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PubMed2005

[Relation between left atrial dimension and exercise capacity in endomyocardial fibrosis].

OBJECTIVE: To assess whether exercise capacity is related to left atrial dimension (LAD) in patients with biventricular endomyocardial fibrosis. METHODS: This study comprised 38 patients in sinus rhythm, with a mean age of 37.5 +/- 11.5 years (range, 11 to 59 years), 25 of whom were women. They were divided into 2 groups according to the NYHA functional class on hospital admission as follows: group A (12 patients) and group B (26 patients). All patients underwent cardiopulmonary exercise testing to determine their maximum oxygen consumption (VO2 max), and their left atrial dimension was determined on echocardiography. RESULTS: The VO2max values for groups A and B were 21.8 +/- 4.8 mL.kg(-1).min(-1) and 13.7 +/- 3.5 mL.kg(-1).min(-1), respectively, and the left atrial dimensions were 3.7 +/- 0.7 cm and 4.4 +/- 0.7 cm for groups A and B, respectively. A significant and inverse correlation was found between VO2max and LAD in the groups studied. CONCLUSION: The increase in left atrial dimension is associated with impairment in exercise capacity in patients with endomyocardial fibrosis. Our findings support the use of left atrial dimension to estimate a more complex and difficult to assess index of functional capacity, such as VO2max.

Adolescent↗
PubMed1984

Arrhythmias after coronary bypass surgery.

Ninety patients undergoing coronary bypass surgery were studied prospectively by bedside and subsequent ambulatory electrocardiographic monitoring to investigate the incidence, possible causes, and prevention of atrial fibrillation. Patients with good left ventricular function were divided randomly into a control group or groups treated with digoxin or propranolol. In the control group the incidence of atrial fibrillation was 27% and of significant ventricular extrasystoles 3%. Propranolol reduced the incidence of atrial fibrillation (14.8%), whereas digoxin had no effect and increased the incidence of ventricular extrasystoles. Age, sex, severity of symptoms, cardiomegaly, heart failure, previous myocardial infarction, and number of grafts did not affect the result. The operative myocardial ischaemic time was related to the occurrence of atrial fibrillation. There was also a significant relation between atrial fibrillation and bundle branch block. Atrial fibrillation is common after coronary artery grafting; it may be due to diffuse myocardial ischaemia or hypothermic injury. The incidence may be reduced by beta blockade.

Adult↗
PubMed2006

Immediate functional effects of left ventricular reduction: a Doppler echocardiographic study in the rat.

BACKGROUND: Immediate functional effects of left ventricle reduction (LVR) are not yet fully defined. Those effects have been studied in the experimental model of myocardial infarction scar plication (MISP) in the rat. METHODS AND RESULTS: A Doppler echocardiogram was performed immediately before and after MISP in 20 rats with infarction of the left ventricle (LV) larger than 40%. LV diastolic volume reduction (475 +/- 114 versus 185 +/- 65 muL) was accompanied by heart rate decrease (230 +/- 25 versus 166 +/- 27 beats/min) and increase of ejection fraction (37 +/- 7 versus 67 +/- 12%), fractional shortening (18 +/- 3 versus 46 +/- 8%) and posterior wall shortening velocity (1.50 +/- 0.62 versus 2.01 +/- 0.46 cm/s). LV diastolic volume/stroke volume slope was steeper after LVR, suggesting enhancement of the Frank-Starling mechanism. Restrictive pattern of left atrial emptying was alleviated after LVR (E wave: 101 +/- 15 versus 66 +/- 14 cm/s; E/A ratio: 6.8 +/- 2.9 versus 5.0 +/- 2.2; E wave deceleration time: 36 +/- 6 versus 51 +/- 10 msec) even though left atrial diameter (0.69 +/- 0.07 versus 0.66 +/- 0.06 cm) and A wave (18.0 +/- 9.4 versus 15.8 +/- 7.8 cm/s) did not vary. Additionally, a pulmonary flow profile suggesting pulmonary hypertension was observed in 12 of 17 animals before, and in only 3 after, LVR. CONCLUSION: LVR favors cardiac function not only by reducing afterload. The present data are in consonance with previous suggestions that the Frank-Starling mechanism is enhanced after MISP and, in addition to LV ejection function improvement, the unprecedented facilitation of left atrial emptying after LVR was particularly noteworthy. Even though LVR restricts ventricular distensibility, atrial emptying can be facilitated, probably on account of LV ejection improvement.

Animals↗
PubMed1983

Left ventricular function after long-term treatment with ventricular inhibited compared to atrial triggered ventricular pacing.

The long-term effect of ventricular inhibited (VVI) and atrial triggered ventricular (VAT) pacing on cardiac performance was determined by cardiac catheterization at rest and during exercise in 9 patients with high-degree AV block. Cardiac output (Q) increased at rest by 22% during VAT vs. VVI (5.5 vs. 4.5 l/min, p less than 0.01). An increased stroke volume constituted the difference (75 vs. 63 ml, p less than 0.05). Mean working capacity increased by 12% in the supine position with VAT vs. VVI (p less than 0.05). During exercise Q increased by 40% with VAT vs. VVI (10.2 vs. 7.3 l/min, p less than 0.01) due to an increase in heart rate. Most pressures were largely unchanged. Stroke work and atrial rate decreased during VAT vs. VVI, which may indicate a lower sympathetic activity with VAT vs. VVI. The study demonstrated that hemodynamics advantages of VAT are still obtainable after several years of VVI pacing.

Adult↗
PubMed2002

Extrinsic left atrial compression in a patient with achalasia.

Left atrial compression by the esophagus, the stomach, or both is an uncommon but important cause of hemodynamic compromise. Achalasia is a disease of the esophagus with dilatation of the distal part and constriction of the lower oesophageal sphincter. Dilated esophagus is a rare cause of left atrial compression. Timely and precise diagnosis is of paramount importance in cases of left atrial compression and echocardiography enables clinicians to make a differential diagnosis successfully in most cases. Correction of primary pathology will usually lead to the return of normal hemodynamic function. We describe a case of extrinsic left atrial compression caused by the dilated esophagus due to achalasia that caused paroxysms of atrial tachycardia and hemodynamic compromise.

Constriction, Pathologic↗
PubMed1976

[Function and reserve of the hypertrophic left ventricle in aortic valve disease].

Left ventricular function was analyzed by angiography in 31 patients with aortic valve disease and in 12 patients without heart disease (control group). Ejection fraction, percentage shortening of minor equator, mean velocity of fiber shortening and men left atrial pressure were considered as parameters of left ventricular function. Contractile reserve was tested by a single postextrasystolic beat. Patients with pure aortic stenosis and an increase of left ventricular muscle mass to 220% of the normal value showed no impairment of left ventricular function. Patients with pure aortic regurgitation and a left ventricular muscle mass of 260% of normal showed no significantly impaired function. Both groups increased ejection fraction and percentage shortening of the minor equator after premature beat comparable to the control group. Patients with combined lesions of the aortic valve had a left ventricular muscle mass of 360% of normal. This group showed decreased ejection fraction, percentage shortening of minor equator and mean velocity of fiber shortening as compared to the control group while mean left atrial pressure was significantly elevated. After premature beat all parameters remained depressed as compared to control group. We conclude that the degree of hypertrophy determinates cardiac function in aortic valve disease. Moderate hypertrophy shows normal function at rest, while severe hypertrophy shows impaired function.

Adult↗
PubMed1990

[Opening of a foramen ovale during liver transplantation. The value of transesophageal echocardiography].

A case is reported of a foramen ovale becoming patent during orthotopic liver transplantation (OLT). The patient had a hepatoma secondary to post-hepatitis cirrhosis. Monitoring included transesophageal echocardiography (TEE). A veno-venous shunt between the right femoral, portal and left axillary veins was used so as to maintain the venous return during portal and caval clamping. The patient's haemodynamic state remained quite stable throughout this period, and no vasoactive drug was required. Five min after graft reperfusion, pulmonary arterial pressure increased suddenly (mean PAP: 27 mmHg). TEE revealed paradoxical movements of the atrial septum. Colour coded Doppler ultrasound showed blood flowing from the right to the left atrium through a patent foramen ovale. Fifteen min later, mean PAP decreased (18 mmHg) and TEE no longer showed any flow between the two atria. Several studies have reported transient pulmonary hypertension after unclamping when the donor liver is reperfused. This could induce right ventricular failure, with transient inversion of the atrial pressure gradient, which, in turn, could result in a right-to-left shunt through a patent foramen ovale. TEE can monitor regional and overall left ventricular function as well as the atrial septum. This technique might therefore to be useful for cardiac monitoring during OLT.

Cardiomyopathies↗
PubMed1995

[Anticoagulant treatment and dilated cardiomyopathy].

The prevalence of intracardiac thrombi in patients with dilated cardiomyopathy is very variable from one study to another, but is generally high: 20 to 25% for interatrial thrombi and 50% for intraventricular thrombi. There is also a high incidence of left atrial spontaneous contrast (30-40%). Left atrial thrombosis or spontaneous contrast is more common in atrial fibrillation, when the LA diameter is increased with low velocity intra-left atrial blood flow on Doppler examination and when there are disturbances of haemorrheological factors (increased fibrinogen levels and plasma viscosity). Ventricular thrombi are more common when the fractional shortening is decreased (< 11% = 80% of thrombi). The frequency of embolism is controversial. It varies between 1.4 and 12 events per 100 patients per year. The risk of complications is higher in patients with intracavitary thrombosis. The number of cerebral haemorrhagic complications in patients on long-term oral anticoagulants is far from negligible. Large prospective multicenter trials should be instituted, as for atrial fibrillation to evaluate systematic anticoagulation with respect to the risks. In the meantime, it would seem to be prudent to prescribe oral anticoagulants to all patients with dilated cardiomyopathy with an intracardiac thrombus and/or atrial fibrillation, and to perform echocardiography regularly when left ventricular function is very poor.

Anticoagulants↗
PubMed2003

A new device for beating heart bipolar radiofrequency atrial ablation.

OBJECTIVE: A technique for mimicking left atrial atriotomies using an ablation device that can be deployed without cardiopulmonary bypass has been developed. METHODS: In 12 healthy large (35-50 kg) adult pigs, maze-like ablation lesions were directly applied to the left atrial epicardium on the beating heart. The ablation device is irrigated, with a bipolar "hemostat" morphology, utilizing radiofrequency energy. Prior to and after ablation, left atrial electromechanical properties were measured during sinus rhythm in the latest 5 pigs using percutaneous endocardial catheter electromechanical mapping and intracardiac echocardiography. Pathologic analysis was performed acutely. RESULTS: All ablation lesions demonstrated conduction block along their entire course. Global left atrial conduction time (49.4 +/- 8.8 milliseconds before vs 58.8 +/- 9 milliseconds after) and pattern were not significantly altered. Although a significant amount (17.12% +/- 9%) of myocardium was either ablated or electrically isolated, ablation was not associated with significant alterations in global left atrial mechanics (left atrium ejection fraction 19% before vs 17% after; pulmonary vein peak flow velocity 1.22 m/s before vs 1.38 m/s after; peak mitral inflow velocity 2.34 m/s before vs 2.64 m/s after), mitral valve function, nor left ventricular function. There was no evidence of atrial thrombus formation. Transmurality was achieved in most lesions with no evidence of charring or barotrauma. CONCLUSIONS: Utilizing this ablation device, atrial lesions similar to the left component of the Maze procedure were deployed with uniform success in a beating heart without cardiopulmonary bypass or atriotomy and without adverse effects on left atrial electromechanics.

Animals↗
PubMed1987

Effect of left atrial to left femoral artery bypass and renin-angiotensin system blockade on renal blood flow and function during and after thoracic aortic occlusion.

Temporary thoracic aortic occlusion can result in renal insufficiency with or without adjuncts to avoid distal hypoperfusion. In a canine model of thoracic aortic occlusion, left atrial to left femoral bypass was compared with blockade of the renin-angiotensin system. Renin-angiotensin system blockade with the converting enzyme inhibitor, MK422, resulted in restoration of baseline renal blood flow and glomerular filtration 30 minutes after cross-clamp release. Left atrial to left femoral bypass resulted in significant reduction in both renal blood flow and glomerular filtration 30 minutes after cross-clamp release. Stimulation of the renin-angiotensin system plays a significant role in the altered renal hemodynamics and glomerular filtration rates after thoracic aortic occlusion.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2005

The relationship between P wave dispersion and diastolic dysfunction.

We investigated the relationship between P wave dispersion, which is easily measured on the surface electrocardiogram and may be used in evaluating the risk of atrial fibrillation, and left ventricular diastolic function. There were 133 patients: 73 with diastolic dysfunction and 60 without. P wave dispersions were calculated by measuring minimum and maximum P wave duration values on the surface electrocardiogram. The relationships between P wave dispersion and the presence, cause, severity, and echocardiographic measurements of diastolic dysfunction were investigated. P wave dispersion was 53 +/- 9 ms in patients with diastolic dysfunction and 43 +/- 9 ms in the control group (P < 0.01). When patients were grouped according to stage of diastolic dysfunction, P wave dispersion was 48 +/- 7 ms in stage 1, 54 +/- 8 ms in stage 2, and 58 +/- 9 ms in stage 3. As the severity of diastolic dysfunction increased, P wave dispersion increased but the difference did not reach statistical significance (P < 0.05). When the cause of diastolic dysfunction was considered, P wave dispersion was 53 +/- 8 ms in patients with ischemic heart disease and 52 +/- 9 ms in patients with left ventricular hypertrophy (P > 0.05). We conclude that P wave dispersion increases in diastolic dysfunction, but that this increase is not related to the severity or cause of diastolic dysfunction. When clinical and echocardiographic variables are taken into account, there is a weak but significant correlation only between P wave dispersion and left ventricular ejection fraction.

Atrial Fibrillation↗
PubMed1996

Echocardiographic assessment of left ventricular filling during isoflurane anaesthesia.

PURPOSE: To determine the effect of isoflurane on left ventricular diastolic function, as assessed by Doppler echocardiography. METHODS: Ten patients with normal cardiovascular function were enrolled. Doppler measurements of mitral inflow velocities, and pulmonary venous blood flow velocities were measured preoperatively (transthoracic echocardiography), and intraoperatively (transesophageal echocardiography) at isoflurane MAC 1 and MAC 1.5. Heart rate and blood pressure were measured concomitantly. Variables were compared with repeated measures ANOVA. RESULTS: Isoflurane at both doses caused equal decreases in mitral inflow A(atrial systole) velocity (control: 43 +/- 12.3 cm.sec-1 vs MAC 1: 31 +/- 6.0 cm.sec-1 and MAC 1.5: 31.3 +/- 7.9 cm.sec-1 P < 0.01), the deceleration time of the mitral inflow E (early) velocity (control: 178 +/- 31.7 msec versus MAC 1: 127 +/- 38.3 msec and MAC 1.5: 137 +/- 28.4 msec, P < 0.01), and mean blood pressure (control: 91.1 +/- 15.4 mmHg versus MAC 1: 76.1 +/- 8.8 mmHg and MAC 1.5: 71.9 +/- 6.2 mmHg, P < 0.002). Isoflurane at both doses caused an equal increase in the E/A ratio (control: 1.5 +/- 0.57 vs MAC 1: 2.0 +/- 0.6 and MAC 1.5: 2.2 +/- 0.78, P < 0.01). No changes in mitral inflow E or pulmonary venous velocities were seen. CONCLUSION: The changes in Doppler velocities of mitral inflow and pulmonary venous flow with isoflurane are not consistent with prolonged left ventricular relaxation nor increased myocardial restriction, but are more likely the result of alterations in left ventricular loading conditions and atrial systolic function.

Adolescent↗
PubMed1993

[A case of left atrial plication for mitral valvular disease with giant left atrium].

A case of plication of giant left atrium complicating mitral valvular disease is reported. The patient was a 44-year-old female with mitral stenosis and regurgitation, whose respiratory function was severely disturbed. Chest X-ray showed severe stenosis of the left main bronchus and widening of the tracheal bifurcation secondary to compression by the left atrium. Mitral valve replacement and left atrial plication was performed. Postoperative respiratory weaning was uneventful and respiratory function was improved. We concluded that plication is very beneficial in patients with giant left atrium who have signs of compression of the bronchus and lungs.

Adult↗
PubMed1987

Effect of altered thyroid status on in vitro cardiac performance in rats.

Effect of a chronic excess or deficit of thyroid hormone on intrinsic myocardial performance in rats was assessed. Animals were thyroidectomized or treated with thyroid hormone or vehicle 6-7 wk before the study. Body weight and heart weight were decreased in the hypothyroid group, and heart weight was elevated in the hyperthyroid group. Hearts were removed from thyroidectomized, euthyroid or thyroid-treated animals and studied as isolated, perfused working heart preparations. Ventricular function curves were generated by increasing left atrial filling pressure, whereas outflow resistance was not varied. Coronary flow, aortic outflow (and thus cardiac output), heart rate, and peak aortic systolic pressure were measured as a function of preload. These studies showed that performance of hearts from hyperthyroid animals was similar to that of euthyroid controls. Hearts from hypothyroid rats had decreased rate, pressure, and cardiac output but normal stroke volume. Since heart weight was 55% lower than control, normalization of volume work to dry heart weight reversed the difference in cardiac output. Comparison of hearts from hypothyroid animals to control rats of similar weight showed minimal differences in pump function. Thus hyperthyroidism did not result in altered in vitro cardiac output or peak systolic pressure as a function of changing preload when compared with age-matched euthyroid controls, hypothyroidism resulted in a decreased in vitro heart rate but greater cardiac output normalized to heart weight when compared with age-matched controls and hyperthyroid animals; external pacing of hypothyroid hearts yielded myocardial work parameters that were comparable to euthyroid control rats of similar body weight; and cardiac efficiency was significantly greater in hypothyroid hearts than in hyperthyroid hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed2004

The anatomic variability of the coronary vasculature of the human heart--part I: functional vascular zones--a morphological view.

The myocardium may be divided into distinct zones which act as functional units of the coronary vascular network. The basic principle of this functional systematization of cardiac blood vessels is a constant relationship between the "distributing" and the "delivering" vessels. Six arterial zones of the myocardium are identified under this scheme: anterior right ventricular, lateral left ventricular, posterior left ventricular, interventricular septal, posterior right ventricular, and atrial. The distributing vessels of functional myocardial zones are most frequently both arterial and venous. However, between the lateral and posterior left ventricular zones there is sometimes only the left marginal vein (24%) or left marginal artery (20%). Between the atrial and posterior right ventricular zones there is sometimes only the right coronary artery (52%), or only the small cardiac vein (14%) as a distributing vessel. Between the left and the right posterior ventricular zones there is sometimes an arterial and sometimes a venous distributing vessel (10%). Between the posterior and anterior right ventricular zones there is either the artery (21%) or the right marginal vein (8%) as a distributing vessel. The permanence of the six functional myocardial zones is determined not only by the arterial but also by the venous distributing vessels, and in some cases the venous vessels are the only distributing vessels between certain zones.

Adolescent↗
PubMed1987

Left atrial abnormalities indicating diastolic ventricular dysfunction in cardiopathy of obesity.

Electrocardiograms and M-mode echocardiograms were evaluated in lean and obese patients, either normotensive or hypertensive, who were paired for mean arterial pressure, age, and sex. Electrocardiographic evidence of left atrial abnormalities (LAA) occurred more frequently (p less than 0.01) and left atrial size was greater in the obese than in the lean patients (p less than 0.01). The left atrial emptying index, an indicator of early diastolic ventricular function, was reduced in obese patients (p less than 0.01), most markedly in those with obesity-hypertension. The left atrial emptying index was reduced in obese patients with electrocardiographic LAA compared to obese patients without this electrocardiographic sign (p less than 0.02). A close correlation (r = 0.61, p less than 0.001) was obtained between the left atrial emptying index and atrial ECG abnormalities. These left atrial abnormalities in obesity and particularly in obesity-hypertension indicate diastolic ventricular dysfunction.

Adult↗