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PubMed2006

Cardiovascular features of heart failure with preserved ejection fraction versus nonfailing hypertensive left ventricular hypertrophy in the urban Baltimore community: the role of atrial remodeling/dysfunction.

OBJECTIVES: The purpose of this study was to identify cardiovascular features of patients with heart failure with preserved ejection fraction (HFpEF) that differ from those in individuals with hypertensive left ventricular hypertrophy (HLVH) of similar age, gender, and racial background but without failure. BACKGROUND: Heart failure with preserved ejection fraction often develops in HLVH patients and involves multiple abnormalities. Clarification of changes most specific to HFpEF may help elucidate underlying pathophysiology. METHODS: A cross-sectional study comparing HFpEF patients (n = 37), HLVH subjects without HF (n = 40), and normotensive control subjects without LVH (n = 56). All subjects had an EF of >50%, sinus rhythm, and insignificant valvular or active ischemic disease, and groups were matched for age, gender, and ethnicity. Comprehensive echo-Doppler and pressure analysis was performed. RESULTS: The HFpEF patients were predominantly African-American women with hypertension, LVH, and obesity. They had vascular and systolic-ventricular stiffening and abnormal diastolic function compared with the control subjects. However, most of these parameters either individually or combined were similarly abnormal in the HLVH group and poorly distinguished between these groups. The HFpEF group had quantitatively greater concentric LVH and estimated mean pulmonary artery wedge pressure (20 mm Hg vs. 16 mm Hg) and shorter isovolumic relaxation time than the HLVH group. They also had left atrial dilation/dysfunction unlike in HLVH and greater total epicardial volume. The product of LV mass index and maximal left atrial (LA) volume best identified HFpEF patients (84% sensitivity, 82% specificity). CONCLUSIONS: In an urban, principally African American, cohort, HFpEF patients share many abnormalities of systolic, diastolic, and vascular function with nonfailing HLVH subjects but display accentuated LVH and LA dilation/failure. These latter factors may help clarify pathophysiology and define an important HFpEF population for clinical trials.

Age Distribution↗
PubMed1993

Load independence of early diastolic filling parameters in the anesthetized canine model.

To evaluate radionuclide diastolic filling indices during acute pharmacologic changes in ventricular loading, 11 atrially paced dogs underwent simultaneous micromanometer left atrial and left ventricular pressure measurements. During phenylephrine infusion, systolic blood pressure increased from 110 +/- 16 (s.d.) to 147 +/- 19 mmHg (p < 0.01), causing the atrioventricular gradient to increase from 5 +/- 2 to 8 +/- 5 mmHg (p < 0.03) with no change in the time constant of isovolumic relaxation (Tau). Absolute peak filling rate increased from 40 +/- 21 to 59 +/- 44 kcts/sec (p < 0.05), but there was no change in first-half filling fraction. During dobutamine infusion, Tau shortened from 43 +/- 13 msec to 33 +/- 5 msec (p < 0.01) and first-half filling fraction increased from 39% +/- 19% to 56% +/- 18% (p < 0.05), with no change in atrioventricular gradient or absolute peak filling rate. Absolute changes from baseline for the first-half filling fraction were inversely proportional to absolute changes in Tau (r = -0.76, p < 0.05). We conclude that the left ventricular absolute peak filling rate is a load dependent index of diastolic function. In contrast, the radionuclide first-half filling fraction is independent of loading conditions, but is sensitive to substantial alterations in the rate of left ventricular isovolumic myocardial relaxation.

Animals↗
PubMedDate not supplied

Pulmonary venous velocity patterns in mitral stenosis.

Pulmonary venous (PV) velocities obtained by transthoracic echocardiography are used to assess diastolic function. The systolic/diastolic (S/D) PV velocity ratio is increased with impaired early diastolic filling and decreased with elevated mean left atrial pressure (LAP). Mitral stenosis (MS) is characterized by impaired filling and elevated LAP. We hypothesized that the S/D ratio would be increased in MS except in severe MS with high LAP, in which the S/D ratio would be decreased. Patients with isolated MS who underwent transthoracic echocardiography were studied. The PV S/D ratio was compared in mild (n = 18), moderate (n = 16), and severe (n = 7) MS. There was no characteristic PV pattern, with each category showing a wide range of S/D ratios (mild, S/D ratio = 1.42 +/- 0.56; moderate, S/D ratio = 1.19 +/- 0.59, and severe, S/D ratio = 1.33 +/- 0.53) (mean +/- SD). Furthermore, there was no relationship between the S/D ratio and any index of severity of MS. There is no characteristic PV velocity pattern in MS.

Atrial Function, Left↗
PubMed1989

Pulsed Doppler evaluation of atrial mechanical function after electrical cardioversion of atrial fibrillation.

Full recovery of atrial mechanical activity may not occur immediately after successful electrical cardioversion of atrial fibrillation to sinus rhythm. To examine the time course of recovery of left atrial mechanical function, serial two-dimensional, M-mode and transmitral pulsed Doppler echocardiographic studies were performed in 21 patients after elective direct current cardioversion of atrial fibrillation of 3 weeks' to 24 months' duration (mean 5 months). Over 3 months of follow-up, there were significant increases in both peak A wave velocity (p less than 0.005) and percent atrial contribution to total left ventricular filling (p less than 0.005). Compared with values in a normal control population, peak A wave velocity and percent atrial contribution to total left ventricular filling did not return to normal until 3 weeks after cardioversion in patients who remained in sinus rhythm. Left atrial dimension also decreased over the follow-up period (p less than 0.05) in patients with persistent sinus rhythm. These results may have important implications in guiding the appropriate duration of anticoagulant therapy after cardioversion, and in clinically assessing the hemodynamic benefit of restoring sinus rhythm in an individual patient.

Aged↗
PubMed1991

Noninvasive estimation of left atrial pressure in patients with congestive heart failure and mitral regurgitation by Doppler echocardiography.

A completely noninvasive method for estimating left atrial pressure in patients with congestive heart failure and mitral regurgitation has been devised with the use of continuous-wave Doppler echocardiography and brachial sphygmomanometry. Of 46 patients studied with mitral regurgitation, 35 (76%) had jets with distinct Doppler spectral envelopes recorded. The peak ventriculoatrial gradient was obtained by measuring peak mitral regurgitant velocity in systole and using the modified Bernoulli equation. This gradient was then subtracted from peak brachial systolic blood pressure, an estimate of left ventricular systolic pressure, to yield left atrial pressure (left atrial pressure = systolic blood pressure - mitral regurgitant pressure gradient). Noninvasive estimates of left atrial pressure from 35 patients were plotted against simultaneous recordings of mean pulmonary capillary wedge pressure resulting in the correlation y = 0.88x + 3.3, r = 0.88, standard error of estimate = +/- 4 mm Hg (p less than 0.001). Therefore, continuous-wave Doppler echocardiography and sphygmomanometry may be used in selected patients with congestive heart failure and mitral regurgitation for noninvasive estimation of left atrial pressure.

Atrial Function, Left↗
PubMed1993

Cardiac-renal-neural reflex plays a major role in natriuresis induced by left atrial distension.

The role of cardiac-renal-neural reflex in the natriuresis induced by left atrial balloon inflation was investigated in conscious dogs. Female mongrel dogs were assigned randomly to 1) sham-operated (n = 8), 2) cardiac-denervated (n = 6), and 3) renal-denervated (n = 8) groups. The dogs were chronically instrumented with a bipolar stainless steel wire electrode for measurement of renal sympathetic nerve activity (RSNA). Balloon inflation induced a step increase in left atrial pressure (Pla) by 7.7 +/- 1.7 mmHg, a step decrease in RSNA (-66.6 +/- 5.5%), and concomitant increases in urine flow (441 +/- 142%), osmolal excretion (60 +/- 12%), and sodium excretion (300 +/- 69%) in sham-operated dogs. Renal denervation abolished the diuresis and natriuresis during balloon inflation. Chronic cardiac denervation abolished also the diuresis and natriuresis in the face of a similar increase in Pla. RSNA did not change significantly throughout the experimental period in cardiac-denervated dogs. It is concluded that a sustained reduction of RSNA originating from left atrial mechanoreceptors plays a major role in the natriuresis during left atrial distension in conscious dogs.

Animals↗
PubMed1994

[Cor triatriatum sinistrum and atrial septal defect].

The cor triatriatum sinistrum is a rare congenital malformation. Frequently, the patients become symptomatic in infancy with clinical signs of severe congestive heart failure. We report on an adult patient with only mild symptoms with cor triatriatum sinistrum and atrial septal defect. The embryological basis of the disorder and the hemodynamic conditions which permitted this patient to remain symptom free for a long period are discussed.

Atrial Function, Left↗
PubMed2006

Left atrial volume predicts the risk of atrial fibrillation after cardiac surgery: a prospective study.

OBJECTIVES: This study sought to identify preoperative predictors of postoperative atrial fibrillation (POAF) among patients undergoing cardiac surgery. BACKGROUND: Postoperative atrial fibrillation is frequent after cardiac surgery and is associated with increased morbidity, mortality, prolonged hospital stay, and increased costs. Left atrial volume (LAV), a marker of chronically elevated left ventricular filling pressure, is a predictor of atrial fibrillation (AF) in the nonsurgical setting. METHODS: A total of 205 patients (mean age 62 +/- 16 years; 35% women) undergoing cardiac surgery were prospectively enrolled. Clinical risk factors were obtained by detailed medical record review and patient interview. Preoperative transthoracic echocardiograms were performed for assessment of LAV, left ventricular ejection fraction, and diastolic function. Follow-up was complete. Detection of POAF was based on documentation of AF episodes by continuous telemetry throughout hospitalization. RESULTS: Postoperative atrial fibrillation occurred in 84 patients (41.4%) at a median of 1.8 days after cardiac surgery. The LAV was significantly larger in patients in whom AF developed (49 +/- 14 ml/m2 vs. 39 +/- 16 ml/m2, p = 0.0001). Patients with LAV >32 ml/m2 had an almost five-fold increased risk of POAF, independently of age and clinical risk factors (adjusted hazard ratio 4.84, 95% confidence interval 1.93 to 12.17, p = 0.001). Age and LAV were the only independent predictors of POAF. The area under the receiver-operator characteristics curve to predict POAF was 0.729 for LAV and 0.768 for the combination of LAV and age (both p < 0.0001). CONCLUSIONS: The LAV is a strong and independent predictor of POAF. Risk stratification using LAV and age enables clinicians to identify high-risk patients before cardiac surgery.

Adult↗
PubMed2002

Intraoperative saline-irrigated radiofrequency modified Maze procedure for atrial fibrillation.

BACKGROUND: This study was conducted to evaluate the effectiveness of the saline-irrigated radiofrequency modified Maze operation for treatment of chronic atrial fibrillation, and to compare the results of the left and biatrial procedures. METHODS: During a period of 11 months, 62 patients with chronic atrial fibrillation who were having concomitant cardiac surgery underwent the procedure. The mean age of the patients was 52 +/- 14 years. Patients underwent either a biatrial (group A; n = 39) or left atrial (group B; n = 23) procedure. RESULTS: Two patients (3.2%) died early in the postoperative period. Three patients (4.8%) required reoperation for bleeding. One patient in group A (1.6%) received a permanent pacemaker. Patients in both groups were free of atrial fibrillation at the end of the procedure (group A: sinus 86.9%, pacemaker 13%; group B: sinus 90.5%, pacemaker 9.5%) (p > 0.05). At 1-month and longer-term follow-up, sinus rhythm was maintained in 92% and 95% of cases in group A, respectively, whereas this rate was 71% and 81% in group B (p > 0.05). Holter monitor surveillance revealed a higher rate of atrial fibrillation, atrial arrhythmias, and atrial flutter in group B (p < 0.05). Transthoracic echocardiography revealed improvement over time in left atrial transport function in both groups (p < 0.05). CONCLUSIONS: The saline-irrigated radiofrequency modified Maze procedure was performed safely and efficiently. Both the left and biatrial procedures were successful in terms of restoring sinus rhythm during short-term follow-up. Long-term follow-up with more cases is needed to show the superiority of one method over the other.

Atrial Fibrillation↗
PubMed1994

The effect of residual strain on the diastolic function of the left ventricle as predicted by a structural model.

The unloaded heart is not stress-free. It is subjected to residual stress and strain. Their extent and influence on the global performance of the left ventricle and on local phenomena in the ventricular wall are studied by model simulation. The analysis focuses on the equatorial region of the ventricle, with an approximate thick-walled cylindrical geometry. The in vivo myocardium is considered to be incompressible, consisting of fibers embedded in a fluid matrix, with transmurally varying anisotropic microstructure in accordance with morphological characteristics. The results show that residual strain is transmurally distributed with a pattern and magnitude which agree well with measurements. The calculated residual strains are within mean +/- one standard deviation of the measured ones. Their magnitude was found to increase with increasing opening angle and with increasing wall thickness. The residual strain was found to have several effects on ventricular function: At volumes higher than the reference one it gives rise to more uniform transmural distributions of stress and intramyocardial pressure; it causes about 50% increase in the ventricular compliance at high volumes and doubles the suction of atrial blood at low volumes, thus facilitating the diastolic filling. In addition, residual strains cause bias of in vivo measured strains from their true values. This may significantly affect physiological interpretation of measured ventricular deformations. In conclusion, the present structural analysis predicts that residual strain has favorable effect on left-ventricular diastolic performance, and gives rise to more uniform ventricular stress distribution.

Atrial Function, Left↗
PubMed1994

[Atrial fibrillation--the value of transesophageal echocardiography].

Transesophageal echocardiography is superior to transthoracic echocardiography in detection of superior to transthoracic echocardiography in detection of left atrial thrombi and spontaneous echocardiographic contrast, particularly in patients with atrial fibrillation and spontaneous echocardiographic contrast, thrombus formation is likely. In addition to the morphology, Doppler-echocardiography can be used to access left atrial appendage function. In patients with lone atrial fibrillation, reduced velocity was found in 60%, and no flow was detected in the left atrial appendage in 40%. These patients had a higher risk for spontaneous echocardiographic contrast and thrombus formation. As left atrial thrombi are found in 12% of patients, transesophageal echocardiography can be used to avoid cardioversion in these patients, which may lead to cerebral or peripheral emboli. Despite ruling out left atrial thrombi, embolism occurred after cardioversion when anticoagulation was insufficient or not performed. Current investigations are undertaken in order to demonstrate the clinical benefit of transesophageal echocardiography in patients with left atrial fibrillation.

Atrial Fibrillation↗
PubMed1999

Hemodynamic and cardiorespiratory function following internal atrial defibrillation for chronic atrial fibrillation.

Internal atrial defibrillation (IAD) is able to restore sinus rhythm in patients with chronic atrial fibrillation (AF) and failed external electrical and/or pharmacologic cardioversion. To assess whether cardiorespiratory and hemodynamic function improve after IAD, 35 patients were prospectively investigated during constant workload exercise by spiroergometry and Doppler echocardiography before IAD, and 1 day and 1 month after IAD. Oxygen uptake kinetics, ventilation, left atrial mechanical function, and pulmonary artery pressure were determined simultaneously at rest and during steady state. During the serial follow-up, 20 patients maintained sinus rhythm. The time interval for achieving the steady state (146 +/- 53 vs 132 +/- 42 seconds; p = 0.5) and the oxygen deficit (645 +/- 190 vs 670 +/- 174 ml; p = 0.7) were not different before and 1 day after IAD, but decreased significantly after 1 month (98 +/- 16 seconds, p = 0.01 and 487 +/- 72 ml, p = 0.02). Exercise pulmonary artery systolic pressures were 38 +/- 13 mm Hg before IAD, increased significantly to 46 +/- 11 mm Hg on day 1 (p = 0.03), and decreased below baseline values at 1 month to 31 +/- 12 mm Hg (p = 0.07). Peak A-wave velocities increased from 0.51 +/- 0.1 m/s after 1 day to 0.67 +/- 0.2 m/s after 1 month (p = 0.03). Restoration of sinus rhythm in patients with AF resistant to external electrical and/or pharmacologic cardioversion improves hemodynamic and cardiorespiratory function at daily activity exercise levels.

Atrial Fibrillation↗
PubMed2001

Effects of desflurane and sevoflurane on length-dependent regulation of myocardial function in coronary surgery patients.

BACKGROUND: Desflurane and sevoflurane have negative inotropic effects. The current study investigated whether these effects resulted in an altered left ventricular response to increased cardiac load and affected length-dependent regulation of myocardial function. Length-dependent regulation of myocardial function refers to the ability of the heart to improve its performance when preload is increased. METHODS: A high-fidelity pressure catheter was positioned in the left ventricle and left atrium in 20 coronary surgery patients with a preoperative ejection fraction greater than 40%. Studies were performed before the initiation of cardiopulmonary bypass. Left ventricular response to increased cardiac load, obtained by leg elevation, was assessed during control conditions and during increasing concentrations of desflurane (2, 4, and 6% end tidal; n = 10) or sevoflurane (1, 2, and 3% end tidal; n = 10). Effects on contraction were evaluated by analysis of changes in maximal rate of pressure development. Effects on relaxation were assessed by analysis of changes in minimum rate of pressure development and by analysis of the load dependence of myocardial relaxation (R = slope of the relation between time constant tau of isovolumic relaxation and end-systolic pressure). Peak left atrial-left ventricular pressure gradients were analyzed during early left ventricular filling. RESULTS: With both desflurane and sevoflurane, maximal and minimum rates of pressure development decreased while tau increased. Peak left atrial-left ventricular pressure gradients remained unchanged. The hemodynamic effects of leg elevation were similar at the different concentrations. Changes in parameters of contraction and relaxation during leg elevation were coupled and were not altered by desflurane or sevoflurane. CONCLUSIONS: Despite their negative inotropic and lusitropic effects, neither desflurane nor sevoflurane adversely affect length-dependent regulation of left ventricular function. In the conditions of our study, the ability of the left ventricular to respond to increased cardiac load is not altered by the use of desflurane or sevoflurane.

Aged↗