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[Mechanism of changes in renal functions in osmotic irritation of the right atrium].

Chronic experiments conducted on 17 dogs whose ureters were brought out on the skin of the abdomen showed that administration of solutions of saccharose (1150 mmol/l) and NaCl (515 mmol/l) into the right atrium reduces diuresis and increases natriuresis. The concentration of atrial natriuretic factor in the blood does not change, vasopressin and cortisol secretion increases while that of aldosterone decreases. It is concluded that, in addition to the cardiopeptide mechanism regulating the blood volume, the right atrium possesses a reflex osmoregulatory mechanism.

Animals↗
PubMed1996

Right and left atrial phasic volumetric function in mildly symptomatic dilated and hypertrophic cardiomyopathy: cine MR imaging assessment.

PURPOSE: To characterize biatrial phasic volumetric function in dilated and hypertrophic cardiomyopathy with cine magnetic resonance (MR) imaging. MATERIALS AND METHODS: Eight patients with dilated cardiomyopathy (mean age, 47 years), eight with hypertrophic cardiomyopathy (mean age, 39 years), and eight healthy subjects (mean age, 41 years) underwent cardiac-gated long-axis cine MR imaging of both atria. RESULTS: Left atrial minimum volume averaged 94 mL +/- 37 (standard deviation) in dilated cardiomyopathy, 86 mL +/- 40 in hypertrophic cardiomyopathy, and 51 mL +/- 14 in control subjects (P = .04). Left atrial ejection fraction averaged 16% +/- 6 in dilated cardiomyopathy, 19% +/- 12 in hypertrophic cardiomyopathy, and 28% +/- 7 in control subjects (P = .03). Right atrial minimum volume and ejection fraction were not altered in either form of cardiomyopathy. The normalized filling and emptying rates of either atrium were decreased in both forms of cardiomyopathy. CONCLUSION: In mildly symptomatic dilated and hypertrophic cardiomyopathy, and left atrium is enlarged and its relative cyclic volume changes are reduced. The right atrium is of normal size, but its reservoir function is compromised particularly in dilated cardiomyopathy. Three-dimensional volume measurements with cine MR imaging enable the exposure of altered atrial volumetric function.

Adult↗
PubMed2002

Survival in primary pulmonary hypertension: the impact of epoprostenol therapy.

BACKGROUND: Primary pulmonary hypertension (PPH) is a severe and progressive disease. Without treatment, the median survival is 2.8 years, with survival rates of 68%, 48%, and 34% at 1, 3, and 5 years, respectively. Intravenous epoprostenol was the first Food and Drug Administration-approved therapy for PPH. The long-term impact that epoprostenol has made on PPH remains to be defined. METHODS AND RESULTS: One hundred sixty-two consecutive patients diagnosed with PPH and treated with epoprostenol were followed for a mean of 36.3 months (median, 31 months). Data including functional class, exercise tolerance, and hemodynamics were recorded in a customized database. Vital status was verified in each patient. Observed survival with epoprostenol therapy at 1, 2, and 3 years was 87.8%, 76.3%, and 62.8% and was significantly greater than the expected survival of 58.9%, 46.3%, and 35.4% based on historical data. Baseline predictors of survival included exercise tolerance, functional class, right atrial pressure, and vasodilator response to adenosine. Predictors of survival after the first year of therapy included functional class and improvement in exercise tolerance, cardiac index, and mean pulmonary artery pressure. CONCLUSIONS: Intravenous epoprostenol improves long-term survival in PPH.

Adult↗
PubMed1994

Incompetence of the foramen ovale in preterm infants supported by mechanical ventilation.

Fifty-one preterm infants (< 1500 gm) who were supported by mechanical ventilation were studied by use of serial color Doppler echocardiography to determine the hemodynamic impact of incompetence of the foramen ovale. Right and left ventricular stroke volume, measured by two-dimensional and Doppler echocardiography, were used to determine the ratio of pulmonary to systemic flow (Qp/Qs). The diameter of the color flow mapping of any interatrial shunt was measured together with pattern and velocity of that shunt. Ductal patency status was established. Most infants had some atrial shunting. The dominant direction of shunting was left to right within a bidirectional shunt pattern (75%). When the ductus was closed, there was a significant correlation between color Doppler diameter of the atrial shunt and Qp/Qs (r = 0.71). When this diameter was less than 2 mm, there was minimal impact on Qp/Qs. Measurable effects on Qp/Qs were usually seen at diameters > 3 mm when Qp/Qs ratios of up to 2:1 were recorded. Longitudinally, atrial shunting could be divided into four groups. Group 1 (n = 23) had minimal shunt or small shunts (< 3 mm) that resolved early, group 2 (n = 11) had small shunts that persisted, group 3 (n = 9) had large shunts (> 3 mm) that resolved, and group 4 (n = 6) had large shunts that persisted. Clinically there were no significant differences between the groups except that patients in groups 2 to 4 tended to having worse acute lung disease than patients in group 1 and had significantly more chronic lung disease. We conclude that many preterm infants have left-to-right atrial shunts that have a noninvasively measurable hemodynamic impact. This may have an effect on acute and chronic respiratory outcome and is likely to affect assessments of ductal shunting.

Atrial Function, Left↗
PubMed1991

Differentiation of arrhythmias by measurement of intracardiac pressures in man.

Antitachycardia devices currently use sustained high rate, abrupt changes in cycle length, and probability density function to determine the onset of ventricular tachycardia. Hemodynamic changes occur with the onset of tachycardia and may provide a method of discriminating supraventricular from ventricular tachycardia. In this study, patients had atrial and ventricular pressures measured during rapid atrial and ventricular pacing. Right atrial pressure increased significantly with ventricular pacing but not with atrial pacing. Right ventricular pressures did not significantly differ with atrial or ventricular pacing. The change in atrial pressure compared to baseline was greater, with ventricular pacing compared to atrial pacing. Right ventricular pressure increased compared to baseline with atrial or ventricular pacing, but there was no significant difference between pacing modalities. Measurement of right atrial pressure might prove useful in discriminating supraventricular from ventricular tachycardia.

Atrial Function, Right↗
PubMed1997

[Atrial septum defect and open foramen ovale. Diagnosis, clinical aspects and therapy using a catheter technique].

The purpose of this report is to describe the pathophysiology and clinical symptoms of atrial septal defects with emphasis on right ventricular failure and the risk of paradoxical embolism in the setting of a patent foramen ovale. The diagnosis of both the atrial septal defects and the patent foramen ovale, usually is made by echocardiography. Percutaneous transcatheter occlusion of an atrial septal defect and a patent foramen ovale has gained interest for some years as a treatment alternative to surgical closure. Preliminary results of different devices have been encouraging and the method appears to be a viable alternative to surgical closure.

Atrial Function, Right↗
PubMed1994

Effect of isradipine and nifedipine on diastolic function in patients with left ventricular dysfunction due to coronary artery disease: a randomized, double-blind, nuclear, stethoscope study.

To elucidate the effect of isradipine and nifedipine on left ventricular (LV) systolic and diastolic function, each drug was given intravenously (i.v.) in equihypotensive doses to 10 patients accepted for coronary arteriography for stable angina pectoris. All 20 patients had LV ejection fraction (LVEF) of < 40% owing to previous myocardial infarction (MI). Systolic and diastolic function was assessed by standard hemodynamic parameters and pressure-volume relations measured by nuclear stethoscope. All measurements were taken at rest and during ischemia caused by right atrial pacing. Both systolic and diastolic parameters improved equally with isradipine and nifedipine. LVEF and cardiac output (CO) increased owing to peripheral vasodilatation. A decrease in P/Vmax, indicating a negative inotropic effect, was noted in patients at rest with both medications, but not during pacing-induced ischemia. With either medication, the time constant of relaxation and the end-diastolic elasticity constant decreased during pacing, indicating improvement in diastolic function, probably owing to relief of myocardial ischemia.

Adult↗
PubMed2006

Diversion of blood flow from noncompliant to compliant vasculature in awake dogs: mechanical impact on right atrial pressure.

The distribution of cardiac output between compliant vasculature (e.g., splanchnic organs and skin) and noncompliant vasculature (e.g., skeletal muscle) is proposed to constitute an important determinant of the amount of blood available to the heart (central blood volume and pressure). The aim here was to directly test the hypothesis that diversion of blood flow from a relatively noncompliant vasculature (muscle) to compliant vasculature (splanchnic organs and skin) acts to reduce right atrial pressure. The approach was to inflate an occluder cuff on the terminal aorta for 30 s in one of two modes of ventricular pacing in five awake dogs with atrioventricular block and autonomic blockade. In one trial, cardiac output was maintained constant, meaning cuff inflation caused a portion of terminal aortic flow (a noncompliant circulation) to be diverted to the splanchnic and skin circulations (compliant circulations). In the other trial, arterial pressure was maintained constant, meaning blood flow to these other regions did not change. The response of right atrial pressure (corrected for differences in arterial pressure between the two trials) fit our hypothesis, being lower when blood flow was diverted to compliant regions. We conclude that a small (4% of cardiac output) diversion of blood flow from a noncompliant region to a compliant region reduces right atrial pressure by 0.7 mmHg.

Animals↗
PubMed2002

Agitated colloid is superior to saline and equivalent to levovist in enhancing tricuspid regurgitation Doppler envelope and in the opacification of right heart chambers: a quantitative, qualitative, and cost-effectiveness study.

BACKGROUND: Doppler spectrum of tricuspid regurgitation (TR) is used to noninvasively assess right ventricular (RV) pressure. With mild TR, the native (Nat) TR envelope may not allow accurate pressure evaluation. Proprietary contrast agents, such as Levovist (Lev) can be used to augment TR Doppler and opacify right-sided heart chambers, but they are expensive, and their efficacy has not been objectively evaluated in patients with difficult baseline studies or compared with less expensive saline (Sal) or colloid solutions, such as Gelofusine (Gel). METHODS: Twenty-five consecutive patients with poor quality Nat TR envelopes on transthoracic echocardiogram were reexamined after serial intravenous injection of 3 contrast agents (Sal, Gel, and Lev). Doppler signals for each agent recorded on video and digitally on optical disk were assessed for signal quality, estimated RV pressure, interobserver and intraobserver variation, and longevity of signal. Quality of right ventricular-right atrial (RV-RA) opacification was also determined for Sal and Gel. Of the 25 patients, 9 underwent percutaneous right-sided heart catheterization. We used the pressures obtained from the catheterization to independently evaluate the pressure estimates from echocardiography. RESULTS: All 3 contrast agents significantly improved the mean quality grade (grades 0-5) of TR envelopes (Nat 1.12, Sal 1.97, Gel 2.56, Lev 2.41, P <.001), decreased the number of uninterpretable envelopes (grade 0) (Nat 49%, Sal 12%, Gel 4%, Lev 12%, P <.0001 for comparison of each agent relative to Nat), and improved the correlation between echocardiographic and catheter-derived RV-RA pressure measurements (Nat r = 0.65, Sal r = 0.75, Gel r = 0.90, Lev r = 0.88). The persistence of enhanced Doppler signals of interpretable quality (> grade 1) was greater for Lev (15.8 seconds) and Gel (15 seconds) than Sal (7.6 seconds) (P =.002). Opacification of RV and RA, measured as mean luminosity score during 2-dimensional harmonic imaging, was significantly higher for Gel than Sal (92.84 +/- 31.2 vs 56.06 +/- 25.6, respectively; P =.0003). Sal, Gel and Lev, respectively, cost $0.10, $2.50, and $75.00 per study. CONCLUSION: Agitated colloid is a novel, effective, and inexpensive alternative to proprietary agents and saline for the assessment of pulmonary systolic pressure and right-sided heart opacification.

Atrial Function, Right↗
PubMed1991

Incessant ectopic atrial tachycardia and sudden death.

A patient with refractory and incessant ectopic atrial tachycardia (IEAT) is reported in whom it was possible to document, during ECG (Holter) the occurrence of aborted sudden death by spontaneous ventricular fibrillation (VF). Following the second of two attempts at surgical ablation of the origin of the IEAT, the patient has been asymptomatic without antiarrhythmic drugs and in sustained sinus rhythm for 24 months. Although we cannot exclude the residual action of amiodarone and flecainide (proarrhythmia) or the residual peripartum cardiomyopathy it is probable that the observed VF was a true complication of a cardiomyopathy induced by a chronically increased heart rate (HR). Although unclear, this VF might be considered as a form of adrenergic-dependent long QT syndrome due to early afterdepolarization in the presence of predisposing myocardial conditions.

Adult↗
PubMed2003

One and a half ventricle repair for Ebstein's anomaly.

The surgical strategy for patients having Ebstein's anomaly and hypoplastic right ventricle is controversial. An 11-year-old boy patient having such condition, with estimated end-diastolic volume index of the atrialized and functional right ventricle being 70% of normally expected values, underwent biventricular repair. Immediately after the surgery, however, he developed right heart failure with the central venous pressure of 11 mmHg. He consequently underwent additional bidirectional cavopulmonary anastomosis, thereby converting the biventricular repair into one and a half ventricle repair. He recovered uneventfully and is doing well 2 years after the surgery.

Central Venous Pressure↗
PubMed2003

Atrial stunning: basics and clinical considerations.

Conversion of atrial fibrillation and flutter to sinus rhythm results in a transient mechanical dysfunction of atrium and atrial appendage, termed atrial stunning. Atrial stunning has been reported with all modes of conversion of atrial fibrillation and flutter to sinus rhythm including both transthoracic and low energy internal electrical, pharmacological, and spontaneous cardioversion, and conversion by overdrive pacing and by radiofrequency ablation. Atrial stunning is a function of the underlying arrhythmia becoming apparent at the restoration of sinus rhythm, not the function of the mode of conversion, and does not develop after the unsuccessful attempts of cardioversion or the delivery of electric current to the heart during rhythms other than atrial fibrillation or flutter. Tachycardia-induced atrial cardiomyopathy, cytosolic calcium accumulation, and atrial hibernation are the suggested mechanisms of atrial stunning. Atrial stunning is at maximum immediately after cardioversion and improves progressively with a complete resolution within a few minutes to 4-6 weeks depending on the duration of the preceding atrial fibrillation, atrial size, and structural heart disease. Atrial stunning causes postcardioversion thromboembolism despite restoration of sinus rhythm. Duration of anticoagulation therapy after successful cardioversion should depend on the duration of atrial stunning. Lack of improvement in cardiac output and functional recovery of patients immediately after cardioversion is attributed to the atrial stunning. Verapamil, acetylstrophenathidine, isoproterenol, and dofetilide have been reported to protect from atrial stunning in animal and small human studies. Right atrium stunning is less marked and improves earlier than that of left atrium, resulting in a differential atrial stunning explaining the rare occurrence of pulmonary edema after cardioversion.

Animals↗