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Atrial Fibrillation in Dogs*
Br.
vel. ]. ( 1971 ),
127, 485
ATRIAL FIBRILLATION IN DOGS* Bv
F. K.
BoHNt,
D. F.
PATTERsoN:f: AND
R. L.
PYLE§
University of Pennsylvania, School of Veterinary Medicine, Comparative Cardiovascular Studies Unit a nd Department of Clinical Studies, Philadelphia, Pa.
SUMMARY
A study is reported of the age, breed, and sex distributions of atrial fibrillation in dogs, its association with various types of underlying heart disease, and its prognostic significance. Clinical heart disease was present in 877 of 30,663 dogs surveyed, and 55 (6·27 per cent) had chronic atrial fibrillation. Prevalence, which was significantly higher in giant breeds, increased with age and was higher in males than in femal es. INTRODUCTION
Atrial fibrillation (AF) is one of the most common abnormal arrhythmias found in dogs with naturally occurring heart disease. It is the purpose of this paper to describe the age, sex, and breed distribution of AF in a veterinary clinic population of 30,663 dogs and to assess its association with various types of underlying heart disease. In addition, information regarding the life expectancy of dogs with atr:al fibrillation will be presented, and the influence of body size on susceptibility to this arrhythmia will be examined. LITERATURE
The clinical and electrocardiographic features of atrial fibrillation in dogs have been reported by a number of authors. A brief selection of these reports is presented in Table I. In a previous report from our clinic (Detweiler, 1957), the prevalence of AF in dogs was found to be o·6 per rooo (22 cases were found among 39,387 dogs presented during the same time period). More recently, a screening survey was reported from the same clinic, in which 3000 dogs presented consecutively were examined specifically for the presence of cardiac arrhthymias (Patterson, Detweiler, Hubben & Botts, Ig6r ). In the latter series, I 3 dogs with AF were found, giving a prevalence rate of 4·3 per rooo. Although these and other papers give some indication of the frequency with which AF is found in dogs presented to a veterinary clinic and of the types of heart disease which underly it, age, sex and breed specific prevalence rates have not been previously reported. A number of authors have recognized that chronic * Supported in part by Grant USPH HE 4885. f Assistant Professor of Medi cine.
t Professor of Medicine. § Instructor in Cardiology.
BRITISH VETERINARY JOURNAL, 127,
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atrial fibrillation is a serious prognostic sign in the dog, but survival times in a large series of dogs have not been presented. TABLE I REVIEW AND EXTRA C T OF V E TERINARY LITERAT U RE OF C LINI C AL C ASES OF ATRIAL F IBRILLATION IN DOG S
Author
Comment
Roos ( I924) Gyarmati {I939)
Case report: 3 cases Veterinary dissertation: clinical electrocardiographic examination Textbook comments Ecg features and case report Case report Textbook comments Textbook comments Textbook comments Case report Case report Ecg and clinical features on 22 cases with AF Tachycardias and arrhythmias, Ecg features and AF case report Types and frequency of spontaneous arrhythmias Comments General clinical features and arrhythmias Comments and prevalence data on arrhythmias in dogs Case report: quinidine treatment General Ecg features and conversion Case reports: AF in cases of generalized myocardial disease Case reports : 6 cases; Decountershock Case reports: 3 cases with paroxysmal AF Case reports: 2I5 arrhythmias in dogs; 26 had AF
Marek et al. ( 1945) Lannek {I949 ) Fried ( I949) Marek et al. {I95I ) Detweiler {I952b) Hutyra et al. ( I 954) Pedini {I954) Andre {I955) Detweiler {I957) Gratz! {I96o) Patterson et al. {I96I ) Detweiler ( I 96 I) Buchanan {I965) Detweiler & Patterson (1965) Pyle {I966) Ett inger & Tashjian {I966) Bolm {I967 ) Ettinger {I968 ) Bohn {I969) Kersten, Winterfeld & Brass (1969)
Although paroxysmal atrial fibrillation has been described in the dog (Bohn, Ig6g), observations in our clinic have indicated that AF in dogs is nearly always associated with severe cardiac disease and is seldom reversible. In contrast to dogs, AF occurs in horses with mild degrees ofunderlying heart disease, and can often be successfully converted to normal sinus rhythm by quinidine therapy (Detweiler & Patterson, I g63). Cattle also appear to develop AF without overt signs of serious cardiac disease, and have been found to revert spontaneously to normal rhythm (Broijmans, I g67). These observations, plus the lack of reports of proven AF in cats and other animals smaller than dogs, have suggested that susceptibility to AF may be related to heart size. This suggestion is supported by observations made experimentally; although sustained atrial fibrillation can be induced by electrical stimulation in normal cattle,
ATRIAL FIBRILLATION IN DOGS
the same methods produced only transient bouts of AF in calves, goats, and sheep (Moore, Fisher, Detweiler & Moe, I96o, I965 ). Experimentally induced atrial fibrillation will not persist in dog hearts unless the mass of atrial tissue is greater than a critical size (Moe & Abildskov, I 959). If differences in heart size account for the apparent interspecies variation in AF, a critical mass of atrial tissue being necessary for sustained AF (Moore et al.J I96o, Ig6s ), then differences in susceptibility to AF should also be apparent within a species where the range of body size is great. The dog offers a convenient model in which to test this hypothesis; in no other domestic species is the range of body size so great. MATERIALS AND METHODS
The data included in this paper was gathered over a period of six years from I963 to I968. During this time, 30,663 dogs were presented to the Small Animal Clinic of the University of Pennsylvania. Animals with signs of cardiac disease on routine physical examination were referred to the Heart Station, · where complete cardiovascular examinations were made, including cardiac auscultation, ten lead electrocardiograms, and thoracic roentgenograms. Cardiac catheterization and angiocardiography were performed in some cases. Only dogs with chronic atrial fibrillation are reported in this paper. Paroxysmal atrial fibrillation (Bohn, I969), observed transiently during surgery, or immediately preceeding death, is not included.
Diagnosis and definition qf atrial fibrillation In all cases included in this report, the diagnosis of AF was based on the presence of the following electrocardiographic findings: (I) absence of P waves in all leads; (2) presence of a rapid ventricular rate (greater than I 40) with absolute arrhythmia. In most cases, rapid, irregular undulations of the base line (fibrillation waves) were visible. A typical tracing is presented in Fig. I. These electrocardiographic signs were accompanied by tachycardia with absolute irregularity on auscultation, there being a variation in both the timing and intensity of the heart sounds. A pulse-deficit was usually present.
RESULTS
Age and sex The prevalence of atrial fibrillation in dogs of various age groups is shown in Table II. The prevalence increased gradually with increasing age, from I ·4 per 1000 in dogs I to 4 years old, to 6·2 per 1000 in dogs I3 years of age or older. The prevalence in males was higher than in females in all age groups. Underlying heart disease In the population of 30,663 dogs included in this study, definite signs of heart
BRITISH VETERINARY JOURNAL,
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\r"r"rv"'r'\r, v-v •
I.
Lead II electrocardiogram of an 8-year-old male Great Dane with atrial fibrillation.
~
"\[
Fig.
127 , 10
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disease were recorded in 877 dogs, of which 55 ( r ·8 per woo ) had atrial fibrillation (6 ·27 per cent). The frequency with which AF occurred with various types of underlying cardiovascular lesions is given in Table III. By far the greatest proportion of dogs with AF had clinical signs of mitral valve insufficiency owing to chronic valvular disease, but this was a result of the preponderance of this type of heart disease in the clinic population. Although the number of animals in many disease categories was too small to draw definite conclusions, it appears that dogs with mitral insufficiency are no more likely to have AF than dogs with many forms of congenital heart disease. The prevalence of AF in dogs with cor pulmonale due to heartworm disease was less than in dogs with chronic valvular disease but the difference was not statistically significant (P > o· IO ) . The increasing frequency of AF with age, and the preponderance of males with this arrhythmia is explained by the increasing prevalence of chronic valvular disease with age, and the tendency for males to be more frequently and more severely affected (Detweiler, Patterson, Hubben & Botts, rg6r; Detweiler & Patterson, rg65; Detweiler, Luginbuhl, Buchanan & Patterson, r g68) . Pathological studies have shown that arteriosclerotic narrowing of the small intramural coronary arteries and focal myocardial necrosis and fibrosis of the myocardium are usually associated with severe chronic valvular disease (Detweiler et al., rg6r; Detweiler & Patterson, rg65).
Breed and body size Breed specific prevalence rates for AF are shown in Table IV. The prevalence rates ranged from o·g per IOOO in mixed breeds to 56·6 per IOOO in Newfoundlands. The arrhythmia was not found in dogs of many breeds, particularly toy breeds, and appeared to be most common in larger breeds.
~
TABLE II
......
> I:'"
AGE SPECIFIC PREVALENCE RATES OF ATRIAL FIBRILLATION IN DOGS
"rj
......
Age s-Byears Male Female Total
Male
g-I2years Female Total
Male
555 1
4339
9890
6090
4829
10919
2976
2689
5665
1742
I645
Number with atrial fibrillation
0
0
0
'3
3
r6
20
0
20
II
3
Prevalence rate per thousand
0
0
0
Male
1-4years Female Total
b:l ~ ......
2: I3years
lv!ale
Female
Total
I:'" I:'"
3387
379
432
802
14
0 z
4
I
5
2'3
6·2
~
Number in population
2'1
o·6
I'4
6·7
0
3'5
6·3
1·8
4'1
!0'5
z t:::J
0 0 en
.;:.. 00
BRITISH VETERINARY JOURNAL, 127, 10
490
TABLE Ill FREQUENCY OF ATRIAL FIBRILLATION IN DOGS WITH VARIOUS TYPES OF HEART DISEASE
Number with lesion
Number with
Chronic valvular disease, mitral insufficiency Chronic valvular disease, mitral insufficiency, cor pulmonale due to Dirofilaria immitis infection Cor pulmonale due to Dirofilaria immitis infection Patent ductus arteriosis Subaortic stenosis* Pulmonic stenosis Other heart disease
5 15
32
6·2 1
10
2
20•00
37
2
2'29
63 16 25 191
5 4 9
7'94 25'00 4'00 4'71
All lesions
877
55
6·38
Lesion
AF
Percmtage with
AF
* Some had mitral insufficiency as well. TABLE IV BREED SPECIFIC PREVALENCE RATES OF ATRIAL FIBRILLATION IN DO GS
Number in population
Number with
AF
Crude prevalence rate per 1000
Great Dane
324
8
24·6
St. Bernard
273
4
'4'6
Newfoundland
53
3
56·6
Irish Wolfhound
24
Breed
Doberman Pinscher Bloodhound Irish Setter German Shepherd Collie Afghan Hound German Shorthair Pointer Whippet
4 1'6
382
3
2 181
5'5
3624
8
944
2
2'2 2'1 18·1
55 102
12
7'3 50'0
/
"
9'7 83'3
Boxer
827
3
3'6
Poodle
2840
3
1'0
Cocker Spaniel
1013
6
5'9
Boston Terrier
266
Basset Hound
196
Mixed Breed
7376
7
0'9
12,169
0
o·o
30,663
55
J•8
Other Purebreed
3'7 5'1
ATRIAL FIBRILLATION IN DOGS
49 1
The prevalence of AF in dogs grouped according to body size is given in Table V . Atrial fibrillation was not observed in toys. After adjustment for age and sex, it is seen that AF occurred more than 40 times as often in giant breeds as in other dogs. This association between body size and the prevalence of atrial fibrillation is highly significant (differences as great or greater than those shown in Table V would be expected to occur by chance less often than once in rooo such samples, qs·r; df = 2; P < o·oor ). Congestive heart failure Of the 55 dogs with AF, 50 (go·g per cent) had signs of congestive heart failure (pulmonary congestion and oedema with or without generalized venous TABLE V PREVALENCE OF ATRIAL FIBRILLATION IN DOGS OF DIFFERENT SIZE S
Number in j;opulation
Si ze Giant*
Number with AF
Prevalence rate per 1ooo Crude Age and sex adjusted
670
!6
22"4
45"8
1,670
0
o·o
o ·o
Other
28,9 13
39
1'3
1"3
All dogs
30,663
55
J•8
Toyt
* Giant dogs arc defined as members of the Great Dane, St. Bernard, Newfoundland and Irish Wolfhound breeds. t Toy dogs are defined as members of the Affenpinscher, Chihuahua, English Toy Spaniel, Brussels Griffon, Italian Greyhound, Japanese Span iel, Maltese, Manchester Terrier (Toy), Papillon, Pekingese, Miniature Pinscher, Pomeranian, Pug, Silky Terrier, and Yorkshire Terrier breeds. (Toy Poodles are included with other Poodles in the category "Other". ) Under the hypothesis of no difference in the prevalence of atrial fibrillation between the 3 groups of dogs above, the Chi Square value of this tab le is 175· 1; df = 2; P < o·oot.
TABLE VI BREED INFL U ENCE ON OCCURRENCE OF CONGESTIVE HEART FAILURE IN DOG S WITH ATRIAL FIOO.ILLATION
Congestive heart failure
No congestive heart failure
Total
Giant breeds*
12
4
16
Other breeds
38
All breeds
50
Breed
39 5
55
* Giant breeds are defined as members of the Great Dane, St. Bernard, Newfoundland , and Irish Wolfhound breeds. Under the hypohesis that among dogs with atrial fibrillation, members of giant breeds are no more likely to have congestive heart failure than other dogs, the observed or more extreme distributions would be expected to occur with P = o·oo82 (Fisher's exact probability test, one tailed ).
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126, 10
engorgement, hepatomegaly, ascites). As shown in Table VI, atrial fibrillation in giant breeds was not associated with signs of congestive heart failure in four of the r6 of the cases studied (25 per cent), whereas in other breeds only one of 39 dogs (2·6 per cent) with AF lacked concurrent signs of congestive heart failure. Under the hypothesis that, among dogs with AF, members of giant breeds are no more likely to have congestive heart failure than other dogs, the observed or more extreme distributions would be expected to occur with P = o·oo82 (Fisher's exact probability test, one tailed). This finding supports the view that AF may occur with less severe underlying heart disease and should be considered a less serious prognostic sign in dogs of giant breeds than in other dogs.
Life expectancy Information was available on the length of survival after diagnosis in 58 dogs with AF, including 44 from the present series and 14 from previous time periods. The survival history of these dogs is presented numerically in Table VII and graphically in Fig. 2. It should be recognized that the picture provided by this group of dogs is biased by the fact that it does not include animals which were lost to the study for one reason or another. It contains only those dogs in which the eventual fate of the animal is known, a sample whose history may differ from that of the true history of all dogs with atrial fibrillation. Notwithstanding this difficulty, it seemed worthwhile to use the best estimate available.
100 Survival of 58 dogs with atrial fibrillation
90 80 70
I I yr.
I
2yrs.
1
3yrs
Time from diagnosis (day~)
Fig.
2.
Survival time of 58 dogs of different breeds and mixed breeds with atrial fibrillation .
TABLE VII SURVIVAL OF DOG S WITH AT R IAL FIBRILLATION
Time afterdiagnosis days
N umber ative at beginning oj time period
Number dying of accidents during period
Number exposed to r-isk of dying during period·
3
5 6 '5
I7
11 '5
2
Proportion dying during periodt
Proportion sur-viving the periodt
Propor-tion surviving to end of periodfrom diagnosis§
26
0'7 61
0'2 3 9
' 02 39
3
0 ' 43 5
0 '56 5
0 ' 135
0 ' 16 7
0,833
0 ' 112
0'200
0 ,800
0 ' 08 9
0 ' 250
0'75 0
0' 06 7
N umber- dying during period Euthanasia
"Natural" death
0-89
58
9 0--179
12
180--269
6
0
6
2 70--359
5
0
5
36 0--449
4
0
4
0
450--539
3
0
3
0
0
0 ' 000
1' 000
0' 06 7
3
0
3
0
0
0 ' 000
1'000
0 ' 06 7
0
0'333
0,667
0 '045
5 40--6 2 9
0 0
> I-:l ~
......
> t""' ~ ......
t:C
~ ...... t""'
S ......
630--7 1 9
3
0
3
720--8 0 9
2
0
2
0
0
0'000
1'000
0 '04 5
~
0
0
0'000
1'000
0'04 5
~
0
0 ' 5 00
0'500
0' 022
0
0'000
1' 000
0 '022
0
0'000
1'000
0 ' 022
0
1'000
0'000
0 ' 000
810--899
2
0
2
9<>0-989
2
0
2
990-- 10 79
0
0
1080--1169
0
0
1170-- 12 59
0 22
4
• Number exposed to risk of dying (column 4) = number in column
2
minus
32 1/2
of number in column 3,
t Proportion dying during period (column 7) = Number dying during period (column 5 + column 6) ,
Number exposed to risk of dying (column 4) proportion dying during period (column 7) , § Proportion surviving to end of given period from diagnosis (column 9) = Proportion surviving the period (column 8) X product of proportions surviving each of the previous time periods (column 8),
t Proportion surviving period (column 8)
=
I
-
0
......
t::;
0 Q en
494
BRITISH VETERINARY JOURNAL,
127, 10
All dogs whose histories were known eventually died from congestive heart failure or were put down because of intractable heart failure. As seen in Table VII and Fig. 2, only 24 per cent of the dogs with AF survived the first go days after diagnosis. Thereafter, the proportion surviving declined more gradually. Less than IO per cent survived to the end of the first year, less than 5 per cent beyond the end of the second year, and less than 3 per cent beyond the third. CONCLUS IONS AND DISCUSSION
The prevalence of atrial fibrillation in the veterinary clinic population studied increased with age, being higher in males than females in all age groups. The highest prevalence rate was found in males over I 3 years of age, in which it occurred in slightly more than I per cent of dogs presented to the clinic. The most common form of underlying heart disease in dogs with atrial fibrillation was mitral insufficiency due to chronic valvular disease which has been reported previously (Detweiler, I 952b, I 955, I 956, I 958, I 959; Detweiler, Hubben & Patterson, Ig6o; Detweiler, Ig6I; Detweiler et al., Ig6r; Detweiler, I g62; Detweiler & Patterson, I g62; Patterson, I g63, I g65; Buchanan, Baker & Hill, I g66; Patterson, I g68). Judging from the lesion-specific prevalence rates of atrial fibrillation in this series, the probability of developing atrial fibrillation may be no greater in dogs with chronic valvular disease and mitral insufficiency than in dogs with a number of types of congenital heart disease. The lowest frequency of atrial fibrillation was found in dogs with cor pulmonale due to heartworm infection. . The breed specific prevalence rates of atrial fibrillation vary widely between breeds, being significantly higher in giant breeds than in other dogs as a group. Atrial fibrillation in this series was not observed in toy breeds. Signs of congestive heart failure were significantly less common with AF in giant breeds than with AF in other breeds. These findings could be interpreted as indicating that AF occurs with less severe degrees of underlying heart disease in large dogs and supports the previous suggestion that susceptibility to atrial fibrillation increases with increasing atrial mass (Moe & Abildskov, I959). Studies in cattle indicate that adults are more susceptable to experimentally induced atrial fibrillation than calves (Moore et al., Ig6o, I965). These interspecies variations in the frequency of naturally occurring atrial fibrillation also suggest increasing susceptibility with increasing size, but other anatomical and physiological variations between species might account for this difference. This study provides the first evidence of a relationship between heart size and susceptibility to naturally occurring atrial fibrillation within a single species. Atrial fibrillation in the dog is a serious prognostic sign, particularly in dogs of non-giant breeds. In our series, approximately 75 per cent of dogs with atrial fibrillation died or were put down because of intractable cardiac failure within three months of the time of diagnosis; only 7 per cent survived as long as I 2 months. One dog out of 58, a member of a giant breed, survived for over three years.
ATRIAL FIBRILLATION IN DOGS
495
REFERENCES
ANDRE, T. (1955). Nord. VetMed. 7• 905. Cited by Detweiler, 1952a. BoHN, F. K. ( 1967) . Zentbl. VetMed. A14. 416. BoHN, F. K. ( 1g6g). Dt. tieriirztl. Wschr. 76, 198. BROIJMANS, A. W. M. (1967). Electrocardiography in Horses and Cattle. Thesis, State University, Utrecht. BucHANAN, J. W . (1965). Ann. N.Y. Acad. Sci. 127, 491. BucHANAN, J. W., BAKER, G. J. & HILL, J. D. ( 1966). Vet. Rec. 79• 496. DETWEILER, D. K. (1952a). Proc. Book Am. vet. Med. Ass., p. 119. DETWEILER, D. K. (1952b). Univ. Penn. Bull. Vet. Exl.en. Quart. 52, 21. DETWEILER, D. K. (1955). Vet. Scope, 1, 3· DETWEILER, D. K. (1956). Schweiz. Arch. Tierheilk. g8, 475· DETWEILER, D. K. (1957). Zentbl. VetMed. 6, 6og. DETWEILER, D. K. (1958). 6th Ann. Hlth . Conf., U.S. Dept. Hlth. p. 27. DETVVEILER, D. K. (1959). In Canine Medicine, ed. Hoskins, H., Lacroix, J. and Mayer, K. , p. 275 . Santa Barbara, Calif.: American Veterinary Publications. DETWEILER, D. K. ( 1961 ). In Cardiology Encyclopaedia, ed. Louisada, A. A. New York: McGraw-Hill. DETWEILER, D. K. (1962). Zentbl. VetMed. g, 317. DETWEILER, D. K., HuBBEN, K. & PATTERSON, D. F. (196o) . Am.]. vet. Res. :u, 329. DETWEILER, D. K., LuGINBOHL, H., BucHANAN,]. W. & PATTERSON, D. F. (1968). Ann. N.Y. A cad. Sci. 147, 318. DETWEILER, D . K. & PATTERSON, D. F. (1962) . Small Anim. CliTI. 2, 79· DETWEILER, D. K. & PATTERSON, D. F. ( 1963). In Equine MediciTte and Surgery, 1st edn., ed. Bone, J . F., p. 338. Santa Barbara, Calif.: American Veterinary Publications. DETWEILER, D. K. & PATTERSON, D. F. (1965). Ann. N.Y. Acad. Sci. 127, 481. DETWEILER, D. K., PATTERSON, D. F., HuBBEN, K. & BoTTs, R. P. (1g61) . Am.]. publ. Hlth. 51· 228. ETTINGER, S. (1g68). ]. Am. vet. med. Ass. 152, 41. ETTINGER, S. & TASHJIAN, F. J. (1g66). Mod. vet. Prac. 47• 34· FRIED, K. J. (1949). Cas. csl. vet. 5, 98. Cited by Detweiler, 1952a. GRATZL, D. (1g6o). Wien. tieriirztl. Mschr. 47- 5,281. GYARMATI, D. (1939). Doctoral Dissertation, Univ. Budapest. HuTYRA F. V. & MAREK]. (1954). In Spezielle Pathologic und Therapie die Haustiere. Bd. II, p. 433· Jena: Fischer. KERSTEN, V., WINTERFELD, D. & BRAss, W. (1969). Tieriirztl. Umschau. 24> no. LANNEK, N. (1949). Doctoral Dissertation, Univ. Stockholm. MAREK, ]., MANNINGER. R. & Mocsv J. F. (1945). In Spezielle Pathologic und Therapie die Haustiere, Bd. II. J ena: Fischer. MAREK, J., MANNINGER, R. & Mocsv, J. F., (1951) . In Lehrbuch der klinischen Diagnostik der inneren Krankheiten der Haustiere. Jena: Fischer. MoE, G. K. & ABILDSKOV, J. A. (1959) · Am. H eart]. sB, 59· MooRE, E. N., FISHER, G., DETWEILER, D. K. & MoE, G. K. (1g6o) . Physiologist. 3, 116. MooRE, E. N., FISHER, G., DETVVEILER, D. K. & MoE, G. K . (1965) . Int. Symp. Camp. Med., p. 229. New York: Eaton Laboratories. PATTERSON, D. F. (1963). In Scientific Proceedings, 10oth Ann. Meet., Am. vet. med. Ass., p. 128. PATTERSON, D. F. (1965). Ann. N.Y. Acad. Sci. 127, 393· PATTERSON, D. F. (1968). Circ. Res. 23, 171. PATTERSON, D. F., DETWEILER, D. K., HuBBEN, K. & BoTTS, R . P. (1g61). Am.]. vet. Res. 22, 355· PEDINI, B. ( 1954) . Vet . !tal. 5, 905. Cited by Detweiler, I 952a. PYLE, R. L. (1967). ]. Am. vet. med. Ass., 151, 582. Roos, J. (1924). Arch. wiss. prakt. Tierheilk. 1-7, 51, 280.
Fibrillation de l'oreillette chez les chiens
(Bohn et a/.) Re~wne. On presente une etude sur la distribution des fibrillations de l'oreillette chez les chiens suivant l'age, Ia race, le sexe, sur leur association avec diverses maladies de coeur qui en sont a Ia base, et sur leur signification prognostique. 11 y avait une maladie de coeur clinique
BRITISH VETERINARY JOURNAL, 127, 10 chez 877 des 30663 chiens examines, et 55 (6,27 pour cent) avaient une fibrillation chronique de l'oreillette. La prevalence, qui de fac;:on significative etait plus grande chez les races geantes, augmentait avec l'age et etait plus grande chez les males que chez les femelles.
VorhofHinunern bei Hunden (Bohn et a/.) Zusammenfassung. Bericht tiber eine Untersuchung tiber das Alter, die Zucht und die Geschlechtsverteilung bei Hunden, bei denen Vorhoffiimmern aufgetreten ist. Ferner wurde untersucht, in welcher Weise dies mit den verschiedenen zugrunde liegenden Herzerkrankungen assoziiert ist, und die prognostische Signifikanz. Klinische H erzerkrankungen waren vorhanden bei 877 der untersuchten 30683 Hunden, und 55 (6,27 prozent) zeigten chronisches Vorhoffiimmern. Dessen Vorkommen war signifikant hoher bei sehr grossen Hunden, vermehrte sich mit dem Alter und trat mehr bei mii.nnlichen als bei weiblichen Hunden auf.
Fibrilacion auricular en perros (Bohnet al.) Resumen. Se presenta un estudio sobre la fibrilaci6n auricular en perros de acuerdo con su edad, raza, sexo, asi como su asociaci6n a diversos tipos de cardiopatias subyacentes y su significado pron6stico. Sintomas clinicos de enfermedad cardiaca se encontraron en 877 perros de los 30663 examinados, de los cuales 55 (6,27 por ciento) presentaban fibrilaci6n auricular. La prevalencia, que fue significativamente mayor en las razas gigantes, aument6 con la edad y fue mayor en los machos que en las hembras.
vel. ]. ( 1971 ),
127, 485
ATRIAL FIBRILLATION IN DOGS* Bv
F. K.
BoHNt,
D. F.
PATTERsoN:f: AND
R. L.
PYLE§
University of Pennsylvania, School of Veterinary Medicine, Comparative Cardiovascular Studies Unit a nd Department of Clinical Studies, Philadelphia, Pa.
SUMMARY
A study is reported of the age, breed, and sex distributions of atrial fibrillation in dogs, its association with various types of underlying heart disease, and its prognostic significance. Clinical heart disease was present in 877 of 30,663 dogs surveyed, and 55 (6·27 per cent) had chronic atrial fibrillation. Prevalence, which was significantly higher in giant breeds, increased with age and was higher in males than in femal es. INTRODUCTION
Atrial fibrillation (AF) is one of the most common abnormal arrhythmias found in dogs with naturally occurring heart disease. It is the purpose of this paper to describe the age, sex, and breed distribution of AF in a veterinary clinic population of 30,663 dogs and to assess its association with various types of underlying heart disease. In addition, information regarding the life expectancy of dogs with atr:al fibrillation will be presented, and the influence of body size on susceptibility to this arrhythmia will be examined. LITERATURE
The clinical and electrocardiographic features of atrial fibrillation in dogs have been reported by a number of authors. A brief selection of these reports is presented in Table I. In a previous report from our clinic (Detweiler, 1957), the prevalence of AF in dogs was found to be o·6 per rooo (22 cases were found among 39,387 dogs presented during the same time period). More recently, a screening survey was reported from the same clinic, in which 3000 dogs presented consecutively were examined specifically for the presence of cardiac arrhthymias (Patterson, Detweiler, Hubben & Botts, Ig6r ). In the latter series, I 3 dogs with AF were found, giving a prevalence rate of 4·3 per rooo. Although these and other papers give some indication of the frequency with which AF is found in dogs presented to a veterinary clinic and of the types of heart disease which underly it, age, sex and breed specific prevalence rates have not been previously reported. A number of authors have recognized that chronic * Supported in part by Grant USPH HE 4885. f Assistant Professor of Medi cine.
t Professor of Medicine. § Instructor in Cardiology.
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atrial fibrillation is a serious prognostic sign in the dog, but survival times in a large series of dogs have not been presented. TABLE I REVIEW AND EXTRA C T OF V E TERINARY LITERAT U RE OF C LINI C AL C ASES OF ATRIAL F IBRILLATION IN DOG S
Author
Comment
Roos ( I924) Gyarmati {I939)
Case report: 3 cases Veterinary dissertation: clinical electrocardiographic examination Textbook comments Ecg features and case report Case report Textbook comments Textbook comments Textbook comments Case report Case report Ecg and clinical features on 22 cases with AF Tachycardias and arrhythmias, Ecg features and AF case report Types and frequency of spontaneous arrhythmias Comments General clinical features and arrhythmias Comments and prevalence data on arrhythmias in dogs Case report: quinidine treatment General Ecg features and conversion Case reports: AF in cases of generalized myocardial disease Case reports : 6 cases; Decountershock Case reports: 3 cases with paroxysmal AF Case reports: 2I5 arrhythmias in dogs; 26 had AF
Marek et al. ( 1945) Lannek {I949 ) Fried ( I949) Marek et al. {I95I ) Detweiler {I952b) Hutyra et al. ( I 954) Pedini {I954) Andre {I955) Detweiler {I957) Gratz! {I96o) Patterson et al. {I96I ) Detweiler ( I 96 I) Buchanan {I965) Detweiler & Patterson (1965) Pyle {I966) Ett inger & Tashjian {I966) Bolm {I967 ) Ettinger {I968 ) Bohn {I969) Kersten, Winterfeld & Brass (1969)
Although paroxysmal atrial fibrillation has been described in the dog (Bohn, Ig6g), observations in our clinic have indicated that AF in dogs is nearly always associated with severe cardiac disease and is seldom reversible. In contrast to dogs, AF occurs in horses with mild degrees ofunderlying heart disease, and can often be successfully converted to normal sinus rhythm by quinidine therapy (Detweiler & Patterson, I g63). Cattle also appear to develop AF without overt signs of serious cardiac disease, and have been found to revert spontaneously to normal rhythm (Broijmans, I g67). These observations, plus the lack of reports of proven AF in cats and other animals smaller than dogs, have suggested that susceptibility to AF may be related to heart size. This suggestion is supported by observations made experimentally; although sustained atrial fibrillation can be induced by electrical stimulation in normal cattle,
ATRIAL FIBRILLATION IN DOGS
the same methods produced only transient bouts of AF in calves, goats, and sheep (Moore, Fisher, Detweiler & Moe, I96o, I965 ). Experimentally induced atrial fibrillation will not persist in dog hearts unless the mass of atrial tissue is greater than a critical size (Moe & Abildskov, I 959). If differences in heart size account for the apparent interspecies variation in AF, a critical mass of atrial tissue being necessary for sustained AF (Moore et al.J I96o, Ig6s ), then differences in susceptibility to AF should also be apparent within a species where the range of body size is great. The dog offers a convenient model in which to test this hypothesis; in no other domestic species is the range of body size so great. MATERIALS AND METHODS
The data included in this paper was gathered over a period of six years from I963 to I968. During this time, 30,663 dogs were presented to the Small Animal Clinic of the University of Pennsylvania. Animals with signs of cardiac disease on routine physical examination were referred to the Heart Station, · where complete cardiovascular examinations were made, including cardiac auscultation, ten lead electrocardiograms, and thoracic roentgenograms. Cardiac catheterization and angiocardiography were performed in some cases. Only dogs with chronic atrial fibrillation are reported in this paper. Paroxysmal atrial fibrillation (Bohn, I969), observed transiently during surgery, or immediately preceeding death, is not included.
Diagnosis and definition qf atrial fibrillation In all cases included in this report, the diagnosis of AF was based on the presence of the following electrocardiographic findings: (I) absence of P waves in all leads; (2) presence of a rapid ventricular rate (greater than I 40) with absolute arrhythmia. In most cases, rapid, irregular undulations of the base line (fibrillation waves) were visible. A typical tracing is presented in Fig. I. These electrocardiographic signs were accompanied by tachycardia with absolute irregularity on auscultation, there being a variation in both the timing and intensity of the heart sounds. A pulse-deficit was usually present.
RESULTS
Age and sex The prevalence of atrial fibrillation in dogs of various age groups is shown in Table II. The prevalence increased gradually with increasing age, from I ·4 per 1000 in dogs I to 4 years old, to 6·2 per 1000 in dogs I3 years of age or older. The prevalence in males was higher than in females in all age groups. Underlying heart disease In the population of 30,663 dogs included in this study, definite signs of heart
BRITISH VETERINARY JOURNAL,
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\r"r"rv"'r'\r, v-v •
I.
Lead II electrocardiogram of an 8-year-old male Great Dane with atrial fibrillation.
~
"\[
Fig.
127 , 10
\1 ....
1
¥
\r
\{'-'"
disease were recorded in 877 dogs, of which 55 ( r ·8 per woo ) had atrial fibrillation (6 ·27 per cent). The frequency with which AF occurred with various types of underlying cardiovascular lesions is given in Table III. By far the greatest proportion of dogs with AF had clinical signs of mitral valve insufficiency owing to chronic valvular disease, but this was a result of the preponderance of this type of heart disease in the clinic population. Although the number of animals in many disease categories was too small to draw definite conclusions, it appears that dogs with mitral insufficiency are no more likely to have AF than dogs with many forms of congenital heart disease. The prevalence of AF in dogs with cor pulmonale due to heartworm disease was less than in dogs with chronic valvular disease but the difference was not statistically significant (P > o· IO ) . The increasing frequency of AF with age, and the preponderance of males with this arrhythmia is explained by the increasing prevalence of chronic valvular disease with age, and the tendency for males to be more frequently and more severely affected (Detweiler, Patterson, Hubben & Botts, rg6r; Detweiler & Patterson, rg65; Detweiler, Luginbuhl, Buchanan & Patterson, r g68) . Pathological studies have shown that arteriosclerotic narrowing of the small intramural coronary arteries and focal myocardial necrosis and fibrosis of the myocardium are usually associated with severe chronic valvular disease (Detweiler et al., rg6r; Detweiler & Patterson, rg65).
Breed and body size Breed specific prevalence rates for AF are shown in Table IV. The prevalence rates ranged from o·g per IOOO in mixed breeds to 56·6 per IOOO in Newfoundlands. The arrhythmia was not found in dogs of many breeds, particularly toy breeds, and appeared to be most common in larger breeds.
~
TABLE II
......
> I:'"
AGE SPECIFIC PREVALENCE RATES OF ATRIAL FIBRILLATION IN DOGS
"rj
......
Age s-Byears Male Female Total
Male
g-I2years Female Total
Male
555 1
4339
9890
6090
4829
10919
2976
2689
5665
1742
I645
Number with atrial fibrillation
0
0
0
'3
3
r6
20
0
20
II
3
Prevalence rate per thousand
0
0
0
Male
1-4years Female Total
b:l ~ ......
2: I3years
lv!ale
Female
Total
I:'" I:'"
3387
379
432
802
14
0 z
4
I
5
2'3
6·2
~
Number in population
2'1
o·6
I'4
6·7
0
3'5
6·3
1·8
4'1
!0'5
z t:::J
0 0 en
.;:.. 00
BRITISH VETERINARY JOURNAL, 127, 10
490
TABLE Ill FREQUENCY OF ATRIAL FIBRILLATION IN DOGS WITH VARIOUS TYPES OF HEART DISEASE
Number with lesion
Number with
Chronic valvular disease, mitral insufficiency Chronic valvular disease, mitral insufficiency, cor pulmonale due to Dirofilaria immitis infection Cor pulmonale due to Dirofilaria immitis infection Patent ductus arteriosis Subaortic stenosis* Pulmonic stenosis Other heart disease
5 15
32
6·2 1
10
2
20•00
37
2
2'29
63 16 25 191
5 4 9
7'94 25'00 4'00 4'71
All lesions
877
55
6·38
Lesion
AF
Percmtage with
AF
* Some had mitral insufficiency as well. TABLE IV BREED SPECIFIC PREVALENCE RATES OF ATRIAL FIBRILLATION IN DO GS
Number in population
Number with
AF
Crude prevalence rate per 1000
Great Dane
324
8
24·6
St. Bernard
273
4
'4'6
Newfoundland
53
3
56·6
Irish Wolfhound
24
Breed
Doberman Pinscher Bloodhound Irish Setter German Shepherd Collie Afghan Hound German Shorthair Pointer Whippet
4 1'6
382
3
2 181
5'5
3624
8
944
2
2'2 2'1 18·1
55 102
12
7'3 50'0
/
"
9'7 83'3
Boxer
827
3
3'6
Poodle
2840
3
1'0
Cocker Spaniel
1013
6
5'9
Boston Terrier
266
Basset Hound
196
Mixed Breed
7376
7
0'9
12,169
0
o·o
30,663
55
J•8
Other Purebreed
3'7 5'1
ATRIAL FIBRILLATION IN DOGS
49 1
The prevalence of AF in dogs grouped according to body size is given in Table V . Atrial fibrillation was not observed in toys. After adjustment for age and sex, it is seen that AF occurred more than 40 times as often in giant breeds as in other dogs. This association between body size and the prevalence of atrial fibrillation is highly significant (differences as great or greater than those shown in Table V would be expected to occur by chance less often than once in rooo such samples, qs·r; df = 2; P < o·oor ). Congestive heart failure Of the 55 dogs with AF, 50 (go·g per cent) had signs of congestive heart failure (pulmonary congestion and oedema with or without generalized venous TABLE V PREVALENCE OF ATRIAL FIBRILLATION IN DOGS OF DIFFERENT SIZE S
Number in j;opulation
Si ze Giant*
Number with AF
Prevalence rate per 1ooo Crude Age and sex adjusted
670
!6
22"4
45"8
1,670
0
o·o
o ·o
Other
28,9 13
39
1'3
1"3
All dogs
30,663
55
J•8
Toyt
* Giant dogs arc defined as members of the Great Dane, St. Bernard, Newfoundland and Irish Wolfhound breeds. t Toy dogs are defined as members of the Affenpinscher, Chihuahua, English Toy Spaniel, Brussels Griffon, Italian Greyhound, Japanese Span iel, Maltese, Manchester Terrier (Toy), Papillon, Pekingese, Miniature Pinscher, Pomeranian, Pug, Silky Terrier, and Yorkshire Terrier breeds. (Toy Poodles are included with other Poodles in the category "Other". ) Under the hypothesis of no difference in the prevalence of atrial fibrillation between the 3 groups of dogs above, the Chi Square value of this tab le is 175· 1; df = 2; P < o·oot.
TABLE VI BREED INFL U ENCE ON OCCURRENCE OF CONGESTIVE HEART FAILURE IN DOG S WITH ATRIAL FIOO.ILLATION
Congestive heart failure
No congestive heart failure
Total
Giant breeds*
12
4
16
Other breeds
38
All breeds
50
Breed
39 5
55
* Giant breeds are defined as members of the Great Dane, St. Bernard, Newfoundland , and Irish Wolfhound breeds. Under the hypohesis that among dogs with atrial fibrillation, members of giant breeds are no more likely to have congestive heart failure than other dogs, the observed or more extreme distributions would be expected to occur with P = o·oo82 (Fisher's exact probability test, one tailed ).
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engorgement, hepatomegaly, ascites). As shown in Table VI, atrial fibrillation in giant breeds was not associated with signs of congestive heart failure in four of the r6 of the cases studied (25 per cent), whereas in other breeds only one of 39 dogs (2·6 per cent) with AF lacked concurrent signs of congestive heart failure. Under the hypothesis that, among dogs with AF, members of giant breeds are no more likely to have congestive heart failure than other dogs, the observed or more extreme distributions would be expected to occur with P = o·oo82 (Fisher's exact probability test, one tailed). This finding supports the view that AF may occur with less severe underlying heart disease and should be considered a less serious prognostic sign in dogs of giant breeds than in other dogs.
Life expectancy Information was available on the length of survival after diagnosis in 58 dogs with AF, including 44 from the present series and 14 from previous time periods. The survival history of these dogs is presented numerically in Table VII and graphically in Fig. 2. It should be recognized that the picture provided by this group of dogs is biased by the fact that it does not include animals which were lost to the study for one reason or another. It contains only those dogs in which the eventual fate of the animal is known, a sample whose history may differ from that of the true history of all dogs with atrial fibrillation. Notwithstanding this difficulty, it seemed worthwhile to use the best estimate available.
100 Survival of 58 dogs with atrial fibrillation
90 80 70
I I yr.
I
2yrs.
1
3yrs
Time from diagnosis (day~)
Fig.
2.
Survival time of 58 dogs of different breeds and mixed breeds with atrial fibrillation .
TABLE VII SURVIVAL OF DOG S WITH AT R IAL FIBRILLATION
Time afterdiagnosis days
N umber ative at beginning oj time period
Number dying of accidents during period
Number exposed to r-isk of dying during period·
3
5 6 '5
I7
11 '5
2
Proportion dying during periodt
Proportion sur-viving the periodt
Propor-tion surviving to end of periodfrom diagnosis§
26
0'7 61
0'2 3 9
' 02 39
3
0 ' 43 5
0 '56 5
0 ' 135
0 ' 16 7
0,833
0 ' 112
0'200
0 ,800
0 ' 08 9
0 ' 250
0'75 0
0' 06 7
N umber- dying during period Euthanasia
"Natural" death
0-89
58
9 0--179
12
180--269
6
0
6
2 70--359
5
0
5
36 0--449
4
0
4
0
450--539
3
0
3
0
0
0 ' 000
1' 000
0' 06 7
3
0
3
0
0
0 ' 000
1'000
0 ' 06 7
0
0'333
0,667
0 '045
5 40--6 2 9
0 0
> I-:l ~
......
> t""' ~ ......
t:C
~ ...... t""'
S ......
630--7 1 9
3
0
3
720--8 0 9
2
0
2
0
0
0'000
1'000
0 '04 5
~
0
0
0'000
1'000
0'04 5
~
0
0 ' 5 00
0'500
0' 022
0
0'000
1' 000
0 '022
0
0'000
1'000
0 ' 022
0
1'000
0'000
0 ' 000
810--899
2
0
2
9<>0-989
2
0
2
990-- 10 79
0
0
1080--1169
0
0
1170-- 12 59
0 22
4
• Number exposed to risk of dying (column 4) = number in column
2
minus
32 1/2
of number in column 3,
t Proportion dying during period (column 7) = Number dying during period (column 5 + column 6) ,
Number exposed to risk of dying (column 4) proportion dying during period (column 7) , § Proportion surviving to end of given period from diagnosis (column 9) = Proportion surviving the period (column 8) X product of proportions surviving each of the previous time periods (column 8),
t Proportion surviving period (column 8)
=
I
-
0
......
t::;
0 Q en
494
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All dogs whose histories were known eventually died from congestive heart failure or were put down because of intractable heart failure. As seen in Table VII and Fig. 2, only 24 per cent of the dogs with AF survived the first go days after diagnosis. Thereafter, the proportion surviving declined more gradually. Less than IO per cent survived to the end of the first year, less than 5 per cent beyond the end of the second year, and less than 3 per cent beyond the third. CONCLUS IONS AND DISCUSSION
The prevalence of atrial fibrillation in the veterinary clinic population studied increased with age, being higher in males than females in all age groups. The highest prevalence rate was found in males over I 3 years of age, in which it occurred in slightly more than I per cent of dogs presented to the clinic. The most common form of underlying heart disease in dogs with atrial fibrillation was mitral insufficiency due to chronic valvular disease which has been reported previously (Detweiler, I 952b, I 955, I 956, I 958, I 959; Detweiler, Hubben & Patterson, Ig6o; Detweiler, Ig6I; Detweiler et al., Ig6r; Detweiler, I g62; Detweiler & Patterson, I g62; Patterson, I g63, I g65; Buchanan, Baker & Hill, I g66; Patterson, I g68). Judging from the lesion-specific prevalence rates of atrial fibrillation in this series, the probability of developing atrial fibrillation may be no greater in dogs with chronic valvular disease and mitral insufficiency than in dogs with a number of types of congenital heart disease. The lowest frequency of atrial fibrillation was found in dogs with cor pulmonale due to heartworm infection. . The breed specific prevalence rates of atrial fibrillation vary widely between breeds, being significantly higher in giant breeds than in other dogs as a group. Atrial fibrillation in this series was not observed in toy breeds. Signs of congestive heart failure were significantly less common with AF in giant breeds than with AF in other breeds. These findings could be interpreted as indicating that AF occurs with less severe degrees of underlying heart disease in large dogs and supports the previous suggestion that susceptibility to atrial fibrillation increases with increasing atrial mass (Moe & Abildskov, I959). Studies in cattle indicate that adults are more susceptable to experimentally induced atrial fibrillation than calves (Moore et al., Ig6o, I965). These interspecies variations in the frequency of naturally occurring atrial fibrillation also suggest increasing susceptibility with increasing size, but other anatomical and physiological variations between species might account for this difference. This study provides the first evidence of a relationship between heart size and susceptibility to naturally occurring atrial fibrillation within a single species. Atrial fibrillation in the dog is a serious prognostic sign, particularly in dogs of non-giant breeds. In our series, approximately 75 per cent of dogs with atrial fibrillation died or were put down because of intractable cardiac failure within three months of the time of diagnosis; only 7 per cent survived as long as I 2 months. One dog out of 58, a member of a giant breed, survived for over three years.
ATRIAL FIBRILLATION IN DOGS
495
REFERENCES
ANDRE, T. (1955). Nord. VetMed. 7• 905. Cited by Detweiler, 1952a. BoHN, F. K. ( 1967) . Zentbl. VetMed. A14. 416. BoHN, F. K. ( 1g6g). Dt. tieriirztl. Wschr. 76, 198. BROIJMANS, A. W. M. (1967). Electrocardiography in Horses and Cattle. Thesis, State University, Utrecht. BucHANAN, J. W . (1965). Ann. N.Y. Acad. Sci. 127, 491. BucHANAN, J. W., BAKER, G. J. & HILL, J. D. ( 1966). Vet. Rec. 79• 496. DETWEILER, D. K. (1952a). Proc. Book Am. vet. Med. Ass., p. 119. DETWEILER, D. K. (1952b). Univ. Penn. Bull. Vet. Exl.en. Quart. 52, 21. DETWEILER, D. K. (1955). Vet. Scope, 1, 3· DETWEILER, D. K. (1956). Schweiz. Arch. Tierheilk. g8, 475· DETWEILER, D. K. (1957). Zentbl. VetMed. 6, 6og. DETWEILER, D. K. (1958). 6th Ann. Hlth . Conf., U.S. Dept. Hlth. p. 27. DETVVEILER, D. K. (1959). In Canine Medicine, ed. Hoskins, H., Lacroix, J. and Mayer, K. , p. 275 . Santa Barbara, Calif.: American Veterinary Publications. DETWEILER, D. K. ( 1961 ). In Cardiology Encyclopaedia, ed. Louisada, A. A. New York: McGraw-Hill. DETWEILER, D. K. (1962). Zentbl. VetMed. g, 317. DETWEILER, D. K., HuBBEN, K. & PATTERSON, D. F. (196o) . Am.]. vet. Res. :u, 329. DETWEILER, D. K., LuGINBOHL, H., BucHANAN,]. W. & PATTERSON, D. F. (1968). Ann. N.Y. A cad. Sci. 147, 318. DETWEILER, D . K. & PATTERSON, D. F. (1962) . Small Anim. CliTI. 2, 79· DETWEILER, D. K. & PATTERSON, D. F. ( 1963). In Equine MediciTte and Surgery, 1st edn., ed. Bone, J . F., p. 338. Santa Barbara, Calif.: American Veterinary Publications. DETWEILER, D. K. & PATTERSON, D. F. (1965). Ann. N.Y. Acad. Sci. 127, 481. DETWEILER, D. K., PATTERSON, D. F., HuBBEN, K. & BoTTs, R. P. (1g61) . Am.]. publ. Hlth. 51· 228. ETTINGER, S. (1g68). ]. Am. vet. med. Ass. 152, 41. ETTINGER, S. & TASHJIAN, F. J. (1g66). Mod. vet. Prac. 47• 34· FRIED, K. J. (1949). Cas. csl. vet. 5, 98. Cited by Detweiler, 1952a. GRATZL, D. (1g6o). Wien. tieriirztl. Mschr. 47- 5,281. GYARMATI, D. (1939). Doctoral Dissertation, Univ. Budapest. HuTYRA F. V. & MAREK]. (1954). In Spezielle Pathologic und Therapie die Haustiere. Bd. II, p. 433· Jena: Fischer. KERSTEN, V., WINTERFELD, D. & BRAss, W. (1969). Tieriirztl. Umschau. 24> no. LANNEK, N. (1949). Doctoral Dissertation, Univ. Stockholm. MAREK, ]., MANNINGER. R. & Mocsv J. F. (1945). In Spezielle Pathologic und Therapie die Haustiere, Bd. II. J ena: Fischer. MAREK, J., MANNINGER, R. & Mocsv, J. F., (1951) . In Lehrbuch der klinischen Diagnostik der inneren Krankheiten der Haustiere. Jena: Fischer. MoE, G. K. & ABILDSKOV, J. A. (1959) · Am. H eart]. sB, 59· MooRE, E. N., FISHER, G., DETWEILER, D. K. & MoE, G. K. (1g6o) . Physiologist. 3, 116. MooRE, E. N., FISHER, G., DETVVEILER, D. K. & MoE, G. K . (1965) . Int. Symp. Camp. Med., p. 229. New York: Eaton Laboratories. PATTERSON, D. F. (1963). In Scientific Proceedings, 10oth Ann. Meet., Am. vet. med. Ass., p. 128. PATTERSON, D. F. (1965). Ann. N.Y. Acad. Sci. 127, 393· PATTERSON, D. F. (1968). Circ. Res. 23, 171. PATTERSON, D. F., DETWEILER, D. K., HuBBEN, K. & BoTTS, R . P. (1g61). Am.]. vet. Res. 22, 355· PEDINI, B. ( 1954) . Vet . !tal. 5, 905. Cited by Detweiler, I 952a. PYLE, R. L. (1967). ]. Am. vet. med. Ass., 151, 582. Roos, J. (1924). Arch. wiss. prakt. Tierheilk. 1-7, 51, 280.
Fibrillation de l'oreillette chez les chiens
(Bohn et a/.) Re~wne. On presente une etude sur la distribution des fibrillations de l'oreillette chez les chiens suivant l'age, Ia race, le sexe, sur leur association avec diverses maladies de coeur qui en sont a Ia base, et sur leur signification prognostique. 11 y avait une maladie de coeur clinique
BRITISH VETERINARY JOURNAL, 127, 10 chez 877 des 30663 chiens examines, et 55 (6,27 pour cent) avaient une fibrillation chronique de l'oreillette. La prevalence, qui de fac;:on significative etait plus grande chez les races geantes, augmentait avec l'age et etait plus grande chez les males que chez les femelles.
VorhofHinunern bei Hunden (Bohn et a/.) Zusammenfassung. Bericht tiber eine Untersuchung tiber das Alter, die Zucht und die Geschlechtsverteilung bei Hunden, bei denen Vorhoffiimmern aufgetreten ist. Ferner wurde untersucht, in welcher Weise dies mit den verschiedenen zugrunde liegenden Herzerkrankungen assoziiert ist, und die prognostische Signifikanz. Klinische H erzerkrankungen waren vorhanden bei 877 der untersuchten 30683 Hunden, und 55 (6,27 prozent) zeigten chronisches Vorhoffiimmern. Dessen Vorkommen war signifikant hoher bei sehr grossen Hunden, vermehrte sich mit dem Alter und trat mehr bei mii.nnlichen als bei weiblichen Hunden auf.
Fibrilacion auricular en perros (Bohnet al.) Resumen. Se presenta un estudio sobre la fibrilaci6n auricular en perros de acuerdo con su edad, raza, sexo, asi como su asociaci6n a diversos tipos de cardiopatias subyacentes y su significado pron6stico. Sintomas clinicos de enfermedad cardiaca se encontraron en 877 perros de los 30663 examinados, de los cuales 55 (6,27 por ciento) presentaban fibrilaci6n auricular. La prevalencia, que fue significativamente mayor en las razas gigantes, aument6 con la edad y fue mayor en los machos que en las hembras.