Annelies Decloedt

Publications (9) View all

• Article: Evaluation of tissue Doppler imaging for regional quantification of radial left ventricular wall motion in healthy horses.

  Annelies Decloedt, Tinne Verheyen, Stanislas Sys, Dominique De Clercq, Gunther van Loon
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  ABSTRACT: Objective-To compare the feasibility and repeatability of tissue Doppler imaging (TDI) for quantification of radial left ventricular (LV) velocity and deformation from different imaging planes and to correlate cardiac event timing data obtained by TDI to M-mode and pulsed-wave Doppler-derived time intervals in horses. Animals-10 healthy adult horses. Procedures-Repeated echocardiography was performed by 2 observers from right and left parasternal short-axis views at papillary muscle and chordal levels. The TDI measurements of systolic and diastolic velocity, strain rate, strain peak values, and timing were performed in 8 LV wall segments (LV free wall and interventricular septum from right parasternal views; left and right region of LV wall from left parasternal views). The inter- and intraobserver within- and between-day variability and measurement variability were assessed. The correlation between TDI-based measurements and M-mode and pulsed-wave Doppler-based time measurements was calculated. Results-TDI measurements of velocity, strain rate, and strain were feasible in each horse, although deformation could often not be measured in the LV free wall. Systolic and diastolic time intervals could be determined with low to moderate variability, whereas peak amplitude variability ranged from low to high. The TDI-based time measurements were significantly correlated to M-mode and pulsed-wave Doppler measurements. Conclusions and Clinical Relevance-TDI measurements of radial LV velocity and deformation were feasible with low to moderate variability in 8 LV segments. These measurements can be used for evaluating LV function in further clinical studies.
  American Journal of Veterinary Research 01/2013; 74(1):53-61. · 1.27 Impact Factor
• Article: Influence of Atrioventricular Interaction on Mitral Valve Closure and Left Ventricular Isovolumic Contraction Measured by Tissue Doppler Imaging.

  Annelies Decloedt, Tinne Verheyen, Stanislas Sys, Dominique De Clercq, Bart Bijnens, Gunther van Loon
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  ABSTRACT: BACKGROUND: -The influence of atrioventricular (AV) interaction on mitral valve closure (MVC) and left ventricular (LV) isovolumic contraction is not fully clarified. We investigated the relationship between AV delay, MVC and LV isovolumic contraction using a horse model because of the low heart rate and physiologically long AV delay. METHODS AND RESULTS: -Six horses were evaluated during sinus rhythm (SR), right ventricular pacing without preceding atrial contraction (RVP) and dual-chamber pacing at AV delays of 150-350 ms, programmed at a constant rate. Right parasternal four-chamber views were recorded for simultaneous measurements of MVC from anatomical M-mode and radial tissue Doppler-based LV pre-ejection velocity and isovolumic acceleration (IVA). During SR and long AV delays (≥300 ms), two positive pre-ejection velocity peaks were present. The first peak was identified as LV recoil during atrial relaxation and consistently preceded MVC by 33±17 ms. The second peak was related to LV isovolumic contraction, occurring after MVC. This suggests that MVC was caused by atrial relaxation and followed by true isovolumic contraction. During short AV delays (<300 ms) and RVP, MVC occurred significantly later. Only one pre-ejection peak was present, of which the end coincided with MVC with a mean difference of -1.5±10 ms. This suggests that LV contraction caused MVC. Peak velocity and IVA were significantly higher (P<0.001) as the mitral valve was open at the onset of LV contraction. CONCLUSIONS: -Depending on the AV delay, MVC can be atrio- or ventriculogenic, resulting in significant alterations of the LV peak pre-ejection velocity and IVA.
  Circulation Cardiovascular Imaging 11/2012; · 5.94 Impact Factor
• Article: Ventricular response during lungeing exercise in horses with lone atrial fibrillation.

  T Verheyen, A Decloedt, N van der Vekens, S Sys, D De Clercq, G van Loon
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  ABSTRACT: REASONS FOR PERFORMING THE STUDY: Atrial fibrillation (AF) is the most important dysrhythmia affecting performance in horses and has been associated with incoordination, collapse and sudden death. Limited information is available on ventricular response during exercise in horses with lone AF. OBJECTIVES: To investigate ventricular response in horses with lone AF during a standardised lungeing exercise test. METHODS: A modified base-apex electrocardiogram was recorded at rest and during a standardised lungeing exercise test from 43 horses diagnosed with lone AF. During the test horses walked for 7 min, trotted for 10 min, cantered for 4 min, galloped for 1 min and recovered for 7 min. RESULTS: Individual average heart rate during walk ranged from 42 to 175 beats/min, during trot from 89 to 207 beats/min, during canter from 141 to 269 beats/min, and during gallop from 191 to 311 beats/min. Individual beat-to-beat maximal heart rate ranged from 248 to 492 beats/min. Ventricular premature depolarisations were present in 81% of the horses: at rest (16%), during exercise (69%), and during recovery (2%). In 33% of the horses, broad QRS complexes with R-on-T morphology were found. CONCLUSIONS: Exercising horses with lone AF frequently develop disproportionate tachycardia. In addition, QRS broadening and even R-on-T morphology is frequently found. QRS broadening may originate from ventricular ectopic foci or from aberrant intraventricular conduction, for example due to bundle branch block. This might explain the high number of complexes currently classified as ventricular premature depolarisations. POTENTIAL RELEVANCE: Prevalence of QRS broadening and especially R-on-T was very high in horses with AF and was found at low levels of exercise. These dysrhythmias are considered risk factors for the development of ventricular tachycardia and fibrillation and they might explain signs of weakness, collapse or sudden death that have been reported in horses with AF.
  Equine Veterinary Journal 08/2012; · 1.46 Impact Factor
• Article: Tissue Doppler imaging and 2-dimensional speckle tracking of left ventricular function in horses exposed to lasalocid.

  A Decloedt, T Verheyen, S Sys, D De Clercq, G van Loon
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  ABSTRACT: Tissue Doppler imaging (TDI) and 2-dimensional speckle tracking (2DST) can quantify left ventricular (LV) function in horses. To evaluate LV function by TDI and 2DST in horses with myocardial dysfunction after accidental ionophore intoxication. Sixty-seven horses exposed to lasalocid in feed. Prospective study. Horses were included in the study if a full cardiac examination was performed, consisting of determination of cardiac troponin I (cTnI), electrocardiography, and echocardiography. By TDI, radial systolic velocity and strain were measured. By 2DST, circumferential (SC) and radial (SR) strain at papillary muscle and chordal level and longitudinal (SL) strain were measured. Twenty horses showed signs of myocardial injury. Forty-nine examinations were performed on these horses between day 30 and 490 after suspected onset of exposure. Five horses had increased cTnI and ventricular tachycardia and 15 had increased cTnI without ventricular tachycardia. Horses with mild myocardial damage showed few significant differences compared with a control group. Horses with severe myocardial damage showed severely decreased TDI, 2DST and fractional shortening measurements (P < .05), indicating impaired LV function. Long-term follow-up of 2 surviving horses demonstrated full recovery in 1 horse and permanent myocardial fibrosis in the other. The lowest measurements per horse (n = 20) for all TDI measurements, SL, SR at chordal level, and FS correlated significantly with maximal cTnI (P < .05). Over all examinations (n = 49), TDI and 2DST measurements correlated well with FS (P < .05). The TDI and 2DST measurements allowed accurate detection and quantification of LV dysfunction in horses exposed to lasalocid.
  Journal of Veterinary Internal Medicine 07/2012; 26(5):1209-16. · 1.99 Impact Factor
• Article: Cardiac changes in horses with atypical myopathy.

  T Verheyen, A Decloedt, D De Clercq, G van Loon
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  ABSTRACT: Atypical myopathy (AM) is an acute, fatal rhabdomyolysis in grazing horses that mainly affects skeletal muscles. Postmortem examinations have shown that myocardial damage also occurs. Limited information is available on the effect of AM on cardiac function in affected and surviving horses. To describe electrocardiographic and echocardiographic changes associated with AM in the acute stage of the disease and after follow-up. Horses (n = 12) diagnosed with AM in which cardiac ultrasound examination and ECG recording were available. All horses underwent clinical examinations, serum biochemistry, electrocardiography, and echocardiography. Four surviving horses underwent the same examinations after 2-10 weeks. All but 1 horse had increased cardiac troponin I concentrations and 10 horses had ventricular premature depolarizations (VPDs). All horses had prolonged corrected QT (QT(cf) ) intervals on the day of admission and abnormal myocardial wall motion on echocardiography. One of the surviving horses still had VPDs and prolonged QT(cf) at follow-up after 10 weeks. The AM results in characteristic electrocardiographic and echocardiographic changes and may be associated with increased cardiac troponin I concentrations and VPDs. In survivors, abnormal cardiac function still may be found at follow-up after 10 weeks. Additional research in a larger group of horses is necessary to identify the long-term effects of AM on cardiac function.
  Journal of Veterinary Internal Medicine 05/2012; 26(4):1019-26. · 1.99 Impact Factor