Arrhythmias malignant ventricular

Garberoglio, L., Giustetto, C., Wolpert, C. and Gaita, F. (2007) Is acquired short QT due to digitalis intoxication responsible for malignant ventricular arrhythmias Journal of Electrocardiology, 40, 43—46. 

As conduction times are prolonged, the chance of developing reentry arrhythmias grows. Malignant ventricular arrhythmias are uncommon in mild or moderate overdoses, but they are more likely in severe cases. 

Administration of arsenite in cancer chemotherapy regimens, often at a daily dose of 10-20 mg for weeks to a few months, has been associated with prolongation of the QT interval on the electrocardiogram and occasionally has resulted in malignant ventricular arrhythmias such as torsade de pointes. 

A 10-year-old child had status epilepticus controlled with a combination of valproate, oxcarbazepine, and 48 hours of propofol infusion in a dose of 5.5 mg/kg/ hour. After weaning from propofol, a classic ketogenic diet was instituted in an attempt to provide long-term control of the seizures. A day later status epilepticus recurred and propofol was restarted at a rate of 6-9 mg/ kg/hour to suppress seizure activity (the diet, valproate, and oxcarbazepine were also continued). Shortly thereafter, he developed the classical constellation of malignant ventricular arrhythmias, hyperlipidemia, rhabdomyolysis, lactic acidosis, and biventricular cardiac failure. He did not survive. 

Hypokalemia results in decreased T-wave amplitude and ST-segment depression however, accurate QT interval measiuement is difficult. Malignant ventricular arrhythmias result when potassium concentrations become very low. Hypercalcemia shortens the QT interval while hypocalcemia produces ST-segment prolongation. 

Mohiuddin SM, Esterbrooks D, Mooss AN, Dahl JM, Hilleman DE. Efficacy and tolerance of tocainide during long-term treatment of malignant ventricular arrhythmias. Clin Cardiol 1987 10(8) 457-62. 

Phenothiazines Sertraline may inhibit metabolism of thioridazine or mesoridazine, potentially leasing to malignant ventricular arrhythmias. 

Domanski MJ, Sakseena S, Epstein AF, et al. Relative effectiveness of the implantable cardioverter-defibrillator and antiarrhythmic drugs in patients with varying degrees of left ventricular dysfunction who have survived malignant ventricular arrhythmias. AVID investigators. Antiarrhythmics Versus Implantable Defibrillators. J Am Coll Cardiol 1999 34(4) 1090-5. 

MirowskiM, Reid PR, Mower MM etal( 1980) Termination of malignant ventricular arrhythmias with an implanted automatic defibrillator in human beings. N Engl J Med 303(6) 322-324... 

Statins may lower mortality in heart failure patients independent of any effects on coronary artery disease. This has been shown through SCD-HeFT data. Statins can also reduce appropriate ICD discharge in few studies including MADIT II post hoc subanalysis (92,115). To date, no randomized controlled trial has evaluated the influence of statins on malignant ventricular arrhythmias or cardiac death independent of the effect on coronary artery disease. 

Biasucci, L.M., et ah, C reactive protein is associated with malignant ventricular arrhythmias in patients with ischaemia with implantable cardioverter-defibrillator. Heart, 2006. 92(8) p. 1147-8. 

Although rate is the primary method that ICDs use to detect malignant ventricular arrhythmias, other arrhythmias, such as atrial fibrillation, atrial flutter, or sinus tachycardia may be associated with ventricular rates that would fall within the rate-detection criteria. Manufacturers have developed additional... 

Hypercalcemia of malignancy develops quickly and is associated with anorexia, nausea and vomiting, constipation, polyuria, polydipsia, and nocturia. Hypercalcemic crisis is characterized by acute elevation of serum calcium to greater than 15 mg/dL, acute renal failure, and obtundation. Untreated hypercalcemic crisis can progress to oliguric renal failure, coma, and life-threatening ventricular arrhythmias. 

Halothane has the highest blood/gas partition coefficient of the volatile anaesthetic agents and recovery from halothane anaesthesia is comparatively slow. It is pleasant to breathe and is second choice to sevoflurane for inhalational induction of anaesthesia. Halothane reduces cardiac output more than any of the other volatile anaesthetics. It sensitises the heart to the arrhythmic effects of catecholamines and hypercapnia arrhythmias are common, in particular atrioventricular dissociation, nodal rhythm and ventricular extrasystoles. Halothane can trigger malignant hyperthermia in those who are genetically predisposed (see p. 363). 

Billman, G.E., 1993. The effect of adrenergic receptor antagonists on cocaine-induced ventricular fibrillation alpha but not beta adrenergic receptor antagonists prevent malignant arrhythmias independent of heart rate. J. Pharmacol. Exp. Ther. 269, 409-416. 

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