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PubMed2006

Right atrial size and function in patients with pulmonary hypertension associated with disorders of respiratory system or hypoxemia.

BACKGROUND AND AIM: Pulmonary hypertension (PH) determines various adaptive changes in right ventricular (RV) geometry which may progressively lead to hypertrophy, mechanical dysfunction and dilatation with pump failure. Right atrium (RA) is theoretically involved in this physiopathological process, but its role has never been investigated. We hypothesized that RA increases volume and function to assist RV during the chronic pressure overload exposition due to PH. METHODS: We prospectively enrolled 66 consecutive patients referred to our echolab with a diagnosis of PH [defined as pulmonary artery systolic pressure (PASP) >30 mmHg] associated with disorders of the respiratory system and/or hypoxemia and normal RV systolic function. Ejection force was taken up as index of RA systolic function and calculated according to the Manning's formula. Thirty-three healthy subjects for whom PH was definitely excluded by echoDoppler evaluation were used as controls. RESULTS: PASP was 42+/-10 and 20+/-8 mmHg in PH patients and controls, respectively; p=0.00001). In comparison with controls, PH patients exhibited higher RA volume (37+/-13 vs 32+/-13 ml, p=0.04) and RA ejection force (6.7+/-3.0 vs 3.5+/-1.8 Kdynes, p=0.00001). Both variables were positively related to PASP (r=0.23 and 0.48, p=0.02 and 0.00001, respectively). CONCLUSIONS: In patients with chronic PH, RA size and systolic function significantly increase and parallel signs of activation of the Frank-Starling mechanism in both right chambers. The magnitude of these phenomena is positively related to PASP levels.

Adaptation, Physiological↗
PubMed2000

Influence of left ventricular dysfunction on the role of atrial contraction: an echocardiographic-hemodynamic study in dogs.

OBJECTIVES: The purpose of this study was to understand the significance of an effective atrial systole and the interactions between atrial and ventricular function. BACKGROUND: The significance of atrial function is controversial, particularly in the setting of left ventricular (LV) dysfunction. METHODS: Serial, rapid pacing in five dogs that had undergone radiofrequency ablation and implantation of right atrial and ventricular pacemakers produced reversible atrial and ventricular dysfunction (alone and in combination). Atrial function (echocardiograph-determined transmitral diastolic flow, left atrial appendage emptying, and pulmonary venous flow), cardiac output, and right heart pressures were measured at matched paced heart rates of 80 beats/min. RESULTS: Isolated rapid atrial pacing (LV ejection fraction approximately 60%) decreased atrial booster pump in the body and appendage of the left atrium, but increased the conduit function of the left atrium. Isolated LV dysfunction (LV ejection fraction approximately 34%) increased atrial booster pump function. The decreased atrial booster pump function in animals with combined atrial and ventricular dysfunction was incompletely compensated by the redistribution of the reservoir and conduit functions of the left atrium. As a result, cardiac output decreased and right heart pressures increased only after superimposed pacing. CONCLUSIONS: In the presence of a normal left ventricle (LV), atrial failure has little effect on cardiac output and right heart pressures because of compensatory conduit function, but when early LV dysfunction coexists, changes in reservoir and conduit functions are insufficient to compensate for an impairment of atrial contraction.

Animals↗
PubMed1995

Right ventricular function and plasma atrial natriuretic peptide levels during fiberbronchoscopic alveolar lavage in critically ill, mechanically ventilated patients.

STUDY OBJECTIVE: To assess the influence of fiberbronchoscopic alveolar lavage on hemodynamics, right ventricular function, and plasma atrial natriuretic peptide (ANP) concentrations in critically ill, mechanically ventilated patients. DESIGN: Prospective investigation. SETTING: Eight-bed ICU of a university hospital. PATIENTS: Fourteen patients with cardiovascular instability due to a systemic inflammatory response syndrome who were mechanically ventilated. INTERVENTIONS: Fiberbronchoscopic alveolar lavage after fluid replacement, deep sedation, and paralyzation. Intervention time: 10 min. After inspection of the endobronchial system, one lavage of 40 mL sterile saline solution was instilled in each lung and recovered. MEASUREMENTS AND RESULTS: The fiberbronchoscopic procedure induced a prompt increase in mean pulmonary arterial pressure after 3 min (median[range]: 25 [13 to 39] to 30 [19 to 45] mm Hg, p < 0.05), which increased further after 6 min (34 [17 to 46] mm Hg, p < 0.01). Cardiac index increased simultaneously (4.25 [3.1 to 5.7] to 4.85 [4.3 to 6.9] L/min.m2 after 6 min, p < 0.01), whereas mean arterial pressure and heart rate remained unchanged. Central venous pressure rose from 12 (3 to 18) mm Hg before procedure to 14 (4 to 20) mm Hg after 6 min (p < 0.01). The right ventricular function was measured using a "fast response" ejection fraction thermodilution catheter: end-diastolic volume increased (238 [137 to 358] to 280 [150 to 4ll] mL after 9 min, p < 0.05), as well as stroke volume (88 [54 to 113] to 103 [67 to 153] mL after 9 min, p < 0.01). Right ventricular ejection fraction (37 [25 to 50] %) did not change significantly during the procedure, but the stroke work index was reinforced (8.2 [4.7 to 15.7] to 13.3 [2.4 to 41.3] gm.M/M2 after 6 min, p < 0.01). Plasma c-ANP concentration rose from 135 (24 to 350) to 196.5 (44 to 830 pg/ml after 20 min (p < 0.05). Systemic vascular resistance decreased from 533 (390 to 1,042) to 429 (281 to 684) dynes.s/cm5 after removal of the bronchoscope (p < 0.01). CONCLUSIONS: Although acute pulmonary hypertension was observed during the fiberbronchoscopic procedure, the right ventricular performance did not deteriorate in hemodynamically unstable patients. To maintain a "hyperdynamic cardiovascular state," the right ventricular stroke work was reinforced, presumably by the "Frank-Starling mechanism." We assume that the acute distention of the right side of the heart resulted in elevated ANP concentrations. The marked decrease in systemic vascular resistance might be due to high ANP levels.

Adult↗
PubMed1987

Presence of functional receptors for atrial natriuretic peptide in human pheochromocytoma.

Pheochromocytoma, a catecholamine-secreting adrenomedullary tumor, has been shown to contain the functional receptor for human atrial natriuretic peptide(h-ANP). Release of catecholamines from tissue slices of pheochromocytoma was inhibited by h-ANP in a dose-dependent manner. Binding assays using 125I-ANP revealed a single class of high affinity binding sites for ANP. When covalently tagged with 125I-ANP and electrophoresed under non-reducing and reducing conditions, the receptor migrated as a 140-kDa band and a 70-kDa band, respectively, reflecting its disulfide-linked subunit structure. The presence of ANP receptor in pheochromocytoma was further demonstrated by immunohistochemistry; the tumor was positively stained with an antireceptor antiserum. The antiserum was also useful to establish the zona glomerulosa localization of ANP receptor in the normal human adrenal gland.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Effects of hypoxia, simulated ischemia and reoxygenation on the contractile function of human atrial trabeculae.

Hypoxia, ischemia and reoxygenation cause contractile dysfunction which will be characterized by the time course of isometric contraction of human atrial trabeculae. Post-rest potentiation (PRP) and postextrastimulatory potentiation (PEP) were elicited to obtain indirect information about the the role of the sarcoplasmic reticulum (SR) in excitation-contraction coupling. As lipid peroxidation could cause SR dysfunction, thiobarbituric acid reactive substances (TBARS) were measured. After 30 min of hypoxia (H) or simulated ischemia (H combined with acidosis-SI), contractile force decreased to 15% and 6%, respectively, of control (p < or = 0.05), whereas the normalized rate of both contraction and relaxation increased. In group H, rapid reoxygenation produced a recovery of contractile force to about 60%. After post-hypoxic reoxygenation the TBARS concentration was increased. In group SI, rapid reoxygenation and a rather gradual correction of acidosis produced complete recovery of contractile force. PRP and PEP were maintained during H and SI. Particularly post-ischemic reoxygenation caused a marked depression of PRP and partly of PEP. Thus, alteration of SR Ca2+ handling occurs predominantly during reoxygenation rather than during H or SI, probably associated with the damaging effect of increased oxygen radicals. The depression of potentiation occurred along with delayed relaxation, temporary increased resting force, mechanical alternans, and spontaneous activity which are further characteristics for SR dysfunction. Thus, for a possibly beneficial effect of low pH during SI combined with its gradual correction during reoxygenation on the recovery of contractile function, developed force should not be the only index.

Action Potentials↗
PubMed1984

Atrial trigeminy induced by a normally functioning DVI pacemaker.

Atrial trigeminy was seen in a patient with a normally functioning DVI pacemaker (Byrel-5992). Atrial competition resulted from coincidence of sinus and atrial escape rates together with late ventricular sensing. This resulted in atrial output stimuli occurring within the QRS complex. Alternate impulses occurred late enough to conduct to the ventricle after recovery of the AV node. Reprogramming the pacemaker to either a faster DVI rate or to VVI abolished the arrhythmia.

Arrhythmias, Cardiac↗
PubMed2005

Relation of left atrial size to function as determined by transesophageal echocardiography.

One hundred thirty-nine patients who underwent transesophageal echocardiographic studies were grouped by their maximal left atrial (LA) volumes, and their stroke volumes, emptying fractions, and fractional shortening were calculated. In large atria, an inverse relation was found between further increases in LA volume and LA function, determined by emptying fractions and fractional shortening.

Atrial Function, Left↗
PubMed1995

Dynamic electrophysiological behavior of human atria during paroxysmal atrial fibrillation.

BACKGROUND: The aims of our study were to investigate the meaning of local atrial activation and its behavior during paroxysmal atrial fibrillation and to study the effect of overdrive pacing on local atrial activity. METHODS AND RESULTS: Twenty-five patients with lone paroxysmal atrial fibrillation underwent electrophysiological study. Functional and effective atrial refractoriness was determined. Mean and fifth percentile values of 100 consecutive atrial fibrillation intervals (FF) were evaluated at three atrial sites either at arrhythmia onset or at self-termination (or at minute 5). A high-voltage burst pacing was performed after 6 minutes of stable atrial fibrillation in 10 patients. Mean FF intervals were evaluated 5 seconds before and after atrial pacing. Forty-nine atrial fibrillation episodes were induced: 39 self-terminating within 5 minutes and 10 long-lasting. A significant correlation was found between mean FF and atrial functional refractory period (r = .73, P < .001) and between fifth percentile FF and atrial effective refractory period (r = .57, P < .005). Atrial fibrillation self-termination was associated with significant mean FF prolongation, whereas long-lasting fibrillation behaved the opposite. In 10 patients, burst pacing resulted in significant shortening of the mean FF at the stimulation site; no changes were observed in the two distant recording sites. CONCLUSIONS: The analysis of the FF intervals demonstrates a strict correlation with atrial functional refractoriness. The self-termination of atrial fibrillation is related to a prolongation of the functional refractoriness (mean FF), whereas a shortening of both functional and effective refractoriness (fifth percentile) is associated with atrial fibrillation persistence. The provoked shortening of the mean FF at the stimulation site is consistent with the presence of a gap of excitability during atrial fibrillation in the human atria.

Adult↗
PubMed1995

Recurrent seizures alter renal function and plasma atrial natriuretic peptide levels in rats.

Status epilepticus can lead to impaired renal function, which has been attributed to complications of myoglobinuria. We confirmed changes in renal function in the absence of myoglobinuria by measuring renal hemodynamics, fluid and electrolyte excretions, and plasma levels of renin and atrial natriuretic peptide (ANP) before and after a 30-min period of recurrent generalized seizures in anesthetized, paralyzed rats. Renal plasma flow (RPF), renal blood flow (RBF) and glomerular filtration rate (GFR) decreased by approximately 60% after seizures. In contrast, urinary sodium excretion, urine flow, and plasma ANP levels increased approximately threefold. Urinary potassium excretion and plasma renin levels were unchanged. Renal function is profoundly altered after 30 min of seizures, primarily due to intense renal vasoconstriction precipitating a dramatic reduction in GFR. The concomitant increases in sodium and urine excretion may be mediated by the marked increase in plasma ANP levels. The decreases in GFR and RBF might contribute to the renal failure observed in some patients after status epilepticus.

Acute Kidney Injury↗
PubMed1984

Simultaneous changes of left ventricular and left atrial size and function in normal subjects during exercise.

We performed dual M-mode exercise echocardiography, which records left ventricular (LV) and left atrial (LA) echocardiograms simultaneously, in 10 normal subjects to investigate mechanisms of cardiac adaptation to dynamic exercise. The LV end-diastolic dimension (EDD) increased significantly as exercise increased from mild to moderate (3-5%, p less than 0.05 and 0.001). At peak exercise the EDD was slightly increased, but it returned to the baseline during recovery. The LV end-systolic dimension (ESD) showed a progressive decrease with the severity of exercise (5-13%, p less than 0.05 and 0.001). It decreased further immediately after exercise (17-20%) and then returned to the resting value. The LV stroke dimension and fractional shortening increased as exercise changed from mild to moderate and reached a plateau at peak exercise. During recovery, they showed a transient increase and then decreased. By contrast, the LA dimensions, both maximum and minimum, increased significantly as exercise changed from mild to moderate (15-16% and 16-19%, p less than 0.01 and 0.001, respectively), but they were lower at peak exercise (12 and 14%). They returned rapidly to the resting values immediately after exercise. Thus, during exercise, LV function is augmented by the Frank-Starling mechanism in combination with increased contractility, while the LA is enlarged to receive the increased venous return accompanying dynamic exercise. These exercise-induced changes in LV performance return gradually to the resting state, but LA size recovers rapidly after the cessation of exercise.

Adolescent↗
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↗
PubMed2005

Assessment of atrial regional and global electromechanical function by tissue velocity echocardiography: a feasibility study on healthy individuals.

BACKGROUND: The appropriate evaluation of atrial electrical function is only possible by means of invasive electrophysiology techniques, which are expensive and therefore not suitable for widespread use. Mechanical atrial function is mainly determined from atrial volumes and volume-derived indices that are load-dependent, time-consuming and difficult to reproduce because they are observer-dependent. AIMS: To assess the feasibility of tissue velocity echocardiography (TVE) to evaluate atrial electromechanical function in young, healthy volunteers. SUBJECTS AND METHODS: We studied 37 healthy individuals: 28 men and nine women with a mean age of 29 years (range 20-47). Standard two-dimensional (2-D) and Doppler echocardiograms with superimposed TVE images were performed. Standard echocardiographic images were digitized during three consecutive cardiac cycles in cine-loop format for off-line analysis. Several indices of regional atrial electrical and mechanical function were derived from both 2-D and TVE modalities. RESULTS: Some TVE-derived variables indirectly reflected the atrial electrical activation that follows the known activation process as revealed by invasive electrophysiology. Regionally, the atrium shows an upward movement of its walls at the region near the atrio-ventricular ring with a reduction of this movement towards the upper levels of the atrial walls. The atrial mechanical function as assessed by several TVE-derived indices was quite similar in all left atrium (LA) walls. However, all such indices were higher in the right (RA) than the LA. There were no correlations between the 2-D- and TVE-derived variables expressing atrial mechanical function. Values of measurement error and repeatability were good for atrial mechanical function, but only acceptable for atrial electrical function. CONCLUSION: TVE may provide a simple, easy to obtain, reproducible, repeatable and potentially clinically useful tool for quantifying atrial electromechanical function.

Atrial Function↗
PubMed2005

Left atrium: no longer neglected.

Left atrial evaluation is strongly linked to the history of cardiac imaging. In the past, the importance of this chamber has been largely downplayed because cineangiography could not visualize it directly. Nowadays echocardiography can easily assess left and right atrial size and function. Left atrial enlargement is frequent in many cardiac diseases. A main determinant of left atrial volume is ventricular diastolic function. It has recently been suggested that left atrial volume might be the morphophysiologic expression of chronic diastolic function. In fact the left atrium is exposed directly to left ventricular diastolic pressure through the open mitral valve and because of its thin wall structure it tends to dilate with increasing pressure. Other important determinants of atrial volume are the degree of ventricular remodeling, mitral regurgitation and the presence of atrial fibrillation. The degree of left atrial enlargement is associated with adverse prognosis in different clinical settings. Patients with dilated cardiomyopathy and with a left atrial volume > 68 ml/m2 have a 3.8-fold risk compared with those with smaller left atrial volume. The predictive value of left atrial volume is independent of left ventricular systolic and diastolic function, mitral regurgitation and atrial fibrillation. This is noteworthy because these factors are both determinant of left atrial volume and have a strong impact on outcome. It might be concluded that left atrial volume represents a powerful predictive marker because it is a window allowing comprehensive evaluation of several factors associated with bad prognosis, which are often difficult to document separately.

Animals↗
PubMed2004

Simultaneous biplane single-beat assessment of left ventricular systolic function in patients with atrial fibrillation.

Left ventricular systolic function was studied in 40 patients with atrial fibrillation using a matrix-array transducer, which enables 2 simultaneous orthogonal views to be obtained in a biplane mode. Bland-Altman analysis showed excellent correlation and agreement between the systolic parameters of a single beat with identical RR1 and RR2 intervals and the measured average value over all cardiac cycles.

Aged↗
PubMed2001

Improvement of afterload mismatch of left atrial booster pump function with positive inotropic agent.

OBJECTIVES: The objective of this study was to examine the hypothesis that a positive inotropic agent improves left ventricular (LV) filling during left atrial (LA) contraction in the presence of markedly elevated LV filling pressure. BACKGROUND: In patients with old myocardial infarction (MI), an increase in the operational LV chamber stiffness reduces LV filling during the LA contraction, resulting from an "afterload mismatch" of the LA booster pump function. METHODS: We investigated the effect of dobutamine infusion (3 microg/kg/min) on the LA pump function in the presence of elevated LV filling pressure induced by aortic constriction (Aoc) during acute MI in 10 dogs. Transmitral flow velocity was determined by transesophageal echocardiography, LV pressure by a micromanometer and LV volume by a conductance catheter. We measured the early (E) and late (A) diastolic peak transmitral flow velocities (cm/s) and LV chamber stiffness (deltaP/deltaV: mm Hg/ml; where deltaP is developed pressure and deltaV is the absolute filling volume during LA contraction). RESULTS: When the deltaP/deltaV was increased by Aoc during MI (from 1.1 +/- 0.8 to 3.1 +/- 2.6 mm Hg/ml, p < 0.01), A decreased significantly (from 30 +/- 5 to 22 +/- 8 cm/s, p < 0.01), and the ratio of E to A increased (from 1.0 +/- 0.3 to 1.4 +/- 0.8, p < 0.05) compared with MI without Aoc, showing the pseudonormal transmitral flow pattern, the so called "LA afterload mismatch." Dobutamine under this condition significantly reduced the deltaP/deltaV (to 1.7 +/- 1.2 mm Hg/ml, p < 0.05), resulting in an increase in A (to 31 +/- 8 cm/s, p < 0.01) and a decrease in E/A (to 1.0 +/- 0.3, p < 0.05), and the transmitral flow became a prolonged relaxation pattern as in MI without Aoc in all dogs. There was an inverse correlation between the deltaP/deltaV and the time-velocity integral of A (r = -0.70, p < 0.01). CONCLUSIONS: Dobutamine improved the afterload mismatch of the LA booster pump function. This effect may have been due to the reduction in LV operational chamber stiffness, resulting in an increase in the LA forward ejection into the LV.

Animals↗
PubMed1994

Evidence for functionally distinct dual atrial inputs to the human AV node.

Although conventional models of the human atrioventricular (AV) node assume a single upper common pathway, animal studies demonstrate dual atrial inputs: an anterior input from the interatrial septum and a posterior input from the crista terminalis (running near the os of the coronary sinus in the posteroseptal region). We hypothesized that functionally distinct dual atrial inputs to the AV node also exist in humans and that the anterior input has a lower safety factor for impulse propagation. To evaluate this hypothesis, we examined 20 patients undergoing radiofrequency ablation of the slow AV nodal pathway for AV nodal reentrant tachycardia who underwent subsequent follow-up testing. After ablation near the os of the coronary sinus (and posterior to the compact AV node), 11 patients had no residual slow pathway conduction [SP(-)], whereas 9 did [SP(+)]. The effective refractory period of the fast AV nodal pathway (FP-ERP) and anterograde AV nodal Wenckebach (AVN-W) cycle length were significantly increased at follow-up in the SP(-) patients (FP-ERP = 336 +/- 71 vs. 387 +/- 103 ms, P = 0.02; AVN-W cycle length = 356 +/- 74 vs. 442 +/- 118 ms, P = 0.03) but not in SP(+) patients. Similarly among 10 patients undergoing radiofrequency ablation of a right posteroseptal accessory pathway (near the os of the coronary sinus), 5 developed impaired AV conduction: abnormal anterograde pacing-induced AVN-W cycle length in 4 patients and 2:1 AV nodal block in 1 patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Sinus node function evaluated by spontaneous atrial premature contractions].

Sinus node function was evaluated according to spontaneous premature atrial contractions (APC). In 33 patients, who showed evidence of more than 10 APCs in 24-hour Holter ECG, sinoatrial conduction times (SACT) were measured by the Strauss' method. Time difference between the interval preceding PP, the APC and return cycle following APC was expressed as RC-SC. Patients were categorized in three groups; CSRT less than 500 and 2SACT less than 180 msec (A), 500 less than or equal to CSRT less than 1000 and/or 180 less than or equal to 2SACT less than 250 msec (B), and CSRT greater than or equal to 1000 and or 2SACT greater than or equal to 250 msec (C). There was significant correlation between the mean RC-SC and 2SACT (r = 0.69). Mean RC-SC was greater than 2SACT in all seven patients whose CSRTs exceeded 2000 msec. The mean RC-SC was 0.15 +/- 0.03 in group A, 0.20 +/- 0.02 in group B and 0.25 +/- 0.06 (sec; mean +/- SD) in group C. The max RC-SC was 0.20 +/- 0.03 in group A, 0.28 +/- 0.03 in group B and 0.36 +/- 0.07 sec in group C. The mean RC-SC and max RC-SC differed significantly among the three groups (p less than 0.05). The standard deviation in distribution of the RC-SC was 0.033 +/- 0.008 in group A, 0.044 +/- 0.007 in group B and 0.052 +/- 0.017 sec in group C. RC-SCs equal to or longer than 0.24 sec were observed in 1% in group A, 26% in group B and 58% in group C, and that equal to or longer than 0.30 sec was found in 0, 3 and 28% in groups A, B and C, respectively. The RC-SC reflects not only SACT but sinus node automaticity, and provides more simple detection of sinus dysfunction. Sinus dysfunction may exist when the RC-SC is greater than 0.30 sec.

Adult↗
PubMed1975

Assessment of left ventricular function in secundum atrial septal defect: evaluation by determination of volume, pressure, and external systolic time indices.

Left ventricular function and volume data from 17 control subjects and 27 young patients with secundum atrial septal defect (ASD) without overt left or right ventricular failure were compared. ASD patients were subdivided in low shunt (Qp/Qs less than 2.0) and high shunt (Qp/Qs larger than or equal to 2.0) groups. Mean left ventricular (LV) stroke volume was significantly less in ASD patients (46 +/- 16 ml/m2 in the low shunt and 44 +/- 9 ml/m2 in high shunt group) compared with control patients (51 +/- 13 ml/m2, P less than 0.01 and P less than 0.02, respectively). There was no significant difference in mean left ventricular end-diastolic volume (LVEDV) between any group of patients (control subjects 67 +/- 17 ml/m2; low shunt ASD 66 +/- 17 Ml/m2, and high shunt ASD 62 +/- 12 ml/m2). High shunt ASD had a significantly lower cardiac index compared with control patients (5.0 liters/min/m2 vs. 5.9 liters/min/m2, P less than 0.02). Both low shunt and high shunt ASD showed significantly lower stroke work indices than control subjects (42 +/- 13 GmM/m2 and 37 +/- 8 GmM/m2 compared with 51 +/- 14 GmM/M2 , P less than 0.05 and P less than 0.001, respectively) but only the high shunt group had a significantly lower peak systolic pressure (94 +/- 12 mm Hg vs. 109 +/- 11 mm Hg for control patients, P less than 0.01). There was no significant difference between the control and ASD groups in LV end-diastolic, mean right atrial, right ventricular end-diastolic, and pulmonary pressures. External systolic time intervals were compared in 5 control and 12 ASD patients. There was no significant difference between the two groups of patients in absolute values or indices for pre-ejection period, ejection time, or electromechanical systole. However, the ratio of the pre-ejection period index to left ventricular ejection time index (PEPI/LVETI) was significantly higher in ASD patients (P less than 0.05). In young subjects with large shunt ASD, certain indicators of left ventricular function are depressed. Evaluation of PEPI/LVETI may allow noninvasive determination of LV function.

Adolescent↗