T-wave abnormalities

Time to incapacitation for the 100, 102, 123, 147, and 156 ppm concentrations were 19, 16, 15, 8, and 8 min, respectively the relationship between exposure and time to incapacitation was linear. During exposures, effects consisted of hyperventilation (within 30 s), loss of consciousness, and bradycardia with arrhythmias and T-wave abnormalities recoveries were rapid after exposure. The animal inhaling 147 ppm stopped breathing after 27 min and required resuscitation. Two additional exposures were terminated prior to the end of the 30 min due to severe signs. Animals rapidly recovered and were active during the first 10 min after exposure even though blood cyanide remained at levels that initially caused incapacitation. Purser (1984) states that the hyperventilatory response followed by incapacitation occurs at >80 ppm, but neither paper (Purser 1984 Purser et al. 1984) provides the experimental data for the 80 ppm concentration. At 180 ppm, hyperventilation occured almost immediately, and at 90 ppm the response was delayed for 20 min. 

Bradycardia, arrhythmias, and T-wave abnormalities were observed in monkeys exposed to 100 ppm hydrogen cyanide (96 ppm cyanide) for 30 minutes (Purser et al. 1984). Increased cardiac-specific creatinine phosphokinase activity was measured in blood samples from rats 2 hours after 12.5 minutes of exposure to 200 ppm hydrogen cyanide (192 ppm cyanide) for 20 days at 4-day intervals (O Flaherty and Thomas 1982). However, no treatment-related changes were found in the hearts at histopathology. In addition, no cardiovascular effects were reported at necropsy in rats and monkeys exposed to 25 ppm cyanogen (50 ppm cyanide) for 6 months (Lewis et al. 1984). 

Acute inhalation of hydrogen cyanide resulted in bradycardia, arrhythmia, and T-wave abnormalities (Purser et al. 1984), and increased cardiac-specific creatinine phosphokinase activity (O Flaherty and... 

J hr postexposure Neurologic paresthesias, reversal of hot and cold sensation, pain, weakness 2-5 days postexposure Cardiovascular bradycardia, hypotension, increase in T wave abnormalities... 

At 72 hours after presentation, the patient experienced new-onset chest pain, described as a burning pain in the left shoulder, arm, and epigastrium. The electrocardiogram (ECG) demonstrated only nonspecific T-wave abnormalities and was not different from the one obtained at the time of her initial presentation. Normal sinus rhythm was now present. Nitroglycerin provided some relief. Based on new symptoms, along with recurring T-wave abnormalities and... 

There was no association of lithium with QTC prolongation but it was associated with nonspecific T-wave abnormalities (odds ratio 1.9) and increased QT dispersion (odds ratio 2.9). Caution was suggested if lithium is used with drugs associated with QTC prolongation, such as tricyclic antidepressants, droperidol, and thioridazine. 

Peaked T waves from hyperkalemia may be seen 0 Nonspeeifie ST segment and T wave abnormalities have been reported... 

OPs cause QT prolongation on the ECG that subsequently can degenerate into TdP. In one reported OP case, 79.7% had QT prolongations with ST segment and T wave abnormalities (Karki et al, 2004 Rubinshtein et al, 2002 Saadeh, 2001 Saadeh et al, 1997). Changes are ultimately expressed in arrhythmia, ventricular fibrillation and TdP, and severe disturbance of the energy homeostasis of the heart. 

CHAPTER 3 Electrocardiographic pattern of ischaemia T-wave abnormalities 31... 

The isolated presence of minor T-wave abnormalities has been considered a potential risk marker for future cardiovascular events. This includes, among others, the following ... 

Prineas RJ, Grandits G, Rautaharju PM et al. Long-term prognostic significance of isolated minor electrocardiographic T-wave abnormalities in middle-aged men free of clinical cardiovascular disease (The Multiple Risk Factor Intervention Trial [MRFIT]). Am J Cardiol 2002 90 1391. 

Rate - slow relative to temperature (relative bradycardia) ST-T waves - abnormal, NS... 

ST segment - depressed ST-T wave - abnormality, NS Tachycardia - bidirectional... 

Electrocardiogram ST-segment and T-wave abnormalities ST-segment and T-wave abnormalities Left ventricular hypertrophy Low voltage, conduction defects... 

Doses of chloroquine used for oral therapy of the acute malarial attack may cause GI upset, headache, visual disturbances, and urticaria. Pruritus also occurs, most commonly among dark-skinned persons. Prolonged medication with suppressive doses occasionally causes side effects such as headache, blurring of vision, diplopia, confusion, convulsions, lichenoid skin eruptions, bleaching of hair, widening of the QRS interval, and T-wave abnormalities. These complications usually disappear soon rffter the drug is withheld. Rare instances of hemolysis and blood dyscrasias have been reported. Chloroquine may cause discoloration of nail beds and mucous membranes. 

A 27-year-old schizophrenic woman who was taking thioridazine 100 mg daily and procyclidine 2.5 mg twice daily was found dead in bed 2 hours after taking a single capsule of Contac C (phenylpropanolamine 50 mg with chlorphenamine 4 mg). The principal cause of death was attributed to ventricular fibrillation. Just why this happened is not understood but it is suggested that it may have been due to the combined effects of the thioridazine (known to be cardiotoxic and to cause T-wave abnormalities) and the phenylpropanolamine (possibly able to cause ventricular arrhythmias). 

Chronic ipecac abuse by anorexic or bulimic individuals has been associated with cardiac toxicity characterized by PR prolongation, T-wave abnormalities, QRS abnormalities, congestive cardiomyopathy, and atrial and ventricular dysrhythmia. Generalized muscle weakness, myopathy, diarrhea, mild tremors, edema, dehydration, metabolic disturbances (hypokalemia, hypochloremic acidosis, elevation of creatinine phosphokinase), shock, and death have also been reported after chronic use (Manno and Manno 1977 Quang and Woolf 2000). 

RVH with associated ST-T wave abnormalities (strain), and right axis deviation. ECG taken from a 32 year old fonale with congenital pulmonary stenosis... 

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