Daily Rhythms of Left Atrial Pressure in Beagle Dogs with Mitral Valve Regurgitation

Ishikawa, Taisuke; Tanaka, Ryou; Suzuki, Shuji; Saida, Yuuto; Soda, Aiko; Fukushima, Ryuji; Yamane, Yoshihisa

doi:10.1111/j.1939-1676.2009.0322.x

Cited by 12 publications

(22 citation statements)

References 27 publications

(26 reference statements)

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“…10 Thoracic radiograph and echocardiograph examinations were performed for the presence of pulmonary edema and cardiac dilation. After the radio telemetry transmitter implantation, the dogs were rested for at least 5 weeks, until no major variations were identified on echocardiographic evaluation and LAP.…”

Section: Animalsmentioning

confidence: 99%

“…We have previously reported the 24-hour LAP profiles of and the effect of angiotensin-converting enzyme (ACE) inhibitors on experimentally induced MR dogs with a radio telemetry system. 10,11 The previous study has demonstrated that this system is useful for the evaluation of hemodynamic changes that occur with the administration of furosemide.In the present study, we monitored the LAP of dogs with experimentary induced MR with a radio telemetry system and evaluated the effect of furosemide in different administration routes. Echocardiographic evaluations and blood pressure measurements were also conducted, and the effect of furosemide on MR was evaluated by analyzing of pathophysiological changes.…”

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confidence: 99%

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confidence: 99%

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The Effect of Furosemide on Left Atrial Pressure in Dogs with Mitral Valve Regurgitation

Suzuki¹,

Ishikawa²,

Hamabe³

et al. 2011

Veterinary Internal Medicne

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Background: The effects of furosemide on left atrial pressure (LAP) in dogs with mitral regurgitation (MR) have not been documented in a quantitative manner and between different routes of administration.Objective: To document LAP and echocardiographic parameters in MR dogs administered furosemide IV or PO, in order to document changes in LAP after furosemide treatment.Animals: Five healthy Beagle dogs (3 males and 2 females; aged 2 years) were used. Methods: Experimental, cross-over, and interventional study. LAP was measured before the administration of furosemide, and 30 minutes, 1, 1.5, 2, 3, 4, 5, 6, 8, 12, and 24 hours after administration. Furosemide 1, 2, or 4 mg/kg IV, PO or placebo was administered.Results: LAP was significantly decreased with all administrations of furosemide but not after placebo (P o .05, respectively). The max reduction was observed 1 hour (1 mg/kg IV, 15.04 AE 7.02 mmHg), 3 hours (2, 4 mg/kg IV, 13.28 AE 8.01, 9.23 AE 4.92 mmHg), 4 hours (1 mg/kg PO, 14.68 AE 11.51 mmHg), and 5 hours (2, 4 mg/kg PO, 13.19 AE 10.52, 10.70 AE 7.69 mmHg). E wave and E/Ea were significantly decreased corresponding to the reduction of LAP after administration of 2 and 4 mg/kg (P o .05, respectively).Conclusions and Clinical Importance: LAP was decreased in proportion to the dosage of furosemide, which did not significantly differ between IV and PO of the same dosages. E wave and E/Ea might be useful for the treatment evaluation of furosemide.Key words: Radio telemetry system; Total circulating blood volume; Transmitral blood flow.M itral valve disease is the most common cardiac disease in dogs. As many as three quarters of all dogs with signs of congestive heart failure suffer from mitral regurgitation (MR) caused by myxomatous degeneration of the valve leaflets or the chordae tendineae.1,2 MR increases the left atrial pressure (LAP) which potentially results in left atrial dilation. Elevated LAP causes pulmonary edema that can lead to cough, dyspnea, and even death.3 Therefore, LAP needs to be reduced to avoid these clinical signs.Furosemide, a loop diuretic, has a strong diuretic effect and is commonly used for the treatment of pulmonary edema in patients with MR. 4 Furosemide reduces the total circulating blood volume, which in turn reduces the LAP or the left ventricular filling pressure, and leads to the clinical improvement of the patients. [5][6][7][8][9] There are several administration routes for furosemide, including IV, PO, SC, and IM. Pharmacokinetics of furosemide has been compared between IV and PO administration. However, the effects of furosemide on LAP in dogs with MR have not been well documented in a quantitative manner because there are some difficulties in measuring LAP directly. We have previously reported the 24-hour LAP profiles of and the effect of angiotensin-converting enzyme (ACE) inhibitors on experimentally induced MR dogs with a radio telemetry system. 10,11 The previous study has demonstrated that this system is useful for the evaluation of hemodynamic changes that occur...

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Section: Animalsmentioning

confidence: 99%

mentioning

confidence: 99%

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The Effect of Furosemide on Left Atrial Pressure in Dogs with Mitral Valve Regurgitation

Suzuki¹,

Ishikawa²,

Hamabe³

et al. 2011

Veterinary Internal Medicne

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“…However, there has been few study of the amlodipine in dogs with MR and amlodipine’s effect on LAP has not been fully evaluated in a quantitative manner because of difficulties in directly measuring LAP. We have previously used a radiotelemetry system to report the effects of angiotensin-converting enzyme (ACE) inhibitors and furosemide in dogs with experimentally-induced MR [14-16], and we believe this system would be useful for evaluation of hemodynamic changes after administration of amlodipine.…”

Section: Introductionmentioning

confidence: 99%

Comparative effects of amlodipine and benazepril on Left Atrial Pressure in Dogs with experimentally-induced Mitral Valve Regurgitation

et al. 2012

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BackgroundOne of the purposes of treatment for dogs with mitral regurgitation (MR) is lowering left atrial pressure (LAP). There has been few study of the amlodipine in dogs with MR and amlodipine’s effect on LAP has not been fully evaluated in a quantitative manner because of difficulties in directly measuring LAP. The objective of our study was to compare the short-term effects of amlodipine (0.2 mg/kg PO q12h) vs benazepril (0.5 mg/kg PO q12h), on LAP and echocardiographic parameters in five beagle dogs with experimentally-induced MR. LAP of eight dogs that has own control were measured using radiotelemetry system at baseline and again on days 1, 2, 3, 4, 5, 6, 7 of the drug administration.ResultsMean LAP decreased significantly after amlodipine (11.20 ± 4.19 mmHg vs 14.61 ± 3.81 mmHg at baseline, p < .01) but not after benazepril treatment (13.19 ± 3.47 mmHg, p > .05). LAP was lower after 7 days of amlodipine treatment than after 7 days of benazepril treatment. Significant reduction was seen for the first time 4 days after the administration amlodipine. The rate of the maximal area of the regurgitant jet signals to the left atrium area (ARJ/LAA) of the amlodipine treatment was significantly lower (p < .05) after 7 days compared to baseline. Other echocardiographic parameters did not change significantly.ConclusionsLAP was significantly decreased after amlodipine treatment in dogs with surgically-induced MR but not after benazepril treatment. Although this study did not focus on adverse effects, amlodipine may be an effective drug for helping the patients with acute onset of severe MR, such as rupture of chordae tendinae or end stage patients were the LAP is likely to be elevated. Additional studies in clinical patients with degenerative mitral valve disease and acute chordal rupture are warranted because the blood-pressure lowering effects of amlodipine can decrease renal perfusion and this can further activate the RAAS.

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“…In addition, all the records during the whole experimental period were also used to maintain the dogs' conditions. Preparation of MR model dogs and transmitter implantation: Surgical and postoperative care procedures were as described in the previous report [15]. Follow-up care included the auscultation of lung/cardiac sound and blood test (complete blood cell count, blood urea nitrogen, creatinine, alkaline phosphatase and electrolytes).…”

Section: Study 1 Constructing Regression Equations Between Lap and Ementioning

confidence: 99%

Echocardiographic Estimation of Left Atrial Pressure in Beagle Dogs with Experimentally-Induced Mitral Valve Regurgitation

et al. 2011

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ABSTRACT. Non-invasive and immediate estimation of left atrial pressure (LAP) is very useful for the management of mitral regurgitation (MR), and many reports have assessed echocardiographic estimations of LAP to date. However, it has been unclear of which examination and evaluate article possess the best accuracy for the MR severity. The present research aims to establish the echocardiographic estimation equation of LAP that is well applicable for clinical MR dogs. After the chordae tendineae rupture was experimentally induced via left atriotomy in six healthy beagle dogs (three males and three females, two years old, weighing between 9.8 to 12.8 kg), a radio telemetry transmitter catheter was inserted, which allows the continuous recordings of LAP without the use of sedation. Approximately 5 weeks after the surgery, echocardiographic examination, indirect blood pressure measurement, measurement of plasma atrial natriuretic peptide (ANP) and LAP measurement by way of the radio telemetry system was performed simultaneously. Subsequently, simple linear regression equations between LAP and each variable were obtained, and the equations were evaluated whether to be applicable for clinical MR dogs. As a result, the ratio of early diastolic mitral flow to early diastolic lateral mitral annulus velocity (E/Ea) had the strongest correlation as maximum LAP=7.03*(E/Ea)-54.86 (r=0.74), and as mean LAP=4.94*(E/Ea)-40.37 (r=0.70) among the all variables. Therefore, these two equations associated with E/Ea should bring more precise and instant estimations of maximum and mean LAP in clinical MR dogs.KEY WORDS: atrial natriuretic peptide, mitral annulus velocity, mitral inflow, radio telemetry system. J. Vet. Med. Sci. 73(8): 1015-1024, 2011 Mitral valve regurgitation (MR), secondary to degenerative mitral valve apparatus disease (MVD), is one of the most common cardiac disorders in dogs [1]. Although surgical interventions such as mitral valve repair [11] and replacement [3] have been reported, most owners do not pursue these surgical options due to the cost or the small number of facilities able to perform such interventions. Therefore, most patients follow appropriate drug therapy on the basis of adequate evaluation of clinical symptoms.In dogs with moderate to severe MR, left atrial pressure (LAP) rises markedly as a result of volume overload and regurgitation [1,27]. Echocardiography has been one of the most valuable modalities for evaluating left atrial and ventricular dilation and slower MR velocity which is caused by the elevated LAP [7]. A number of reports have described the echocardiographic estimation of LAP and its alternative, which is the left ventricular filling pressure (LVFP), in humans [5,6,20] and in veterinary medicine [21,26]. Recently, the usefulness of isovolumic ventricular relaxation time (IVRT) [24], pulmonary venous flow (PVF) [14], plasma atrial natriuretic peptide (ANP) concentration [2,17] and tissue Doppler imaging (TDI) [10] have also been reported as noninvasive assessment of LAP in volume ove...

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Daily Rhythms of Left Atrial Pressure in Beagle Dogs with Mitral Valve Regurgitation

Cited by 12 publications

References 27 publications

The Effect of Furosemide on Left Atrial Pressure in Dogs with Mitral Valve Regurgitation

The Effect of Furosemide on Left Atrial Pressure in Dogs with Mitral Valve Regurgitation

Comparative effects of amlodipine and benazepril on Left Atrial Pressure in Dogs with experimentally-induced Mitral Valve Regurgitation

Echocardiographic Estimation of Left Atrial Pressure in Beagle Dogs with Experimentally-Induced Mitral Valve Regurgitation

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