Background: Mitral valve regurgitation (MR) causes increased left atrial pressure (LAP) and is associated with occurrence of clinical signs. It will be useful to understand diurnal variations of LAP for the management of MR.Hypothesis: Circulatory parameters and diurnal rhythm are linked to clinical signs in cardiac diseases. LAP also exhibits a diurnal rhythm in dogs with MR.Animals: Five healthy Beagle dogs weighing 9.8-12.8 kg (3 males and 2 females; aged 2 years) were used. Methods: A radiotelemetry system for continuous measurement of LAP was used in this study. Rupture of the chordae tendineae was experimentally induced via left atriotomy, and a transmitter catheter was inserted into the left atrium. The body of the transmitter was implanted SC. After clinical condition was stabilized, the severity of MR was evaluated by echocardiography, and LAP was recorded for 72 consecutive hours for the analysis of diurnal variation.Results: Abrupt increases in LAP, which averaged 16.7 mmHg, were observed at feeding periods. In contrast, strong diurnal LAP variations were found, with a significant but slight increase in daytime LAP compared with nighttime LAP.Conclusions and Clinical Importance: Diurnal LAP is characterized by a slight but significant nocturnal decrease and abrupt increases in response to excitation. The latter seemed to be more important considering the relationship with clinical manifestations. The clinical relevance of exercise restriction in the management of MR was acknowledged.

ABSTRACT. We performed a retrospective study of 56 dogs with Patent Ductus Arteriosus (PDA) to evaluate the indications for and efficacy of transarterial PDA coil embolization. Transarterial PDA coil embolization was conducted in 37 cases (66.1%) and surgical ligation was conducted in 16 cases (28.6%). Three cases (5.4%) were diagnosed as pulmonary hypertension and were excluded from surgical intervention. Although coil dislodgement was observed in the pulmonary artery in one case, no death occurred during coil embolization or surgical ligation. Echocardiography showed that fractional shortening decreased from 35.4 ± 6.8% to 30.2 ± 5.9% (P<0.05) after transarterial PDA coil embolization. Although slight residual shunts were observed in 18 cases, transarterial PDA coil embolization was effective treatment of PDA. KEY WORDS: canine, interventional cardiology, patent ductus arteriosus (PDA).

Open patch-grafting can be performed in small-breed dogs and decreased the pulmonary pressure gradient in survivors at 3 months postoperatively. However, this technique is more invasive than balloon valvuloplasty and should be used cautiously in severely stenosed patients.

ABSTRACT. Beraprost sodium (BPS) is an orally active prostacyclin analogue. The effects of BPS on the heart, including coronary circulation improvement, myocardial and vascular protection and anti-fibrosis effect on myocardium interstitium, have previously been demonstrated. However, the effects of BPS on hemodynamics, cardiac function and myocardial contractility in patients in the hypertrophic phase have not been clarified. Therefore, in the present study, the effects of BPS under long-term administration were investigated using the hypertension model of salt-sensitive Dahl rats. Six-week-old Dahl rats were divided into three groups, an 8% high salt diet group treated with BPS (BPS group), an untreated 8% high salt diet group (HHF group) and an untreated 0.3% low salt diet group (Control group), and observations were conducted until 17 weeks of age. In the BPS and HHF groups, the survival rates after 11 weeks of high salt diet intake were 87.5% and 47.1%, respectively (p<0.05). At 17 weeks of age, the atrial systolic peak velocity/early diastolic peak velocity and heart weight index of the BPS group decreased significantly compared with the HHF group (p<0.05). The HHF group exhibited significantly more severe myocardial fibrosis mainly in the endocardial layer of the left and right ventricles compared with the BPS and Control groups (p<0.05). In the present study, long-term BPS administration preserved diastolic function and prevented myocardial interstitial fibrosis in the non-compensatory phase. The results of the present study suggest that BPS is effective for treatment of hypertensive cardiac hypertrophy. KEY WORDS: beraprost sodium, Dahl rat, echocardiography, hypertension, myocardial fibrosis.J. Vet. Med. Sci. 69(12): 1271-1276, 2007 Prostacyclin is found in all body tissues and body fluids and is the major metabolite of arachidonic acid in the vasculature [6,16]. It is a potent vasodilator that affects both systemic and pulmonary circulations. Prostacyclin also prevents vascular smooth muscle proliferation and inhibits platelet adhesion and aggregation [6]. These features make it a very attractive substance for treatment of various cardiovascular diseases [6,15,16,20]. Beraprost sodium (BPS) is an orally active prostacyclin analogue that was discovered and developed by Toray Industries in Japan [1,16]. In human medicine, long-term administration of BPS has been approved as a treatment for chronic arterial occlusion [16] and primary pulmonary hypertension [2,8,16]. In addition, oral administration of BPS can be used as a therapeutic treatment for secondary precapillary pulmonary hypertension [17], cerebral infarction [9,13], glomerulonephritis [12,28], diabetic nephropathy [29] and atherosclerotic vascular damage in coronary artery disease [23]. In heart failure with pressure overload, compensated concentric hypertrophy in the left ventricular progresses due to the increase in pressure after overload. As a result, then the interstitial fibrosis changes the myocardial structure [21,26,27]. In addition, th...

CT is a valuable tool for diagnosis of early squamous cell carcinomas, particularly when lesions show polypoid growth and/or invade the cartilaginous layer.

ABSTRACT. A male Pomeranian dog aged 1 year and 8 months was presented for evaluation of severe systolic ejection, cardiac murmur and syncope on excitation. Supravalvular pulmonary stenosis was diagnosed. An echocardiogram showed a supravalvular membranous stricture and a severely increased pulmonary arterial velocity in the stricture (6.49 m/s, pressure gradient of 169 mmHg). The supravalvular stricture was surgically removed by pulmonary arteriotomy with the heart beating using a cardiopulmonary bypass system. The postoperative pulmonary arterial velocity at the narrow area decreased to 3.80 m/s, and the pressure gradient decreased to 57.7 mmHg. Six months after the operation, there were no signs of restenosis, and the dog was in good condition without syncope. Surgical correction of pulmonary stenosis with the heart beating using a cardiopulmonary bypass system is useful because of the improvement it brings in safety and reliability. KEY WORDS: beating heart technique, pump-assisted extracorporeal circulation, supravalvular pulmonary stenosis.J. Vet. Med. Sci. 71(2): 203-206, 2009 Pulmonary stenosis (PS) is the congenital narrowing of the right ventricular outflow tract. It is a relatively common cardiac malformation occurring in approximately 2 out of every 1,000 dogs (0.2%) [8]. Of the three categories of PS (subvalvular, valvular and supravalvular), the supravalvular form is the rarest in dogs. As far as we know, only one canine case of surgical correction of supravalvular PS has been reported [6]. Cardiac catheterization or Doppler echocardiography can be used to identify PS and determine its type and severity [8]. Patients with a severe pressure gradient are at increased risk of sudden death, and surgical intervention is generally recommended [8]. Herein we describe surgical correction of severe supravalvular pulmonary stenosis using a cardiopulmonary bypass system in a dog with its heart beating and the postoperative course.A male Pomeranian aged 1 year and 8 months was referred to the Teaching Animal Hospital of the Tokyo University of Agriculture and Technology because of severe cardiac murmur and sporadic syncope on excitation. The dog weighed 2.60 kg, and its body condition score was normal. Cardiac auscultation revealed a grade V/VI loud systolic murmur with a palpable thrill, the point of maximum intensity of which was in the left heart base, and the dog's heart rate was 90 beats per minute. The CBC and chemistry profile were normal. An electrocardiogram showed a normal sinus rhythm, but lead II showed a mean electric axis of -145° and increased S-wave amplitudes (-1.8 mV). The cardiothoracic ratio was 63.6%, and the vertebral heart size was 9.2V (Fig. 1A, B). An echocardiogram showed severe progression of pulmonary artery velocity in the stricture (6.49 m/s, pressure gradient of 169 mmHg; Fig. 2), pulmonary and tricuspid valves regurgitation, right ventricular hypertrophy (diastolic intraventricular septum thickness; 7.10 mm) and intraventricular septum flattening (Fig. 3). The tricuspid valve...

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ABSTRACT. We studied the effect of a small volume of 7.2% hypertonic saline solution (HSS) or HSS with 6% dextran 70 (HSD) on hemodynamic status, especially on cardiac contractility, in anesthetized dogs using the left ventricular end-systolic volume index (ESVI) and ejection fraction (EF), which can be obtained in noninvasive echocardiography. In the present study, the mean values of ESVI were unaffected by HSS and HSD infusion, whereas the left ventricular end-diastolic volume index (EDVI) was markedly and significant increased. As a result of the changes in EDVI but not in ESVI, EF increased transiently and significantly in the HSS and HSD group, whereas no such significant change was observed in the dogs that received isotonic saline solution. In addition, as a result of the increases in cardiac index but not arterial pressure, system vascular resistances (SVR) decreased transiently and significantly in the HSS and HSD groups, whereas no such significant change was observed in the ISS group. Therefore, the positive inotropic effects of HSS and HSD may be attributable to the increase in left ventricular preload and decreases in SVR rather than direct changes in myocardial contractility. KEY WORDS: canine, cardiac contractility, cardiac index, echocardiography, hypertonic saline.J. Vet. Med. Sci. 70(1): 89-94, 2008 Recent clinical data supports the concept that early restitution of the circulation in severe sepsis and septic shock patients improves oxygenation and increases the survival rate [22]. It is therefore of great importance to restore the intravascular volume and thereby maintain adequate cardiac output (CO) and oxygen delivery. Hypovolemic shock resuscitation with colloids is preferred over crystalloids because colloids result in better regional and microcirculatory blood flow [24]. Small-volume hypertonic saline solution (HSS) has been successfully used to resuscitate dogs with experimentally induced hypovolemic shock [13,28,29]. The beneficial hemodynamic effects of HSS have been attributed to rapid plasma volume expansion caused by body fluid shift from intracellular space [2,7], transient decrease in systemic and pulmonary vascular resistance [27], a vagally mediated reflex dependent stimulation of pulmonary osmoreceptors [13,30] and increased cardiac contractility [29]. These beneficial effects most likely result from an increase in preload and/or decrease in afterload [27].Some studies have found a positive inotropic effect after HSS infusion [9,10,15,17]. HSS induces cellular dehydration through an osmotic effect, thus decreasing cellular water content and directly increasing the calcium level [32]. This could produce a positive inotropic effect of HSS because the increase in intracellular calcium concentration ([Ca 2+ ]in) results in increased cardiac contractility. Myocardial oxygen consumption increases at the end of HSS infusion without significant change in coronary venous oxygen tension and content [15]. However, many in vitro studies have demonstrated that a sudden increase in the ...