Ventricular tachycardia case studies

Cardiovascular Effects. In one case study, a woman who had accidentally consumed about 20 mL of trichloroethylene was reported to have suffered a myocardial infarction within 2 hours of ingestion (Morreale 1976). In two other case studies, men who ingested 350 and 500 mL of trichloroethylene had ventricular arrhythmias that persisted for up to 3 days (Dhuner et al. 1957). The arrhythmias were described as ventricular tachycardia with extrasystoles from different ventricular foci. Cardiac arrhythmia was also reported in a women who drank an unknown amount of trichloroethylene (Perbellini et al. 1991). 

In a prospective study of 187 episodes of tachycardia in 127 unselected patients adenosine was given in an average dose of 9.7 mg (28). In 108 cases, adenosine induced transient ventricular extra beats or non-sustained ventricular tachycardia after successful termination of supraventricular tachycardia more than half had a right bundle branch block morphology that suggested that the dysrhythmias had originated from the inferior left ventricular septum. 

The incidence of major adverse reactions to dipyridamole was determined in a multicenter retrospective study, involving 73 806 patients who underwent intravenous dipjridamole stress imaging in 59 hospitals and 19 countries (4). The main conclusion was that the risk of serious dipjridamole-induced adverse effects is very low, a conclusion that is in line with other reports (5), and comparable to that reported for exercise testing in a similar patient population. Combined major adverse events among the entire patient population included 7 cardiac deaths (0.95 per 10000), 13 non-fatal myocardial infarctions (1.76 per 10000), 6 non-fatal sustained ventricular dysrhythmias (0.81 per 10000) (ventricular tachycardia in 2 and ventricular fibrillation in 4), 9 transient cerebral ischemic attacks (1.22 per 10000), 1 stroke, and 9 severe cases of bronch-ospasm (1.22 per 10000). Minor non-cardiac adverse effects were less frequent among the elderly and more frequent in women and patients taking maintenance aspirin. 

In a retrospective view of 63 patients who received intravenous milrinone for more than 24 hours for advanced cardiac failure, the mean dose was 0.43 micro-gram/kg/minute and the mean duration of therapy 12 (range 1-70) days (14). After 24 hours of therapy there was significant improvement in pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac index. Because of the nature of the study, which was not placebo-controlled, it is impossible to be sure what events could have been attributed to the milrinone. However, the authors reported five cases of asymptomatic, non-sustained ventricular tachycardia, six of symptomatic ventricular tachycardia, and three deaths, one in ventricular tachycardia and two in heart failure. There was no difference in the incidence of these adverse events in patients who received milrinone for more than 7 days compared with the others. 

Truppmann and Ellenby routinely used cardiac monitoring when doing phenol peels, and detected many arrhythmias. In 1979, they published the results of a study on 48 patients treated with phenol peels. Saponified and non-saponified Baker or Litton formulas were studied. They report that 23% of patients treated with phenol showed arrhythmia, on average 17.5 minutes after the phenol was first applied. These arrhythmias were often premature ventricular (Figure 28.3) or supraventricular contractions, bigeminy, or supraventricular (Figure 28.2) or ventricular tachycardias (Figure 28.7). Tachycardia, which in extreme cases can sometimes reach 220—230 beats per minute, can turn into ventricular fibrillation and lead to cardiac arrest. 

Underdetection Ventricular tachycardia will not be detected in some cases, even in the presence of adequate sensing. One troublesome cause of underdetection is slow ventricular tachycardia with rates that are lower than the programmed tachycardia detection rate. Patients who receive concomitant antiarrhythmic drugs may be predisposed to this problem owing to slowing of ventricular tachycardia. In one study, 8% of patients who received ICDs developed ventricular tachycardia with rates that had significant overlap with spontaneous sinus rates (89). Similarly, irregularity of the tachycardia, which causes sensed rates to straddle two zones (between sinus rhythm and ventricular tachycardia or between ventricular tachycardia and ventricular fibrillation). 

Cardiovascular Chronic aluminium exposure associated with cardiotoxic manifestations is rather rarely reported. A recent case study reported Mobitz type I second-degree atrioventricular block and nonsustained ventricular tachycardia (VT) following chronic occupational aluminium exposure [4 ]. 

The most frequent cardiovascular effects of an acute overdose are tachycardia and hypotension. The hypotension is partially related to a relative volume depletion, but correction does not bring complete resolution. Even though radionuclide and catheterization studies have shown that TCAs do not impair LVF, either at therapeutic plasma levels or with overdose, data are not available for victims who died. One study describes two cases of fatal overdose in which ventricular pacing produced regular ventricular depolarization but minimal cardiac output, suggesting that at very high concentrations, TCAs might directly impair the myocardium (as demonstrated in animal studies) (429). 

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