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At least 721 records · Page 40Linked to original sources
PubMed2004

The pseudorestrictive pattern of transmitral Doppler flow pattern after conversion of atrial fibrillation to sinus rhythm: is atrial or ventricular dysfunction to blame?

Patients with paroxysmal atrial fibrillation (AF) who have recently converted from AF to sinus rhythm often exhibit a restrictive Doppler pattern in the transmitral flow (TMF) velocity. However, the mechanism of this phenomenon has not been well defined. We evaluated the temporal change of TMF pattern and hemodynamics after conversion of AF to in sinus rhythm in an animal model. Eight open-chest dogs underwent 3 hours of pacing-induced AF. TMF velocities and pressure data were acquired at baseline (sinus rhythm), immediately after conversion of AF, and every 10 minutes thereafter. Early diastolic TMF velocity was increased immediately after conversion and recovered to the baseline value in 20 minutes. Atrial systolic TMF velocity was reduced after AF and recovered to baseline value in 20 to 30 minutes. Early diastolic/atrial systolic TMF velocity was increased after conversion, and recovered to baseline value in 20 to 30 minutes. The mean left atrial (LA) pressure increased immediately, 10 and 20 minutes after the conversion of AF to sinus rhythm. The left ventricular end-diastolic pressure was increased and positive left ventricular dP/dt and tau were decreased immediately after AF, whereas they recovered within 10 minutes. In conclusion, a pseudorestrictive pattern of TMF after AF occurred as a result of transient LA mechanical functional impairment and increased LA pressure caused by LA stunning. Transient left ventricular diastolic dysfunction also effected the TMF velocity immediately after the conversion from AF to sinus rhythm, although it recovered faster than LA mechanical dysfunction.

Animals↗
PubMed2002

Normal systolic and diastolic functions of the left ventricle and left atrium by cine magnetic resonance imaging.

Volume and phase characteristics of the left ventricle (LV) and left atrium (LA) were assessed in 31 healthy Asian adults (19 males and 12 females) using cine magnetic resonance imaging (MRI) and an automated boundary detection algorithm. Volume indexes of the LV and LA were smaller than published results obtained mostly from Westerners. Other than LV mass index and percent emptying of the LA, there was no gender difference in all LV/LA indexes. In associating LV/LA functions with the body size and heart rate (HR), we found that LV mass and the minimum LA volume correlated strongly with the body surface area, the maximum LA volume and the reservoir volume correlated strongly with the body weight, and the time to LV peak-filling rate (LVPFRt) and the time to LA peak-emptying rate (LAPERt) correlated strongly with the HR. In associating LV with LA functions, we found that LA conduit volume contributed more than 50% of the LV stroke volume, and correlated with both systolic and diastolic functions of the LV. Moreover, LVPFRt and LAPERt were virtually identical, indicating a mechanical coupling between LV and LA during diastole. In conclusion, using time-resolved, three-dimensional volume data obtained from cine MRI, we have established normative values of LV and LA functions and their functional relationships in healthy Asian adults. The imaging acquisition protocol, data analysis algorithms, and the established normative values provide the basis for the study of left heart function in patients.

Adult↗
PubMed1991

Percutaneous balloon mitral valvuloplasty in rheumatic mitral stenosis: an experience of 50 patients in India.

We attempted percutaneous balloon mitral valvuloplasty in 50 patients (27 female and 23 male, age 10-38 years) with rheumatic mitral stenosis. The procedure could be completed in 40 patients. The failures were caused by problems related to transseptal puncture in eight cases and inability to cross the mitral valve in two cases. Immediately after valvuloplasty there was a remarkable reduction in the mean pulmonary artery pressure, left atrial mean pressure, mean diastolic gradient across the mitral valve, and the calculated pulmonary vascular resistance. The calculated mitral valve area increased and the cardiac index increased marginally. Inadequate results with a post valvuloplasty mitral valve area of 0.9 cm2 were seen in only one patient. Repeat hemodynamic evaluation in 25 patients within two weeks of valvuloplasty showed persistent benefit in all except one patient, who showed partial restenosis. Follow-up cardiac catheterization at 3-6 months in 13 patients showed evidence of restenosis (mitral valve area less than 1.0 cm2 and mean diastolic gradient of greater than 10 mmHg) in one patient, while all others maintained hemodynamic benefit. Repeat hemodynamic evaluation at 9-18 months after valvuloplasty in eight patients showed evidence of restenosis in an additional two cases. The patients in our series are young (28 patients less than 20 years), small body surface area (1.35-0.2 m2), and have high left atrial and pulmonary arterial pressures.

Adolescent↗
PubMedDate not supplied

Determinants of left atrial pressure in rheumatic mitral stenosis: role of left atrial compliance and "atrial stiffness".

BACKGROUND: A wide range of left atrial pressures exist in rheumatic mitral stenosis despite similar mitral valve area. Left atrial compliance may be an important determinant of left atrial pressure in mitral stenosis. Data regarding left atrial compliance in rheumatic mitral stenosis and changes following balloon mitral valvotomy are scarce. METHODS AND RESULTS: Left atrial compliance and predictors of left atrial pressure were analyzed in 85 patients with mitral stenosis undergoing balloon mitral valvotomy. The stroke volume was divided by systolic rise in left atrial pressure to calculate the left atrial compliance. Systolic rise in left atrial pressure was computed as difference between amplitudes of left atrial "v" wave and "x" descent. The mean left atrial compliance prior to balloon mitral valvotomy was 2.62+/-1.20 cm3/mmHg. Following successful balloon mitral valvotomy there was a significant fall in pulmonary artery pressure, mean left atrial pressure, transmitral gradient, and significant increase in cardiac output, stroke volume and mitral valve area. There was a marked increase in left atrial compliance from 2.62+/-1.20 to 6.1+/-3.16 cm3/mmHg. On univariate analysis pulmonary artery systolic pressure, pulmonary artery diastolic pressure, pulmonary artery mean pressure, mean transmitral gradient, mitral valve area and left atrial compliance were the only correlates of left atrial pressures, while no correlation was noted with age, gender, left atrial size, cardiac output and stroke volume. Those with higher pulmonary artery pressure, higher transmitral gradient, lower mitral valve area and lower left atrial compliance had higher left atrial mean pressure, and the strongest negative correlation was noted with left atrial compliance. On multivariate analysis the strongest predictors of left atrial mean pressure were transmitral gradient and left atrial compliance. CONCLUSIONS: Patients with rheumatic mitral stenosis have markedly depressed left atrial compliance and hence have "stiff" left atria. Left atrial compliance is an important determinant of left atrial pressure, and improves immediately after successful balloon mitral valvotomy, irrespective of pre-balloon mitral valvotomy left atrial pressures.

Adult↗
PubMed2004

Long-term prognostic significance of left atrial volume in acute myocardial infarction.

OBJECTIVES: The aim of this study was to evaluate the significance of increased left atrial (LA) volume determined within the first 48 h of admission as a long-term predictor of outcome in patients with acute myocardial infarction (MI). BACKGROUND: The LA volume reflects left ventricular (LV) diastolic properties. Whereas other LV Doppler diastolic characteristics are influenced by acute changes in LV function, LA volume is stable and reflects diastolic properties before MI. METHODS: Clinical and echocardiographic parameters were prospectively collected in 395 consecutive patients with acute MI. Patients with LA volume index (LAVI) >32 ml/m(2) (normal + 2 standard deviations) were compared with those with LAVI <==32 ml/m(2). Independent clinical and echocardiographic prognostic risk factors for five years' mortality were determined by the Cox proportional hazard model. RESULTS: Left atrial volume index >32 ml/m(2) was found in 63 patients (19%) who had a higher incidence of congestive heart failure on admission (24% vs. 12%, p < 0.01), a higher incidence of mitral regurgitation, increased LV dimensions, and reduced LV ejection fraction when compared with patients with LAVI <==32 ml/m(2). Their five-year mortality rate was 34.5% versus 14.2% (p < 0.001). Significant independent risk predictors of five years' mortality were age (10 years) (odds ratio [OR] 1.45; 95% confidence interval [CI]1.14 to 1.86), Killip class >/=2 on admission (OR 2.30; 95% CI 1.29 to 4.09), LAVI >32 ml/m(2) (OR 2.22; 95% CI 1.25 to 3.96), diabetes (OR 1.94; 95% CI 1.15 to 3.28), and LV restrictive filling pattern (OR 1.89; 95% CI 1.09 to 3.31). CONCLUSIONS: In patients with acute MI, increased LA volume, determined within the first 48 h of admission, is an independent predictor of five-year mortality with incremental prognostic information to clinical and echocardiographic data.

Aged↗
PubMedDate not supplied

[Phonocardiographic and Doppler echocardiographic study on the mechanism of the presystolic murmur in mitral stenosis, especially the relationship to mitral inflow dynamics].

The cause of the "presystolic murmur" in mitral stenosis was investigated by phonocardiography and continuous wave Doppler echocardiography in 31 patients with mitral stenosis and sinus rhythm classified into two groups: 18 patients with and 13 without "presystolic murmur". 1. The "presystolic murmur" group demonstrated high frequency vibrations preceding the first heart sound coinciding with the initial low frequency component of the first heart sound recorded at the apex in both groups. 2. There were two types of "presystolic murmur": The first type observed in three of the 18 patients occurred during the accelerated phase of the atrial (A) wave of mitral inflow signals and lasted until the first heart sound. The A wave velocity in mitral inflow signals was high at the onset and peak, and rapidly decreased after the peak. The second type observed in 15 patients occurred during the decelerated phase of the A wave and lasted until the first heart sound. The A wave velocity in mitral inflow signals was low at the onset, but high at the peak and rapidly decreased after the peak. 3. The mitral orifice area tended to be smaller in all patients with "presystolic murmur". The peak flow velocity, deceleration rate of the A wave, and maximal pressure gradient across the mitral valve during atrial contraction were significantly increased in all patients with "presystolic murmur". 4. Five patients with newly developed "presystolic murmur" after amyl nitrite inhalation had an increased initial low frequency component of the first heart sound coinciding with the latter half of "presystolic murmur". The rate of increase in the peak flow velocity and the deceleration rate of the A wave were significantly larger and the maximal atrioventricular pressure gradient during atrial contraction tended to be larger in these five patients than those in five who did not develop "presystolic murmur". 5. The peak flow velocity, deceleration rate of the A wave and the maximal atrioventricular pressure gradient during atrial contraction had increased 1 year later compared with those immediately after cardioversion of atrial fibrillation, and newly developed "presystolic murmur" appeared according to the recovery of left atrial mechanical function. These results suggest that the latter half of "presystolic murmur" originates from augmentation and prolongation of the initial low frequency component of the first heart sound up to the audible range caused by the sudden deceleration of mitral inflow velocity due to left ventricular contraction, and that the early half of "presystolic murmur" is the atriosystolic murmur produced by the increase in mitral inflow velocity during atrial contraction.

Blood Flow Velocity↗
PubMed1999

Importance of left atrial appendage flow as a predictor of thromboembolic events in patients with atrial fibrillation.

AIM: The purpose of this study was to investigate the role of transoesophageal echocardiography in predicting subsequent thromboembolic events in patients with atrial fibrillation. METHODS AND PATIENTS: Transoesophageal echocardiography was performed in 88 patients with documented paroxysmal (n=53) or chronic atrial fibrillation (n=35) to assess morphological and functional predictors of thromboembolic events. Prospective selection was from patients with non-valvular atrial fibrillation who had undergone transoesophageal echocardiography because of previous thromboembolism (n=30); prior to electrical cardioversion (n=31); or for other reasons (n=27). All patients were followed up for 1 year. RESULTS: During the period of follow-up new thromboembolic events occurred in 18 of 88 patients (20%/year); 16 of these patients had a stroke and two a peripheral embolism. Univariate analysis revealed that previous thromboembolism (P<0.005; odds ratio 5.3 [CI 1.9, 12. 1]), history of hypertension (P<0.01; odds ratio 4.0 [CI 1.4, 10.4), presence of left atrial spontaneous echo contrast (P<0.025; odds ratio 3.5 [CI 1.2, 10.0]), and presence of left atrial appendage peak velocity </=0.20 m. s-1(P<0.01; odds ratio 4.1 [CI 1.4, 11.6]) were significantly related to subsequent thromboembolic events. Stepwise logistic regression showed that independent predictors of thromboembolic events were: history of thromboembolism (P<0.005), history of hypertension (P<0.05) and low left atrial appendage peak velocity </=0.20 m. s-1(P<0.01). CONCLUSIONS: In patients with atrial fibrillation, the presence of spontaneous echo contrast in the left atrium, and in particular a low left atrial appendage peak flow velocity, can be used to identify a subgroup of atrial fibrillation patients at either increased or decreased risk of subsequent thromboembolism, which might have important implications for anticoagulation therapy.

Aged↗
PubMedDate not supplied

[Role of transesophageal echocardiography in the evaluation of the potential embolic risk in left atrial thrombosis. Report of a clinical case].

We describe the case of a 73-year-old man with cardiac failure due to hypertensive heart disease, chronic atrial fibrillation, prior ischemic stroke and acute ischemia of the left leg probably embolic in nature, in whom transthoracic echocardiography (TTE) detected a large left atrial mass compatible with thrombus. Transesophageal echocardiography (TEE) was performed to better evaluate the atrial mass. TTE showed a mass that was firmly attached to the wall of the left atrium, compact, homogeneous and stationary, indicating a relatively low embolic risk. On the other hand TEE clearly detected a marked motility and echographic unhomogeneity of the atrial mass, suggesting a poorer prognosis and urgent surgical referral due to high impending embolik risk. This case further supports the superiority of TEE to TTE in the assessment of intracardiac masses and, in particular, of embolik risk in a patient with left atrial thrombosis.

Aged↗
PubMed1975

Intra-aortic balloon counterpulsation: potential for therapy in hemorrhagic shock with associated myocardial failure.

After attaching appropriate monitoring devices enabling the measurement of the slope of the left ventricular function curve, left atrial pressure, mean aortic pressure, peak left ventricular pressure, and tension time index, three groups of ten dogs were subjected to varying periods of hemorrhagic shock until a slope of their ventricular function curve was reduced to either 75% (Group I), 50% (Group II), or 25% (Group III) of their baseline value. Resuscitation was attempted in all dogs by the intravenous infusion of shed blood plus additional balanced salt solution. This infusate was administered to maintain either the mean aortic pressure within 15 mm Hg of the baseline value or a left atrial pressure of 15 mm Hg, whichever occurred forst. One half of the dogs received, in addition, intra-aortic balloon counterpulsation. All dogs not receiving counterpulsation expired within two hours. There was no apparent effect of counterpulsation on Group I animals. Three of five animals (Group II) and four of five animals (Group III) receiving counterpulsation survived to the end of the experiment with significant (p smaller than .01) improvement in the parameters monitored. The utilization of counterpulsation as an adjunct to treatment in hemorrhagic shock is suggested.

Animals↗
PubMed1993

A simultaneous study of Doppler-echo and catheterization in noninvasive assessment of the left ventricular dp/dt.

To confirm the feasibility and accuracy of the method for the noninvasive measurement of the left ventricular dp/dt, 53 patients with mitral regurgitation underwent simultaneous determination of left ventricular dp/dt by continuous-wave Doppler echocardiography and cardiac catheterization. Doppler-determined left ventricular dp/dt is derived from the Doppler mitral regurgitant spectrum by dividing the magnitude of the left ventricular-atrial pressure gradient rise between 1 and 3 m/s of the mitral regurgitant velocity signal by the time taken for this change. Left ventricular dp/dt by Doppler ranged from 629 to 3494 mmHg/s (mean +/- SD, 1971 +/- 785 mmHg/s), and that by catheterization varied between 716 and 3650 mmHg/s (mean +/- SD, 1974 +/- 727 mmHg/s). There was a high correlation (r = 0.93, y = 0.862x + 274.77, SEE = 271 mmHg/s, p < 0.001) of left ventricular dp/dt between the two techniques. It is concluded that left ventricular dp/dt is one of the most commonly used parameters for the evaluation of left ventricular systolic function and that Doppler echocardiography provides a new, accurate and noninvasive method of evaluation.

Adolescent↗