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PubMed2005

The determinants of right ventricular function in patients with atrial septal defect.

OBJECTIVE: The purpose of this study was to ascertain the determinants of right ventricular (RV) systolic and diastolic functions in patients with atrial septal defect. METHODS: Thirty-three patients with atrial septal defect having left to right shunt were enrolled in this study. RV function parameters were assessed echocardiographically. RV systolic function was assessed using tricuspid tissue Doppler S velocity (St). With regard to RV diastolic function parameters, E/A ratio, deceleration time (DT), E/Et ratio (Et = tissue Doppler E velocity), RV isovolumetric relaxation time (RVIVRT) were assessed. RV myocardial performance index (MPI) was calculated as an index of both systolic and diastolic function. Pulmonary artery stiffness (PAS) was also calculated. After echocardiography, right and left heart catheterization was performed. Mean pulmonary artery pressure (MPAP), mean right atrial pressure (MRAP), systemic flow (Qs), pulmonary flow (Qp), systemic vascular resistance (SVR), and pulmonary vascular resistance (PVR) were obtained using the data of invasive measurements. RESULTS: In multivariate analysis, MPAP was found to be the parameter closest related to RVIVRT (r = 0.73, p < 0.001) and E/Et (r = 0.66, p < 0.001), while PAS was found to be the parameter closest related to MPI (r = 0.53, p = 0.002). In addition, St velocity was found the only parameter related to PVR (r = -0.39) in univariate analysis. There was no relationship between QP/QS and any of the RV function parameters. CONCLUSION: The pulmonary vascular bed appears to be the predictor of the RV functions in patients with atrial left to right shunts, and the amount of the shunt seems to have no direct adverse influence on the RV functions.

Adult↗
PubMed2000

Effects of different atrioventricular intervals during dual-site right atrial pacing on left atrial mechanical function.

Recent studies have suggested that dual-site right atrial (RA) pacing via the high RA and coronary sinus ostium (CSos) prevents atrial fibrillation (AF). However, the programming of the atrioventricular (AV) interval associated with optimal left atrial (LA) mechanical function during high RA and dual-site RA pacing has not been defined. LA mechanical function was studied by measuring transmitral pulsed Doppler echocardiographic peak A wave velocity and percent A wave filling, in six women and three men, 67 +/- 8 years of age, who had received dual-site RA pacemakers in a randomized study. Serial echocardiographic measurements were performed during high RA or dual-site RA pacing at 80 beats/min with AV intervals of 50, 100, 150, or 200 ms tested in random order. High RA and dual-site RA pacing at an AV interval of 50 ms were associated with significantly lower peak A wave velocity and percent A wave filling, compared to the other AV intervals (all P < 0.05). Compared with high RA pacing, dual-site RA pacing was associated with significantly higher peak A wave velocity (85 +/- 12 vs 72 +/- 17 cm/s, P = 0.04) and percent A wave filling (24 +/- 3 vs 20 +/- 4%, P = 0.02) at an AV interval of 100 ms, but a lower peak A wave velocity at an AV interval of 200 ms (77 +/- 10 vs 84 +/- 8 cm/s, P = 0.004). In conclusion, variations in the AV interval during atrial pacing have significant effects on LA function. As a consequence of altered atrial activation, the AV interval associated with optimal LA mechanical function during dual-site RA pacing was significantly shorter than that during RA pacing. This observation has important implications with respect to the programming of dual-site RA pacemakers implanted to prevent AF for hemodynamic purpose.

Aged↗
PubMed1989

Right ventricular myocardial function after atrial switch operation for transposition of the great arteries.

Postoperative right ventricular (RV) myocardial function was evaluated in 6 patients who underwent atrial switching for simple transposition of the great arteries (TGA). The average age at study was 5.5 years. RV function was evaluated at rest and during administration of methoxamine by cardiac catheterization and RV angiography. The data were compared with left ventricular function in a control group, which consisted of 6 patients, 3 with functional murmur and 3 with pulmonary valvar stenosis. During stress, the TGA group showed a significant increase in end-diastolic pressure, minute work index and end-diastolic and end-systolic volume indexes, along with a significant decrease in ejection fraction. The control group also showed an increase in these variables except for ejection fraction during stress, which did not change. The slope of the work-function curve for the TGA group was lower than that for the control group (p = 0.02). The TGA group had a lower slope of the peak systolic pressure-volume relation than the control group (p = 0.005). There was no significant correlation between the slope of the peak systolic pressure-volume relation and age at repair or study. This study shows that RV pump dysfunction observed in postoperative TGA patients may be caused by depressed myocardial function.

Cardiac Catheterization↗
PubMed1985

Improved right ventricular function after intra-atrial repair of transposition of the great arteries.

Current interest in the arterial switch operation for simple transposition of the great arteries (TGA) has led us to evaluate our latest patients who have undergone intra-atrial repair. Right ventricular function and overall results were compared in 32 patients who had undergone the Senning procedure between 1978 and 1983 and 26 patients who had undergone Mustard repair between 1971 and 1978). Deep hypothermia and circulatory arrest were used in all Senning operations and in 18 of 26 Mustard procedures. Cardiac catheterization was performed an average of 1 year after surgery in all patients. Postoperative right ventricular ejection fraction (EF) was below normal (less than 0.49) in 16 of 32 patients who underwent the Senning procedure and averaged 0.48 +/- 0.09. In the patients in this group with abnormal right ventricular EFs after repair there was a fall in the value after surgery (0.51 to 0.40, p less than .001), while in those with normal right ventricular EFs after repair there was no change (0.57 to 0.55, NS). All 32 patients who underwent the Senning procedure were compared with 26 patients who underwent the Mustard operation (13 treated between 1971 and 1974 and 13 treated between 1975 and 1978). An older age at surgery (12 +/- 7 vs 6 +/- 8 months, p less than .006) and a lower preoperative right ventricular EF (0.46 +/- 0.09 vs 0.54 +/- 0.08, p less than .007) characterized the Mustard vs the Senning group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed2002

Transcatheter closure of atrial septal defect preserves right ventricular function.

OBJECTIVES: To determine the effects of atrial septal defects (ASD) and their closure on systolic and diastolic right and left ventricular function; and by comparing surgical closure with transcatheter device closure, to establish differences attributable to cardiopulmonary bypass. DESIGN: Cross sectionally guided M mode echocardiographic ventricular long axis function was measured prospectively before and within one week after ASD closure by device in 17 patients and by surgery in 12 patients, and compared with 18 normal subjects. RESULTS: All indices of right ventricular function were impaired after surgery: mean total excursion, -1.89 cm (95% confidence interval (CI), -2.18 to -1.59); peak shortening rate, -9.09 cm/s (-10.82 to -7.35); peak lengthening rate, -9.26 cm/s (-11.09 to -7.43). Total excursion and peak lengthening rate were preserved after device closure, at -0.12 cm (-0.28 to 0.05) and 0.01 cm/s (-2.29 to 2.31), respectively. Left ventricular free wall function was unchanged after closure by either method, while all septal measurements were reduced after closure by either method (changes ranging from -3.51 to -0.32; 95% CI ranging from -4.90 to -0.13). CONCLUSIONS: Left ventricular free wall function is unaffected by ASD closure, whereas septal function is impaired, irrespective of the method of closure. Right ventricular function, both systolic and diastolic, is impaired by cardiopulmonary bypass but preserved after device closure. These findings support the transcatheter approach to ASD closure in anatomically suitable defects.

Balloon Occlusion↗
PubMed1994

Recovery of atrial function after atrial compartment operation for chronic atrial fibrillation in mitral valve disease.

OBJECTIVES: We prospectively studied the recovery of atrial function after atrial compartment operation and mitral valve surgery in patients with chronic atrial fibrillation caused by mitral valve disease. BACKGROUND: Chronic atrial fibrillation is the most common arrhythmia in mitral valve disease. This arrhythmia is associated with excessive morbidity and mortality. Mitral valve surgery alone rarely eliminates it. METHODS: Twenty-two patients underwent mitral valve surgery and a new surgical method, atrial compartment operation. Doppler echocardiography was performed in all patients before operation and at 1 week and 2 and 6 months after operation in the successful cardioversion group. Peak early diastolic (E) and atrial (A) filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves were measured. RESULTS: Sinus rhythm was restored immediately after operation in 91% of patients and was maintained for > 1 week in 15 (68%) of 22 patients and > 6 months in 14 (64%) of 22. Eleven of 15 patients had left atrial paralysis (A/E integral ratio 0) at 1 week and 6 of 14 patients at 2 months. Nine of 15 patients had right atrial paralysis (A/E integral ratio 0) at 1 week and 1 of 14 patients at 2 months. Both left and right atrial contractile function (presence of an A wave on Doppler findings) was detected at 6 months in 14 patients. Mean (+/- SD) peak atrial filling velocity of the mitral valve was 15 +/- 26 cm/s at 1 week, 38 +/- 39 cm/s at 2 months and 93 +/- 32 cm/s at 6 months (p < 0.001). Mean peak atrial filling velocity of the tricuspid valve was 14 +/- 19 cm/s at 1 week, 33 +/- 19 cm/s at 2 months and 50 +/- 19 cm/s at 6 months (p < 0.001). Peak early diastolic and atrial filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves increased significantly from 1 week to 6 months. CONCLUSIONS: Chronic atrial fibrillation in mitral valve disease can often be eliminated by atrial compartment operation. No surgical mortality or significant complications were encountered. Both left and right atrial function, as manifested by Doppler findings, recover after compartment operation and improve over time. The mechanical function of the right atrium recovers earlier than that of the left.

Adolescent↗
PubMed1996

Assessment of right and left atrial function in patients with transplanted hearts with the use of magnetic resonance imaging.

BACKGROUND: The purpose of this study was to determine the volumes and cyclic volume changes of the cardiac atria after heart transplantation in physically healthy recipients. METHODS: Ten heart transplant recipients (New York Heart Association grade I) entered the protocol. All operations had been made with classic biatrial anastomoses. Eight healthy volunteers were studied as controls. To measure the volumes of both atria and left ventricular cavity, we used a gradient-echo cine sequence. The 10 mm slices covered both atria over the total cardiac cycle. Images were planimetered, and simultaneous volumes were totalled to give the cavity volume at each time phase. RESULTS: The heart rate of the heart transplant recipients was faster than in controls, which resulted in higher cardiac output. The atrial minimum volumes were significantly larger, and fractional emptying was smaller in transplanted hearts when compared with controls. Reservoir and stroke volumes were smaller and conduit volumes were larger in transplanted hearts than in controls. The atrial filling and emptying rates were lower in heart transplant recipients than in controls. CONCLUSIONS: The classic surgical technique used in heart transplantation results in large atria with decreased volume changes and filling rates even in physically healthy transplant recipients. Magnetic resonance imaging is a reliable tool in assessment of atrial volumes and cyclic function after heart transplantation.

Adult↗
PubMed1998

Evaluation of mean right atrial pressure by two-dimensional and Doppler echocardiography in patients with cardiac disease.

BACKGROUND: Several approaches have been used for noninvasive estimation of right atrial pressure (RAP), but, no currently available method has gained any definite validation. The purpose of this study was to evaluate the accuracy of two-dimensional and Doppler echocardiography in estimating mean RAP in patients with cardiac disease. METHODS: We examined the relation of mean RAP to right atrial size and function, size and respiratory changes of inferior vena cava and Doppler parameters of tricuspid and hepatic vein flow in 114 consecutive patients (77 men, 37 women; mean age 57 +/- 12 years) with various cardiac diseases undergoing cardiac catheterization. Echocardiographic studies were performed within 24 hours before catheterization (mean interval 6 +/- 3 hours). Patients were assigned to 3 groups according to the values of mean RAP (group 1, < or = 8 mmHg; group 2, between 9 and 12 mmHg; group 3, > 12 mmHg). RESULTS: Mean RAP ranged from 3 to 20 mmHg (mean 9.1 +/- 4.3 mmHg). It correlated most strongly with the collapsibility index of inferior vena cava (IVCCI) (r = -0.76), minimal inspiratory diameter of inferior vena cava (r = 0.72) and deceleration time of early tricuspid flow (DT) (r = -0.61). Discriminant analysis demonstrated that IVCCI and DT were major determinants of mean RAP with 81.6% of cases correctly assigned to study groups: 96% of patients of group 1 and 87% of patients of group 3 were identified, whereas the accuracy in identifying the patients of group 2 was lower (46%). An IVCCI > 45% was the best cutoff point in predicting a mean RAP < or = 8 mmHg; an IVCCI < 35% and a DT < 150 msec were the best cutoff points in predicting a mean RAP > or = 15 mmHg. The best multivariate equation predicting mean RAP was: mean RAP = 23.3 - 0.2 IVCCI -0.026 DT (r = 0.80, R2 = 0.64). This equation was 81% sensitive and 84% specific in detecting a mean RAP < or = 8 mmHg and 74% sensitive and 97% specific in detecting a mean RAP > 12 mmHg. CONCLUSIONS: Mean RAP can be estimated noninvasively by two-dimensional and Doppler echocardiography. The combined analysis of IVCCI and DT provides an accurate prediction on mean RAP < or = 8 mmHg and > 12 mmHg, whereas the prediction of intermediate values is less accurate.

Adult↗
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↗
PubMed1994

Right atrial MR imaging studies of cadaveric atrial casts and comparison with right and left atrial volumes and function in healthy subjects.

PURPOSE: To assess magnetic resonance (MR) imaging of the right atrium by measuring volumes of right atrial casts and determining right atrial volume cycles in healthy subjects. MATERIALS AND METHODS: Fourteen human cadaveric atrial casts were imaged and right atrial volumes of eight subjects were measured with cardiac-gated cine MR. Volumes were calculated and right and left atrial volumes were compared. RESULTS: Measured volumes of right atrial casts correlated well (r = .99, P < .001) with true volumes with a small underestimation noted (-7.2 mL +/- 2.3 [standard deviation], P < .001). The maximum in vivo right atrial volume averaged 77 mL/m2 +/- 11 of body area. The right atrial reservoir and conduit functions accounted for, on average, 58% and 19%, respectively, of the ventricular stroke volume; the remaining 23% came from atrial contraction. Right-to-left peak volume ratio averaged 1.41 +/- 0.15 (P < .001), and all volume measurements except conduit volumes were statistically significantly larger in the right atrium than the left. CONCLUSIONS: MR imaging provides a reliable means to study right atrial volumes and phasic function.

Adult↗
PubMed1976

The contribution of atrial contraction to right heart function before and after right ventriculotomy. Experimental and clinical observations.

Effective atrial contraction was abolished by simultaneous atrial and ventricular (A-V) pacing in an acute canine preparation. At constant cardiac output, aortic pressure, and heart rate, only a small rise (1.4 mm. Hg) in mean right atrial pressure was observed before vertical right ventriculotomy, but a larger rise (9.5 mm Hg) occurred after ventriculotomy (p less than 0.01). Right heart failure with tricuspid regurgitation was induced after ventriculotomy by volume overload and A-V pacing. Restoration of atrial contraction (sequential A-V pacing) eliminated regurgitation and lowered average mean right atrial pressure from 22 to 4 mm. Hg (p less than 0.001). After right ventriculotomy, loss of atrial contraction at a constant right atrial pressure resulted in a 42 per cent reduction in cardiac output. In 8 patients who had had right ventriculotomies, abolition of effective atrial contraction by A-V pacing caused an average reduction in cardiac output of 22 per cent, whereas cardiac output fell only 5 per cent in 5 control patients (p less than 0.01).

Animals↗
PubMed2004

Reservoir and conduit function of right atrium: impact on right ventricular filling and cardiac output.

The purpose of this study was to investigate the relationship between right atrial (RA) reservoir and conduit function and to determine how hemodynamic changes influence this relationship and its impact on cardiac output. In 11 open-chest sheep, RA reservoir and conduit function were quantified as RA inflow with the tricuspid valve closed versus open, respectively. Conduit function was separated into early (before A wave) and late (after A wave) components. The effects of inotropic stimulation, partial pulmonary artery occlusion, and pericardiotomy were tested. At baseline with the pericardium intact, reservoir function accounted for 0.56 (SD 0.13) of RA inflow, early conduit for 0.29 (SD 0.07), and late conduit (during RA contraction) for 0.16 (SD 0.11). Inotropic stimulation decreased conduit function and increased reservoir function, but these effects did not reach statistical significance. With partial pulmonary artery occlusion, early conduit function fell to 0.20 (SD 0.11) (P < 0.04), and the conduit-to-reservoir ratio decreased by 41% (P < 0.03). Similarly, after pericardiotomy, early conduit function fell to 0.14 (SD 0.09) (P < 0.004), reservoir function increased to 0.72 (SD 0.08) (P < 0.04), and, consequently, the early conduit-to-reservoir ratio decreased by 63% (P < 0.006). Cardiac output was inversely related to the conduit-to-reservoir ratio (r = 0.39, P < 0.001). This study demonstrated that the right atrium adjusts its ability to act more as a reservoir than a conduit in a dynamic manner. The RA conduit-to-reservoir ratio was directly related to the right ventricular pressure-RA pressure gradient at the time of maximum RA volume, with increased ventricular pressures favoring conduit function, but it was inversely related to cardiac output, with an increase in the reservoir contribution favoring improved cardiac output.

Acute Disease↗
PubMed2005

The relationship between blood pressure, pulse pressure and right ventricular function following an atrial switch procedure for complete transposition of the great arteries.

BACKGROUND: The pressure overload may be responsible for the failure of the systemic ventricle. No study so far has evaluated the association between arterial blood pressure values and right ventricular function in adults with atrially corrected complete transposition. METHODS: This was a retrospective analysis. The studied population consisted of 60 patients with complete transposition, 11.5+/-2.7 years after atrial switch procedure, divided into subgroups according to the severity of systemic ventricular dysfunction (right ventricular ejection fraction < or = 0.40 vs. > 0.40), and the severity of perfusion abnormalities in the radionuclide study (absent or mild vs. moderate-to-severe). RESULTS: All patients had blood pressure values (systolic 109.1+/-11.7 mm Hg and diastolic 72.3+/-9.7 mm Hg) within the normal range. Systolic blood pressure values correlated inversely with right ventricular ejection fraction (r = -0.450; p < 0.001). Compared to patients with systolic blood pressure below median values, patients with "elevated" blood pressure had lower right ventricular ejection fraction (32.6+/-6.3 vs. 38.9.+/-7.2; p < or = 0.002) and more significant perfusion abnormalities (1.5+/-1.0 vs. 2.9+/-1.5; p < or = 0.001). In a multivariate backward logistic regression model age at surgery and at the time of the study, systolic blood pressure at rest predicted impaired right ventricular ejection fraction (p < 0.02). Greater pulse pressure at peak exercise female sex were associated with greater more severe perfusion abnormalities (p < 0.01). CONCLUSIONS: There is a significant correlation between blood pressure values and indices of right ventricular dysfunction in patients who underwent an atrial switch procedure for complete transposition. Blood pressure values might be considered as a surrogate end point in these patients.

Adolescent↗
PubMed2006

Transesophageal echocardiographic assessment of right atrial appendage anatomy and function: comparison with the left atrial appendage and implications for local thrombus formation.

OBJECTIVES: We sought to define right atrial appendage (RAA) anatomic and functional parameters in a consecutive series of participants and to compare these measures with left atrial appendage (LAA) indices among patients with in sinus rhythm and atrial fibrillation (AF). BACKGROUND: With AF, both atria are fibrillating, yet the vast majority of thrombi are located within the LAA. Transesophageal echocardiography provides anatomic and functional information regarding both the LAA and the RAA. METHODS: In a consecutive series of 92 patients (48 men; age 61 +/- 17 years) referred for transesophageal echocardiography, RAA and LAA anatomy (width, length, area) and ejection velocity were measured at two orientations (RAA, 90 and 135 degrees; LAA, 0 and 90 degrees). RESULTS: RAA anatomic measures were similar for both imaging planes, whereas LAA area was larger at 90 degrees. There was a modest correlation between RAA and LAA anatomic measures (area: r = 0.58, P = .001). RAA neck width was substantially greater than LAA neck width (P < .0001) whereas appendage area was similar (P = not significant) and RAA neck width/area was greater than LAA neck width/area (P < .0001). AF was associated with approximately 50% decline in ejection velocity for both the LAA and the RAA with an increase in LAA area (P = .006 vs sinus), but similar anatomic remodeling was not found for the RAA (P = not significant vs sinus). CONCLUSION: In this consecutive series of patients undergoing transesophageal echocardiography, RAA anatomic and functional parameters were found to be independent of imaging plane, with anatomic measures demonstrating a correlation with LAA measures. Although AF is associated with depressed RAA and LAA ejection velocities, anatomic RAA remodeling appears to be absent. The larger RAA width and lack of anatomic remodeling may partially explain the substantially lower prevalence of RAA thrombus found among patients with AF.

Adult↗
PubMed1981

[Diagnostic transesophageal atrial stimulation as a sinus node function test. I. Normal values and comparison with right atrial stimulation].

For the non-invasive functional analysis of the sinus node diagnostic transoesophageal atrial stimulations were performed. By means of transoesophageal premature individual stimulation we succeeded in a calculation of the so-called sinuatrial conduction time in 112 of 118 normal persons (ESACT = 103 +/- 23.5 ms). In comparison to the results in right-atrial stimulation the transoesophageally established times were 20 to 30 ms longer. By means of transoesophageal atrial stimulation with higher frequency in 64 healthy test persons the recreation time of the sinus node was determined in 64 healthy test persons (ESNRT = 968 +/- 218 ms). Taking into consideration the double standard deviation in an upper limit of 1,400 ms was the result which corresponds to the limit in intraatrial stimulation. In the direct comparison of the transoesophageal and right-atrial stimulation technique in patients with and without syndrome of the sinus node for the sinuatrial conduction time (r = 0.81, n = 51) as well as for the recreation time of the sinus node (r = 0.90, n = 36) relatively good correspondences were found. In the transoesophageal stimulation, however, the larger distance of the place of stimulation from the marginal area of the sinus node, the conduction of the impulse over the left to the right atrium as well as a possible vagal irritation are to be taken into consideration.

Adult↗
PubMed1984

Scintigraphic assessment of atrial function in patients with longstanding hypertension.

Right and left atrial function were assessed using Fourier analysis of gated radionuclide images in 14 normal subjects and 50 patients with long-standing essential hypertension. Slopes representing filling and early diastolic emptying were similar for both atria; however, early diastolic emptying of the left atrium was slowed markedly in the hypertensive group (42.6 +/- 18.6 counts/sec., vs. 79 +/- 16 in normal persons; p less than 0.001), implying a reduction in left ventricular compliance. The right ventricular ejection fraction was depressed in hypertensive patients compared with normal subjects (37.1 +/- 6% vs. 43.4 +/- 8.1%; p less than 0.01). These findings may be helpful in understanding the effect of hypertension on the left and right heart and could have prognostic and therapeutic implications as well.

Adult↗
PubMed2001

Conduction left-to-right and right-to-left across the crista terminalis.

A line of block between the vena cava and the crista terminalis (CT) region is important for atrial flutter (AFL), but whether it is fixed or functional is controversial. To test the hypothesis that conduction across the CT normally occurs, but when block occurs in this region it is functional, we analyzed atrial activation during right and left atrial pacing (cycle lengths of 500--130 ms), AFL, and atrial fibrillation in 15 dogs with sterile pericarditis and 7 normal dogs. Electrograms from 396 right, left, and septal atrial sites were simultaneously recorded. Activation across the CT occurred during atrial pacing, AFL, and atrial fibrillation. Activation wave fronts from the right to the left atrium and vice versa traveled over several routes, including Bachmann's bundle and inferior to the inferior vena cava, as well as across the CT. In these models, there is no fixed conduction block across the CT, and when block in the CT region occurs, as during AFL, it is functional.

Animals↗