Ventricular fibrillation secondary

Nelson MR, SmithD, Erskine D, GazzardBG. Ventricular fibrillation secondary to itraconazole induced hypokalae-mia. J Infect 1993 26(3) 348. 

The indications for implantation of an ICD have expanded considerably (Table 17-7). Initially, its efficacy was evaluated in patients who had already suffered a documented episode of ventricular tachycardia or ventricular fibrillation (secondary prevention), but now primary prevention trials have been published or are being planned. These results will help clinicians in choosing the proper therapy for patients with life-threatening arrhythmias. For instance, the Sudden Cardiac Death in Heart Failure Trial (SCD-Heft) is a primary prevention trial that evaluated survival in patients withLV dysfunction... 

Although quinidine often is successful in producing normal sinus rhythm, its administration in the presence of a rapid atrial rate (flutter and possibly atrial fibrillation) can lead to a further and dangerous increase in the ventricular rate secondary to inhibition of basal vagal tone upon the A-V node. For this reason, digitalis should be used before quinidine when one is attempting to convert atrial flutter or atrial fibrillation to normal sinus rhythm... 

Death after intravenous administration of DMHP in dogs is preceded by ventricular fibrillation, which may be secondary to hypothermia. However, there are no fatalities if the animals rectal temperature is kept from falling. 

Burke TG and Mutnick AH (1993) Ventricular fibrillation and anoxic encephalopathy secondary to astemizole overdose. Annals of Pharmacotherapy 9 23-25. 

In contrast, patients who have ventricular fibrillation associated with acute MI (i.e., during the first 24 hours after symptom appearance) usually have little risk of recurrence. Of all patients who die from an acute MI, approximately 50% die suddenly prior to hospitalization. Ventricular fibrillation associated with acute MI can be subdivided into two types primary ventricular fibrillation and complicated or secondary ventricular fibrillation. Primary ventricular fibrillation occurs in an uncomplicated MI not associated with heart failure secondary ventricular fibrillation occurs in an MI complicated by heart failure. The time course, incidence, mechanisms, treatment, and com-... 

Mobitz type I heart block was reported after ingestion of uncooked pokeweed leaves (Hamilton et al., 1995). Hypotension, bradycardia, tachycardia, and ventricular fibrillation have also been reported after pokeweed consumption (French, 1900 Lewis and Smith, 1979 Jaeckle and Freeman, 1981 Roberge et al., 1986). These cardiovascular effects of pokeweed have been attributed to nonspecific vagal or sympathetic stimulation secondary to gastrointenstinal irritation (Roberge et al., 1986 Hamilton et al., 1995). Of note, however, is the observation that pokeroot evaporated fluid extract administered intravenously to cats produced circulatory depression at a dose of 1 mL, and at 4 mL "paralyzed. .. the heart" (Macht, 1937). 

Although resynchronization is proven to prolong survival compared with standard medical therapy of heart failure, it should be noted that there is no direct evidence that resynchronization therapy improves survival when compared with ICD therapy alone (24). It is also curious to note that the addition of resynchronization did not reduce ICD therapies for ventricular tachy-cardia/ventricular fibrillation in either the CONTAK CD or MIRACLE ICD trials (10,11). It is possible that these observations may reflect the relatively large proportion of secondary prevention patients enrolled in these trials (28), as well as the relatively short duration of follow-up. Indeed, a recent retrospective analysis of the InSync III Marquis trial showed that responders to CRT demonstrated significantly fewer single premature ventricular contractions beats, or PVC runs, and fewer treated episodes of ventricular tachycardia or fibrillation (VT/VF) (P = 0.050) than nonresponders by 6 months of follow-up (29). 

The clinical consequences of significant mitral regurgitation are numerous and include impaired quality of life (particularly with dyspnea and fatigue on exertion), left ventricular enlargement and dysfunction, arrhythmias such as atrial fibrillation, secondary pulmonary hypertension and sudden cardiac death. Concomitant mitral regurgitation can be particularly deleterious in patients with either congestive heart failure or ischemic heart disease (15,16). 

A 47-year-old man with NYHA nf-IV heart failure developed ventricular fibrillation and ventricular tachycardia, which was attributed to torsade de pointes secondary to a combination of dofetiUde and h3rpokalemia. After stabilization he was given dronedarone 400 mg bd. By day 4 he developed a clinical picture consistent with acute renal and hepatic failure, possibly due to worsening heart failure. Dronedarone was withdrawn on day 10 and he was given milrinone for cardiogenic shock. Laboratory markers of renal and hepatic function improved and he was discharged on day 20. 

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). 

Class I Indications for an ICD (1) Survivors of cardiac arrest secondary to ventricular tachycardia and ventricular fibrillation except when due to a reversible cause. (2) Sustained vaitricular tachycardia associated with structural heart disease. (3) Syncope of unclear etiology with an inducible ventricular tachycardia or ventricular fibrillation at electrophysiology study. (4) Nonsustained ventricular tachycardia in patients with coronary artery disease, left ventricular dysfunction, and inducible ventricular tachycardia or fibrillation at electrophysiology study that is not suppressed will by an antiarrhythmic drug. (5) Spontaneous sustained ventricular tachycardia in patients without structural heart disease who are not amenable to medical therapy. 

Horan LG, Hand C, Johnson JC, Sridharan MR, Rankin TB, Flowers NC (1978) A theoretical examination of ventricular repolarization and the secondary T wave. Circ Res 42 750-757 Mandel WJ, Burgess MJ, Neville J, Abildskov JA (1968) Analysis of T waveform abnormalities associated with myocardial infarction using a theoretical model. Circulation 38 178-188 Moe GK, Abildskov JA, Han J (1964) Factors responsible for initiation and maintenance of ventricular fibrillation. In Sudden Cardiac Death , NY Grune Stratton 56-63 Nielsen BL (1973) ST-segment elevation in acute myocardial infarction. Prognostic importance. Circulation 48 338-345... 

Verapamil Severe left ventricular dysfunction cardiogenic shock and severe CHF, unless secondary to a supraventricular tachycardia amenable to verapamil therapy and in patients with atrial flutter or atrial fibrillation and an accessory bypass tract. 

The AVID trial, a large multicenter prospective NIH-sponsored trial, compared antiarrhythmic drug (amiodarone or sotalol) therapy to ICD implant in patients who survived life-threatening hemodynamically destabilizing ventricular arrhythmias (ventricular tachycardia and ventricnlar fibrillation). One thousand sixteen patients were randomized (45% with ventricnlar fibrillation and 55% with poorly tolerated ventricular tachycardia). The mean ejection fraction was 0.32. Patients with sustained ventricular tachycardia who were enrolled had associated syncope or a left ventricular ejection fraction < 0.40 (118). The AVID trial is the most persuasive and influential secondary prevention trial to date. At the time this trial was initiated, several centers refnsed to participate because of the belief that the ICD had already been shown to be the best therapy. Fifty-six U.S. and Canadian centers participated. 

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