PMID- 10487232
OWN - NLM
STAT- MEDLINE
DCOM- 19991122
LR  - 20190516
IS  - 0916-7250 (Print)
IS  - 0916-7250 (Linking)
VI  - 61
IP  - 8
DP  - 1999 Aug
TI  - Pathologic and electrocardiographic findings in sudden cardiac death in 
      racehorses.
PG  - 921-8
AB  - Five racehorses in apparently normal condition succumbed to sudden cardiac death 
      (SCD) during or shortly after intensive training exercise. Cardiopathologic 
      examination was performed. In 1 of the 5 horses, the use of an electrocardiogram 
      (ECG) recording taken continuously for 440 sec enabled us to analyze some of the 
      arrhythmias in the terminal event of SCD. The ECG tracing exhibited the R-on-T 
      phenomenon following a pair of ventricular premature contractions (VPCs). The 
      phenomenon rapidly degenerated into ventricular fibrillation, which led to 
      cardiac arrest. In all 5 horses cardiopathologic examination revealed the 
      following lesions: (i) foci of myocardial fibrosis in the right atrium located 
      close to the sinoatrial (SA) node, (ii) fibrotic and/or fibroplastic changes in 
      the upper portion of the interventricular septum, including the atrioventricular 
      (AV) conduction system, and (iii) arterio- and arteriolosclerosis of the SA and 
      AV node vessels. Pathogenetically, the process by which the focal lesions of 
      myocardial ischemia secondary to vascular sclerosis progressed into fibrosis 
      and/or fibroplasia could play a major role in the genesis of arrhythmias. 
      Presumably the fibrotic and/or fibroplastic changes in the area of the AV bundle 
      and its bundle branches are closely related to the onset of fatal ventricular 
      arrhythmias such as VPCs, deteriorating into ventricular fibrillation. SCD in 
      training and racing Thoroughbred horses appears to be due to arrhythmia.
FAU - Kiryu, K
AU  - Kiryu K
AD  - Department of Veterinary Pathology, Tokyo University of Agriculture and 
      Technology, Fuchu, Japan.
FAU - Machida, N
AU  - Machida N
FAU - Kashida, Y
AU  - Kashida Y
FAU - Yoshihara, T
AU  - Yoshihara T
FAU - Amada, A
AU  - Amada A
FAU - Yamamoto, T
AU  - Yamamoto T
LA  - eng
PT  - Case Reports
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Japan
TA  - J Vet Med Sci
JT  - The Journal of veterinary medical science
JID - 9105360
SB  - IM
MH  - Animals
MH  - Death, Sudden, Cardiac/*veterinary
MH  - Electrocardiography/veterinary
MH  - Fibrosis/pathology/veterinary
MH  - Horse Diseases/*pathology
MH  - Horses
MH  - Myocardium/pathology
EDAT- 1999/09/16 00:00
MHDA- 1999/09/16 00:01
CRDT- 1999/09/16 00:00
PHST- 1999/09/16 00:00 [pubmed]
PHST- 1999/09/16 00:01 [medline]
PHST- 1999/09/16 00:00 [entrez]
AID - 10.1292/jvms.61.921 [doi]
PST - ppublish
SO  - J Vet Med Sci. 1999 Aug;61(8):921-8. doi: 10.1292/jvms.61.921.