Effects of chronic, rapid right atrial pacing on cardiac hemodynamics and myofibrillar ATPase activity in piglets

Niels G. Giddins, Kim F Duncan, Rabindranath Persad, James S.C. Gilchrist, Grant N. Pierce

Research output: Contribution to journalArticle

Abstract

Objectives: To determine whether chronic, rapid right atrial pacing in newborn neonatal piglets has any effects on cardiac hemodynamics, and whether these changes are associated with intrinsic alterations in cardiac contractile potential as shown by cardiac myofibrillar calcium ATPase activity. Background: Although many studies have examined aspects of heart function in models of supraventricular tachycardia, far less is known about its effects in neonatal animals. It is thought that rapid pacing induces a dilated cardiomyopathy in immature pigs. Animals and methods: Two-week-old piglets underwent rapid right atrial pacing (250 beats/min) for 10 days, and their cardiac hemodynamic response was monitored. To obtain subcellular mechanistic information regarding systolic dysfunction, cardiac myofibrils were isolated and calcium adenosine triphosphatase activity was measured. Results: Control piglets had a heart rate of 185 beats/min at the end of the experimental period. Pulmonary artery flow, pulmonary artery flow index and left ventricular end-diastolic diameter were unchanged as a function of rapid, chronic right atrial pacing. Aortic pressure decreased in the paced piglets. Left atrial pressure increased approximately threefold in the paced animals. Left ventricular end-systolic diameter was also significantly higher after pacing, but left ventricular end-diastolic diameter was unchaged. Left ventricular shortening fraction was depressed approximately 50%. Myofibrillar calcium adenosine triphosphatase activity was significantly depressed as a function of pacing. Conclusions: Neonatal piglets undergoing chronic supraventricular tachycardia exhibit systolic dysfunction in the absence of dilation. The depression in contractile protein calcium adenosine triphosphatase activity provides information at a subcellular level regarding the mechanism responsible for this cardiomyopathy.

Original languageEnglish (US)
Pages (from-to)157-161
Number of pages5
JournalCanadian Journal of Cardiology
Volume18
Issue number2
StatePublished - Apr 29 2002

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Calcium-Transporting ATPases
Adenosine Triphosphatases
Hemodynamics
Supraventricular Tachycardia
Pulmonary Artery
Newborn Animals
Contractile Proteins
Atrial Pressure
Myofibrils
Dilated Cardiomyopathy
Cardiomyopathies
Dilatation
Arterial Pressure
Swine
Heart Rate

Keywords

  • Atria
  • Pacing
  • Proteins
  • Tachycardia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Effects of chronic, rapid right atrial pacing on cardiac hemodynamics and myofibrillar ATPase activity in piglets. / Giddins, Niels G.; Duncan, Kim F; Persad, Rabindranath; Gilchrist, James S.C.; Pierce, Grant N.

In: Canadian Journal of Cardiology, Vol. 18, No. 2, 29.04.2002, p. 157-161.

Research output: Contribution to journalArticle

Giddins, Niels G. ; Duncan, Kim F ; Persad, Rabindranath ; Gilchrist, James S.C. ; Pierce, Grant N. / Effects of chronic, rapid right atrial pacing on cardiac hemodynamics and myofibrillar ATPase activity in piglets. In: Canadian Journal of Cardiology. 2002 ; Vol. 18, No. 2. pp. 157-161.
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