History, Rest and Exercise Score (HRE-S) for assessment of disease severity in horses with trigeminal-mediated headshaking

BACKGROUND

In horses with trigeminal-mediated headshaking (TMHS), clinical signs are likely to be expression of neuropathic facial pain. Currently, subjective assessment of disease severity is used as measure of compromise of animal's welfare.

OBJECTIVES

To develop and validate a precise scoring system for TMHS: History, Rest and Exercise Score (HRE-S). The HRE-S consists of three subscores: history score (H-S), resting score (R-S) and exercise score (E-S).

STUDY DESIGN

Retrospective observational study.

METHODS

Seven masked observers with different experience used HRE-S to score 40 video recordings taken during rest and lungeing including five duplicates. Video recordings were taken from nine horses with TMHS and three controls. Inter- and intraobserver reliability and practicability of HRE-S were assessed. For every video recording severity of clinical signs was graded by every observer using an intuitive global-type-scale and interobserver reliability was calculated. Convergent validity was evaluated comparing HRE-S to groups created by an existing score (grade 0-3). Discriminant validity was analysed comparing HRE-S to groups created by intuitive global-type-scale.

RESULTS

Reliability for HRE-S was excellent, irrespective of observers experience: Spearman's Rho = 0.946, p < 0.001 (intraobserver reliability) and intraclass correlation coefficient = 0.98, p < 0.001 (interobserver reliability). Interobserver reliability for intuitive global-type-scale was fair to substantial: Fleiss' κappa = 0.48 (R-S) -0.63 (E-S). Groups created by intuitive global-type-scale had significantly different R-S and E-S (p < 0.05), demonstrating discriminant validity. Convergent validity was proven as horses with grade 3/3 had significantly higher average E-S and total scores compared with an existing score than those with grade 0/3 or 1/3 (p < 0.001).

MAIN LIMITATIONS

Retrospective nature, video recordings, sample size.

CONCLUSIONS

HRE-S is a valid and reliable score evaluating disease severity in TMHS, independent of observers' experience.

[Comparison of different electrocardiographic techniques for the detection of arrhythmias in horses]

OBJECTIVE

The aim of the study was to extend the range of the electrocardiographic examination in horses, evaluating the practicability of special electrocardiographic techniques (exercise- and Holter-ECG) and comparing these with more common techniques (resting-ECG) in equine medicine.

MATERIAL AND METHODS

Electrocardiographic examination (resting-ECG for 1 minute, exercise-ECG and Holter-ECG) was performed in 20 horses without any clinical or echocardiographic findings and in 80 patients with abnormal findings (valvular regurgitation and/or atrial fibrillation).

RESULTS

In comparison with the resting-ECG, the exercise-ECG demonstrated more atrial and ventricular premature beats, while the Holter-ECG had a higher detection rate of 2nd degree atrioventricular or sinuatrial blocks, and of ventricular and atrial premature depolarisations (p < 0.001). In comparison to the exercise-ECG, the Holter-ECG registered more 2nd degree atrioventricular blocks (p < 0.001) and ventricular (p < 0.001) or atrial premature contractions (p < 0.01). Atrial fibrillation was detected in every recorded ECG-type, but Holter-ECG provided additional information. Three of 16 horses with atrial fibrillation had R-on-T-episodes during Holter-monitoring. In addition to more common findings in the ECG, Holter-monitoring detected a 2nd degree atrioventricular block associated with an adjacent ventricular escape beat in a horse without any clinical or echocardiographic findings. An accelerated idioventricular rhythm was identified in a horse without any clinical or echocardiographic findings and in a horse with mitral valve insufficiency.

CONCLUSION AND CLINICAL RELEVANCE

The Holter-ECG is a useful tool in the evaluation of heart disease and could supply additional information when compared to the usual diagnostic electrocardiographic procedures used in horses. Exercise-ECG should not be replaced by Holter-ECG, however, Holter-EGC can provide additional diagnostic value.

Vergleichende Untersuchung von elektrokardiographischen Techniken zur Diagnostik von Herzrhythmusstörungen beim Pferd

Das Ziel dieser Studie war, die Befunde des Langzeit-EKGs beim Pferd mit denen des Belastungs- und des Ruhe-EKGs zu vergleichen. Material und Methode: Zwanzig klinisch und echokardiographisch unauffällige Kontrolltiere und 80 Patienten mit Klappeninsuffizienzen und/oder Vorhofflimmern wurden elektrokardiographisch untersucht. Die elektrokardiographischen Aufzeichnungen umfassten ein einminütiges Ruhe-EKG, ein Belastungs-EKG an der Longe und ein Langzeit-EKG über 24 Stunden. Ergebnisse: Im Vergleich zum Ruhe-EKG wurden Vorhof- und ventrikuläre Extrasystolen mithilfe des Belastungs-EKGs signifikant (p < 0,001) häufiger erkannt. Anhand des Langzeit-EKGs konnten signifikant mehr AV-Blöcke 2. Grades, sinuatriale Blöcke sowie Vorhof- und ventrikuläre Extrasystolen festgestellt werden als mithilfe des Ruhe-EKGs (p < 0,001). Beim Vergleich zwischen Belastungs-EKG und Langzeit-EKG zeigten sich im Langzeit-EKG signifikant häufiger AV-Blöcke 2. Grades (p < 0,001) sowie Extrasystolen atrialen (p < 0,001) und ventrikulären Ursprungs (p < 0,01). Vorhofflimmern wurde mit allen drei EKG-Techniken erfasst. Mittels Langzeit-EKG ließen sich allerdings neben dem Vorhofflimmern weitere elektrokardiographische Befunde erheben. Drei Tiere mit Vorhofflimmern zeigten zusätzlich das R-auf-T-Phänomen. Bei einem Pferd ohne klinische und echokardiographische Befunde traten im Langzeit-EKG Phasen mit je einem ventrikulären Ersatzschlag direkt nach einem AV-Block 2. Grades auf. Außerdem zeigten ein Kontrolltier und ein Pferd mit Mitralklappeninsuffizienz einen akzelerierten idioventrikulären Rhythmus. Schlussfolgerung und klinische Relevanz: Insgesamt erscheint es sinnvoll, das Langzeit-EKG wegen seines zusätzlichen Informationsgehalts in der Diagnostik von Herzerkrankungen häufiger anzuwenden als bisher üblich. Dabei sollte jedoch das Belastungs-EKG nicht ersetzt, sondern durch die Informationen des Langzeit-EKGs ergänzt werden.