Page 452 - Clinical Small Animal Internal Medicine

420 Section 5 Critical Care Medicine

pacing is begun. Once pacing has begun, the voltage of bypass, significantly limiting its availability in veterinary
VetBooks.ir the pacing leads is gradually increased until they are medicine at this time.
“captured” by the heart. Evaluation of ECG, pulse oxime-
try or digital palpation of the pulses can be used to verify
capture. Transcutaneous pacing is always a stopgap Prognosis
measure to allow time for the placement of either a tem-
porary transvenous pacing mechanism or a permanent Published mortality rates for cardiogenic shock in veteri-
pacemaker and should not be considered if these options nary patients are lacking, but many human studies report
are not available. mortality rates of 50–80%. In most instances, the devel-
Management of caval syndrome secondary to heart- opment of cardiogenic shock is a sequela to a severe
worm infection often requires direct removal of the underlying structural or progressive conductive disease.
worms from the right heart. The use of a transvenous Therefore, both the short‐ and long‐term prognosis
approach has been well described and, provided the dog should be considered guarded to poor. Patients that
survives the perioperative period, appears to be very recover from cardiogenic shock are usually left with resid-
effective for management of acute caval syndrome. ual cardiac dysfunction that is irreversible in nature. The
Surgical management is also the best treatment for well‐ exception to this may be dogs that are treated for caval
defined intracardiac tumors. Unfortunately, open‐heart syndrome secondary to canine heartworm disease and
surgery requires total venous inflow occlusion or cardiac animals receiving a pacemaker for bradyarrhythmias.

Further Reading

Bonagura JD, Schober KE. Can ventricular function be outcome in 146 cats. J Vet Intern Med 2007; 21:
assessed by echocardiography in chronic canine mitral 1002–7.
valve disease? J Small Anim Pract 2009; 50(Suppl. 1): Humm KR, Keenaghan‐Clark EA, Boag AK. Adverse
12–24. events associated with pericardiocentesis in dogs: 85
Bove CM, Gordon SG, Saunders AB, et al. Outcome of cases (1999–2006). J Vet Emerg Crit Care 2009; 19(4):
minimally invasive surgical treatment of heartworm 352–6.
caval syndrome in dogs: 42 cases (1999–2007). J Am Pedro B, Lopez‐Alvarez J, Fonfara S, et al. Retrospective
Vet Med Assoc 2010; 236(2): 187–92. evaluation of the use of amiodarone in dogs with
Brown AJ, Davison E, Sleeper MM. Clinical efficacy of arrhythmias from 2003 to 2010. J Small Anim Pract
sildenafil in treatment of pulmonary arterial hypertension 2012; 53: 19–26.
in dogs. J Vet Intern Med 2010; 24: 850–4. Yoon WK, Choi R, Lee SG, et al. Comparison of 2 retrieval
Hall DJ, Shofer J, Meier CK, et al. Pericardial effusion in devices for heartworm removal in 52 dogs with heavy
cats: a retrospective study of clinical findings and worm burden. J Vet Intern Med 2013; 27: 469–73.