Moderate hypothermia in the management of resistant automatic tachycardias in children.

Balaji, Seshadri; Sullivan, Ian D.; Deanfield, John; James, Ian

doi:10.1136/hrt.66.3.221

Cited by 68 publications

(29 citation statements)

References 11 publications

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“…Others have found that hypothermia may slow the automaticity of cardiac pacemaker cells, resulting in slower HRs and improved hemodynamics in some patients with automatic tachycardias. 7 These studies suggest electrophysiological mechanisms by which there was less refibrillation in our hypothermic animals.…”

Section: Discussionmentioning

confidence: 88%

“…[1][2][3] Animal studies in which brain injury models were used have demonstrated decreased ischemic cellular injury, decreased brain infarct size, and improved functional status from neurological damage in those animals receiving hypothermic treatment; clinical studies have shown that this is feasible and safe. [2][3][4][5][6] Induced hypothermia has also been advocated for various cardiac conditions, including treatment of refractory arrhythmias 7 and attempts to decrease myocardial infarct size in patients undergoing primary angioplasty for acute myocardial infarction. 8 Induced hypothermia during cardiac surgery has been used successfully to protect the brain from global ischemia since the 1950s.…”

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confidence: 99%

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Hypothermia Improves Defibrillation Success and Resuscitation Outcomes From Ventricular Fibrillation

et al. 2005

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Background-Induced hypothermia is recommended to improve neurological outcomes in unconscious survivors of out-of-hospital ventricular fibrillation (VF) cardiac arrest. Patients resuscitated from a VF arrest are at risk of refibrillation, but there are few data on the effects of already existing hypothermia on defibrillation and resuscitation. Methods and Results-Thirty-two swine (meanϮSE weight, 23.0Ϯ0.6 kg) were divided into 4 groups: normothermia (nϭ8), mild hypothermia (35°C) (nϭ8), moderate hypothermia (33°C) (nϭ8), and severe hypothermia (30°C) (nϭ8). Hypothermia was induced by surrounding the animal with ice, and VF was electrically induced. After 8 minutes of unsupported VF (no CPR), the swine were defibrillated (biphasic waveform) with successive shocks as needed and underwent CPR until resumption of spontaneous circulation or no response (Ն10 minutes). First-shock defibrillation success was higher in the moderate hypothermia group (6 of 8 hypothermia versus 1 of 8 normothermia; Pϭ0.04). The number of shocks needed for late defibrillation (Ն1 minute after initial shock) was less in all 3 hypothermia groups compared with normothermia (all PϽ0.05). None of the 8 animals in the normothermia group achieved resumption of spontaneous circulation compared with 3 of 8 mild hypothermia (PϭNS), 7 of 8 moderate hypothermia (Pϭ0.001), and 5 of 8 severe hypothermia (Pϭ0.03) animals. Coronary perfusion pressure during CPR was not different between the groups. Conclusions-When VF was induced in the setting of moderate or severe hypothermia, resuscitative measures were facilitated with significantly improved defibrillation success and resuscitation outcome. The beneficial effect of hypothermia was not due to alteration of coronary perfusion pressure, which suggests that changes in the mechanical, metabolic, or electrophysiological properties of the myocardium may be responsible.

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Section: Discussionmentioning

confidence: 88%

mentioning

confidence: 99%

Hypothermia Improves Defibrillation Success and Resuscitation Outcomes From Ventricular Fibrillation

et al. 2005

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“…Profound hypothermia with circulatory arrest is increasingly used as an adjunct to non-cardiac surgical procedures to facilitate operative exposure and repair (Swain et al 1990). Hypothermia reduces the automaticity of cardiac pacemaker cells and is therefore valuable in the treatment of tachycardia in children (Balaji et al 1991). Bailes et al (1991) have demonstrated the possibility of achieving successfully complete exsanguination, blood substitution and ultra-profound body temperature, while continuous circulation of the blood substitute is maintained.…”

Section: Introductionmentioning

confidence: 98%

“…Blood pH during hypothermia profoundly affects the heart (McConnell et al 1975;Swain et al 1984) and other organs (Norwood et al 1979). Hypothermia is known to reduce cardiac output (Wilford et al 1986) and increase systemic vascular resistance (Balaji et al 1991;Swain et al 1990). The oxygen demand is also reduced such that the oxygen supply balance is unaffected, provided the shivering response to hypothermia has been abolished by the use of paralysis and artificial ventilation (Balaji et al 1991).…”

Section: Introductionmentioning

confidence: 99%

Detrimental effect of hypothermia during acute normovolaemic haemodilution in anaesthetized cats

Talwar

Fahim

1998

International Journal of Biometeorology

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Haemodynamic responses to hypothermia were studied at normal haematocrit and following the induction of acute normovolaemic haemodilution. Experiments were performed on 20 cats anaesthetized with a mixture of chloralose and urethane in two groups. In one group (n = 10) the effects of hypothermia on various haemodynamic variables were studied at normal haematocrit (41.0 +/- 1.7%) and in the second group of cats (n = 10) the effects of hypothermia on various haemodynamic variables were studied after the induction of acute normovolaemic haemodilution (14.0 +/- 1.0%). The haemodynamic variables left ventricular pressure, left ventricular contractility, arterial blood pressure, heart rate and right atrial pressure were recorded on a polygraph. Cardiac output was measured using a cardiac output computer. In both groups hypothermia was induced by surface cooling with the help of ice. Cardiovascular variables were recorded at each 1 degree C fall in body temperature. Hypothermia produced a significant (P < 0.05) drop in heart rate, cardiac output, arterial blood pressure and left ventricular contractility in both groups. However, the percentage decrease in these variables in response to hypothermia was significantly (P < 0.05) higher in cats with low haematocrit than in those with normal haematocrit. The severity of hypothermia--induced cardiovascular effects is evident from the drastic decrease in heart rate, cardiac output, arterial blood pressure and myocardial contractility in cats with low haematocrit, indicating a higher risk of circulatory failure under anaemic conditions at low temperatures.

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“…Intensive care characteristically includes surface cooling, atrial pacing, and antiarrhythmic rate-control therapy (3,6). Although catecholamines may worsen the tachyarrhythmia, such inotropes are commonly used to support the circulation.…”

Section: Introductionmentioning

confidence: 99%

Cardiopulmonary Bypass Surgery in Children - Minimizing the Incidence of Postoperative Junctional Ectopic Tachycardia after Surgical Technique Modification

Azhar¹,

Arabia²

2012

Am. J. Biomed. Sci.

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Background: Mechanical injury to tissues in and surrounding the Atrioventricular node is considered a major factor in the aetiology of postoperative Junctional Ectopic Tachycardia (JET).Objectives: The study aims to evaluate the effect of retractor modification used during cardiopulmonary bypass surgery and the incidence of postoperative JET in children.Material & Methods: The study involves retrospective chart review of all pediatric patients who had undergone cardiopulmonary bypass surgery in Children Hospital of Eastern Ontario, Canada, between 1993 and 1996. Patients treated between 1993 to 1994 with wide eyelid retractor (depth 23mm; width 18 mm) were classified as Group A, and the patients treated with narrow retractor (depth 10 mm; width 8 mm) between 1995 to 1996 were classified as Group B, respectively.Results: Of the study subjects, Group A had 209 while Group B had 186 subjects. The age and weight of group A subjects was "mean ± standard deviation" (4.4±4.1 year and 17±12 kg), while that of Group B was (4.7±4.7 year and 20±15 kg). The overall incidence of postoperative JET and mortality was lower in Group B than Group A (2% vs. 10%; p=0.0008; 0% vs. 21%; p<0.05, respectively).Conclusion: A decrease in the incidence of JET and mortality was noticed after the use of narrow retractor.

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Moderate hypothermia in the management of resistant automatic tachycardias in children.

Abstract: Background-Automatic focus tachy-

Cited by 68 publications

References 11 publications

Hypothermia Improves Defibrillation Success and Resuscitation Outcomes From Ventricular Fibrillation

Hypothermia Improves Defibrillation Success and Resuscitation Outcomes From Ventricular Fibrillation

Detrimental effect of hypothermia during acute normovolaemic haemodilution in anaesthetized cats

Cardiopulmonary Bypass Surgery in Children - Minimizing the Incidence of Postoperative Junctional Ectopic Tachycardia after Surgical Technique Modification

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