C reactive protein concentration and recurrence of atrial fibrillation after electrical cardioversion.

BACKGROUND: To test the hypothesis that a high C reactive protein (CRP) concentration would predict recurrence of atrial fibrillation (AF) after cardioversion in patients taking antiarrhythmic drugs. METHODS: 111 patients who underwent direct current cardioversion for symptomatic AF were enrolled. Blood was drawn for CRP determination before cardioversion on the same day. All patients were taking antiarrhythmic drugs before and after electrical cardioversion. RESULTS: After a mean follow up of 76 days, 75 patients had recurrence of AF. In univariate analysis, the median CRP concentration was significantly higher in patients with AF recurrence (3.95 mg/l v 1.81 mg/l, p = 0.002). Among the 55 patients with CRP in the upper 50th centile, 44 (80%) experienced recurrence of AF over a total follow up of 8.98 patient years, whereas among the 56 patients with CRP in the lower 50th centile, 31 (55%) experienced recurrence of AF over a total follow up of 14.3 patient years (p < 0.001). The adjusted hazard ratio comparing the upper 50th centile of CRP with the lower 50th centile of CRP was 2.0 (95% confidence interval 1.2 to 3.2, p = 0.007). CONCLUSIONS: CRP is independently associated with recurrence of AF after electrical cardioversion among patients taking antiarrhythmic drugs. These results suggest that inflammation may have a role in the pathogenesis of AF resistant to antiarrhythmic drugs.

Dofetilide (Tikosyn): a new drug to control atrial fibrillation.

UNLABELLED: Dofetilide, a new class III antiarrhythmic agent, selectively blocks a specific cardiac potassium channel, IKr, increasing the effective refractory period of the myocyte and thereby terminating reentrant arrhythmias. Given orally, it appears to effectively convert atrial fibrillation and atrial flutter to sinus rhythm and maintain sinus rhythm after conversion in appropriately selected patients. This paper reviews the pharmacology of dofetilide, the evidence of its effectiveness, and the appropriate precautions in using it. KEY POINTS: Dofetilide is generally well tolerated but like other class III drugs can cause torsades de pointes. The risk is dose-dependent and can be minimized by adjusting the dosage according to creatinine clearance and QT interval, by excluding patients with known risk factors for long QT syndrome and torsades de pointes, and by starting treatment in an inpatient monitored setting for the first 3 days. Unlike other antiarrhythmic agents, oral dofetilide did not increase the mortality rate in clinical studies in postmyocardial infarction patients or those with congestive heart failure at high risk for sudden cardiac death. Concomitant use of drugs that increase the plasma level of dofetilide is contraindicated; these include cimetidine, ketoconazole, trimethoprim-sulfamethoxazole, and verapamil.

Ventricular tachycardia syndromes.

Better understanding of the underlying mechanism and substrate of different VTs has made it possible to tailor treatment strategies properly. The advent of sophisticated device-based therapy and of more precise and effective catheter ablation approaches will expand clinicians' ability to gain control of this multifaceted arrhythmia syndrome.

Long-term follow-up of heart transplant recipients requiring permanent pacemakers.

BACKGROUND: Permanent pacemaker implantation after heart transplantation is contentious. Indications for these devices in this population are uncertain. The goals of this project were to (1) analyze the time course of donor sinus node dysfunction and atrioventricular block after heart transplantation; (2) evaluate which selected parameters (donor age, ischemic time, heart rate before pacer insertion, and number of rejection episodes) might relate to persistent permanent pacing need, and (3) assess pacemaker complications during follow-up. METHODS: A retrospective analysis of pacemaker implantations (22 cases) was performed in 286 consecutive heart transplantations performed between February 1984 and April 1994 at The Methodist Hospital and Baylor College of Medicine, Houston, Texas. RESULTS: Permanent pacemakers were inserted early after transplantation in 19 patients (mean 24 days); 14 pacemakers were for sinus node dysfunction (bradycardia in five, sinus arrest with junctional escape in eight, and optimization of hemodynamics in one). Symptomatic complete heart block prompted insertion late in two patients (3 and 47 months), and symptomatic sinus pause was the indication for late insertion in one. Recipient mean age was 52.4 years, with mean donor age 29.7 years in patients with pacemakers. By 3 months, 13 of 19 patients receiving pacemakers early (mean preinsertion heart rate 58.3 beats/min) became pacer independent with subsequent mean intrinsic heart rate of 97 beats/min. Recipient or donor age, ischemic time, and rejection episodes did not appear related to long-term pacing need early or late after transplantation. CONCLUSIONS: Inferences from these observations include the fact that many patients with early sinus node dysfunction and bradycardia are not pacer dependent at 3 months. However, those with atrioventricular block early appear to require long-term pacing support. However, the possibility that more aggressive and long-term oral chronotropic medication use after transplantation would obviate early permanent pacemaker need is not addressed. Finally, prospective clinical trials are necessary to precisely characterize benefit of permanent pacemakers and define optimal pacing modes after heart transplantation.

Comparison of echocardiographic assessment of cardiac hemodynamics in the intensive care unit with right-sided cardiac catheterization.

Estimation of left ventricular filling pressure and cardiac index is important in the management of patients requiring right heart catheterization. Doppler echocardiography can provide a noninvasive measure of these parameters, but its accuracy in individual measurements, predicting hemodynamic subgroups, and in tracking serial changes in critically ill patients remains to be elucidated. Left ventricular filling pressure and cardiac index were assessed in 49 critically ill patients requiring right heart catheterization and Doppler echocardiographic studies. Two or more serial studies were performed in 18 of these subjects. Patients were placed into 1 of 4 hemodynamic subgroups for each technique based on the acquired hemodynamic parameters. Left ventricular filling pressure and cardiac index by Doppler echocardiography and right heart catheterization were similar (21 +/- 8 vs 20 +/- 8 mm Hg; 3.0 +/- 1.2 vs 2.9 +/- 1.2 L/min/m2, respectively) and correlated well with each other (left ventricular filling pressure, r = 0.88; cardiac index, r = 0.92). The Doppler technique accurately placed 73 of 76 studies into the correct hemodynamic subgroup. The noninvasive technique also reliably tracked serial hemodynamic measurements. We conclude that Doppler echocardiography accurately assesses left heart hemodynamics in critically ill patients. Since this technique can be readily acquired, it can be ideal for the rapid assessment of hemodynamic parameters in critically ill patients, especially when right heart catheterization is delayed or is problematic.