The relationship between the atrial systole-ventricular systole interval and left ventricular function.
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BACKGROUND: The importance of establishing correlations between cardiac function (cardiac output and stroke volume) and total body water (TBW) content in normal and hypertensive pregnancy focuses primarily on their potential relevance in treatment. Total body water content and cardiac function were evaluated in 25 normotensive (N) and 22 gestational hypertensive (GH) pregnant women matched for age, gestational age, and pre-pregnancy body mass index (BMI) during the third trimester of gestation. MATERIAL/METHODS: Patients underwent maternal echocardiography, bioelectrical impedance analysis (BIA), and hematocrit (Hct) evaluation, and the water balance index (WBI), i.e. the ratio of total body water to hematocrit, was computed. Hematocrit showed significantly lower values in normal than in GH women (31.9+/-2.2% vs. 36.2+/-2.5%; p<0.001). RESULTS: There was no difference in TBW between the two groups. The WBI was higher in normal than in GH women (1.35+/-0.20 l.kg-1.m-2 vs. 1.19+/-0.18 l.kg-1.m-2; p<0.001). Normal subjects showed a higher stroke volume than GH patients (78.0+/-9.7 ml vs 67.9+/-10.2 ml; p=0.001). Atrial function was also higher in normal than in GH women (left atrial fractional area change: 57.4+/-5.1% vs. 42.5+/-7.5%; p<0.001). Correlation was found between stroke volume and WBI (r=0.93, p<0.0001). CONCLUSIONS: Maternal cardiac function and the water balance index are strongly related and might help in comprehending the mechanisms of adaptation in physiologic and hypertensive pregnancy.
Faster heart rates shorten refractoriness more in some tissues than in others. This study investigates whether faster heart rates shorten relative refractoriness more in the right than left bundle branch in humans. Premature atrial stimulation at 2 or more basic cycle lengths was performed in 314 patients with no evidence of atrioventricular conduction system disease. In 10 patients, both functional right and left bundle branch block (BBB) developed with premature atrial stimulation. Functional right BBB occurred at the longer basic cycle length, and functional left BBB at the shorter cycle length in 8 patients. In 2 patients functional right and functional left BBB were present at the same cycle length, but functional left BBB occurred at a shorter premature atrial coupling interval. For all patients, the mean functional right bundle branch relative refractoriness was 438 ms at a basic cycle length of 847 ms, and functional left bundle branch relative refractoriness was 357 ms at a cycle length of 622 ms (p less than 0.01). The HV interval was 45 +/- 15 ms at control and increased with functional left BBB to 77 +/- 19 ms (p less than 0.01), but not with functional right BBB. Thus, relative refractoriness of the right and left bundle branches are rate-dependent and discordant. At longer cycle lengths, relative refractoriness of the right bundle branch is greater than that of the left bundle branch, and at shorter cycle lengths relative refractoriness of the left bundle branch is greater than that of the right bundle branch. The relative refractory period curves "cross over" and can explain the presence of both functional right and left BBB in the same patient.
UNLABELLED: Aim of our study was to determine the dynamics of selected echocardiographic parameters after sinus rhythm (SR) restoration and maintenance in pts with persistent nonvalvular atrial fibrillation (AF) during one year follow-up period. MATERIAL AND METHODS: Our study population comprised 104 pts (F/M 33/71; mean age 60.4 +/- 7.4) assigned to SR restoration and maintenance with serial antiarrhythmic drug usage, for whom transthoracic echocardiographic (TTE) variables were recorded prior to, 2 and 12 months after cardioversion (CD). Left ventricle diastolic diameter and fractional shortening were variables of interest. RESULTS: SR was presented in 66 (63.5%) pts at one year. There was no significant differences in left ventricle diastolic diameter during the follow up. A significant increase in left ventricular fractional shortening (29.9 +/- 6.9% vs 34.5 +/- 8.9%; p < 0.001) was found in pts assigned to the sinus rhythm restoration according to intention-to-treat analysis. Such trend was noted only in pts who maintained SR during the follow up (29.9 +/- 7.6% vs 35.6 +/- 9.3%; p < 0.001). CONCLUSIONS: Among all considered variables only value of left ventricular fractional shortening increased after successful CV of persistent AF in one year follow-up.
OBJECTIVES: The aim of this study was to examine the effect of cardioversion on left and right atrial volume in patients with chronic atrial fibrillation and to determine the influence of mitral valve disease on atrial size. BACKGROUND: Atrial enlargement is a common finding in atrial fibrillation and has been associated with an increased risk for embolic stroke. In addition, atrial enlargement may hamper long-term maintenance of sinus rhythm after cardioversion. METHODS: Forty-one patients with chronic atrial fibrillation (mean duration +/- SD, 45 +/- 62 months) underwent two-dimensional echocardiography before and 6 months after cardioversion to determine left and right atrial dimensions. Underlying heart disease was present in 26 patients: mitral valve disease in 12 (stenosis in 5, regurgitation in 5 and a combination in 2 patients) and other heart diseases in 14. Fifteen patients had lone atrial fibrillation. Patients with sustained sinus rhythm were compared with those who had a relapse of the arrhythmia 6 months after cardioversion. RESULTS: Six months after cardioversion, 28 patients still had sinus rhythm, whereas 13 patients had a relapse of the arrhythmia. In the 28 patients who had sinus rhythm after 6 months, left and right atrial volume decreased from a mean (+/- SD) 72.6 +/- 15.1 to 58.5 +/- 13.8 cm3 (-20%, p < 0.05) and from 68.7 +/- 14.6 to 58.6 +/- 11.6 cm3 (-14%, p < 0.05), respectively. Atrial dimensions also decreased significantly in the subgroup of patients with mitral valve disease. In contrast, no change in atrial size occurred in the 13 patients who had a relapse of atrial fibrillation. Left ventricular function did not change between the two echocardiographic studies, although New York Heart Association class improved in patients who had sinus rhythm after 6 months. CONCLUSIONS: Restoration of sinus rhythm reverts the process of left and right atrial enlargement in patients with chronic atrial fibrillation and mitral valve disease. Therefore, cardioversion may reduce the incidence of thromboembolic complications and prevent the arrhythmia from becoming refractory to medical therapy.
To evaluate the clinical effects of milrinone in patients with severe heart failure, heart function and clinical observations were performed on 25 patients with severe congestive heart failure treated with domestic intravenous milrinone for 15 days. Results showed that the total response rate to milrinone was 96% while 60% of them had significant improvement. Heart function and diameter of left atrial, left ventricle, and right ventricle were measured by pulsed Doppler and M-mode echocardiographg before and after the treatment. The systolic function of the left ventricle (such as SV, CO, EF, FS, IVST, PLVWT) was significantly improved. The diastolic function of the left ventricle (such as E peak, A peak, IRT) was also improved. Diameter of left atrial, left ventricle, and right ventricle was significantly reduced. The heart rate and blood pressure remained unchanged. No obvious side-effect was found in our observation. The domestic intravenous milrinone is a drug of choice for the management of patients with severe congestive heart failure.
We postulated that the abnormal shape, size, and function of the right heart and adjoining ventricular septum in adults with Ebstein's anomaly of the tricuspid valve might in turn alter the shape and function of the left ventricle. Seven adult patients with uncomplicated Ebstein's anomaly were studied. Left ventricular geometry was determined by two-dimensional echocardiography. Left ventricular function was assessed by treadmill exercise and radionuclide angiography at rest and with exercise. Paradoxic ventricular septal motion was consistently present. Left ventricular eccentricity (ratio of two minor axes in the short-axis view) was uniformly abnormal, averaging 1.35 +/- 0.23 (normal = 1.02 +/- 0.05). The ratio of right to left ventricular cavity size averaged 1.70 +/- 0.44 (normal 0.65 +/- 0.30), and tricuspid valve displacement into the right ventricular cavity averaged 52% (normal 8%). Functional right atrial size averaged 27.6 +/- 5.2 cm2 (normal right atrial area = 13.1 +/- 2.2 cm2). Resting left ventricular ejection fractions were below 50% in all but two patients. In response to Bruce protocol exercise stress, there were consistently appropriate increments in heart rate, blood pressure, and peak double product and, with one exception, radionuclide left ventricular ejection fraction. There were significant correlations between tricuspid valve displacement and functional right atrial size versus resting left ventricular ejection fraction and left ventricular eccentricity. These data support the hypothesis that derangements in right heart morphology and function in Ebstein's anomaly contribute to significant alterations in left ventricular geometry, but the geometric alterations are associated with tangible but less significant changes in left ventricular systolic function.
Two-dimensional echocardiography was applied in 10 closed-chest dogs to evaluate, in several left ventricular (LV) short-axis cross sections and subsegments, the regional contractile response to right atrial pacing. Compared with sinus rhythm (81 +/- 10 beats/min), which exhibited a moderate 7.2 +/- 12.0% (mean +/- standard deviation) base-to-apex increment in function, this gradient was significantly augmented to 34 +/- 12% by pacing at a heart rate of 180 beats/min. Measurements of wall thickening and perimeter shortening exhibited similar trends. Differences also were observed in subsegments of individual cross sections: in sinus rhythm the base-to-apex difference in function was relatively minor in the anterior and lateral aspects of the left ventricle (-9.1 +/- 18% and -1.9 +/- 19%), whereas a significant increase was noted in posterior and midseptal zones (18 +/- 17% and 22 +/- 30%). In response to pacing, the anterior and lateral wall base-to-apex gradients were significantly augmented (25 +/- 8% and 35 +/- 34%), but there was no further change in the posterior or septal regions. In conclusion, apical regions of the canine left ventricle responded to right atrial pacing with significant augmentation of contractile function, whereas more basal levels showed little response. Circumferentially, response to atrial pacing was most pronounced in the anterior and lateral segments.
Amino acid enrichment of cardioplegic solutions has been shown to improve both the metabolic and functional recovery of ischemic myocardium. However, because of the marked systemic vasodilatation involved, use of amino acid enrichment is limited to the periods of induction and reperfusion. Fumarate is a Krebs' cycle intermediate whose conversion to succinate is responsible for the generation of adenosone triphosphate and the oxidation of the reduced form of nicotinamide-adenine nucleotide which is the pathway by which aspartate exerts its effect. Fumarate may also function as a free-radical scavenger and is involved in calcium transport. To determine if fumarate-enriched blood cardioplegia would improve the functional recovery of the neonatal heart, 14 neonatal piglet hearts were isolated and placed on a blood-perfused working heart circuit. After the baseline functional and metabolic assessment was done, cold ischemic arrest was initiated with either standard blood cardioplegic solution (group I; N = 7) or fumarate-enriched (13 mmol/L) blood cardioplegic solution (group II; N = 7). Cardioplegic solution was given at a pressure of 40 mm Hg every 20 minutes for 2 hours, and topical hypothermia was used. Sixty minutes after warm whole blood reperfusion, the functional recovery at left atrial pressures of 3, 6, 9, and 12 mm Hg was 70%, 66%, 66%, and 65%, respectively, in group I, versus 102%, 106%, 105%, and 109%, respectively, in group II (p < 0.05). The tissue creatinine phosphate levels after reperfusion were significantly higher in group II hearts (15.0 +/- 1.2 mumol/g dry heart tissue) than in group I hearts (9.2 +/- 1.9 mumol/g dry heart tissue), although the adenosine triphosphate levels were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)
The clinical characteristics of supraventricular tachyarrhythmias (SVTA) and their relation to left ventricular dysfunction were assessed in 208 consecutive patients with recent myocardial infarction. Arrhythmias were quantified on hospital discharge by 24 hour electrocardiographic recording. All the variables were evaluated between the second and the fourth week after infarction. SVTA occurred in 113 (54%) patients: Supraventricular premature beats (SVPB) in 49 (24%), frequent or repetitive SVPB in 37 (18%), atrial or junctional tachycardia in 23 (11%), atrial flutter or fibrillation in 4 (2%). Most of these arrhythmias occurred in the absence of symptoms, and the most complex forms were always selflimiting. No relation was found among the presence of different forms of SVTA and sex, coronary risk factors, previous history of ischemic heart disease, type or site of acute myocardial infarction, NYHA functional class. Age, left atrial dimension (LAD), cardio-thoracic ratio (CTR) and left ventricular ejection fraction (LVEF) at rest differed significantly among three groups of patients: those without SVTA, those with SVPB less than 100 per hour and those with frequent-repetitive SVPB or atrial-junctional tachycardia. The more SVTA complexity, the worse LAD, CTR, LVEF and the higher the age. Multivariate discriminant analysis showed that CTR was directly and LVEF inversely related to the occurrence of SVPB less than 100 per hour, while the presence of frequent-repetitive SVPB or supraventricular tachycardia was closely related to increasing age, LAD, CTR and decreasing LVEF. Patients with atrial fibrillation always showed the worst values of LAD, CTR, LVEF and age. The results of the present study show that different types of SVTA occurring at discharge from hospital after myocardial infarction are clinically benign, but always suggestive of different degrees of left ventricular dysfunction.
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Transesophageal echocardiography, especially in the emerging generation of biplane and multiplane probes with the availability of continuous wave Doppler, has increased our capability for evaluating intracardiac hemodynamics and ventricular function. Transesophageal studies have expanded their role both in clinical research and routine monitoring. The available hemodynamic data (assessment of left and right ventricular function, estimation of left atrial and pulmonary artery pressures, evaluation of the hypotensive patient) apply not only to patients monitored in the operating room but also to patients in the critical care and ambulatory setting. These data can be combined with the anatomic pathology to provide bedside diagnoses and often facilitate appropriate therapy. Further improvements in the quality of both images and computer software are likely to allow more detailed studies of subtle changes in cardiac function in humans.
BACKGROUND: Clinical features that consistently predict ischemic stroke in patients with nonvalvular atrial fibrillation have been identified, while echocardiographic risk factors are less well defined. OBJECTIVE: To determine whether the results of transthoracic echocardiography add independent information to the clinical risk factors for stroke in patients with atrial fibrillation. METHODS: Transthoracic echocardiographic findings and clinical features from 1066 patients with atrial fibrillation assigned to placebo or control in 3 randomized trials (Boston Area Anticoagulation Trial for Atrial Fibrillation, Stroke Prevention in Atrial Fibrillation I Study, and Veterans Affairs Prevention in Atrial Fibrillation Study) were correlated with subsequent ischemic stroke by multivariate analysis. RESULTS: The mean + SD age of patients was 67 +/- 10 years, 78% were men, 55% had a history of hypertension, 19% had a history of diabetes, 7% had a previous transient ischemic attack or stroke, and 27% had a history of heart failure. During a mean follow-up of 1.6 years, 78 ischemic strokes occurred (annual rate, 4.7%). Moderate to severe left ventricular systolic dysfunction shown via 2-dimensional echocardiography was a strong independent predictor of stroke (relative risk, 2.5; P<.001) in the 1010 patients in whom echocardiographic values for left ventricular function were available. Left atrial diameter by M-mode echocardiography did not predict stroke (relative risk, 1.02/mm; P = .10). Of 163 patients categorized as low risk based on clinical features (annual stroke rate, 0.8%; 95% confidence interval, 0.2%-3.0%), 10 had moderate to severe left ventricular dysfunction shown via 2-dimensional echocardiography and a 9.3% per year risk of stroke (95% confidence interval, 1.3%-66%). Conversely, 728 of the 847 patients at high risk for stroke based on clinical criteria had normal or mildly abnormal left ventricular function; their stroke rate was 4.4% (95% confidence interval, 3.4%-5.8%). CONCLUSIONS: Left ventricular systolic dysfunction shown via 2-dimensional transthoracic echocardiography independently predicts risk of stroke in patients with atrial fibrillation. Echocardiography may prove most useful in a small group of patients who have a low risk of stroke according to clinical factors.
BACKGROUND: Repair of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) in infants carries a high operative risk, particularly in infants with myocardial infarction and poor left ventricular function. The marked recovery of left ventricular function reported late after repair, however, suggests that an aggressive approach to repair should be undertaken. METHODS: Of 31 children undergoing primary repair of ALCAPA at our institution from 1987 to 1996, 26 were infants (6 weeks to 9 months old). All but 2 had severe left ventricular dysfunction, and 8 had moderate to severe mitral regurgitation. Seven children were unable to be weaned from cardiopulmonary bypass because of poor left ventricular function and elevated left atrial pressure. These 7 children were placed on mechanical left ventricular support using a centrifugal pump, with support ranging from 2.2 to 70.6 hours. RESULTS: One child died shortly after the start of left ventricular assist (2.2 hours), and another died of arrhythmia within 24 hours after successful decannulation. All 5 survivors had significant improvement in left ventricular function, with 2 requiring late mitral valve repair. CONCLUSIONS: Infants with ALCAPA who have severe left ventricular dysfunction represent a higher risk group for repair. However, with use of mechanical circulatory support in those unable to be weaned from cardiopulmonary bypass, a high survival rate can be achieved with good long-term recovery. We conclude that an aggressive approach to early repair in all children with ALCAPA is warranted, regardless of the degree of left ventricular dysfunction.
A 59 year old woman with aneurysm of the left ventricle anterior wall developed heart failure, class III-IV (NYHA). The radioisotopic angiography showed left ventricular function impairment, ejection fraction of 16% and the aneurysm. She was submitted to aneurysm correction with bovine pericardium patch. In spite of technically successful cardiac surgery, the patient cannot be weaned from cardiopulmonary bypass with maximal pharmacological therapy and intra-ortic balloon pump. Then, we used Biomedicus centrifugal pump for left ventricular assistance. Cannulation was made by aorta and left atrial appendage. Myocardial function evolution was accompanied by hemodynamic parameters and by intra-esophagic echocardiography. The patient was assisted during 42 hours. After this time, assist cannulas were removed in operating room without difficulty. She was submitted to another radioisotopic study on the 50th post-operative day and ejection fraction was 24%. She was discharged from hospital at 52th post-operative day. Nowadays she is in NYHA class II at third post-operative month. More frequent utilization of circulatory assistance devices will reduce global mortality from cardiac surgery and improve safety in surgery of severe cardiac disease.
A retrospective review was done to determine the efficacy and hemodynamic effects of slow intravenous amiodarone administration on invasively monitored patients with acute onset of atrial fibrillation or atrial flutter and left ventricular ejection fractions < 15%. Eight patients met predefined inclusion criteria. All received 300 mg amiodarone intravenously over 1 hour. Seven reverted to sinus rhythm within 1 hour, with return of most hemodynamic variables to baseline. Before reversion, each patient experienced a beneficial slowing of heart rate (mean, 28%) resulting in significant improvement of stroke volume index (mean, 49%) and left ventricular stroke work index (mean, 61%). No patient had hemodynamic deterioration attributable to amiodarone infusion. Slow intravenous infusion of amiodarone appears to be an effective and hemodynamically well-tolerated therapy for atrial fibrillation and atrial flutter in critically ill patients with marked depression of left ventricular systolic function.