Variations in heart rate and rhythm of harbor seal pups during rehabilitation

Abstract

Heart rate and rhythm is regulated by the autonomic nervous system, which matures during the first months of life. Little is known about heart rate and rhythm development and potential arrhythmias in seal pups during rehabilitation in seal centers. Using an iPhone ECG device, 1 min ECGs were obtained from harbor seal pups admitted to a seal rehabilitation facility. ECGs were taken from 55 seals after admission, 53 seals after 14 d, and 52 seals prior to release. From 24 seal pups additional ECGs were taken daily for the first week of rehabilitation. At admission sinus rhythm with a median heart rate of 148 complexes per minute was detected, prior to release sinus bradycardia or sinus arrhythmia with a median heart rate of 104 complexes minute was present. P wave morphology was highly variable and single supraand ventricular premature complexes were recorded in individual animals. The first 14 d were characterized by highly variable heart rates and rhythms, including episodes of sinus tachycardia and 2nd degree atrioventricular blocks. The reduction in heart rates and development of a regular heart rhythm during rehabilitation suggest adaptation to the unfamiliar environment, resolution of disease, and/or maturation of the autonomic nervous system. Key words: harbor seal, ECG, arrhythmia, atrioventricular block, autonomic nervous system, tachycardia, heart rhythm.Heart rate and rhythm is primarily regulated by the autonomic nervous system, which consists of the sympathetic and parasympathetic division. These systems have opposing effects; stimulation of the sympathetic nervous system increases the heart rate, whereas activation of the parasympathetic branch reduces the heart rate (Katz 2011a).During diving, marine mammals demonstrate a response with bradycardia, which is modulated by the parasympathetic nervous system, and peripheral vasoconstriction. While surfacing, parasympathetic withdrawal and an increased sympathetic stimulation results in an increased heart rate (Elliott et al. 2002). The diving response, which allows an energy-sparing metabolism and perfusion of central organs, is important 1

Usefulness of serum cardiac troponin I concentration as a marker of survival of harbor seal (Phoca vitulina) pups during rehabilitation

“…10,12 This compromised state and the unfamiliar environment result in an increase in sympathetic tone, which is reflected by sinus tachycardia. 42 Myocardial ischemia and cTnI release are therefore possible. Significant (Friedman test, P < 0.001) differences were identified among measurement points for all serum biochemical analytes except potassium (P = 0.08).…”

Use of AliveCor Heart Monitor for Heart Rate and Rhythm Evaluation in Dairy Water Buffalo Calves (Bubalis Bubalis)

“…In some cases the device is replacing the traditional Holter monitor for ECG monitoring due to its portability and ease of use [4]. There are reports in the literature of the device's use in a wide variety of animals including pigs [5], Harbor Seal pups [6] and a Savanah Monitor [7].…”

Heart Rate Changes Before, During, and After Treadmill Walking Exercise in Normal Dogs

“…Thus, either of these monitors could be used to evaluate the HR during commonly performed therapeutic exercises, such as cavalettis and balance work or during underwater TE (the latter has been performed in our clinic with water at shoulder height with the HOLTER). Although it is possible submersion in the treadmill water could alter measured HR, the HOLTER monitor has already been used to investigate HR in diving seals (46,47), suggesting that submersion in treadmill water would not be an issue.…”

“…A Holter monitor (HOLTER; Dextronix, Sacramento, CA, USA) and a HR monitor (HR MONITOR; Polar USA, Bethpage, NY, USA) were used to assess HR in addition to auscultation with a stethoscope. Both leads and pads of the HOLTER and the HR MONITOR were waterproof, with their electronics completely encased in plastic so water would not interfere with readings (46,47). For HOLTER placement, a 3 × 3 cm area of hair was clipped, and the skin was cleaned with alcohol in three areas, one over the sternum and one each over the ventral left and right thoraces, before each of the three HOLTER ECG pads was applied.…”