Ventricular tachycardia and fibrillation

Cardiovascular effects Several instances of hypotension, hypertension, pulmonary edema, and ventricular tachycardia and fibrillation have been reported in postoperative patients. 

Cardiotoxicity may occur if ipecac syrup is not vomited (noted as hypotension, tachycardia, precordial chest pain, pulmonary congestion, dyspnea, ventricular tachycardia and fibrillation, cardiacarrest). 

Pat ients with cardiovascular disease may experience hypotension or hypertension, ventricular tachycardia and fibrillation, and pulmonary edema. 

Cerrone, M., Colombi, B., Santoro, M., di Barletta, M. R., Scelsi, M., Villani, L., Napolitano, C., and Priori, S. G. (2005). Bidirectional Ventricular Tachycardia and Fibrillation Elicited in a Knock-in Mouse Model Carrier of a Mutation in the Cardiac Ryanodine Receptor. Circ Res 96(10) e77-82. 

Cardiovascular toxicity is also frequently encountered in poisoning. Hypotension may be due to depression of cardiac contractility hypovolemia resulting from vomiting, diarrhea, or fluid sequestration peripheral vascular collapse due to blockade of -adrenoceptor-mediated vascular tone or cardiac arrhythmias. Hypothermia or hyperthermia due to exposure as well as the temperature-dysregulating effects of many drugs can also produce hypotension. Lethal arrhythmias such as ventricular tachycardia and fibrillation can occur with overdoses of many cardioactive drugs such as ephedrine, amphetamines, cocaine, tricyclic antidepressants, digitalis, and theophylline. 

Digoxin (see p. 158) shortens the refractory period in atrial and ventricular myocardial cells while prolonging the effective refractory period and diminishing conduction velocity in Purkinje fibers. Digoxin is used to control the ventricular response rate in atrial fibrillation and flutter. At toxic concentrations, digoxin causes ectopic ventricular beats that may result in ventricular tachycardia and fibrillation. [Note This arrhythmia is usually treated with lidocaine or phenytoin.]... 

Kowey PR, Marinchak RA, Rials SJ, Bharucha DB. Intravenous antiarrhythmic therapy in the acute control of in-hospital destabilizing ventricular tachycardia and fibrillation. Am J Cardiol 1999 84(9A) R46-51. 

Anderson JL, Popat KD, Pitt B. Paradoxical ventricular tachycardia and fibrillation after intravenous bretyhum therapy. Report of two cases. Arch Intern Med 1981 141(6) 801-2. 

Atrial dysrhythmias (including atrial fibrillation) and less often, ventricular extra beats (including refractory ventricular tachycardia and fibrillation) (11-13). 

Trade names Bretylate Critifib Indications Ventricular tachycardia and fibrillation Category Antiarrhythmic class III Half-life 4-17 hours... 

Disopyramide, proprietary name Norpace, is used for maintenance of sinus rhythm in patients with atrial flutter and atrial fibrillation and for prevention of ventricular tachycardia and fibrillation. The mechanism of action of disopyramide is similar to that of quinidine, and the drug can be used as replacement therapy for quinidine when quinidine side effects are intolerable. 

Electrical conduction in normal myocardium is dependent upon the precise tem -ral orchestration of the gating kinetics of ion channels, which collectively result in the initiation and propagation of an action potential. During myocardial ischemia, the kinetics of ion channel gating are altered, resulting in changes in electrophysi-ological properties which predispose ischemic myocardium to lethal ventricular dysrhythmias, such as ventricular tachycardia and fibrillation. 

Ventricular premature contractions Ventricular premature contractions are ectopi-cally focused from anywhere in the ventricles and are not initiated in the SA node. It is a very common arrhythmia, frequently associated with myocardial infarction. It can be the precursor to potentially fatal ventricular tachycardia and fibrillation. 

Cardiovascular System Following systemic absorption, local anesthetics decrease electrical excitabdity, conduction rate, and force of contraction. Most local anesthetics also cause arteriolar dilation. Untoward cardiovascular effects usually are seen only after high systemic concentrations are attained and effects on the CNS are produced. However, on rare occasions, lower doses of some local anesthetics wUl cause cardiovascular collapse and death, probably due to either an action on the pacemaker or the sudden onset of ventricular fibrillation. Ventricular tachycardia and fibrillation are relatively uncommon consequences of local anesthetics other than bupivacaine. The use of local anesthetics as antiarrhythmic drugs is discussed in Chapter 34. Untoward cardiovascular effects of local anesthetic agents may result from their inadvertent intravascular administration, especially if epinephrine also is present. 

Rhythm abnormalities include sinus tachycardia, sinus bradycardia, extrasystoles, atrial fibrillation, ventricular tachycardia, and fibrillation. Other cardiovascular effects include hypertension, hypotension, and noncardiogenic pulmonary edema. Gastrointestinal manifestations such as nausea, vomiting, diarrhea, and abdominal pain arc the first to occur after OP exposure,... 

Sinus tachycardia accompanied by QRS interval prolongation may resemble ventricular tachycardia (see Figure 1-4, p 12). True ventricular tachycardia and fibrillation may also occur. Atypical or polymorphous ventricular tachycardia (torsade de pointes see Figure 1-7, p 15) associated with QT interval prolongation may occur with therapeutic dosing, but is actually uncommon in overdose. Development of bradyanhythmias usually indicates a severely poisoned heart and carries a poor prognosis. 

C. Acute ingestion may cause gastrointestinal burns, severe vomiting and abdominal pain, and diarrhea with smoking stools. Systemic effects include headache, delirium, shock, seizures, coma, and arrhythmias (atrial fibrillation, QT prolongation, ventricular tachycardia, and fibrillation). Metabolic derangements, including hypocalcemia and hyperphosphatemia (or hypophosphatemia), may occur. Fulminant hepatic or renal failure may occur after 2-3 days. 

The connonest cardiac problems with levodopa therapy are sinus tachycardia and premature ventricular contractions, with rare instances of atrial fibrillation. Cardiac deaths with ventricular tachycardia and fibrillation have been reported but drug causation Is unclear. The cardiac side effects of levodopa can be a serious threat particularly to patients... 

Aubert AE, Denys BG, Ector H, De Geest H. Detection of ventricular tachycardia and fibrillation using ECG processing and intramyocardial pressure gradients. Pacing Clin Electrophysiol 1986 9 1084-8. 

Winkle RA, Bach SM, Jr., Echt DS, Swerdlow CD, Imran M, Mason JW, Oyer PE, Stinson EB. The automatic implantable defibriUaton local ventricular bipolar sensing to detect ventricular tachycardia and fibrillation. Am J Cardiol 1983 52 265-70. 

The original intent of the ICD was to prevent recurrent cardiac arrest due to ventricular tachycardia and fibrillation. Secondary prevention of recurrent cardiac arrest was initially the prime reason for ICD implant. Five multicenter prospective randomized secondary prevention trials have been completed AVID (Antiatrhythmics Versus Implantable Defibrillator), CASH (Cardiac Arrest Study Hamburg), CIDS (Canadian Implantable Defibrillator Study), DEBUT (Defibrillator versus beta-Blockers for Unexplained death in Thailand), and MAVERIC (The Midlands Trial of Empirical Amiodarone versus Electrophysiology-guided Interventions and Implantable (Tardioverter-defibrillators) (Table 14.3) (77,118,121,149,170). 

Linenthal, a. J. and Zoll, P. M., Prevention of ventricular tachycardia and fibrillation by intravenous isoproterenol and epinephrine. Circulation 27, 5 (1963). 

Ifosfamide (261 Da) LV dysfunction, arrhythmia, acute heart failure, pulmonary edema, ventricular tachycardia and fibrillation, ECG changes... 

Cardiovascular Intravenous procainamide had a prodysrhythmic effect when it was given as a single 1000 mg bolus during an electrophysiological study in a patient with myotonic dystrophy type 1 [SO J. During ventricular pacing, ventricular tachycardia and fibrillation occurred and required DC cardioversion. By slowing cardiac conduction, procainamide, as do other sodium channel blockers, worsens abnormalities already present in the hearts of patients with myotonic dystrophy t)q)e 1. 

Cardiovascular An overdose of flecainide may manifest as prolongation of the PR, QRS, and QTc intervals on ECG and the development of bradycardia, premature ventricular complex (PVC), ventricular tachycardia, and fibrillation. The ECG changes observed in flecainide toxicity may resemble Brugada syndrome [24]. 

May have separate detection rates (zones) for ventricular tachycardia and fibrillation. 

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