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PubMed1997

The shape of indicator dilution curves used for cardiac output measurement in man.

1. In six patients arterial plasma lithium concentration-time curves were recorded following injection of lithium chloride into the right or left atrium. 2. Lognormal curve fitting was used to derive the areas under the first pass dilution curves. 3. Subjecting the curves produced by left atrial injection to a delay and sequential filtering produced curves that closely approximated those produced by right atrial injection. 4. We conclude that the transfer function of the right heart and lungs is equivalent to a delay and sequential filtering, that the primary indicator dilution curve is closely approximated by a lognormal curve and that loss of lithium in the lungs following right atrial injection is clinically insignificant.

Aged↗
PubMed1995

Comparative study of left ventricular function in patients with unstable angina, non-Q wave myocardial infarction and stable angina pectoris: assessment with atrial pacing and digital ventriculography.

To compare left ventricular global and segmental function at rest and during right atrial pacing in patients with unstable angina, non-Q wave myocardial infarction, and stable angina (class III angina), low-dose digital subtraction ventriculography was performed at rest and after abrupt cessation of pacing in 42 patients with unstable angina, 8 patients with non-Q wave myocardial infarction and 15 patients with stable angina during selective coronary arteriography. Left ventricular ejection fraction was significantly lower at rest in patients with unstable angina (P < 0.01) and non-Q wave myocardial infarction (P < 0.05) and during pacing (P < 0.01). These two groups of patients had significantly higher values of left ventricular end-diastolic and end-systolic volumes at rest and during pacing as compared with stable angina group. In comparing various clinical patterns of unstable angina, ejection fraction was significantly (P < 0.05) lower during pacing in patients with crescendo angina than in new-onset angina. However, ejection fraction was significantly (P < 0.01) lower in crescendo angina only at rest as compared with rest angina. The length of zone of severe hypokinesia was greater in unstable angina (P < 0.01) as well as in non-Q wave myocardial infarction (P < 0.05) both at rest and during pacing as compared with stable angina. Contractility of region of hypokinesia during pacing was higher (P < 0.01) in stable angina than in unstable angina and non-Q wave myocardial infarction. In analyzing segmental function in various subgroups of unstable angina, the authors found that the length of total hypokinesia was significantly higher (P < 0.05) during pacing in crescendo angina than in new-onset angina. Contractility of region of hypokinesia was lowest at rest and during pacing in patients with crescendo angina. This study demonstrates that patients with unstable angina as well as non-Q wave myocardial infarction were characterized by more pronounced global and segmental left ventricular dysfunction at rest and during pacing as compared with patients with stable angina, which may explain the poorer prognosis in the former two groups. This study also shows that patients with crescendo angina have more profound left ventricular global and regional dysfunction as compared with patients with new-onset as well as rest angina.

Adult↗
PubMed1998

Mechanisms of the therapeutic effect of astragalus membranaceus on sodium and water retention in experimental heart failure.

OBJECTIVE: To investigate the therapeutic effect of Astragali on sodium and water retention in aortocaval fistula-caused experimental congestive heart failure and its involved mechanisms. METHODS: In aortocaval fistula-caused chronic (5 wk), heart failure rats treated with and without Astragali 1.0 g/day intraperitoneally, changes of cardiac and renal function, renal response to atrial natriuretic peptide (ANP) were examined. Dot blot analysis was used to determine the effect of Astragali on hypothalamic arginine vasopresin (AVP) mRNA expression, and mRNA expressions of aortic and renal AVP V1a receptor, renal AVP V2 receptor and aquaporin-2 (AQP2) were simultaneously detected by RT-PCR method. RESULTS: Rats with aortocaval fistula impaired cardiac and renal functions evidenced by higher right atrial pressure (RAP), left ventricular end-diastolic pressure (LVEDP), lower + dP/dtmax of left ventricle, glomerular filtration rate (GFR), renal plasma flow (RPF), urine volume (UV), urinary sodium excretion (UNaV) and free water clearance (CH2O) compared with sham-operated control (P < 0.05). There was no change in serum sodium, hematocrit and plasma osmolality. Astragali could remarkably improve the cardiac and renal functions. Dot blot analysis demonstrated upregulated hypothalamic AVP mRNA expression in this experimental heart failure. The AVP V1a receptor mRNA level of aortic arch and renal medulla were reduced, while in renal cortex it was elevated. The mRNA expressions of AVP V2 receptor and AQP2 were increased in renal cortex while decreased in medulla. Astragali could partially or completely correct those abnormal mRNA expressions. Analysis on plasma atrial natriuretic peptide (ANP), urinary cyclic guanidino monophosphate excretion (UcGMP V), urinary cyclic guanidino monophosphate excretion/plasma atrial natriuretic peptide (UcGMP V/pANP), and further correlation and linear regression analysis between UcGMP V and plasma ANP showed that there was blunted renal response to ANP in heart failure rat, and astragali could improve the renal reaction to ANP significantly. CONCLUSION: Chinese herb, astragali have therapeutic effects on sodium and water retention in aortocaval fistula-induced heart failure, the mechanisms of which might be the improvement of cardiac and renal functions, partly correction of abnormal mRNA expressions of AVP system and AQP2, and amelioration of blunted renal response to ANP.

Animals↗
PubMed2000

Infradiaphragmatic totally anomalous pulmonary venous return with two separate descending veins in association with right atrial isomerism.

We present the case of a 1-month-old infant with right atrial isomerism and complex functionally univentricular heart disease, in whom totally anomalous pulmonary venous return drained below the diaphragm via two separate vertical veins. One of the descending vertical veins drained the entire right lung and the left upper lobe, while the other drained the remainder of the left lung. Only one similar case has been described previously.

Anastomosis, Surgical↗
PubMed2005

Long term complications in single and dual chamber pacing are influenced by surgical experience and patient morbidity.

OBJECTIVE: To determine how short and long term complication rates after pacemaker implantation are influenced by patient morbidity, operator experience, and choice of pacing system. DESIGN: Retrospective analysis of 1884 patients who received VVI (n = 610), VDD (n = 371), or DDD devices (n = 903) between 1990 and 2001. Follow up period was 64 (34) months. The influence of age, sex, coronary artery disease, myocardial infarction, reduced left ventricular (LV) function, right ventricular (RV) dilatation, atrial fibrillation, device type, and operator experience on operation time and complication rate were analysed. RESULTS: Operation time was prolonged in patients with coronary artery disease, inferior myocardial infarction, reduced LV function, and RV dilatation. Implantation of DDD pacemakers prolonged operation time, particularly among operators with a low or medium level of experience. The overall complication rate was 4.5%. Sixty seven per cent of these complications occurred within the first three months. Complication rate was increased by age, reduced LV function, and RV dilatation. Implantation of DDD systems led to a higher complication rate (6.3%) than implantation of VVI (2.6%) or VDD pacemakers (3.2%). These differences were present only among operators with a low or medium level of experience. CONCLUSIONS: Operation time and complication rate increased with age, impaired LV function, and RV dilatation. Complication rates were higher with DDD than with VVI or VDD implantation and were excessive among inexperienced but not experienced operators.

Age Factors↗
PubMed1980

[Left ventricular function in coronary disease. Gamma cineangiocardiography at equilibrium with right atrial pacing and nitroglycerine].

25 patients (2 normal and 23 coronary artery disease) were studied by 99m Tc gated blood pool scans at rest, with right atrial pacing, right atrial pacing and nitroglycerine, and finally nitroglycerine alone. Total and regional ejection fractions were measured and the induced and reversible asynergy with right atrial pacing and nitroglycerine was also assessed.

Cardiac Pacing, Artificial↗
PubMed1983

Apparent pulse wave velocity in the canine superior vena cava.

In order to evaluate clinically recorded jugular vein pulses it is necessary to understand the transmission process of the right atrial pressure pulse through the caval veins up to the jugular veins. The transmission speed at distinct points of the venous pressure curve was studied in the superior vena cava of 20 anaesthetised dogs. Under control conditions the propagation velocities varied from 1.2 +/- 0.49 to 2.5 +/- 1.36 m . s-1. During increased preload of the heart propagation velocities rose significantly from 2.2 to 4.2 m . s-1 per kPa as a function of mean venous pressure and from 2.3 to 5.8 m . s-1 per kPa as a function of phasic pressures. Right atrial pacing (between 60 and 120 beats . min-1) did not influence the propagation velocity of the studied distinct points. It was found that the summits of the pressure pulse propagate at only a slightly higher speed than the nadirs.

Animals↗
PubMed2006

Repair of Ebstein anomaly: early and mid-term results.

BACKGROUND: Ebstein anomaly is the downward displacement and adherence of dysplastic septal and posterior tricuspid leaflets into the right ventricle, thereby dividing the ventricle into a so-called atrialized chamber and a functionally reduced right ventricle. We evaluated the early and mid-term results of primary repair of Ebstein anomaly in adult patients. METHODS: Eight consecutive patients undergoing repair of Ebstein anomaly with Danielson technique at Imam Khomeini Medical Center, Tehran, Iran from January 1997 through July 2004 were evaluated. Functional and echocardiographic parameters were studied both preoperatively and postoperatively, as well as demographic status and adverse events. RESULTS: Hospital mortality occurred in one patient because of right ventricular failure. The average follow-up period was 5.3 +/- 3.4 years (median: 3.8 years). The actuarial survival rate was 85.7 +/- 4.8% at 7 years. During the follow-up, six patients were in New York Heart Association functional class I, and one patient was in class II. None of the patients required reoperation related to their Ebstein repair. One patient demonstrated atrioventricular dissociation perioperatively; however, only one patient required permanent pacemaker insertion later. One patient had minimal (1+) regurgitation, with the jet localized along the anterior part of the ventricular septum. Two patients had residual tricuspid valve insufficiency (2+) on echocardiography. CONCLUSION: Ebstein repair has a good functional and hemodynamic outcome in adult patients.

Adolescent↗
PubMed2001

Late pulmonary valve replacement after repair of tetralogy of Fallot.

BACKGROUND: Pulmonary regurgitation appears to be well tolerated early after repair of tetralogy of Fallot; however, it may result in progressive right ventricular dilatation and dysfunction necessitating eventual valve replacement. Our objective was to review our experience with late pulmonary valve replacement after complete repair of tetralogy of Fallot. METHODS AND RESULTS: A total of 42 patients (16 female and 26 male) were operated on between July 1, 1974, and January 1, 1998. Mean age was 22 years (range 2-65 years). The mean interval between tetralogy repair and pulmonary valve replacement was 10.8 years (range 1.6 months-33 years). Mean follow-up was 7.8 +/- 6.0 years (maximum 23 years). Indications for pulmonary valve replacement included decreased exercise tolerance in 58%, right heart failure in 21%, arrhythmia in 14%, syncope in 10%, and progressive isolated right ventricular dilatation in 7%. Heterograft prostheses were used in 33 patients and homografts in 9. Five patients underwent isolated pulmonary valve replacement; concomitant procedures performed in 37 patients included tricuspid valve repair/replacement (n = 18), residual ventricular septal defect repair (n = 12), atrial septal defect closure (n = 4), pulmonary artery patch angioplasty (n = 17), and right ventricular outflow tract enlargement (n = 13). One patient died early (2%) of multiorgan failure. There were 6 late deaths, 3 of which were cardiac related. Survival was 95.1% +/- 3.4% and 76.4% +/- 8.9% at 5 and 10 years, respectively. Functional class of patients was improved significantly; preoperatively, 76% of patients were in New York Heart Association class III-IV, and after pulmonary valve replacement, 97% of surviving patients were in class I-II (P =.0001). Moderate to severe reduction in right ventricular function was noted on preoperative echocardiography in 59% and on late echocardiography in 18% (P =.03). Of the 5 patients who had supraventricular arrhythmias before pulmonary valve replacement, 1 had postoperative recurrence and the arrhythmia is controlled with antiarrhythmic therapy; the other 4 are in normal sinus rhythm at late follow-up. Eight patients subsequently underwent pulmonary valve re-replacement without early mortality at a mean interval of 9.0 +/- 4.2 years (range 3.8-16.8 years). Freedom from pulmonary valve re-replacement was 93.1% +/- 4.7% and 69.8% +/- 10.7% at 5 and 10 years, respectively. The only significant risk factor for re-replacement was young age at the time of the initial pulmonary valve replacement (P =.023). CONCLUSION: Late pulmonary valve replacement after tetralogy repair significantly improves right ventricular function, functional class, and atrial arrhythmias, and it can be performed with low mortality. Subsequent re-replacement may be necessary to maintain functional improvement.

Adolescent↗
PubMed1981

Ebstein's anomaly: surgical treatment with tricuspid replacement without right ventricular plication.

Two patients with Ebstein's anomaly and severe cardiac impairment underwent surgical repair with tricuspid valve replacement and closure of associated congenital septal defects. No attempt was made to plicate the atrialized right ventricle. Good cardiac function was obtained at the end of the procedure, with uniform contractions of the whole right ventricle. Both patients are leading normal and active lives 38 and 32 months after operation. We believe that successful repair is achieved chiefly by placing a competent tricuspid valve on its true anatomical position, leaving the underlying atrialized portion of the ventricular wall undisturbed. That portion will contract and work synchronously with the rest of the right ventricle.

Adolescent↗
PubMed2005

Thrombus formation on an atrial septal defect closure device: a case report and review of the literature.

We report on a case of a mobile left atrial thrombus formation on an atrial septal defect occluder system (28 mm StarFLEX-Occluder) despite 6 months of postprocedural anticoagulation with phenprocoumon and platelet antiaggregation with aspirin in a 69-year-old woman. The closure was performed because of a significant left to right atrial shunt (Qp/Qs 1.8) with enlargement of the right atrial and ventricular cavities and impairment of right ventricular function in the presence of persistent atrial fibrillation and chronic heart failure (NYHA II-III). The 6-month follow up by transoesophageal echocardiography (TEE) revealed the floating thrombus located at the left atrial side of the occluder.

Aged↗
PubMed1981

Atrial pacing in the management of right ventricular infarction.

In a patient with left ventricular failure complicated by shock and impairment of right ventricular function caused by an infarct, right atrial pacing improved cardiac output. We believe right atrial pacing offers an alternative to plasma volume expansion, afterload reducing agents, and inotropic drugs.

Cardiac Pacing, Artificial↗
PubMed1979

Evaluation of right atrial-pulmonary artery conduits for tricuspid atresia. Experimental study.

Blood flow through right atrial-pulmonary artery (RA-PA) conduits was investigated. Experiments were designed to evaluate the pumping function of the right atrium, effects of the atrial versus ventricular pacing site, the necessity of a valve within the conduit, and the effect of positive-pressure ventilation on conduit flow. Twenty foxhounds were subjected to silicone patch closure of 90 percent of the tricuspid valve orifices to create stenosis. Ten dogs successfully underwent RA-PA shunting with a conduit with paralled limbs, one containing a prosthetic valve. The proximal main pulmonary artery was ligated to ensure total diversion of blood via the conduit. Valved and nonvalved conduit flow was significantly correlated with right atrial pressure (RAP): r = 0.95, p less than 0.05; r = 0.98, p less than 0.01, respectively. There was no significant effect of increasing heart rate (p = 0.19), atrial versus ventricular rhythm (p = 0.28), or the presence of a valve (p = 0.63). Increasing tidal volume resulted in increasing tidal conduit flow (expiration-inspiration) (r = 1.0, p less than 0.01), but mean flow was unaffected. Therefore, RAP is the most important factor influencing conduit flow. The absence of a valve, ventricular rhythm, and tachycardia did not significantly alter flow in this acute experimental model.

Animals↗
PubMed2006

The increased angiotensin II (type 1) receptor density in myocardium of type 2 diabetic patients is prevented by blockade of the renin-angiotensin system.

AIMS/HYPOTHESIS: The angiotensin II (type 1) (AT1) receptor mediates many biological effects of the renin-angiotensin system (RAS), leading to remodelling of cardiac tissue. The present study was designed to analyse changes in the function and expression of the AT1 receptor as principal effector of the RAS in myocardium from type 2 diabetic patients compared with non-diabetic myocardium as control. In addition, we determined the effect of treatment with ACE inhibitors or AT1 receptor blockers on expression levels of the receptor in diabetic patients. METHODS: Gene expression of the AT1 receptor was analysed by quantitative RT-PCR and protein expression was determined by immunoblot analysis in human right atrial myocardium. We investigated functional coupling of the receptors by measuring contractility in isolated trabeculae stimulated with increasing concentrations of angiotensin II. RESULTS: Diabetic myocardium showed a significant increase in protein expression (170 +/- 16% of control) and median mRNA expression (186% of control) of the AT1 receptor. The additional receptors were functionally coupled, resulting in a stronger inotropic response upon stimulation with angiotensin II (89 +/- 5.5% vs 29 +/- 1.6% in controls), whereas receptor affinity was similar in both groups. However, myocardium from diabetic patients treated with ACE inhibitors or AT1 receptor blockers showed no increase in AT1 receptor expression. CONCLUSIONS/INTERPRETATION: AT1 receptor expression in myocardium of type 2 diabetic patients is dynamic, depending on the level of glycaemic control and the activity of the RAS. These findings could at least in part explain the strong therapeutic benefit of RAS inhibition in diabetic patients.

Aged↗
PubMed1999

Comparison of acute effects on right ventricular haemodynamics of surgical versus interventional closure of atrial septal defects.

OBJECTIVES: We compared the acute effects on right ventricular haemodynamics of surgical versus transcatheter closure of medium-sized atrial septal defects. METHODS: We studied 47 consecutive patients with a defect in the oval fossa and a ratio of pulmonary to systemic flows between 1.5: 1 and 2: 1. They were divided into two groups according to whether the defects were closed by surgery, performed in 23 patients, or by interventional catheterization, achieved in 24 patients. By means of transthoracic cross-sectional echocardiography, we measured right ventricular end-diastolic and endsystolic volumes and calculated ejection fractions. These calculations were performed before, and between 1 and 7 days after closure of the defect. RESULTS: Before closure of the defect, all patients had an enlarged right ventricle with normal function. After closure by either method, there was no difference in the rate of normalization of end-diastolic volume, but endsystolic volume remained enlarged. Thus, the calculated ejection fraction was lower than before closure. CONCLUSIONS: There was no difference in right ventricular volumes or function early after closure of atrial septal defects, irrespective of whether this was achieved surgically or via transcatheter closure.

Adolescent↗
PubMed2002

[Surgical closure of atrial septal defect before or after the age of 25 years. Comparison with the natural history of unoperated patients].

INTRODUCTION: Surgical closure of an atrial septal defect (ASD) before the age of 25 years has been demonstrated to reduce complications during adulthood. However, the outcome for patients operated after the age of 25 is still debated. METHODS: In a retrospective study we examined the outcome of early and late surgical repair of ASD in adults, as compared with the natural evolution of unoperated patients. The study population was 280 patients (mean age 40 18 years) with non-restrictive ASD: 102 patients (group 1) underwent surgery before the age of 25 years, 90 patients (group 2) underwent surgery after the age of 25 years, and 88 unoperated patients were older than 25 years at the time of study (group 3). The variables analyzed were left ventricular systolic function, left atrial dimensions, systolic pulmonary pressure, right ventricular dimensions, the degree of mitral and tricuspid regurgitation, and the prevalence of late atrial fibrillation. RESULTS: Left ventricular systolic function and the degree of mitral regurgitation were not statistically different between groups. Compared with the patients in group 2, the patients in group 1 had a significantly lower systolic pulmonary arterial pressure (p < 0.001) and less dilated right ventricle (p < 0.001) and left atrium (p < 0.001). The degree of tricuspid regurgitation (p < 0.001) and prevalence of atrial fibrillation (p < 0.001) were significantly higher in the patients of group 2. Compared with group 3, the patients in group 2 had a significantly lower systolic pulmonary arterial pressure (p < 0.001) and less dilated right ventricle (p < 0.001). However, the left atrial dimensions, degree of tricuspid regurgitation, and prevalence of atrial fibrillation did not differ in a statistically significant way between the two groups. CONCLUSIONS: Surgical repair of an atrial septal defect in patients over 25 years of age does not fully prevent hemodynamic deterioration and the development of atrial arrhythmias. Therefore it seems that the surgical closure of ASD before adulthood should be strongly recommended.

Adolescent↗
PubMed2001

Arterial air embolism after venous air infusion in newborn piglets.

UNLABELLED: In the newborn period, decreased right atrial pressure results in functional closure of the foramen ovale (FO). The objective of this study was to investigate whether air bubbles infused in the vena cava will pass through the FO into the arterial circulation in a newborn animal. Since air tends to rise to the highest point in a fluid, the study also investigated whether the animal's position could influence arterialization of air. Twelve 1-3-d-old piglets were anaesthetized and mechanically ventilated, and had catheters placed in the vena cava for infusion of air, in the aorta for blood gas and blood pressure measurements, and in the pulmonary artery for pressure measurements. After stabilization, 0.05 ml kg(-1) per minute of air was infused for 25 min followed by a 3 h observation period. Six piglets were placed in the left, and six in the right lateral recumbent position. Air bubbles in the left atrium or ventricle was monitored by echocardiography. Ultrasound Doppler probes were placed on both carotid arteries for detection of air embolism. Gas bubbles were detected in the left ventricle within 45 s of air infusion in 11 of 12 piglets. Eight piglets had air bubbles in the carotid arteries. Mean pulmonary arterial pressure (PAP) increased significantly after 1 min of air infusion, whereas mean systemic arterial pressure remained unchanged. When arterial air embolism occurred, PAP had not increased significantly. The time to reach maximum PAP with the animals in the left recumbent position was significantly shorter than in the right. CONCLUSION: This study shows that venous gas bubbles enter the arterial circulation through the FO in newborn piglets and that body position may influence the haemodynamic effect of these bubbles.

Air↗