Electrocardiographic changes during therapeutic hypothermia: observational data from a single centre

Background

Therapeutic hypothermia is recommended to reduce the risk of hypoxic brain damage and improve short-term survival after cardiac arrest. It also temporarily affects the cardiac conduction system. The aim of this study was to evaluate electrocardiographic changes during therapeutic hypothermia and their impact on the outcome.

Materials and methods

This retrospective analysis involved 26 patients who underwent therapeutic hypothermia after cardiac arrest in Vilnius University Hospital Santaros Klinikos from 2011 to 2015.

Results

During cooling, a significant reduction in the heart rate (p = 0.013), shortening of QRS complex duration (p = 0.041), and prolongation of the QTc interval (p < 0.001) were observed. During the cooling period, five patients had subtle Osborn waves, which disappeared after rewarming. The association between electrocardiographic changes during cooling and unfavourable neurological outcome or in-hospital mortality was non-significant.

Conclusions

Therapeutic hypothermia after cardiac arrest causes reversible electrocardiographic changes that do not increase the risk of in-hospital mortality or unfavourable neurological outcomes.

Osborn Wave Is Related to Ventricular Fibrillation and Tachycardia in Hypothermic Patients

BACKGROUND

The Osborn wave (OW) is often observed in hypothermic patients; however, whether OW in hypothermic patients is related to the development of fatal ventricular arrhythmia, including ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT), remains undetermined. This study aimed to estimate the association between OW and the incidence of fatal ventricular arrhythmias.Methods and Results: This retrospective study used the Japanese Accidental Hypothermia Network registry database and included 572 hypothermic patients. Patients were divided into the OW group (those with OW) and non-OW group (those without OW). The relationship between the development of fatal arrhythmias and presence of OW was assessed using the chi-squared test. All patients who developed VF/VT (n=10) had OW on electrocardiogram upon hospital arrival. The presence of OW had a sensitivity of 100%, specificity of 47.8%, positive predictive value of 4.0%, and negative predictive value of 100% for VF/VT development. The in-hospital mortality rate was 22.3% in the OW group and 21.2% in the non-OW group (P=0.781).

CONCLUSIONS

OW was observed in all hypothermic patients with VF/VT. The occurrence of ventricular arrhythmias is highly unlikely in the absence of OW on the electrocardiogram. Although the presence of OW might be used to predict these fatal arrhythmias in hypothermic patients, there was no association between the presence of OW and in-hospital mortality.

Hypothermia and targeted temperature management in cats and dogs

OBJECTIVE

To review current knowledge surrounding the effects, treatment, and prognosis of hypothermia in people, dogs, and cats, as well as the application of therapeutic hypothermia in clinical medicine.

ETIOLOGY

Hypothermia may be a primary or secondary condition, and may be due to environmental exposure, illness, medications, anesthesia, or trauma. Hypothermia has been applied therapeutically in human medicine for a variety of conditions, including postcardiac arrest. In veterinary medicine, the technique has been applied in cardiac surgeries requiring bypass and in a patient with intractable seizures.

DIAGNOSIS

Hypothermia can be diagnosed based on presenting temperature or clinical signs, and appropriate diagnosis may require nontraditional thermometers.

THERAPY

Rewarming is the primary treatment for accidental hypothermia, with intensity ranging from passive surface rewarming to extracorporeal rewarming. The goal is to return the core temperature to a level that restores normal physiologic function of all body processes. Other supportive therapies such as intravenous fluids are typically indicated, and if cardiopulmonary arrest is present, prolonged resuscitation may be required. In cases of secondary hypothermia, reversal of the underlying cause is important.

PROGNOSIS

There are few prognostic indicators in human and veterinary patients with hypothermia. Even the most severely affected individuals, including those presenting in cardiopulmonary arrest, have potential for complete recovery with appropriate therapy. Therapeutic hypothermia has been shown to improve outcome in people following cardiac arrest. Further studies are needed to examine this application in veterinary medicine, as well as appropriate therapy and prognosis for cases of spontaneous hypothermia.

Vasospastic angina with J waves formation in patients with sudden loss of consciousness

Vasospastic angina is caused by sudden occlusive vasoconstriction of a segment of an epicardial artery, which can present with a wide spectrum of clinical scenario. We report the cases of two patients diagnosed with vasospastic angina, with one of which presenting with sudden cardiac arrest, while the other presenting with a relatively benign syncope. But both of them have J waves formation on ECG during active ischemia. The diagnosis and management of vasospastic angina, as well as the proposed clinical significance of J waves during coronary spasm are discussed.

Psychotropic drug-associated electrocardiographic presentation of diffuse J-waves in hypothermia: case report and literature review

The use of psychotropic drugs is often associated with electrocardiographic (ECG) QT-interval prolongation, but there are few reports of J-waves. This report describes the case of a schizophrenic patient under treatment with several psychotropic drugs (olanzapine, valproate, and flunitrazepam), in whom ECG J-waves diffusely appeared during a hypothermic episode. We further performed a literature review of psychotropic drug-related J-waves in hypothermia. The present case highlights the importance of recognizing psychotropic drug-related ECG J-waves on an early warning sign to ensure appropriate monitoring and/or treatment for possible life-threatening side effects of such medications.

Dynamic J-Point Elevation Associated with Epileptic Hemiplegia: The Osborn Wave of Todd's Paralysis

THIS CASE REPORT EXPOSES A PHENOMENON WHICH, ALTHOUGH PROPOSED, HAS NOT BEEN DESCRIBED IN CLINICAL LITERATURE: transient postictal hemiplegia (Todd's paralysis) with concomitant electrocardiographic J-point deflection (Osborn waves). Although typically associated with hypothermia, a prominent J-wave on the electrocardiogram (ECG) results from a transmyocardial voltage gradient during ventricular repolarization. Rarely, the Osborn wave may be observed in a non-hypothermic setting such as hypercalcemia or cerebral hemorrhage. Transient postictal hemiplegia has been attributed to localized cerebral hypoperfusion resulting from motor cortex exhaustion following an epileptic seizure. The same central nervous system autonomic dysfunction has been theorized to produce subendocardial hypoperfusion with electrocardiographic change and cardiac troponin T elevation. This is the first described ECG evidence of a dynamically displaced J-point in the setting of postictal hemiplegia.