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PubMed1987

The acute haemodynamic effects of intravenous enalaprilic acid (MK422) in patients with left ventricular dysfunction.

Intravenous enalaprilic acid (2.5 mg) was given to 11 patients with stable cardiac failure (NYHA functional class II-IV). Reductions in mean right atrial, pulmonary artery and pulmonary capillary wedge pressure of 25%, 18% and 30% respectively (P less than 0.01), were observed. Cardiac output rose by 13% (NS) and mean blood pressure fell by 20% (P less than 0.01) with a decrease in systemic vascular resistance of 24% (P less than 0.01). Heart rate was unaltered. The haemodynamic effects correlated with control plasma renin activity (r = 0.78, P less than 0.01). Marked hypotension occurred in several subjects but no other side-effects were noted. The rapid onset of action and mixed venous and arteriolar dilating activity of intravenous enalaprilic acid may be an advantage in some clinical situations where parenteral vasodilating therapy is required.

Aged↗

PubMed1999

Catheter ablation in a patient with a congenital giant right atrial diverticulum presented as Wolff-Parkinson-White syndrome.

A young woman symptomatic for tachycardia showed right ventricular preexcitation on the surface ECG with a pattern during induced atrial fibrillation suggestive of multiple APs. Noninvasive imaging techniques performed prior to catheter ablation demonstrated the presence of a giant right atrial diverticulum confirmed by hemodynamic procedure. This structure functioned as an enormous accessory AP. We performed catheter ablation of this pathway using a special 4-mm multipolar catheter inside the diverticulum. This is the first case of such as anomaly being successfully treated with catheter ablation.

Adult↗

PubMed1980

Widespread distribution and rate differentiation of the atrial pacemaker complex.

In a study to examine the basis of rate-related changes in the electrocardiographic P wave we found a multicentric rather than unifocal origin of the atrial depolarization wave in dogs. Three to five pacemakers, or origin points, were distributed over a 30- to 40-mm area compared to the 11-mm size of the sinus node. Two or three of the sites could excite simultaneously, or one specific site would dominate excitation. Each separate origin point dominated excitation within a specific range of heart rates, and on reaching either the upper or lower limits of this range, a new focus abruptly dominated and initiated the atrial wave front. We have obtained evidence to suggest that these findings may be explained by a widely distributed atrial pacemaker complex. The spatial distribution of this system exceeded the dimensions of the canine sinus node by a factor of three to four times. The pacemaker centers, although distributed, were consistently located at specific positions along the superior vena caval-right atrial junction. Also, each separate pacemaker site appeared functionally differentiated to generate a specific range of heart rates. We propose that in addition to the sinus node there are other specialized atrial pacemaker centers, and that this specialization, including the differentiated response and coordination, is conferred by focal receptor characteristics and their inputs.

Action Potentials↗

PubMed1975

Primitive ventricle with acquired subpulmonary stenosis.

The course and natural history of two children aged 1 yr and 5 yr with primitive ventricle with outlet chamber and normally related great arteries are described. They initially presented as ventricular septal defect with increased pulmonary blood flow and subsequently developed 'cyanotic attacks', chronic cyanosis and diminished pulmonary flow by acquiring subpulmonary obstruction of the bulboventricular foramen. Both had successful surgical treatment utilizing their own normal pulmonary valves by connecting the right atrium to the right ventricular outflow, with a Dacron conduit in one, and in the other by detaching the pulmonary artery and valve from the rudimentary outflow chamber and anastomosing it directly to the right atrial appendage. Changing morphology and its effect on function are discussed.

Cardiomyopathy, Hypertrophic↗

PubMed1986

Severe right ventricular failure after Mustard or Senning operation. Two-stage repair: pulmonary artery banding and switch.

Since early 1981 I have been banding the pulmonary arteries of patients in whom severe right ventricular dysfunction has developed after atrial repair of transposition of the great arteries. The purpose of banding is to "retrain" the left ventricle. Of the four patients so treated, two developed adequate left ventricular pressures and have successfully undergone an arterial switch and takedown of the atrial repair. The early results are impressive. Right ventricular function has returned to normal in both patients and tricuspid valve regurgitation has resolved. In one patient moderate aortic valve regurgitation also appears to have largely resolved.

Blood Pressure↗

PubMed2000

Magnetic resonance imaging and echocardiography in assessment of ventricular function in atrially corrected transposition of the great arteries.

OBJECTIVE: Patients with atrial correction of transposition of the great arteries (TGA) may develop right ventricular (RV) failure with time. A reliable non-invasive method for assessment of ventricular function is therefore needed. To evaluate the accuracy of echocardiography in assessment of ventricular volumes and function in these patients we compared echocardiography with magnetic resonance imaging (MRI) in 10 patients late after the Mustard and Senning procedures. DESIGN: Prospective echocardiography and MRI examinations were performed on the same day. Two different echocardiography technicians examined all patients. All echocardiography and MRI examinations were performed at the university hospital outpatient clinic and MRI department respectively. Ten patients, age 14.0+/-2.9 years, who had been operated on with atrial correction of TGA at 8 (2-60) months of age (median and range) were examined. Echocardiography RV and left ventricular (LV) end-systolic volumes (ESVs), end-diastolic volumes (EDVs), stroke volumes (SVs) and ejection fractions (EFs) were calculated, using the modified Simpson method, and compared with the same measurements obtained from MRI. RESULTS: For RV function there was good agreement between echocardiography- and MRI-derived measurements. Both echocardiography and MRI revealed reduced RV function with EFs of 42.6+/-9.1% and 46.4+/-7.2% respectively. For RV volumes there were no significant differences between echocardiography and MRI. LV function was significantly overestimated by echocardiography (EF with echocardiography = 72.7+/-4.4% vs. MRI = 50.5+/-7.6%) while all LV volumes were greatly underestimated. Echocardiography measurements of volumes in repeated examinations by different technicians showed large variations, 13-50%, for different variables in individual patients. CONCLUSION: Echocardiography can provide clinically important information concerning RV function in follow-up of patients late after atrial correction of TGA. It has limited value in assessment of LV function in these patients. Volume measurements by echocardiography are, however, highly user-dependent and interobserver variation is high. MRI may accordingly serve as an important reference method in individual patients.

Adolescent↗

PubMed1991

Effect of intra-aortic balloon counterpulsation on right-left shunt following right ventricular infarction.

Intra-aortic balloon counterpulsations decrease the left ventricular end-diastolic pressure and, subsequently, the left atrial pressure in patients with impaired myocardial function following myocardial infarction. This paper reports a case of right ventricular infarction in a patient with patency of the oval foramen where the use of intra-aortic balloon counterpulsation led to the perpetuation of the right-to-left shunt.

Coronary Artery Bypass↗

PubMed2005

Invasive optimization of cardiac resynchronization therapy: role of sequential biventricular and left ventricular pacing.

BACKGROUND: Aim of this invasive study was to characterize and quantify changes in left ventricular (LV) systolic function due to sequential biventricular pacing (BV) as compared to right atrial triggered simultaneous BV (BV(0)), LV, and right ventricular (RV) pacing in patients with congestive heart failure (CHF). METHODS: In 22 CHF patients, all in sinus rhythm, temporary multisite pacing was performed prior to implantation of a permanent system. LV systolic function was evaluated invasively by the maximum rate of LV pressure increase (dP/dt(max)). Sequential BV pacing was performed with preactivation of either ventricle at 20-80 ms. RESULTS: In comparison to RV pacing, LV and BV(0) pacing increased dP/dt(max) by 33.9 +/- 19.3% and 34.0 +/- 22.6%, respectively (P < 0.001). In 9 patients, optimized sequential BV pacing further improved dP/dt(max) by 8.5 +/- 4.8% compared to BV(0) (range 3.3-17.1, P < 0.05). In 10 patients exhibiting a PR interval < or =200 ms, LV pacing was either superior (n = 6) or equal to BV(0) pacing (n = 4). In these 10 patients, LV pacing yielded a 7.4 +/- 8.0% higher dP/dt(max) than BV(0) pacing (P < 0.05). CONCLUSIONS: Using sequential BV pacing, generally with LV preactivation, moderate improvements in LV systolic function can be achieved in selected patients. Baseline PR interval may aid in the selection of the optimum cardiac resynchronization therapy (CRT) mode, favoring LV pacing in patients with a PR interval < or =200 ms.

Aged↗

PubMed1993

Influence of the breathing mode on the time course and amplitude of the cyclic inter-atrial pressure reversal in postoperative coronary bypass surgery patients.

The haemodynamic basis for paradoxical embolization in patients with stroke and decompression sickness has not yet been fully elucidated. Therefore right and left atrial pressures were measured simultaneously with peroperatively placed catheters after coronary artery bypass grafting in 17 patients with sinus rhythm and normal left ventricular function. Recordings were made both during spontaneous breathing and positive pressure ventilation. A cyclic pressure reversal in which right atrial pressure exceeded left atrial pressure was reproducibly recorded. It started on average 215 +/- 5 ms (mean +/- SEM) after the onset of the electrocardiographic P-wave, lasted on average 179 +/- 14 ms and had a maximal amplitude of on average 4.1 +/- 0.3 mmHg. During the expiration phase of spontaneous breathing and inspiration phase of positive pressure ventilation, the onset of the pressure reversal occurred later, its duration was shorter and its amplitude smaller. These observations demonstrate the presence of a cyclic inter-atrial pressure reversal and illustrate the importance of the breathing mode for the time course and amplitude of this reversal.

Adult↗

PubMed1975

Massive Ringer's lactate infusion: comparison with dextrose 5% and whole blood.

The objectives of this study were to compare in dogs the effects of massive infusion of Ringer's lactate, 5% dextrose in water, and whole blood. Special interest centered upon lung function, central venous pressure, and dilutional effects upon the blood components. Three groups of 5 healthy dogs each received respectively Ringer's lactate, 5% dextrose, or whole blood over 60 minutes in the amount of 135 ml/kg. Arterial blood gases and pH, right atrial and systemic arterial pressures, hemoglobin and hematocrit values, and plasma sodium, chloride, potassium and protein levels were determined. Coagulograms and serum osmolality were examined in the early experiments. The purpose of the whole blood infusion was primarily to serve for comparison in the study of dilutional effects upon blood components. There was no statistically significant change in the arterial blood gas values or pH following Ringer's lactate infusion. The infusion of 5% dextrose in water produced moderate decline in arterial Pco2 and a temporary, slight fall in blood pH. Ringer's lactate infusion produced a prompt and statistically significant rise in central venous pressure. The infusion of 5% dextrose was followed by a late moderate decline in arterial blood pressure, possibly due to marked dilution of plasma sodium, chloride and potassium. It is concluded that massive Ringer's lactate infusion is capable of increasing right atrial pressure and presumably cardiac output. In healthy dogs, lung function was not impaired sufficiently to alter arterial blood gas values. However, where other previous or concomitant factors have diminished pulmonary reserve, fluid overload may impose a serious additional burden upon cardiopulmonary function.

Aged↗

PubMed1990

Chiari network entrapment of thromboemboli: congenital inferior vena cava filter.

Pulmonary emboli and a right atrial thrombus enmeshed in a Chiari network developed concurrently in a 69-year-old man. The network perhaps functioned as an inferior vena cava filter preventing massive pulmonary embolus. Chiari network should be considered in the differential diagnosis of a right atrial mass and the presence of pulmonary emboli should suggest surgical removal.

Aged↗

PubMed2006

Unusual complication of aortic root reconstruction with sparing of the aortic valve: left ventricular outflow tract to right atrial fistula.

The technique of aortic root reconstruction with sparing of the native aortic valve has been adopted in patients with dilatation or dissection of the aortic root and normal, functional aortic valve leaflets. We report two patients who developed an unusual complication of this surgical procedure: a left ventricular outflow tract to right atrial fistula. The clinical presentation of these patients, the steps leading to the diagnosis of the fistula, and the mechanism of fistula development are outlined. Specific emphasis is placed on echocardiographic diagnosis and differential diagnosis of a left ventricular outflow tract to right atrial fistula.

Adult↗

PubMed1990

Developmental sequelae of fixed-rate ventricular pacing in the immature canine heart: an electrophysiologic, hemodynamic, and histopathologic evaluation.

Permanent, fixed-rate ventricular pacing (VVI) is associated with hemodynamic deterioration in the adult with compromised myocardial function. The effects of this pacing mode on the intact, immature heart, however, are largely unknown. Twelve beagle puppies (age 3 to 4 months) were equally divided into paced and age-matched control groups. All underwent identical hemodynamic and electrophysiologic evaluations. Transepicardial atrioventricular block and pacemaker insertion were additionally carried out in the paced group. After 4 months of observation, repeat hemodynamic and electrophysiologic measurements followed by histopathologic examinations were done in all puppies. The paced group exhibited significant (p less than 0.05) elevations of right atrial and pulmonary artery pressures, alterations in sinus node function, and prolongation of ventricular refractory periods compared with the control group. Initiation of dysrhythmias by programmed electrical stimulation was observed only among the paced group of puppies. Histologic examination demonstrated myofibrillar cellular disarray, dystrophic calcifications, prominent subendocardial Purkinje cells, and an increase in variable-sized, disorganized mitochondria only in the paced specimens. These findings indicate that permanent, apically-initiated VVI pacing ultimately predisposes to adverse cellular changes associated with hemodynamic and electrophysiologic deterioration in the intact, developing immature canine heart.

Animals↗

PubMed1983

Contrast echocardiographic shunts may persist after atrial septal defect repair.

We performed contrast echocardiography on 19 subjects who were asymptomatic in the postoperative period after surgical repair of atrial septal defects. Eighteen of these subjects had adequate right heart echocardiographic contrast to assess the presence or absence of right-to-left shunting. Multiple M-mode and two-dimensional echocardiographic views were studied during several contrast injections with and without the Valsalva manoeuvre. Six patients had postoperative shunts and 12 patients had no postoperative shunts. The age of the six patients with postoperative shunts was 26 +/- 10 years (mean +/- s.d.) and that of the 12 patients without postoperative shunts was 39 +/- 14 years. Four out of six of the postoperative shunt group were males and of these three had patch repairs compared with two males out of 12 with patch repair in the no shunt group. There were no definite differences between the two groups in the following variables: type of atrial septal defect (primum v. secundum), preoperative shunt size, pre-operative peak right ventricular pressure, pre-operative New York Heart Association functional class, pre- or postoperative right ventricular or left ventricular dimensions, aortic and left atrial dimensions. Four of the six patients with postoperative contrast echo shunting underwent cardiac catheterization, showing no significant step-up in oxygen saturation in three, and a significant shunt in one patient who had patch dehiscence at re-operation. We conclude that right-to-left shunts as demonstrated by contrast echocardiography are common in the late postoperative period after atrial septal defect repair. They need not indicate unsuccessful repair or a haemodynamically important residual shunt.

Adolescent↗

PubMed2001

Effect of interatrial block on left atrial function.

Interatrial block produces prolonged P-waves due to conduction delay mainly in the Bachmann bundle, the most direct route from right to left atrium. It is prevalent in patients over age 60 with its main clinical significance its association with eventual atrial fibrillation and/or flutter. Having demonstrated a mean delay in the onset of active left ventricular filling of 37 msec, we defined the electromechanical abnormality further by measuring left atrial volume at key points in the atrial cycle to produce 10 measurements of left atrial function. Compared to the normal left atrium, interatrial block is correlated with a large, poorly contractile left atrium with a delayed and markedly reduced contribution to left ventricular filling and the kinetic energy with which atrial systole propels blood.

Atrial Fibrillation↗

PubMed2000

Unusual eustachian valve function.

The eustachian valve directs oxygen-rich blood from the inferior vena cava toward the foramen ovale and away from the tricuspid valve during fetal development. Ordinarily, it does not prevent reflux of right atrial blood back into the inferior vena cava because it does not function as a true valve. Here we describe an unusual adult patient with severe tricuspid valve regurgitation in whom the eustachian valve did function as a true, albeit regurgitant, valve.

Aged↗

PubMed1995

Primary neural involvement in renal haemodynamic and functional responses to prolonged stimulation of atrial receptors in anaesthetized dogs.

To determine the precise contributory role of neural and humoral factors in the efferent mechanism of the atrial receptor-renal reflex, we have examined the effects of prolonged (45 min) stimulation of left atrial receptors on renal haemodynamics and function simultaneously in both kidneys (right kidney intact and left kidney denervated) of anaesthetized dogs. Aortic pressure in these dogs was held constant by means of an arterial reservoir connected to the aorta; heart rate changes were prevented by blocking beta 1-adrenoceptor activity with atenolol (2 mg kg-1 i.v.). Localized stimulation of atrial receptors in six dogs increased renal blood flow (6 +/- 2%), creatinine clearance (11 +/- 4%), urine flow (9 +/- 3%), sodium excretion (14 +/- 7%) and osmolal excretion (10 +/- 4%), and decreased free water clearance (14 +/- 7%) in intact kidneys, but led to no changes in denervated kidneys. In an additional four dogs, cooling the vagus nerves to 6-7 degrees C or cutting them in the neck abolished the renal responses to stimulation of atrial receptors in these stabilized preparations. These data clearly demonstrate that the renal responses to prolonged stimulation of atrial receptors are primarily mediated via myelinated vagal afferents and renal sympathetic efferents.

Animals↗

PubMed1982

Hemodynamic benefit of atrial pacing in right ventricular myocardial infarction.

Right ventricular and inferior-posterior myocardial infarctions in four patients were complicated by low-output syndrome unresponsive to increasing intravascular volume. Ventricular pacing was started because of bradyarrhythmias, but failed to increase cardiac output; atrial pacing at identical rates resulted in dramatic increases in cardiac output. The importance of atrial contribution to ventricular function, as well as the role of the pericardium in this clinical setting, are discussed. In treating right ventricular myocardial infarction, atrial or atrioventricular sequential cardiac pacing may be preferable to ventricular pacing.

Aged↗