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At least 55 records · Page 3Linked to original sources
PubMed1992

Role of prophylactic anticoagulation for direct current cardioversion in patients with atrial fibrillation or atrial flutter.

The need for prophylactic anticoagulation to prevent embolism before direct current cardioversion is performed for atrial fibrillation or atrial flutter is controversial. To examine this issue further, a retrospective review was undertaken to assess the incidence of embolic complications after cardioversion. The review involved 454 elective direct current cardioversions performed for atrial fibrillation or atrial flutter over a 7 year period. The incidence rate of embolic complications was 1.32% (six patients); the complications ranged from minor visual disturbances to a fatal cerebrovascular event. All six patients had atrial fibrillation, and none had been on anticoagulant therapy (p = 0.026). The duration of atrial fibrillation was less than 1 week in five of the six patients who had embolic complications. Baseline characteristics of patients with a postcardioversion embolic event are compared with those of patients who did not have an embolic event. There was no difference in the prevalence of hypertension, diabetes mellitus or prior stroke between the two groups, and there was no difference in the number of patients who were postoperative or had poor left ventricular function. Left atrial size was similar between the two groups. No patient in the embolic group had valvular disease. No patient with atrial flutter had an embolic event regardless of anticoagulant status; therefore, anticoagulation is not recommended for patients with atrial flutter undergoing cardioversion. Prophylactic anticoagulation is pivotal in patients undergoing elective direct current cardioversion for atrial fibrillation, even those with atrial fibrillation of less than 1 week's duration.

Anticoagulants↗
PubMed1992

Effect of pacing on epinephrine-stimulated atrial natriuretic factor release.

Previous in vitro studies showed that epinephrine stimulation can induce atrial natriuretic factor (ANF) release only form the right atrium but not from the left. In addition, sinus node has been shown to play an important role in the release of ANF. In vitro studies were done in isolated left and right rat atria to determine if pacing can induce the left atria to release ANF during epinephrine stimulation. ANF concentrations in the perfusate were measured by a radioimmunoassay method. Epinephrine increased ANF release in the right atria (from 6.3 +/- 0.8 to 10.8 +/- 0.9 pg/min/mg), but not in the unpaced left atria (4.2 +/- 0.4 and 4.2 +/- 0.3 pg/min/mg). However, when the atria were paced, ANF release rose in both the left (from 6.2 +/- 0.5 to 11.5 +/- 1.4 pg/min/mg) and right (from 8.4 +/- 1.15 to 16.6 +/- 1.8 pg/min/mg) atria with epinephrine addition. These results suggest that atrial contraction and tension play an important role in epinephrine-stimulated ANF release.

Animals↗
PubMed1992

Plasma atrial natriuretic factor during ethanol ingestion in volume-loaded subjects.

The present study was designed to test whether ethanol ingestion affects plasma atrial natriuretic factor (ANF) concentration in healthy volunteers. On the basis of previous studies showing that ethanol induces a diuretic response and a decrease in atrial size (atrial distension), it was hypothesized that ethanol intake might be associated with a decrease in plasma ANF level. To somewhat increase plasma ANF level, the subjects were slightly loaded with water before the trial. As compared with juice, ethanol, 1 g/kg within 1 hr, increased urine output [405 +/- 37 (mean +/- SEM) ml/hr vs. 197 +/- 20 ml/hr, P less than 0.001]. Left atrial size decreased similarly (P less than 0.001) with both drinks. Plasma ANF concentration did not change with either ethanol or juice during the 3-hr study period. No changes were observed in plasma arginine vasopressin concentration and plasma renin activity. Our results are in conflict with previous reports in fasted subjects showing significant changes in plasma concentrations of the same hormones. Thus, the basal fluid balance seems to be crucial to the hormonal response to ethanol. The plasma concentrations of the hormones measured in this study do not directly explain the diuretic response to ethanol observed in slightly volume-loaded subjects.

Adult↗
PubMed1979

Assessment of left ventricular function in secundum atrial septal defect by computer analysis of the M-mode echocardiogram.

Left ventricular function in 53 patients with secundum atrial septal defect was assessed by computer-assisted analysis of the left ventricular echocardiogram and by cardiac catheterization. The patients were divided into two groups, those younger and those older than 60 years, to investigate the effect of aging on left ventricular function. Cavity size was significantly smaller than normal (p less than 0.01) and septal motion was abnormal in 86%, but values for cardiac index, left ventricular end-diastolic pressure, velocity of circumferential fiber shortening, left ventricular filling rate, and duration of rapid filling were normal in both groups. Regional dynamics assessed in terms of peak rates of systolic thickening and diastolic thinning of the septum and posterior wall were also normal in both groups. We concluded that, although left ventricular minor dimensions are small, and septal motion is reversed in the majority of patients with atrial septal defect, left ventricular function is normal, and it does not appear to deteriorate with increased age, pulmonary hypertension, or the presence of right ventricular failure. The abnormal septal motion appears to be compensated for by enhanced septal and posterior wall percentage thickening.

Adolescent↗
PubMed1992

[Clinico-functional correlations of left atrial myocardial excursions in patients with mitral valve defects].

The pre- and intraoperative drug maintenance was evaluated in 50 patients with mitral valvular disease and compared with the types of left atrial myocardial excursions. The maintenance with cardiac glycosides and diuretics was greatly different in 3 groups of patients with various types of left atrial myocardial excursions. In patients with Type I excursions the maintenance was minimal, in those with Type III excursions it was maximal, those with Type II excursions, it was intermediate. It is concluded that the functional characteristics of left atrial myocardial excursions may be used as an indicator of cardiac performance.

Adolescent↗
PubMed1986

Radionuclide left ventricular function curve during atrial pacing in normal subjects and in patients with coronary artery disease.

We used radionuclide angiography during right atrial pacing to assess left ventricular function in 7 normal subjects and 20 patients with coronary artery disease. A left ventricular function curve relating stroke volume to end-diastolic volume was plotted for each patient. The normal pacing ventricular function curve was a straight line passing through the origin of axes. The pacing ventricular function curve was abnormal in 18 of the 20 patients with coronary artery disease, and three different shaped curves were obtained, reflecting decreased contractile force for the same end-diastolic volume during ischemia. Cardiac output and blood pressure do not change during atrial pacing, thus the Frank-Starling relationship is evaluated by this method during almost experimentally controlled conditions. Relating stroke volume to end-diastolic volume, and not end-diastolic pressure, distinguishes between overall left ventricular systolic function and left ventricular compliance.

Adult↗
PubMed1990

[Effect of cardioversion of atrial fibrillation on left ventricular function in dilated cardiomyopathy. A multicenter study].

A group of 73 patients with idiopathic dilated cardiomyopathy were followed up for an average of 22 +/- 7 months to assess the medium term evolution of echocardiographic parameters of left ventricular function and, in particular, the consequences of cardioversion of atrial fibrillation. Seventy nine per cent of patients presented with cardiac failure. Left bundle branch block was observed in 20% and ventricular arrhythmias were frequent in 31%, complex in 62% with episodes of non-sustained ventricular tachycardia in 10% of cases. Left ventricular dilatation was greater in patients with complete left bundle branch block (p less than 0.003). Atrial fibrillation was present in 14 patients (19%) who were generally older than the rest of the study population (p less than 0.02) and was associated with less severe left ventricular dysfunction (p less than 0.01). Return to sinus rhythm was obtained in 9 patients. Echocardiographic data was obtained in 64 patients after an average of 6.2 +/- 1.7 months. Left ventricular function improved during the follow-up period and returned to normal in 12% of cases. Reduction of atrial fibrillation to sinus rhythm was the only predictive factor of normalisation of left ventricular function (p less than 0.02). The changes in left ventricular end diastolic dimension and fractional shortening was less marked in the group of 56 patients in sinus rhythm or chronic atrial fibrillation (normalisation of left ventricular function in 8% of cases) than in the group of 8 patients in which atrial fibrillation was converted to sinus rhythm (normalisation of left ventricular function in 50% of cases).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

A mathematical model of left ventricular function in atrial fibrillation.

Sixty patients with atrial fibrillation (AF) have been studied with Doppler ultrasound to establish the relationship between the duration of R-R intervals and subsequent left ventricular stroke outputs, assessed as stroke distance. Using multiple regression analysis, most of the beat-to-beat variation of stroke distance could be explained in terms of the two preceding R-R intervals (Mean R = 0.82). The relative contribution of these two intervals to the variation of stroke distance was assessed in each patient. In all patients there was a positive correlation between stroke distance and the preceding R-R interval, largely due to the influence of this interval on diastolic filling or preload. In all but one patient the correlation with the second previous R-R interval was negative, the mechanism being changing contractility due to operation of the force-frequency effect. On average, 58% of the variance in stroke distance could be explained by alteration of the previous R-R interval and 10% by alteration of the second previous R-R interval. The relative contribution of the previous R-R interval (preload) falls as left ventricular function declines, and also as mean ventricular rate rises. However, there is a wide individual variation in the pattern of left ventricular function, which may be represented graphically as the haemodynamic profile.

Aged↗
PubMed1985

Furosemide during sustained left atrial hypertension in functionally anephric dogs: intravascular and extravascular pulmonary fluid volumes. V.

The response of intravascular (PBV) and extravascular (EVLW) pulmonary fluid volume was examined using double-indicator techniques (thermal-green dye) in 11 open-chest anesthetized dogs during the production of sustained left atrial (LA) hypertension by a LA balloon over a period of 195 min. In 6 of these animals data were also acquired after the intravenous administration of furosemide (1 mg/kg). The renal effects of the diuretic were blocked by tying off the ureters and the vascular supply of both kidneys. Left atrial pressure (N = 11) was abruptly increased from 2.2 +/- 2.1 mm Hg to 30.2 +/- 4.0 mm Hg (P less than 0.01) and maintained at that level for 120 min. Data were obtained prior to pressure elevation, immediately upon pressure elevation, and then every 60 min for a total of 120 min. At that point EVLW had increased (8.1 +/- 0.8 cc/kg at control to 21.7 +/- 2.0 cc/kg at 120 min, P less than 0.001), as had PBV (6.2 +/- 2.1 cc/kg to 9.1 +/- 3.1 cc/kg P less than 0.01). After furosemide injection (N = 6), LA pressure declined (mean peak reduction of approximately 6 mm Hg at 60-75 min, P less than 0.01), aortic and pulmonary arterial pressure both declined (P less than 0.01). However, EVLW remained unchanged, though PBV decreased significantly (peak decrease at 75 min after furosemide administration of 2.0 +/- 0.4 cc/kg, P less than 0.01). In the untreated dogs, EVLW continued to climb (P less than 0.05 vs treated dogs at 75 min postfurosemide).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Left atrial ejection performance in heart failure as assessed by transesophageal Doppler echocardiography].

To investigate the left atrial ejection performance in heart failure, we observed both the transmitral (TMF) and pulmonary venous flow waves (PVF) by transesophageal Doppler echocardiography in 20 patients with heart failure (16 males, 4 females, 56 +/- 13 years old). In 7 of 20 patients, pulmonary capillary wedge pressures (PC) were also obtained within 72 hours after the transesophageal Doppler echocardiographic examinations. A reversal flow on PVF during atrial systole (atrial backward ejection flow) was observed in all of the 20 patients. Corrected atrial pre-ejection period correlated significantly with PC (r = -0.76, p < 0.05), indicating that the period was shortened in accordance with left atrial Starling's law. This period correlated significantly with both the duration and the time velocity integral of atrial backward flow (r = -0.72, p < 0.005; r = -0.55, p < 0.05, respectively), but not with the atrial ejection time nor with the time velocity integral of atrial systole. These results suggest that in some cases of heart failure, left atrial contractile function is preserved despite the marked augmentation of left atrial afterload, resulting in a decrease of the left atrial forward ejection and an increase of the left atrial backward ejection. Thus, the observations of TMF and PVF by transesophageal Doppler echocardiography are useful for assessing the left atrial ejection performance in patients with heart failure.

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↗
PubMedDate not supplied

Relationship between beat to beat interval and left ventricular function in patients with atrial fibrillation.

In atrial fibrillation, the relation between the rhythm and volume of the pulse has long been of interest. However, changes in preload in this condition have not been fully addressed since beat to beat measurement of filling volume have been difficult until recently. In the present study, we evaluated left ventricular outflow and inflow velocity using pulsed Doppler echocardiography and correlated these results with the R-R interval in the individual patient. The study population consisted of 12 patients with atrial fibrillation, aged 36 to 69 years (mean 54 years). The etiology of atrial fibrillation was idiopathic in 10 and 2 patients had dilated cardiomyopathy. Stroke and filling volume were calculated as a pruduct of the flow velocity integral of left ventricular outflow and inflow velocity, and the cross-sectional area of aortic and mitral annulus, respectively. In 10 patients with idiopathic atrial fibrillation, significant positive correlations were observed between the preceding R-R interval and both the stroke volume and the filling volume of the preceding beat when the R-R interval was shorter than 600 msec. Stroke volume and filling volume of the preceding beat were almost constant, independent of the preceding R-R interval when the preceding R-R interval was longer than 600 msec, the interval necessary for the completion of the preceding rapid filling. In the same preceding R-R interval, a larger stroke volume was observed in a shorter pre-preceding R-R interval. In 2 patients with dilated cardiomyopathy no relationship could be observed between the preceding R-R interval and the filling volume of the preceding beat or the stroke volume. In patients with a normally functioning left ventricle (idiopathic atrial fibrillation), reduced cycle length and filling volume in the preceding cardiac cycle appear to be the underlying cause of the regulation of stroke volume, dependent on Starling's law. However, in patients with dilated cardiomyopathy no significant correlation was observed between the preceding R-R interval and both the filling volume of the preceding beat and the stroke volume. In these patients the left ventricle may have limited contractile reserve and altered diastolic re-coil forces possibly due to degenerative changes of myocardium. Pulsed Doppler echocardiography provides a non-invasive method of evaluating the instantaneous changes in left ventricular flow dynamics caused by atrial fibrillation and understanding its fundamental mechanism.

Adult↗
PubMed1992

[Doppler echocardiographic assessment of left atrial and left ventricular function during right bundle branch block].

Electrocardiographic, echocardiographic and Doppler echocardiographic studies were performed in 44 patients with coronary heart disease and complete right bundle branch block. The patients were found to have an impaired phase pattern of left ventricular systole and diastole as more prolonged length of its isometric relaxation and contraction, lower economic feasibility and efficiency of its contraction, moderate dilation and hypertrophy. Hemodynamic abnormalities in the left heart in these patients are closely correlate with the changes in the phase pattern of right ventricular systole and they turn out to be so greater as the degree of its hypertrophy is. In complete right bundle branch block, left ventricular pump dysfunction leads to decreased cardiac output and cardiac index, increased total peripheral vascular resistance, thus predisposing to impaired greater circulation.

Adult↗
PubMed1992

[Clinical and functional correlations of left atrial excursion characteristics in patients with mitral valve diseases. Part II].

Left atrial myocardial excursions were intraoperatively recorded in patients with mitral valvular disease (33 patients with mitral stenosis and 17 with mitral regurgitations). Three types of atrial myocardial excursions were identified. There was a high correlation between the types of myocardial excursions and the incidence of heart failure. The patients with Types I and II myocardial excursions had no virtually heart failure, those with Type III showed the highest (70%) incidence of heart failure. It is concluded that intraoperative assessment of left atrial myocardial excursions is of great significance in patients with mitral valvular disease.

Adolescent↗
PubMed1978

Failure of left atrial distension to alter renal function in the nonhuman primate.

Experiments were undertaken to determine the influence of increasing left atrial pressure on renal function in the nonhuman primate. Significant elevations of left atrial pressure, produced by using an intra-atrial balloon, had no effect on salt or water excretion, renal plasma flow, or glomerular filtration rate. There were no significant changes in heart rate or blood pressure. We conclude that, unlike those in the dog, atrial receptors in the nonhuman primate play little or no role in modulating salt and water excretion.

Animals↗