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PubMed2003

Novel protection strategy for pulmonary transplantation.

BACKGROUND: Ischemia-reperfusion injury continues to represent a significant challenge to successful lung transplantation. Traditional pulmonary ischemic protection is performed using hypothermic hyperkalemic depolarizing solutions to reduce the metabolic demands of the ischemic organ. Measures to further reduce the effects of ischemic injury have focused on the reperfusion period. We tested the hypothesis that novel physiologic hyperpolarizing solutions-using ATP-dependent potassium channel (K(ATP)) openers-given at the induction of ischemia, will reduce cellular injury and provide superior graft function even after prolonged periods of ischemia. METHODS: An isolated blood-perfused ventilated rabbit lung model was used to study lung injury. Airway, left atrial, and pulmonary artery pressures were measured continuously during the 2-h reperfusion period. Oxygenation, as a surrogate of graft function, was measured using intermittent blood gas analysis of paired left atrial and pulmonary artery blood samples. Graft function was measured by oxygen challenge technique (F(i)O(2) = 1.0). Wet-to-dry ratio was measured at the conclusion of the 2-h reperfusion period. Control (Group I) lungs were perfused with modified Euro-Collins solution (depolarizing) and reperfused immediately (no ischemia). Traditional protection lungs were perfused with modified Euro-Collins flush solution and stored for 4 h (Group II) or 18 h (Group III) at 4 degrees C before reperfusion. Novel protection (Group IV) lungs were protected with a hyperpolarizing solution containing 100 nM Aprikalim, a specific K(ATP) channel opener, added to the modified Euro-Collins flush solution and underwent 18 h of ischemic storage at 4 degrees C before reperfusion. RESULTS: Profound graft failure was measured after 18 h of ischemic storage with traditional protection strategies (Group III). Graft function was preserved by protection with hyperpolarizing solutions even for prolonged ischemic periods (Group IV). Wet-to-dry weight ratio, airway, left atrial, and pulmonary artery pressures were not significantly different between the groups. CONCLUSIONS: We have created a model of predictable lung injury. Membrane hyperpolarization with a K(ATP) channel opener (PCO) provides superior prolonged protection from ischemia-reperfusion injury in an in vitro model of pulmonary transplantation.

Animals↗
PubMed1990

Ringer's acetate and dextran-70 with or without hypertonic saline in endotoxin-induced shock in pigs.

The effects of Ringer's acetate, 6% dextran-70, 7.5% NaCl, and the combination of 7.5% NaCl and dextran-70 were tested in resuscitation from endotoxin shock induced by continuous iv infusion of Escherichia coli endotoxin in pigs. After about 3 h, a reproducible shock state was achieved and treatment was started, governed by the left atrial pressure. The hypertonic solutions (7.5% NaCl and 7.5% NaCl in dextran-70) did not show any overall advantages over the isotonic solutions (Ringer's acetate and dextran-70). Only transient beneficial hemodynamic effects lasting less than 30 min after infusion were seen. When dextran-70 was administered, cardiovascular function was markedly improved and oxygen delivery (DO2) and survival were significantly higher compared with the crystalloid groups (Ringer's acetate and 7.5% NaCl). Administration of large amounts of Ringer's acetate resulted in an immediate deterioration of pulmonary function. It was difficult to elevate left atrial pressure or even to keep it at baseline level, and cardiac index was only transiently increased. The overall result was a deterioration of DO2 and poor survival compared with the dextran-70 treated pigs. We conclude that dextran-70 is superior to Ringer's acetate in resuscitation from endotoxin-induced shock in pigs. Furthermore, we found no role for the use of hypertonic saline, alone or in combination with dextran, in the treatment of this type of prolonged endotoxin shock.

Animals↗
PubMed1986

Regional myocardial protection by retrograde coronary sinus infusion of cardioplegic solution.

Antegrade administration of a cardioplegic solution in the presence of a coronary artery stenosis may lead to the heterogeneous distribution of the agent and poor myocardial cooling distal to a vessel stenosis. To determine the effects of retrograde coronary sinus infusion of cardioplegic solution, coronary stenosis was created in the canine preparation by occluding the left circumflex artery (LCx) during cardioplegic arrest. Left ventricular global and regional function (assessed by sonomicrometry and solid-state micrometers) were studied after 60 min of ischemic arrest. Three groups (all n = 7) were studied: group I (control), cardioplegic solution infused via the aortic root without LCx occlusion; group II, same as group I except with LCx occlusion; group III, retrograde coronary sinus infusion of cardioplegic solution with LCx occlusion. Heart rate was controlled by atrial pacing. Statistically significant differences in global function between the three groups were seen at low filling pressures but were not seen during volume challenge. However, the recovery ratio of regional function in the LCx area at a left atrial pressure of 5 mm Hg in group II was 77.2% (% shortening) and 48.5% (segment work), which was significantly less (p less than .01) than recovery in group I (111.7% and 75.9%) and group III (108.3% and 81.5%). These differences persisted during volume loading, to a mean left atrial pressure of 15 mm Hg. Regional compliance in group II was also significantly (p less than .01) depressed after cardioplegic arrest but was well preserved in groups I and III.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Effect of mitral regurgitation on left ventricular thrombus formation in dilated cardiomyopathy.

To assess whether the presence of mitral regurgitation has a protective effect on left ventricular thrombus formation in a heterogeneous group of patients with dilated cardiomyopathy, a group of 103 patients with dilated cardiomyopathy identified by means of echocardiographic criteria was assembled over 1 year. The purpose of the study was to define a subgroup of patients with dilated cardiomyopathy from whom long-term anticoagulation might be withheld. Each echocardiogram was evaluated for the presence of left ventricular thrombus, presence and severity of mitral regurgitation, and ejection fraction. The role of clinical factors and clotting factors in left ventricular thrombus formation was assessed. Left ventricular thrombus was not present in 91 patients (group A) and was present in 12 patients (group B). Group B had larger left atrial and left ventricular systolic dimensions and decreased left ventricular systolic function. Mitral regurgitation jet area and ratio between mitral regurgitation jet area and left atrial area were lower (signifying less severe mitral regurgitation) among patients in group B. Although mitral regurgitation was equally present in group A and group B, severe mitral regurgitation was found only in group A patients ( 11 of 91 patients). Among patients with dilated cardiomyopathy, left ventricular ejection fraction is the factor most associated with left ventricular thrombus formation. The presence of severe mitral regurgitation may have a protective role in left ventricular thrombus formation.

Anticoagulants↗
PubMed1987

Enhanced myocardial depression in diabetic rats during E. coli sepsis.

The aim of this study was to determine whether diabetes enhanced the sensitivity of the myocardium to the deleterious effects of in vivo-administered Escherichia coli. Diabetes was induced in two groups of animals. One group received 70 mg/kg streptozotocin (iv) and exhibited a severe diabetes with elevated fasting and fed blood glucose concentrations and a markedly abnormal response to an oral glucose load. The second group received 45 mg/kg streptozotocin, was mildly diabetic (termed "latent" diabetes), and was characterized by normal fasting blood glucose but slightly elevated fed blood glucose and an abnormal response to a glucose load. A third group of rats received vehicle and served as time-matched control animals. Four weeks after induction of diabetes, all animals were catheterized under ether anesthesia and some received intraperitoneal injections of live E. coli. In vitro myocardial performance was assessed using the isolated, perfused working heart preparation. Ventricular function curves were generated by changing left atrial filling pressure and measuring changes in heart rate, cardiac output, and aortic peak systolic pressure. Cardiac performance in the severe diabetic group was depressed at the highest preload but was unchanged at lower preloads. Function in the latent diabetic group was not different from control. Sepsis induced a slight decrease in cardiac performance in the control group and resulted in larger reductions in the latent and severe diabetic groups. A depression in aortic flow was the major consequence of sepsis in the latent diabetic group, whereas decreased coronary flow was the primary change in the severe diabetic group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

[Mitral valve repair--indication and late results].

In recent years, mitral valve repair has become more widespread because it promises a reduction in both mortality and morbidity compared with valve replacement. As the incidence of rheumatic valve disease has declined in Japan, degenerative disease has become the most common cause of mitral regurgitation (MR), for which repair techniques can be successfully applied. The standard repair techniques, including artificial chordal implantation, increase the indications for valve repair to up to 95% of patients with MR and improve the long-term results. The indications for surgical intervention in patients with MR have evolved. Asymptomatic patients are considered for surgery when left ventricular function begins to deteriorate or atrial arrhythmias appear.

Cardiac Surgical Procedures↗
PubMed1979

[Echocardiographic evaluation of left ventricular function in man].

Comparison of ultrasound and invasive measurements has shown that accuracy and reproducibility of echocardiographic assessment of left ventricular performance are suitable for clinical use. We determined the influence of changes in heart rate, afterload, inotropic state and diastolic cycle length after premature beats and in atrial fibrillation on various ejection phase indices of myocardial contractility in man. Mean and maximal velocity of circumferential fiber shortening (VCF mean' VCF max) showed a slight increase during rapid atrial pacing. In contrast fractional shortening (FS%) and delta-VCF were not influenced by acute changes in heart rate. During intravenous infusion with Dobutamine VCF max and delta-VCF proved to be particular sensitive indices of left ventricular function. After permature beats and in atrial fibrillation the results indicate a linear correlation between all indices of the ejection phase and diastolic cycle length.

Arrhythmias, Cardiac↗
PubMed1993

Myocardial function in early hours after coronary artery bypass grafting: comparison of two cardioplegic methods.

The theoretical advantages of retrograde blood cardioplegia combined with anterograde blood cardioplegia and warm reperfusion before aortic unclamping during coronary surgery were evaluated in 41 patients (group 2). The early postoperative myocardial function of this group was compared with that of 55 patients (group 1) in whom cold crystalloid cardioplegia was administered. The following variables were measured and analyzed by multivariate statistical analysis: heart rate, left atrial pressure, systemic arterial pressure, cardiac index, left ventricular stroke work index, ventricular function, oxygen delivery, hemoglobin, partial oxygen pressure in mixed venous blood, arteriovenous oxygen difference, carbon dioxide production per square meter, and cardiac isoenzyme of creatine-kinase. The myocardial function improved progressively and cardiac enzymatic release was low for both groups 9 hours after admission to the intensive care unit. However, group 2 had significantly higher oxygen delivery, carbon dioxide production per square meter, cardiac index, left ventricular stroke work index, and ventricular function and significantly lower left atrial pressure and mean systemic arterial pressure than that of group 1. The best separation of group 2 from group 1 occurred at the ninth hour, with a probability of correct recognition of 92.1%.

Blood Pressure↗
PubMed2002

[Autoantibodies: new upstream targets of paroxysmal atrial fibrillation in patients with congestive heart failure].

OBJECTIVES: The clinical implications of autoantibodies (Abs) were investigated as upstream indicators of paroxysmal atrial fibrillation in patients with congestive heart failure. METHODS: Circulating Abs against myosin (M-Abs) detected by immunofluorescence, Abs against beta 1-adrenergic receptors (Beta 1-Abs) detected by enzyme-linked immunosorbent assay (ELISA), and Abs against NA-K-ATPase (NKA-Abs) detected by ELISA were screened in 95 congestive heart failure patients with < or = 45% left ventricular ejection fraction (coronary artery disease, n = 48; dilated cardiomyopathy, n = 47) and 48 age-matched control patients with hypertension. No patient received antiarrhythmic therapy. All patients were enrolled with angiotensin converting enzyme inhibitors in the chronic stable state. Relationship of the presence of paroxysmal atrial fibrillation to other clinical variables were assessed by 48-hour Holter monitoring. RESULTS: No control patient had Abs. However, M-Abs, Beta 1-Abs, and NKA-Abs were detected in 22%, 26% and 16% of patients with congestive heart failure (coronary artery disease; 8%, 10%, and 4%, dilated cardiomyopathy; 36%, 43%, and 28%, respectively). Paroxysmal atrial fibrillation was more frequent in patients with dilated cardiomyopathy than in those with coronary artery disease (47% vs 15%, p < 0.01). Multivariate analysis suggested that NKA-Abs was an independent risk factor for the occurrence of paroxysmal atrial fibrillation (p < 0.01), although there were no differences in other clinical factors: age, sex, New York Heart Association functional class, concomitant medication, left ventricular ejection fraction, left atrial diameter, severity of mitral regurgitation, serum potassium, plasma norepinephrine, and atrial natriuretic peptide concentration. CONCLUSIONS: Autoantibodies against sarcolemmal Na-K-ATPase were closely related to the occurrence of paroxysmal atrial fibrillation in patients with congestive heart failure, so an autoimmune process may be an upstream factor in atrial fibrillation.

Atrial Fibrillation↗
PubMed1985

The influence of streptozotocin-induced diabetes on myocardial contractile performance in vitro.

The influence of streptozotocin-induced diabetes has been studied on rabbit isolated cardiac muscle responses to noradrenaline and calcium. Seven weeks after treatment with streptozotocin (70 mg/kg i.v.), right atrial contractile rate was found to be depressed, whereas left ventricular papillary muscle function was markedly enhanced. Neither the atrial nor the ventricular (papillary) muscle strip exhibited a remarkable alteration in sensitivity to noradrenaline. Although sensitivity to calcium was not altered in the atrial muscle, papillary muscle strips obtained from diabetic rabbits were supersensitive to calcium. These results suggest that in diabetic animals, right atrial pacemaker function is depressed, while ventricular muscle activity is enhanced. In the diabetic state, this enhanced ventricular muscle function is likely to be associated with an alteration in calcium utilization.

Animals↗
PubMed1992

The role of Doppler echocardiography in the assessment of left ventricular diastolic function.

The role of Doppler echocardiography of transmitral filling velocities in the assessment of diastolic function in man has not been adequately defined. It is now appreciated that multiple interacting factors such as loading conditions influence the transmitral velocity profile independent of intrinsic left ventricular diastolic function. Extrapolating the status of diastolic function from the transmitral velocity profile is complicated by these factors. The load dependence of ventricular filling has tempered the initial enthusiasm for the clinical application of the Doppler technique. In the present review, studies examining invasive parameters of diastolic function and Doppler indices of diastolic filling are discussed to gain greater insight and understanding of the role of Doppler echocardiography in the noninvasive assessment of diastolic function. These studies have demonstrated a relatively consistent influence of left ventricular relaxation, chamber stiffness, and left atrial pressure on the transmitral velocity filling profile. Impairment of relaxation impedes early filling and may result in a compensatory increase in atrial contribution to filling. An independent decrease in left atrial pressure from altered loading conditions may also reduce filling in early diastole. Increased left ventricular chamber stiffness (i.e., noncompliant left ventricle) impairs atrial contribution to filling and may enhance early filling. Theoretically, reduced left atrial contractility may decrease atrial contribution to filling. Pulmonic vein flow demonstrating increased retrograde flow during atrial systole helps to exclude impaired left atrial contractility. An increased left atrial pressure from altered loading conditions may also augment early filling. Therefore, an invasive or clinical assessment of left atrial pressure as being increased, decreased, or normal greatly aids in the interpretation of the transmitral filling velocity profile when inferences on the status of diastolic function are being made. Diastolic dysfunction is likely when a given pattern of filling cannot be explained on the basis of left atrial pressure. In situations where reasonable estimates on the status of left atrial pressure cannot be done, striking alterations in the transmitral velocity filling profile may be useful.

Animals↗
PubMed1991

Time course of improvement in ventricular function after ablation of incessant automatic atrial tachycardia.

A patient with dilated cardiomyopathy and supraventricular tachycardia presumed to be of sinus origin was referred for cardiac transplantation. The extreme rate of the tachycardia during exercise, profound fluctuations in heart rate, and the presence of an abnormal P wave axis suggested the diagnosis of incessant ectopic atrial tachycardia rather than compensatory sinus tachycardia. Electrophysiologic study with endocardial activation sequence mapping confirmed the diagnosis of an ectopic left atrial automatic tachycardia, after which surgical cryoablation of the left atrial focus was carried out successfully and sinus rhythm was restored. Serial radionuclide angiocardiograms obtained before and after surgery demonstrated a very rapid recovery of left ventricular function to nearly normal within the first month after surgery, followed by further improvement to normal over the next several months. The diagnosis of tachycardia-related cardiomyopathy should be seriously considered in any patient with apparently end-stage dilated cardiomyopathy and persistent resting tachycardia.

Adolescent↗
PubMed1993

Hemodynamics by transesophageal echocardiography.

The transesophageal approach has improved echocardiographic investigation of cardiac structure and function. As a new window to the heart with markedly improved resolution, TEE gives better insight into cardiac morphology and pathology than does precordial imaging. Specifically, the LA and mitral valve can be better visualized due to the immediate retrocardiac position of the imaging transducer. Similarly, TEE is also widely used to estimate left ventricular functional status. Specifically in the perioperative setting, methods have been developed and tested to analyze global and regional left ventricular function. In addition, methods of estimating left atrial pressure (pulmonary capillary wedge pressure) have recently been developed using pulsed Doppler echocardiography of pulmonary venous flow and interatrial septal dynamics. Transesophageal pulsed Doppler echocardiography of pulmonary venous flow provides a useful clinical tool to estimate pulmonary capillary wedge pressure reliably in the setting of impaired systolic function, diastolic dysfunction, or both. Furthermore, pulmonary venous flow is characteristically altered in patients with severe MR and can be useful in grading its severity. Transesophageal continuous wave Doppler echocardiography may prove useful to estimate systolic pulmonary artery pressure as another clinically useful hemodynamic parameter. Therefore, TEE adds significantly to the noninvasive assessment of cardiac hemodynamics.

Echocardiography, Transesophageal↗
PubMed1995

The levoatriocardinal vein: morphology and echocardiographic identification of the pulmonary-systemic connection.

OBJECTIVES: This study considers the array of pulmonary-systemic connections made by the levoatriocardinal vein. The primary and associated lesions that play a role in forming this vein are examined, and echocardiography is discussed as a method for its rapid identification. BACKGROUND: The levoatriocardinal vein is a pulmonary-systemic connection that provides an alternative egress for pulmonary venous blood in left-sided obstructive lesions. It is thought to result from the persistence of anastomotic channels that connect the capillary plexus of the embryonic foregut to the cardinal veins. Only 12 cases of levoatriocardinal vein have been reported since its first description in 1926. A comprehensive description of the morphology and echocardiographic identification of this lesion has been unavailable because of its rarity. METHODS: A retrospective study was performed in 13 patients with a levoatriocardinal vein from the University of California, San Francisco. Echocardiographic findings were compared with those obtained by angiography or at necropsy. In addition, the details of 12 previously published case reports were reviewed. Age at presentation, primary obstruction to pulmonary venous return, integrity of the atrial septum and origin and drainage of the levoatriocardinal vein were compared. RESULTS: Patient age at presentation was < 2 years, with most patients presenting before age 6 months. Variations of the hypoplastic left heart syndrome accounted for the majority of primary defects encountered, although multiple but less severe left-sided lesions were seen. The atrial septum was functionally intact in most patients. The levoatriocardinal vein, defined echocardiographically, originated predominantly from the smooth-walled left atrium and drained to the superior vena cava or innominate vein; however, variations of this pattern existed. CONCLUSIONS: As a physiologic entity, the levoatriocardinal vein provides a mechanism for decompression of pulmonary venous return primarily in patients with left ventricular inflow obstruction. A levoatriocardinal vein is thought to form when the atrial septum fails to provide an alternate egress for left atrial blood. However, when a septal defect or alternative shunt occurs in conjunction with a levoatriocardinal vein, the clinical presentation may be postponed. Echocardiography provides a rapid, noninvasive modality for identifying the pulmonary-systemic connection, which may masquerade as the vertical vein in anomalous pulmonary venous connection or act as an occult source of left to right shunting in patients undergoing surgery for hypoplastic left heart syndrome.

Coronary Circulation↗
PubMed1991

Pulmonary venous flow patterns by transesophageal pulsed Doppler echocardiography: relation to parameters of left ventricular systolic and diastolic function.

We have previously shown that the systolic and diastolic pulmonary venous flow (PVF) distribution is predictive of left atrial pressure. This study was designed to define the confounding influences of left atrial expansion, descent of the mitral anulus, and left ventricular contractile function on that relationship; to define normal PVF patterns; and to document the interaction of PVF with mitral inflow. Therefore we studied 27 consecutive intraoperative patients with coronary artery disease (22 men and 5 women, ages 35 to 78 years) using transesophageal echocardiography. A group of 12 normal subjects served as a control. Doppler and two-dimensional echocardiographic parameters were obtained simultaneously with monitoring pulmonary capillary wedge pressure (PCWP). We found that neither left atrial expansion nor the descent of the mitral anulus influenced the relationship between PVF and PCWP, but that left ventricular fractional shortening confounded this relationship. In normal subjects PVF was dominant in systole, whereas PVF in patients with elevated PCWP was dominant in diastole (systolic fraction of 68 +/- 6% [SD] in normals versus 42 +/- 15% in patients with PCWP greater than or equal to 15 mm Hg). PVF velocities interacted with transmitral flow velocities. Peak early diastolic mitral inflow velocities increased linearly with peak early diastolic PVF velocities (r = 0.62). We conclude that systolic and diastolic PVF distribution is mainly determined by the level of PCWP and to a lesser extent by left ventricular contraction, but not by left atrial expansion or by mitral anulus descent. Transesophageal pulsed Doppler echocardiography of PVF provides useful clinical information about the level of PCWP in intraoperative patients with coronary artery disease.

Adult↗
PubMed1996

A work-performing heart preparation for myocardial performance analysis in murine hearts.

UNLABELLED: The mouse has become the animal of choice for genetic manipulations resulting in altered myocardial function, but assessment of cardiac function is extremely difficult due to the animal's size. This study was designed to establish a work-performing isolated mouse heart preparation to objectively investigate myocardial performance in murine hearts. Isolated work-performing cardiac functional studies were performed on a modified Langendorff apparatus using 15 mice [25 to 28 g, +/-0.4 (SEM)]. The hearts were instrumented with a transonic flow meter and micromanometers to measure on-line aortic flow (AF), aortic pressure, and left atrial pressure (preload). A VAX cardiac function analyzing system was used to determine cardiac parameters including heart rate, contractility (max dP/dt), stroke volume (SV), and stroke work (SW) at various preload levels compared to a baseline preload of 5 mm Hg before and after 7 min of warm ischemia. AF increased from 1.01 ml/min (+/- 0.26) at 5 mm Hg of preload to 4.15 ml/min (+/- 1.03, P < 0.05) at 20 mm Hg of preload and decreased to 3.64 ml/min (+/- 0.62) at 25 mm Hg. SV, dP/dt, and SW increased with higher preload levels. There was a significant decrease in cardiac function postischemia. CONCLUSIONS: A valid isolated work-performing preload-dependent murine heart preparation involving minimal instrumentation of the heart is established to measure cardiac function and myocardial performance. Significant ischemia-reperfusion injury occurred after 7 min of ischemia. This model is a reliable and objective tool by which to evaluate murine cardiac function and to study ischemia-reperfusion injury.

Animals↗
PubMed1992

Right atrial thrombus migration during echocardiography: a case for urgent intervention.

A 65-year-old woman presented with increasing shortness of breath, chest pain and ST-T wave abnormalities on the electrocardiogram suggestive of unstable angina. Cross-sectional echocardiography performed to assess wall-motion abnormality and left ventricular function revealed a pedunculated right atrial thrombus prolapsing into the right ventricle which suddenly dislodged and migrated into the pulmonary circulation during the examination. A diagnosis of recurrent pulmonary thromboembolism was made, necessitating urgent pulmonary angiography with infusion of streptokinase. The patient made an uneventful recovery.

Aged↗
PubMed1997

The effect of atrial fibrillation and the ventricular rate control on exercise capacity.

BACKGROUND: Atrial fibrillation (AF) is a common cardiac arrhythmia, affecting approximately 1.5 million patients in the United States. HYPOTHESIS: This study was designed to determine the effect of AF and the ventricular rate control during AF on cardiovascular performance as measured by exercise endurance on a standard Bruce protocol. METHODS: Sixty-three patients with AF who underwent exercise stress testing during both sinus rhythm and AF were analyzed. Heart rate, blood pressure, heart rate acceleration, exercise duration, and left ventricular (LV) systolic function were measured. RESULTS: Atrial fibrillation resulted in a small but statistically significant decrease in exercise endurance (426 +/- 180 vs. 402 +/- 168 s, p < 0.05). The drop in exercise tolerance was consistent regardless of the underlying heart condition or adequate ventricular rate control during AF. Heart rate in AF was consistently faster than in sinus rhythm, at rest, and at peak exercise (63 vs. 79 beats/min and 125 vs. 149 beats/min, respectively, p < 0.001). CONCLUSION: Our analyses indicated that (1) the loss of atrioventricular synchrony had minimal effect on cardiovascular performance in patients with preserved LV function, (2) the decrease in cardiovascular performance was related to loss of atrioventricular synchrony but not to underlying heart disease or ventricular rate control, and (3) compensation for the loss of the atrial contribution was provided by consistently faster heart rate during AF.

Atrial Fibrillation↗