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Biomedical subjects

Kiyotaka Fukamachi

Publications and source records attributed to Kiyotaka Fukamachi.

At least 19 recordsLinked to original sources
PubMed2007

Impact of left atrial appendage exclusion on left atrial function.

OBJECTIVES: We sought to investigate the short-term and midterm effects of left atrial appendage exclusion on left atrial function. Left atrial appendage exclusion is considered a possible therapeutic option for stroke prevention in patients with atrial fibrillation. Favorable outcomes have encouraged widespread use of left atrial appendage exclusion for cardiac surgical patients-even for patients in sinus rhythm who have stroke risk factors; however, the chronic effects on left atrial function of left atrial appendage exclusion are unclear. METHODS: Nineteen mongrel dogs (29.7 +/- 5.2 kg) in sinus rhythm were studied. The Doppler signals from the pulmonary venous flow, transmitral flow, and tissue Doppler imaging of mitral annular motion were obtained before and after left atrial appendage exclusion. Dogs were evaluated in the same manner at 7 days (n = 2), 30 days (n = 7), or 90 days (n = 10) after left atrial appendage exclusion. RESULTS: Except for a significant increase in early diastolic transmitral flow velocity after left atrial appendage exclusion (P = .01), no significant differences were found in any parameters related to the transmitral flow and tissue Doppler imaging measurements throughout follow-up. The systolic components of pulmonary venous flow at follow-up revealed a significant reduction relative to baseline (peak systolic velocity P < .0001, systolic velocity-time integral P < .0001), despite the lack of significant changes in left atrial pressure, left ventricular volume, and stroke volume. CONCLUSION: Left atrial appendage exclusion may affect left atrial reservoir function in the short-term and midterm periods. Further long-term studies with more clinically relevant models are needed.

Animals↗
PubMed2006

Ventral cardiac denervation increased right coronary arterial blood flow.

BACKGROUND: Cardiac denervation accompanied with coronary artery bypass surgery has been widely performed for the treatment of vasospastic angina associated with atherosclerotic coronary artery disease. However, the effect of cardiac denervation on phasic coronary blood flow patterns of the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX) and right coronary artery (RCA) remains unknown. This study aimed to investigate the effect of cardiac denervation on phasic coronary blood flow patterns of the LAD, LCX and RCA. METHODS: Phasic coronary blood flow patterns were analyzed using three flow probes placed around the LAD, LCX and RCA with and without LAD stenosis. Ventral cardiac denervation (VCD) was performed in 8 pigs, and 16 pigs were used as control subjects. Autonomic activities before and after the VCD were quantified by wavelet analysis of heart rate variability. RESULTS: The mean LAD flow (34.4+/-9.4 to 32.6+/-7.1 ml/min, p=0.638) and mean LCX flow (26.3+/-10.2 to 27.2+/-6.0 ml/min, p=0.825) showed no significant change after VCD, while the mean RCA flow (31.3+/-9.0 to 38.2+/-11.2 ml/min, p=0.003) significantly increased. The hemodynamic variables in the VCD group were well maintained after creation of LAD stenosis, while they deteriorated in the control group. The low-frequency components, high-frequency components and their ratio did not change after VCD. CONCLUSIONS: VCD prevented the deterioration of cardiac function after creation of an LAD stenosis and resulted in an increase of the mean RCA flow. VCD did not affect autonomic nervous system activity.

Angina Pectoris↗
PubMed2006

Scaling of diastolic intraventricular pressure gradients is related to filling time duration.

In early diastole, pressure is lower in the apex than in the base of the left ventricle (LV). This early intraventricular pressure difference (IVPD) facilitates LV filling. We assessed how LV diastolic IVPD and intraventricular pressure gradient (IVPG), defined as IVPD divided by length, scale to the heart size and other physiological variables. We studied 10 mice, 10 rats, 5 rabbits, 12 dogs, and 21 humans by echocardiography. Color Doppler M-mode data were postprocessed to reconstruct IVPD and IVPG. Normalized LV filling time was calculated by dividing filling time by RR interval. The relationship between IVPD, IVPG, normalized LV filling time, and LV end-diastolic volume (or mass) as fit to the general scaling equation Y = kM beta, where M is LV heart size parameter, Y is a dependent variable, k is a constant, and beta is the power of the scaling exponent. LV mass varied from 0.049 to 194 g, whereas end-diastolic volume varied from 0.011 to 149 ml. The beta values relating normalized LV filling time with LV mass and end-diastolic volume were 0.091 (SD 0.011) and 0.083 (SD 0.009), respectively (P < 0.0001 vs. 0 for both). The beta values relating IVPD with LV mass and end-diastolic volume were similarly significant at 0.271 (SD 0.039) and 0.243 (SD 0.0361), respectively (P < 0.0001 vs. 0 for both). Finally, beta values relating IVPG with LV mass and end-diastolic volume were -0.118 (SD 0.013) and -0.104 (SD 0.011), respectively (P < 0.0001 vs. 0 for both). As a result, there was an inverse relationship between IVPG and normalized LV filling time (r = -0.65, P < 0.001). We conclude that IVPD decrease, while IVPG increase with decreasing animal size. High IVPG in small mammals may be an adaptive mechanism to short filling times.

Adult↗
PubMed2006

Transmural distribution of myocardial blood perfusion and phasic coronary blood flow pattern in a canine model of acute ischemia.

BACKGROUND: Although several investigators have analyzed coronary artery blood flow under various conditions, almost all these studies have measured only some branches of the left anterior descending (LAD), left circumflex (LCX), or right coronary (RCA) artery. METHODS: In a canine model of acute ischemia (n = 5), we simultaneously assessed (a) regional myocardial blood perfusion using microspheres and (b) phasic coronary blood flow patterns as measured by three epicardial flow probes placed around the LAD, LCX, and RCA. RESULTS: The results from this study indicated that the LAD supplies blood to the epicardial (r = 0.687, p<0.0001), midwall (r = 0.556, p = 0.0021), and endocardial layers (r = 0.666, p = 0.0001) of the LAD area; the LCX supplies the midwall (r = 0.514, p = 0.0051) and endocardial layer (r = 0.621, p = 0.0004) of the LCX area, antero-lateral papillary muscle (r = 0.548, p = 0.0025), and postero-medial papillary muscle (r = 0.641, p = 0.0002), especially during the diastolic phase; and the RCA supplies the right ventricular apex (r=0.559, p=0.0020), left atrium (r = 0.618, p = 0.0005), right atrium (r = 0.471, p = 0.0114), and postero-medial papillary muscle (r = 0.486, p = 0.0088), especially during the systolic phase. CONCLUSIONS: These results are potentially relevant to understanding the physiology of myocardial blood perfusion and to improving treatment of acute myocardial ischemia and infarction.

Animals↗
PubMed2006

Chronic hydrocephalus-induced changes in cerebral blood flow: mediation through cardiac effects.

Decreased cerebral blood flow (CBF) in hydrocephalus is believed to be related to increased intracranial pressure (ICP), vascular compression as the result of enlarged ventricles, or impaired metabolic activity. Little attention has been given to the relationship between cardiac function and systemic blood flow in chronic hydrocephalus (CH). Using an experimental model of chronic obstructive hydrocephalus developed in our laboratory, we investigated the relationship between the duration and severity of hydrocephalus and cardiac output (CO), CBF, myocardial tissue perfusion (MTP), and peripheral blood flow (PBF). Blood flow measures were obtained using the microsphere injection method under controlled hemodynamic conditions in experimental CH (n=23) and surgical control (n=8) canines at baseline and at 2, 4, 8, 12, and 16 weeks. Cardiac output measures were made using the Swan-Ganz thermodilution method. Intracranial compliance (ICC) via cerebrospinal fluid (CSF) bolus removal and infusion, and oxygen delivery in CSF and prefrontal cortex (PFC) were also investigated. We observed an initial surgical effect relating to 30% CO reduction and approximately 50% decrease in CBF, MTP, and PBF in both groups 2 weeks postoperatively, which recovered in control animals but continued to decline further in CH animals at 16 weeks. Cerebral blood flow, which was positively correlated with CO (P=0.028), showed no significant relationship with either CSF volume or pressure. Decreased CBF correlated with oxygen deprivation in PFC (P=0.006). Cardiac output was inversely related with ventriculomegaly (P=0.019), but did not correlate with ICP. Decreased CO corresponded to increased ICC, as measured by CSF infusion (P=0.04). Our results suggest that CH may have more of an influence on CO and CBF in the chronic stage than in the early condition, which was dominated by surgical effect. The cause of this late deterioration of cardiac function in hydrocephalus is uncertain, but may reflect cardiac regulation secondary to physiologic response or brain injury. The relationship between cardiac function and CBF should be considered in the pathophysiology and clinical treatment of CH.

Animals↗
PubMed2006

Experimental study of new diagnostic system for coronary artery disease using coronary transit index.

OBJECTIVES: Noninvasive cardiac imaging techniques have had an increasing role in the diagnosis of coronary artery disease. However, these techniques are not widely available as a tool in the office setting. The purpose of this study was to provide an accurate assessment of coronary artery disease for screening purposes using Coronary Transit Index (CTI) assessment with small, high-resolution gamma cameras. METHODS: Total coronary blood flow was measured with ultrasonic flow probes placed around the left anterior descending coronary artery, left circumflex coronary artery, and right coronary artery in a total of 33 conditions in 5 healthy mongrel dogs. The coronary blood flow was reduced stepwise with vascular occluders placed around the coronary arteries. The procedure for obtaining CTI included 4 parts: 1) The animal was injected intravenously with a bolus of a radioactive tracer (2.5-5.0 mCi of (99m)Tc-DTPA); 2) Dedicated gamma sensors monitored the passage of the injected bolus; 3) Time-activity curves were measured at the left ventricle with and without its wall; 4) The ratio of the washout rates of the 2 curves determined the CTI. RESULTS: Coronary Transit Index was successfully obtained from the left ventricle. The coronary blood flows measured by flow probes were well correlated with the regional myocardial blood flow. The percentage of the baseline value of the total coronary blood flow had the highest correlation (R=0.807, p<0.0001) with the Coronary Transit Index. CONCLUSIONS: These data indicated that a new diagnostic system using CTI successfully identified reduced coronary blood flow.

Animals↗
PubMed2006

Duration of inotropic support after left ventricular assist device implantation: risk factors and impact on outcome.

OBJECTIVES: Because duration of inotropic support after left ventricular assist device implantation has been recognized as a surrogate for right ventricular dysfunction, we sought to (1) identify its preimplantation risk factors, particularly its association with preimplantation right ventricular dysfunction, and (2) assess its impact on clinical outcomes. METHODS: Between 1991 and 2002, left ventricular assist devices were implanted in 207 patients, exclusive of those receiving preoperative mechanical circulatory support, which precluded measuring right ventricular stroke work. Duration of inotropic support was analyzed as a continuous variable, truncated by death or transplantation, and in turn as a risk factor for these 2 events. RESULTS: Inotropic support decreased from 100% on the day of implantation to 57%, 33%, and 22% by days 7, 14, and 21. Its duration was strongly associated with lower preimplantation right ventricular stroke work index, older age, and nonischemic cardiomyopathy and was associated (P < .04) with higher mortality before transplantation but not with transition to transplantation. We identified no preimplantation risk factors for right ventricular assist device use because of its relatively infrequent use in this population (18 patients, only 4 of whom survived to transplantation). CONCLUSION: Duration of inotropic support after left ventricular assist device insertion is strongly correlated with low preimplantation right ventricular stroke work index. In turn, it was associated with reduced survival to transplantation. Thus, right ventricular stroke work measured before implantation might be useful in decision making for biventricular support, destination therapy, or total artificial heart.

Cardiomyopathies↗
PubMed2006

Evaluation of a novel device for left atrial appendage exclusion: the second-generation atrial exclusion device.

BACKGROUND: The left atrial appendage is a frequent source of thromboemboli in patients with atrial fibrillation. Exclusion of the left atrial appendage may reduce the risk of stroke in patients with atrial fibrillation. The atrial exclusion device, previously developed to perform left atrial appendage exclusion on a beating heart, was modified to accommodate different anatomic patterns of the human left atrial appendage and to ensure uniform pressure and occlusion. The purpose of this study was to evaluate this second-generation atrial exclusion device during a midterm period in a canine model. METHODS: Ten mongrel dogs (mean weight 28.9 +/- 4.6 kg) were used in this study. The atrial exclusion device, constructed from two parallel and rigid titanium tubes and two nitinol springs with a knit-braided polyester fabric, was implanted at the base of the left atrial appendage through a left thoracotomy on a beating heart using a specially designed delivery tool. Dogs were evaluated at 30 days (n = 4) and 90 days (n = 6) by epicardial echocardiography, left atrial and coronary angiography, gross pathology, and histologic inspection. RESULTS: Device implantation was performed without complications in all dogs. Complete left atrial appendage exclusion without device migration or hemodynamic instability was confirmed, and there was no damage to the left circumflex artery or pulmonary artery. Macroscopic and microscopic assessments revealed favorable biocompatibility during midterm follow-up. CONCLUSION: The atrial exclusion device enabled rapid, reliable, and safe exclusion of the left atrial appendage. Clinical application may provide a new therapeutic option for reducing the risk of stroke in patients with atrial fibrillation.

Animals↗
PubMed2006

An experimental rabbit model for off-pump left ventricular reconstruction following left ventricular aneurysm.

BACKGROUND: Cardiac electromechanical remodeling following left ventricular reconstruction (LVR) surgery is not fully understood. Further development of an animal model will facilitate investigations in this area. In the present study, we aimed to establish a novel LVR procedure without the use of cardiopulmonary bypass in a rabbit left ventricular (LV) aneurysm model. METHODS: LV aneurysm was created in 6 rabbits by ligation of the distal left coronary artery. More than a month later, LVR aneurysm surgery was performed off-pump using a purse-string suture around the aneurysm. Cardiac dimensions and function were evaluated using echocardiographic techniques perioperatively and 4 weeks after LVR surgery. Six structurally normal hearts were used as controls. RESULTS: LVR surgery was successfully performed in all 6 rabbits. Both LV end-diastolic volume (LVEDV, 4.6 +/- 0.9 to 3.3 +/- 0.6 mL; P < .01) and LV end-systolic volume (LVESV, 2.5 +/- 0.6 to 1.5 +/- 0.2 mL, P < .01) were decreased immediately postsurgery versus presurgery, and LV ejection fraction (LVEF) was increased (44.5 +/- 5.3 to 55.6 +/- 4.8%, P < .001). For comparison, in normal rabbits (n = 6), LVEDV, LVESV and LVEF were 3.1 +/- 0.7 mL, 1.2 +/- 0.5 mL, and 64.5 +/- 8.8%, respectively. During follow-up, one rabbit died 3 weeks after surgery from an unknown cause. In the remaining 5 animals, improvements of LVEDV (3.7+/- 0.4 mL, P < .05), LVESV (1.7 +/- 0. 3 mL, P < .01), and LVEF (53.1 +/- 2.8%, P < .01) were maintained versus presurgery values for more than 4 weeks after LVR. CONCLUSIONS: Off-pump LVR of rabbit LV aneurysm is an effective and less invasive surgery that resulted in sustained improvement in cardiac function with no gross intraoperative or postoperative mortality. This may be a useful model for investigations of electromechanical remodeling following LVR.

Animals↗
PubMed2005

Phasic coronary blood flow pattern during a continuous flow left ventricular assist support.

OBJECTIVE: Continuous flow left ventricular assist devices (LVADs) have been introduced and tested as a bridge to heart transplantation, bridge to recovery, and destination therapy, and several studies have been conducted to assess the physiologic effects of continuous flow LVADs. However, the effect of reduced pulsatility on the phasic coronary blood flow pattern is unknown. The aim of this study was to investigate the phasic coronary blood flow patterns during continuous flow LVAD support. METHODS: Phasic coronary blood flow patterns and hemodynamic data were analyzed using three flow probes placed around the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX), and the right coronary artery (RCA) in 16 pigs before and after initiating the LVAD support with or without creating LAD stenosis. RESULTS: The total coronary blood flow (TCBF, 112.8+/-31.4 mL/min) gradually decreased when the continuous flow LVAD support increased to 2.0 L/min (110.7+/-29.0 mL/min, P = 0.571), 2.5 L/min (103.7+/-26.1 mL/min, P = 0.079), and 3.0 L/min (101.5+/-27.2 mL/min, P = 0.027) because of decreases in LAD flow and LCX flow. LVAD support caused decrease in systolic and peak systolic LAD flow, LCX flow, and RCA flow, whereas diastolic RCA flow increased. In the presence of LAD stenosis, the TCBF (97.7+/-36.1 mL/min) decreased when the continuous flow LVAD support increased to 2.0 L/min (83.9+/-22.1 mL/min, P = 0.029), 2.5 L/min (83.2+/-25.2 mL/min, P = 0.012), and 3.0 L/min (87.6+/-23.4 mL/min, P = 0.005) because of decreases in LCX flow. CONCLUSION: Use of a continuous flow LVAD decreased TCBF, LAD flow, and LCX flow secondary to reduced systolic LAD flow and LCX flow, and decreased TCBF and LCX flow in the presence of LAD stenosis. These findings are potentially relevant to understanding the physiology of myocardial blood perfusion during continuous flow LVAD support especially in patients with coronary artery disease.

Animals↗
PubMed2005

Myocardial compliance was not altered after acute induction of atrial fibrillation in sheep.

BACKGROUND: Although left ventricular (LV) contractility in atrial fibrillation (Af) is known to change in a beat-to-beat fashion, little is known about the changes in LV compliance in Af. MATERIAL/METHODS: We experimentally induced tachycardic Af (average heart rate - 154 beats per minute) in 18 sheep. LV volume and pressure were simultaneously monitored using a conductance catheter. LV end-diastolic volume (V(ED)) and pressure (P(ED)) were plotted in a beat-to-beat fashion and fitted to the following exponential equation (P(ED)=gamma x e(b x V(ED))) in each animal. A random effects model was constructed to determine if the intercepts and slopes differ. RESULTS: In all animals, those plots after the induction of Af fit quite well to the exponential function (r=0.834+/-0.184) by gating short preceding interval (RR1) beats. By simply taking the natural logarithm of both sides in the equation, the linear relationship (ln(P(ED)) =alpha+ betaxV(ED), where a = lng) was observed in all animals before (normal sinus rhythm, NSR) and after the induction of Af. Only two of 18 intercepts and four of 18 slopes deviate between NSR and Af. Most interestingly, the random effects model clearly detailed that the average animal had intercepts and slopes that were not discernibly different between NSR and Af. CONCLUSIONS: Unlike LV contractility, myocardial compliance did not change after the acute induction of Af. These interesting results may give us insights into the understanding of the physiology in acute rapid Af.

Animals↗
PubMed2005

Alloreactive T cell responses and acute rejection of single class II MHC-disparate heart allografts are under strict regulation by CD4+ CD25+ T cells.

Skin but not vascularized cardiac allografts from B6.H-2bm12 mice are acutely rejected by C57BL/6 recipients in response to the single class II MHC disparity. The underlying mechanisms preventing acute rejection of B6.H-2bm12 heart allografts by C57BL/6 recipients were investigated. B6.H-2bm12 heart allografts induced low levels of alloreactive effector T cell priming in C57BL/6 recipients, and this priming was accompanied by low-level cellular infiltration into the allograft that quickly resolved. Recipients with long-term-surviving heart allografts were unable to reject B6.H-2bm12 skin allografts, suggesting potential down-regulatory mechanisms induced by the cardiac allografts. Depletion of CD25+ cells from C57BL/6 recipients resulted in 15-fold increases in alloreactive T cell priming and in acute rejection of B6.H-2bm12 heart grafts. Similarly, reconstitution of B6.Rag(-/-) recipients with wild-type C57BL/6 splenocytes resulted in acute rejection of B6.H-2bm12 heart grafts only if CD25+ cells were depleted. These results indicate that acute rejection of single class II MHC-disparate B6.H-2bm12 heart allografts by C57BL/6 recipients is inhibited by the emergence of CD25+ regulatory cells that restrict the clonal expansion of alloreactive T cells.

Acute Disease↗
PubMed2005

MagScrew total artificial heart in vivo performance above 200 beats per minute.

PURPOSE: Downsizing pulsatile devices requires an increase of beat rate if flow capacity is to be maintained. We applied this concept to the preclinical MagScrew total artificial heart (TAH). DESCRIPTION: The device fills passively with a stroke volume of 45 ml and beat rates up to 250 beats per minute (bpm). EVALUATION: Stable hemodynamics were observed during a 30-day bovine implant with a flow of 8.7 +/- 1.2 L/min at beat rates of 204 +/- 18 bpm. Device filling was exceptional up to 250 bpm generating flow of greater than 12 L/min. Beat rate adapted to preload in a way similar to a Frank-Starling response. Left and right atrial pressures were balanced. The aortic pulse pressure was 49-70 mm Hg, which translates to a pulsatility index of 0.49-0.77. Organ functions were preserved and blood damage did not occur. CONCLUSIONS: Increasing the beat rate while downsizing the MagScrew TAH was successful with strong flow generation by passive filling. Pulsatility was maintained at high beat rates. This innovative approach may be used to develop small pulsatile pumps.

Animals↗
PubMed2005

Giant flow reversal in pulmonary venous flow as a possible mechanism for asynchronous pacing-induced heart failure.

BACKGROUND: Mechanistic roles of the immediate increase in left atrial (LA) pressure in pacing-induced congestive heart failure have not been clearly understood. We evaluated the impact of asynchronous rapid ventricular pacing on LA hemodynamics in this model. METHODS: Transthoracic and transesophageal echocardiography and hemodynamic assessment were performed in 23 healthy mongrel dogs. Data were acquired before and 5 minutes after initiation of rapid right ventricular pacing (200/min). RESULTS: At 5 minutes after initiation of the pacing, giant pulmonary venous (PV) flow reversal (-76 cm/s) was observed in association with 1:1 ventriculoatrial conduction or complete atrioventricular dissociation. This giant PV flow reversal corresponded to an inappropriately timed atrial contraction, especially during systole. Cardiac output (3.21 vs 2.00 L/min, P < .001) was decreased corresponding to the decrease in the forward blood volumes as described by decrease in the Doppler left ventricular (LV) outflow (8.99 vs 4.73 cm, P < .0001), mitral inflow (6.89 vs 3.19 cm, P < .0001), and PV flow (14.15 vs 7.22 cm, P < .0001) velocity integrals. As a result, there was a marked elevation of the mean pulmonary capillary wedge (9.1 vs 17.1 mm Hg, P < .001) and LV end-diastolic (8.2 vs 17.4 mm Hg, P < .01) pressures leading to congestive heart failure. CONCLUSIONS: The giant PV flow reversal seen during asynchronous rapid right ventricular pacing corresponds to an inappropriate atrial contraction, immediately elevates LA pressure, and may initially promote congestive heart failure. The increase in LV end-diastolic pressure associated with decreased LV ejection fraction caused decrease in the LV filling volume leading to further increase in the LA pressure. This sustained marked elevation in the LA pressure and LV end-diastolic pressure could contribute to the heart failure process.

Animals↗
PubMed2005

Mitral annulus size links ventricular dilatation to functional mitral regurgitation.

We compared the impact of annulus size and valve deformation (tethering) on mitral regurgitation in the animal dilated cardiomyopathy model, and assessed if acute left ventricular volume changes affect mitral annulus dimensions. We performed 3-dimensional echocardiography in 30 open-chest dogs with pacing-induced cardiomyopathy. Mitral annulus area was calculated from its two orthogonal diameters, whereas valve tethering was quantified by valve tenting area measurement. Mitral valve regurgitant volume showed the highest correlation with annulus area (r = 0.64, P < .001), left atrial volume (r = 0.40, P < .01), and left ventricular end-diastolic volume (r = 0.37, P < .01). Regurgitant volume showed poorer correlation with valve tethering in both septolateral and intercommissural planes (r = 0.35 and r = 0.31, P < .05 for both). Annulus dimensions correlated with acute changes of left ventricular end-diastolic volume (r = 0.68, P = .002). Mitral annulus dilation is the strongest predictor of functional mitral regurgitation in this animal dilated cardiomyopathy model.

Animals↗
PubMed2005

A novel device for left atrial appendage exclusion.

OBJECTIVE: The left atrial appendage is a frequent source of thromboemboli in patients with atrial fibrillation. Exclusion or excision of the left atrial appendage may reduce the risk of stroke in patients with atrial fibrillation. We evaluated the ability of a novel device to exclude the left atrial appendage during early and intermediate follow-up periods in a canine model. METHODS: Eight mongrel dogs (mean weight 29.1 +/- 4.0 kg) were used in this study. The occlusion device, constructed from 2 stainless steel strips covered with a knit braided polyester fabric, was implanted at the base of the left atrial appendage through a left thoracotomy on a beating heart. Dogs were evaluated at 7 days (n = 2), 30 days (n = 2), and 90 days (n = 4) by epicardial echocardiography, left atrial angiography, histologic inspection, and gross pathology. RESULTS: Device implantation was performed without complications in all animals. Complete exclusion of the left atrial appendage from the circulation was confirmed acutely and chronically by echocardiographic and angiographic evaluations. There was no device migration or damage to adjacent structures. CONCLUSION: This novel device enables rapid, reliable, and safe exclusion of the left atrial appendage. The device provides a new therapeutic option for reducing the risk of stroke in patients with atrial fibrillation.

Animals↗