

Presence of a ventricular septal defect and the Mustard operation are risk factors for late mortality after the atrial switch operation: thirty years of follow-up in 417 patients at a single center.

BACKGROUND: Survival and functional status of patients with transposition of the great arteries treated by atrial switch are reported to be reasonably good within the first 15 postoperative years. However, in some patients, the function of the systemic right ventricle deteriorates, leading to significant morbidity or even to late mortality. This study seeks to identify risk factors for late death. METHODS AND RESULTS: Records of 329 patients after the Senning operation and 88 after the Mustard operation at a single center were retrospectively reviewed for demographic, anatomic, and echocardiographic predictors and outcomes. Mean follow-up interval was 19.1+/-6.5 years and was 95% complete. Survival 25 years after the Mustard procedure was 75.9+/-4.8% and after the Senning procedure was 90.9+/-2.3% (P=0.002). Mustard patients died more often of arrhythmia than Senning patients (P<0.001) and needed more baffle-related reoperations (P<0.0001). Ventricular septal defect closure at the time of the atrial switch operation (hazard rate=2.3; 95% confidence interval, 1.1 to 4.7; P=0.025) and the Mustard operation (hazard rate=2.0; 95% confidence interval, 1.01 to 3.8; P=0.045) emerged as independent risk factors for late mortality in multivariate analysis. At follow-up, 85.8% of the patients led a normal life with full-time work, and 11.8% were able to do part-time work. Only 2.4% experienced noticeable limitation of activities. CONCLUSIONS: Our patient data reveal satisfactory results at long term in this historic collective. Patients who had undergone ventricular septal defect closure at the time of the atrial switch operation and those who had undergone a Mustard operation are at higher risk for late death. Close follow-up, especially of these subgroups, is warranted.

Adolescent↗
PubMed1987

Compared efficacy of quinidine, amiodarone and diltiazem on both nomotopic and ectopic automaticity in the rat heart.

The effect of quinidine, amiodarone and diltiazem have been studied on both nomotopic (isolated right atria) and ectopic automaticity (induced by a local injury in the isolated right ventricle) in the rat heart. The efficacy of these three drugs, measured by the corresponding ID25, was diltiazem greater than quinidine greater than amiodarone on atrial rate and amiodarone greater than quinidine greater than diltiazem on ectopic ventricular automaticity. A depression of isolated right atria rate (sinus node function) could be regarded as an adverse effect of the drug tested (toxicity-index). On the other hand, the reduction of ectopic ventricular automaticity by the antiarrhythmic agent is considered as desired effect (effectiveness-index). We conclude that this method might be useful to evaluate the effectiveness-toxicity ratio, as a first experimental step in the development of new antiarrhythmic drugs with a direct action on cardiac tissue.

Amiodarone↗
PubMedDate not supplied

[Usefulness of electrophysiologic studies. Report of 224 cases].

Two hundred and twenty four electrophysiologic studies were performed in 194 patients during a two-year period. One hundred and six (54.6%) had tachyarrhythmias: 21 had atrial tachycardia, 28 had the Wolff-Parkinson-White syndrome. Of 51 patients with a normal electrocardiogram a concealed left Kent bundle was observed in 21 cases and only one concealed right Kent bundle; functional James fibers were seen in 7 patients and Mahaim fibers in two. In 15 patients A-V nodal reentry was diagnosed and functional ectopy was observed in 5 patients. The sick-sinus-syndrome was seen in 24 patients and atrial arrest in three. Thirty patients underwent a second electrophysiologic study to evaluate proper antiarrhythmic therapy. Atrioventricular conduction was evaluated in 52 patients. A "suprahisian" delay was found in 34%, troncular lesions were diagnosed in 31%, a distal delay in 25% and mixed conduction disturbances in 10%. We conclude that electrophysiologic studies are a useful procedure to: 1) establish the etiologic diagnosis of tachyarrhythmias; 2) evaluate their potential danger; 3) objectively evaluate antiarrythmic therapy; 4) establish the need for surgical treatment; 5) give the topographic diagnosis and severity of A-V conduction disturbances and 6) indicate the need for definitive pacemaker implant.

Arrhythmias, Cardiac↗
PubMed1979

Assessment of left ventricular function in secundum atrial septal defect by computer analysis of the M-mode echocardiogram.

Left ventricular function in 53 patients with secundum atrial septal defect was assessed by computer-assisted analysis of the left ventricular echocardiogram and by cardiac catheterization. The patients were divided into two groups, those younger and those older than 60 years, to investigate the effect of aging on left ventricular function. Cavity size was significantly smaller than normal (p less than 0.01) and septal motion was abnormal in 86%, but values for cardiac index, left ventricular end-diastolic pressure, velocity of circumferential fiber shortening, left ventricular filling rate, and duration of rapid filling were normal in both groups. Regional dynamics assessed in terms of peak rates of systolic thickening and diastolic thinning of the septum and posterior wall were also normal in both groups. We concluded that, although left ventricular minor dimensions are small, and septal motion is reversed in the majority of patients with atrial septal defect, left ventricular function is normal, and it does not appear to deteriorate with increased age, pulmonary hypertension, or the presence of right ventricular failure. The abnormal septal motion appears to be compensated for by enhanced septal and posterior wall percentage thickening.

Adolescent↗