Patients In Normal Sinus Rhythm Research Articles

Digoxin and Reduction in Mortality and Hospitalization in Geriatric Heart Failure: Importance of Low Doses and Low Serum Concentrations

Digoxin reduces hospitalizations due to heart failure (HF) and may also reduce mortality at low serum digoxin concentrations (SDC). Most HF patients are > or = 65 years, yet the effects of digoxin on outcomes in these patients have not been well studied. Of the 7788 ambulatory chronic HF patients in normal sinus rhythm in the Digitalis Investigation Group trial (1991-1995), 5548 (2890 were > or = 65 years) were alive at 1 month and were either receiving placebo or had data on SDC. Of these patients, 982 had low (0.5-0.9 ng/mL) and 705 had high (> or = 1 ng/mL) SDC. Among patients > or = 65 years, compared with 38% placebo patients, 34% low SDC patients died during 39 months of median follow-up (adjusted hazard ratio [AHR] = 0.81; 95% confidence interval [CI] = 0.68-0.96; p =.017). All-cause hospitalizations occurred in 70% of placebo and 68% of low-SDC patients (AHR = 0.86; 95% CI = 0.76-0.98; p =.019). Reduction in hospitalizations for HF occurred in both low and high SDC groups. High SDC was not independently associated with all-cause hospitalization or all-cause mortality. Age, impaired renal function, and pulmonary congestion reduced the odds of low SDC. Low-dose digoxin (< or = 0.125 mg/d) was the strongest independent predictor of low SDC (adjusted odd ratio = 2.37; 95% CI = 1.65-3.39); p <.0001). Digoxin at low SDC was associated with a reduction in mortality and hospitalization in chronic geriatric HF, and low-dose digoxin was the strongest predictor of low SDC.

Management of Dofetilide Overdose in a Patient with Known Cocaine Abuse

Dofetilide, a class III antiarrhythmic agent, is prescribed for conversion to and maintenance of normal sinus rhythm in patients with persistent atrial fibrillation or atrial flutter. Most antiarrhythmics have significant toxicities such as torsade de pointes, and patients should be closely monitored while receiving antiarrhythmic therapy. However, we know of no reports concerning management of intentional overdose of dofetilide that have been published. We report the case of a 33-year-old man who was treated for ingestion of approximately 5 mg of dofetilide as a suicide attempt. In addition, he had a known history of cocaine abuse. He came to the emergency department approximately 45 minutes after the ingestion; examination revealed a QTc interval of approximately 570 msec. He was treated with activated charcoal and sorbitol by nasogastric tube and received aggressive supplementation with potassium and magnesium. The patient was monitored by telemetry for several days and responded well. Cardiac toxicity is the utmost concern when treating dofetilide overdose. The mainstay of treatment focuses on supportive care and prevention of drug absorption. Ventricular dysrhythmias or torsade de pointes should be treated according to advanced cardiac life support guidelines.

Update of the Clinical Impact and Issues Surrounding Dofetilide (Tikosyn) Therapy

Dofetilide (Tikosyn) is an oral anti-arrhythmic medication approved by the Food and Drug Administration (FDA) in 1999 for the management of persistent atrial fibrillation and flutter. A cautionary statement describing the side effect profile, including life-threatening arrhythmias and conduction abnormalities as well as monitoring strategies, accompanied the drug’s approval. The dofetilide package insert contains a black box warning that addresses the special requirements for initiation of the drug and prescribing and dispensing privileges. 1 As part of the warning, the FDA required that a distribution and education program for prescribers be developed to minimize the risk of potentially life-threatening arrhythmia as a condition for approval of dofetilide in the United States. In response, Pfizer developed a risk-management program that: 1) restricts dofetilide initiation to hospitalized patients, 2) places restrictions on outpatient dispensing, 3) requires prescribing physicians, physician assistants, and nurse practitioners complete an educational program on dofetilide, and 4) directs that healthcare institutions establish detailed dosing and monitoring recommendations for the drug. Additional information on this program can be found at www.tikosyn.com. Dofetilide is available only to hospitals and prescribers who have received appropriate dofetilide dosing and treatment initiation education. Retail pharmacies must be enrolled in the TIPS’ (Tikosyn in Pharmacy System) program in order to stock and dispense dofetilide. The black box warning also states that healthcare facilities should provide continuous electrocardiographic (ECG) monitoring, creatinine clearance calculation, and have cardiac resuscitation capability during the first 3 days of initiation and re-initiation of dofetilide. Indications Dofetilide is indicated for the conversion to and maintenance of normal sinus rhythm in patients with persistent atrial fibrillation or atrial flutter. Dofetilide should be used only in highly symptomatic patients (eg, palpitations, chest pain, dyspnea, fatigue, lightheadedness, syncope, and heart failure exacerbation) because of the risk of life-threatening ventricular arrhythmias associated with its administration. Adequate ventricular rate control can be achieved by using such agents as � -blockers (eg, esmolol or metroprolol), calcium channel blockers (such as diltiazem or verapamil), or digoxin. Management of atrial fibrillation

Dronedarone: A new antiarrhythmic agent

Dronedarone (SR 33589; N,N-dibutyl-3-[4-([2-butyl-5-methylsulphonamido] benzofuran-3-yl-carbonyl) phenoxy]propylamine) is a new synthetic noniodinated derivative of amiodarone that is currently undergoing phase III clinical trials. It demonstrates electrophysiologic patterns similar to amiodarone and shows equivalent efficacy in preventing or converting various ventricular and atrial arrhythmias in laboratory animals. Two phase III trials demonstrated that dronedarone is safe and effective for the maintenance of normal sinus rhythm in patients with atrial fibrillation or atrial flutter. Dronedarone at the dose of 400 mg twice daily was effective in preventing both symptomatic and asymptomatic recurrences of atrial fibrillation or atrial flutter and had a safety profile similar to that of placebo. Further studies are needed to determine the long-term effectiveness and safety of dronedarone in various groups of patients with atrial fibrillation. Other clinical applications of this novel antiarrhythmic drug need to be determined in future clinical trials.

Relation of initial resting ventricular rate to the ability to achieve and maintain normal sinus rhythm in patients with atrial fibrillation

Rate-control and rhythm-control strategies in the management of atrial fibrillation (AF) have been shown to have similar effects on morbidity and mortality. Data are lacking as to whether specific electrocardiographic features of AF affect the ability to achieve rate or rhythm control. This study evaluated the relation between initial resting ventricular rate (IRVR) during AF and the subsequent achievement of rate control and rhythm control in the AFFIRM Study. The independent relations between IRVR and the achievement of rate and rhythm control were assessed using multivariate Cox's proportional hazards modeling. In addition, we evaluated whether IRVR was associated with major cardiovascular end points. IRVR was analyzed in 4,059 patients. IRVR was higher in women, smokers, patients who had a first episode of AF, and in patients who had preserved left ventricular systolic function but lower in patients who had coronary artery disease, hypertension, left atrial enlargement, and a qualifying episode of AF that lasted >48 hours. A higher IRVR was independently associated with the achievement (p <0.0001) and maintenance (p = 0.0002) of sinus rhythm, whereas the ability to achieve adequate rate control was independent of IRVR. A higher IRVR was associated with an increased risk of cardiovascular hospitalization (p <0.0001). In the appropriate clinical setting, a rhythm-control strategy should be considered for patients who have a higher IRVR.

Interatrial block as a predictor of embolic stroke

Interatrial block (IAB), defined as a prolonged (>/=110 ms) P wave, is remarkably prevalent in general hospital populations and is associated with an enlarged, poorly contractile left atrium. The investigators sought to determine whether there is an increased incidence of IAB in patients with embolic strokes. Patients' medical records were reviewed for evidence of embolic cerebrovascular events and IAB. One hundred four patients were identified. In 61 patients in normal sinus rhythm, 49 (80%) had IAB. This was almost twice the prevalence of 2 previous studies (41% and 47%). Therefore, IAB may represent a new risk factor for stroke.

Sotalol versus propafenone for long-term maintenance of normal sinus rhythm in patients with recurrent symptomatic atrial fibrillation

This prospective, randomized, single-blinded, placebo-controlled study compared the efficacy and safety of sotalol and propafenone when used for long-term prevention of atrial fibrillation. For the long-term maintenance of normal sinus rhythm, propafenone seems to be more effective than sotalol.

Long-term Maintenance of Normal Sinus Rhythm in Patients With Current Symptomatic Atrial Fibrillation: Amiodarone vs Propafenone, Both in Low Doses

To compare the efficacy and safety of amiodarone and propafenone when used for the prevention of atrial fibrillation (AF) and maintenance of normal sinus rhythm in patients with refractory AF. Prospective, randomized, single-blind trial. Tertiary cardiac referral center. One hundred forty-six consecutive patients (72 men; mean age, 63 +/- 10 years [+/- SD]) with recurrent symptomatic AF. We studied 146 patients after restoration of sinus rhythm; patients were randomized to amiodarone, 200 mg/d, or propafenone, 450 mg/d. Follow-up clinical evaluations were conducted at the first, second, fourth, and sixth months, and at 3-month intervals thereafter. The proportion of patients relapsing to AF and/or experiencing side effects was calculated for each group using the Kaplan-Meier method. End point of the study was recurrence of AF or occurrence of side effects necessitating discontinuation of medication. Of 146 patients, 72 received amiodarone and 74 received propafenone. The two groups were clinically similar. Of the 72 patients receiving amiodarone, AF developed in 25 patients, after an average of 9.8 months, compared to 33 of the 74 patients receiving propafenone after an average of 3.8 months. Twelve patients receiving amiodarone and 2 patients receiving propafenone had side effects necessitating withdrawal of medication while still in sinus rhythm. Amiodarone tends to be more effective than propafenone in maintaining sinus rhythm in patients with AF, but this advantage is offset by a higher incidence of side effects.

Effect of an implantable cardioverter defibrillator with atrial detection and shock therapies on patient-perceived, health-related quality of life

BackgroundThis study used a device (DDD implantable cardioverter defibrillator [ICD]) capable of delivering pacing and shock therapies to restore normal sinus rhythm in patients with atrial tachycardias or atrial fibrillation (AF). The purpose of this study was to assess the effect of the device on patient-perceived, health-related quality of life (QOL). MethodsThe DDD ICD was implanted in 267 patients with drug refractory, symptomatic AF from 45 centers across Europe, the United States, and Canada. Patients completed self-reported, validated QOL assessments at baseline and at 3- and 6-month follow-up visits (The Medical Outcomes Short Form 36 [SF-36] and the Symptom Checklist [SCL]). ResultsThe mean age of the study group was 62 ± 12 years, and 73% of the patients were male. A total of 150 patients completed SF-36 assessments, and 138 patients completed SCL assessments at all 3 times. Baseline scores were more impaired (P < .05) on most SF-36 scales compared with norms for a general population, but were similar to a comparison group of patients with AF who were referred to tertiary care centers. The role-physical, physical functioning, vitality, mental health, and social functioning scales all improved significantly with time (all P < .04). Similarly, symptom frequency and severity (SCL) also improved significantly from baseline to 6 months (both P < .01). Shock therapy was delivered in 86 of the 150 patients (57%) with complete SF-36 evaluations. There was no evidence that receiving shocks decreased the relative improvement in QOL associated with implantation of the device. ConclusionsIn a 6-month period, QOL improves after implantation of a DDD ICD with atrial shock and pacing therapies. These improvements were not attenuated by receipt of shocks.

Effects of chronic atrial fibrillation on gap junction distribution in human and rat atria

OBJECTIVESTo elucidate the structural basis for the electrophysiologic remodeling induced by chronic atrial fibrillation (AF), we investigated connexin40 and connexin43 (Cx40 and Cx43) expression and distribution in atria of patients with and without chronic AF and in an animal model of AF with additional electrophysiologic investigation of anisotropy (ratio of longitudinal and transverse velocities).BACKGROUNDAtrial fibrillation is a common arrhythmia that has a tendency to become persistent. Since gap junctions provide the syncytial properties of the atrium, changes in expression and distribution of intercellular connections may accompany the chronification of AF.METHODSAtrial tissues isolated from 12 patients in normal sinus rhythm at the time of cardiac surgery and from 12 patients with chronic AF were processed for immunohistology and immunoblotting for the detection of the gap junction proteins. The functional study of the cardiac tissue anisotropy was performed in rat atria in which AF was induced by 24 h of rapid pacing (10 Hz).RESULTSImmunoblotting revealed that AF did not induce any significant change in Cx43 content in human atria. In contrast, a 2.7-fold increase in expression of Cx40 was observed in AF. Immunohistologic analysis indicated that AF resulted in an increase in the immunostaining of both connexins at the lateral membrane of human atrial cells. A similar spatial redistribution of the Cx43 signal was seen in isolated rat atria with experimentally-induced AF. In addition, AF in rat atria resulted in decreased anisotropy with slightly enhanced transverse conduction velocity.CONCLUSIONSThis experimental study showed that AF is accompanied by spatial remodeling of gap junctions that might induce changes in the biophysical properties of the tissue.

Amiodarone, Sotalol, or Propafenone in Atrial Fibrillation: Which Is Preferred to Maintain Normal Sinus Rhythm?

This randomized study compared the efficacy and safety of amiodarone, propafenone and sotalol in the prevention of atrial fibrillation. The population consisted of 214 consecutive patients (mean age 64 +/- 8 years, 106 men) with recurrent symptomatic atrial fibrillation. After restoration of sinus rhythm, patients were randomized to amiodarone (200 mg/day), propafenone (450 mg/day) or sotalol (320 +/- 20 mg/day). Follow-up evaluations were conducted at 1, 2, 4 and 6 months, and at 3-month intervals thereafter. The proportion of patients developing recurrent atrial fibrillation and/or experiencing unacceptable adverse effects was measured in the three groups by the Kaplan-Meier method. Recurrent atrial fibrillation occurred in 25 of the 75 patients treated with amiodarone compared to 51 of the 75 patients treated with sotalol and 24 of the 64 patients treated with propafenone. Fourteen patients treated with amiodarone, five with sotalol, and one with propafenone experienced adverse effects while in sinus rhythm, necessitating discontinuation of treatment (P < 0.001 for amiodarone and propafenone vs sotalol). The difference between amiodarone and propafenone was statistically nonsignificant when all events were included in the analysis. However, if the analysis was limited to recurrent atrial fibrillation events, amiodarone was more effective than propafenone (P < 0.05). Amiodarone and propafenone were superior to sotalol in maintaining long-term normal sinus rhythm in patients with atrial fibrillation. Amiodarone tended to be superior to propafenone, though its long-term efficacy was limited by adverse side effects.

Clinical predictors of prognosis in severe aortic stenosis in unoperated patients ≥75 years of age

In elderly patients with severe aortic stenosis, clinical evaluation can dictate decision making. Asymptomatic patients in normal sinus rhythm, without left atrial enlargement and without bundle branch block, can be safely followed clinically, regardless of echocardiographic findings.

Dofetilide: A new antiarrhythmic agent approved for conversion and/or maintenance of atrial fibrillation/atrial flutter.

Dofetilide is a new antiarrhythmic agent recently approved for the conversion of and maintenance of sinus rhythm in patients with atrial fibrillation (AF) and atrial flutter (AFl). Dofetilide is a selective class III antiarrhythmic drug which works by selectively blocking the rapid component of the delayed rectifier outward potassium current (I(kr)). Dofetilide has been shown to prolong the effective refractory period which is accompanied by a dose-dependent prolongation of the QT and QTc intervals, with parallel increases in ventricular refractoriness. Approximately 80% of dofetilide is excreted in the urine which requires dose adjustments in renal insufficiency. The elimination half-life is approximately 10 h in patients with normal renal function. The therapeutic blood level range of dofetilide is presently unknown and monitoring of dofetilide blood levels is not available at this time. Clinical trials have shown dofetilide to be superior to flecainide in converting AFl patients to normal sinus rhythm (NSR) (70% vs. 9%; p<0.01). It also was more effective than sotalol in converting AF and AFl patients to NSR (29% vs. 6%; p<0.05) and maintaining these patients in NSR for up to 1 year (p<0.05). Most patients convert to NSR within 24-36 h. Torsade de pointes is the most serious side effect occurring in 0.3-10.5% of patients and is dose related. Other common side effects include headache, chest pain and dizziness. To minimize the risk of induced arrhythmia, patients initiated or reinitiated on dofetilide should be hospitalized for a minimum of 3 days where continuous electrocardiographic monitoring, evaluation of renal function and serum electrolytes and cardiac resuscitation can be provided.

Antiarrhythmic agents for atrial fibrillation: focus on prolonging atrial repolarization

Atrial fibrillation (AF) has been the subject of considerable attention and intensive clinical research in recent years. Current opinion among physicians on the management of AF favors the restoration and maintenance of normal sinus rhythm. This has several potential benefits, including the alleviation of arrhythmia-associated symptoms, hemodynamic improvements, and possibly a reduced risk of thromboembolic events. After normal sinus rhythm has been restored, antiarrhythmic therapy is necessary to reduce the frequency of AF recurrence. In the selection of an antiarrhythmic agent, both efficacy and safety should be taken into consideration. Many antiarrhythmic agents have the capacity to provoke proarrhythmia, which may result in an increase in mortality. This is of particular concern with sodium-channel blockers in the context of patients with structural heart disease. Flecainide and propafenone are well tolerated and effective in maintaining sinus rhythm in patients without significant cardiac disease but with AF. Recent interest has focused on the use of class III antiarrhythmic agents, such as amiodarone, sotalol, dofetilide (recently approved), ibutilide (approved for chemical conversion of AF and atrial flutter), and azimilide (still to be approved) in patients with AF and structural heart disease. To date, amiodarone and sotalol still hold the greatest interest, and although controlled clinical trials with these agents have been few, a number are in progress and some have been recently completed. These agents are effective in maintaining normal sinus rhythm in patients with paroxysmal and persistent AF and are associated with a low incidence of proarrhythmia when used appropriately. Because of the relative paucity of placebo-controlled trials of antiarrhythmic agents in patients with AF, experience until recently has tended to dictate treatment decisions. Increasingly, selection of drug therapy is being based on a careful and individualized benefit–risk evaluation by means of controlled clinical trials, an approach that is likely to dominate the overall approach to the control of atrial fibrillation in the largest numbers of cases of the arrhythmia. Pharmacologic therapy is likely to be dominated by compounds that exert their predominant effect by prolonging atrial repolarization.

Mitral balloon valvotomy for patients with mitral stenosis in atrial fibrillation: Immediate and long-term results

OBJECTIVESThe purpose of this study was to examine the effect of atrial fibrillation (AF) on the immediate and long-term outcome of patients undergoing percutaneous mitral balloon valvuloplasty (PMV).BACKGROUNDThere is controversy as to whether the presence of AF has a direct negative effect on the outcome after PMV.METHODSThe immediate procedural and the long-term clinical outcome after PMV of 355 patients with AF were prospectively collected and compared with those of 379 patients in normal sinus rhythm (NSR).RESULTSPatients with AF were older (62 ± 12 vs. 48 ± 14 years; p < 0.0001) and presented more frequently with New York Heart Association (NYHA) class IV (18.3% vs. 7.9%; p < 0.0001), echocardiographic score >8 (40.1% vs. 25.1%; p < 0.0001), calcified valves under fluoroscopy (32.4% vs. 18.8%, p < 0.0001) and with history of previous surgical commissurotomy (21.7% vs. 16.4%; p = 0.0002). In patients with AF, PMV resulted in inferior immediate and long-term outcomes, as reflected in a smaller post-PMV mitral valve area (1.7 ± 0.7 vs. 2 ± 0.7 cm2; p < 0.0001) and a lower event free survival (freedom of death, redo-PMV and mitral valve surgery) at a mean follow-up time of 60 months (32% vs. 61%; p < 0.0001). In the group of patients in AF, severe post-PMV mitral regurgitation (≥3+) (p = 0.0001), echocardiographic score >8 (p = 0.004) and pre-PMV NYHA class IV (p = 0.046) were identified as independent predictors of combined events at follow-up.CONCLUSIONSPatients with AF have a worse immediate and long-term outcomes after PMV. However, the presence of AF by itself does not unfavorably influence the outcome, but is a marker for clinical and morphologic features associated with inferior results after PMV.

Atrial L-type Ca2+ currents and human atrial fibrillation.

Chronic atrial fibrillation (AF) is characterized by decreased atrial contractility, shortened action potential duration, and decreased accommodation of action potential duration to changes in activation rate. Studies on experimental animal models of AF implicate a reduction in L-type Ca2+ current (I(Ca)) density in these changes. To evaluate the effect of AF on human I(Ca), we compared I(Ca) in atrial myocytes isolated from 42 patients in normal sinus rhythm at the time of cardiac surgery with that of 11 chronic AF patients. I(Ca) was significantly reduced in the myocytes of patients with chronic AF (mean -3.35+/-0.5 pA/pF versus -9.13+/-1. 0 pA/pF in the controls), with no difference between groups in the voltage dependence of activation or steady-state inactivation. Although I(Ca) was lower in myocytes from the chronic AF patients, their response to maximal beta-adrenergic stimulation was not impaired. Postoperative AF frequently follows cardiac surgery. Half of the patients in the control group (19/38) of this study experienced postoperative AF. Whereas chronic AF is characterized by reduced atrial I(Ca), the patients with the greatest I(Ca) had an increased incidence of postoperative AF, independent of patient age or diagnosis. This observation is consistent with the concept that calcium overload may be an important factor in the initiation of AF. The reduction in functional I(Ca) density in myocytes from the atria of chronic AF patients may thus be an adaptive response to the arrhythmia-induced calcium overload.

Effects of beta-adrenergic blocking therapy on left ventricular diastolic relaxation properties in patients with dilated cardiomyopathy.

The hemodynamic mechanism for the improvement in left ventricle (LV) end-diastolic pressure in cardiomyopathy patients treated with beta-adrenergic blocking agents is controversial. We hypothesized that the salutary effect of this kind of therapy on LV end-diastolic pressure would be indicative of an improvement in late, passive diastolic relaxation properties. We studied 14 cardiomyopathy patients in normal sinus rhythm with no arteriographic evidence of coronary artery disease and an LV ejection fraction of </=40% by radionuclide angiography both before and after 6 months of metoprolol therapy with simultaneous micromanometry and biplane cineventriculography. Four comparable patients who were not treated with metoprolol were studied in a similar fashion and served as control subjects. In those receiving metoprolol, LV end-diastolic pressure decreased (P=0.001). The isovolumic relaxation index, tau(ln), shortened (P=0.03). In a similar fashion, the LV chamber stiffness constant, kappa, decreased (P=0.02), LV volume elastance improved (P=0.04), and the myocardial stiffness constant, kappa(e), decreased (P=0.02). A multiple regression analysis revealed that the decrease in LV end-diastolic pressure was indicative of significant improvements in tau(ln) and kappa(e) with the relationship: LV end-diastolic pressure=-4.73+0.27 tau(ln)+0.54 kappa(e) (r=0.81, P<0.0001). These LV diastolic relaxation properties did not change or worsened in the control cardiomyopathy patients. We conclude that the decrease in LV end-diastolic pressure in cardiomyopathy patients treated with metoprolol is an indicator of improvement in LV diastolic properties resulting from more complete myocardial relaxation.

Comparison of sotalol versus quinidine for maintenance of normal sinus rhythm in patients with chronic atrial fibrillation

Many clinicians choose sotalol for the prevention of recurrences of atrial fibrillation (AF) as an alternative to quinidine, which has been associated with an increase in long-term mortality. Using meta-analytic techniques, we compared the effects on maintenance of sinus rhythm and mortality of combined groups of patients with chronic AF treated with sotalol, quinidine, or a control drug. Rates of conversion at 6 months and mortality were combined for each group after performing sensitivity analysis to test for homogeneity. Bayesian estimates and corresponding 95% credibility intervals were constructed to compare the probabilities of achieving sinus rhythm and mortality among groups. A literature search revealed 4 sotalol studies, 6 quinidine studies, and 5 control studies that met inclusion criteria established a priori. The point estimates for maintaining normal sinus rhythm (at 6 months) and corresponding credibility intervals for the 3 groups were sotalol 50% (range 42% to 58%), quinidine 53% (range 48% to 59%), and control 32% (range 26% to 39%). When combining and comparing mortality effects, the following studies met the same inclusion criteria: 4 sotalol studies, 9 quinidine studies, and 7 control studies. The point estimates and corresponding credibility intervals for mortality in the 3 groups were sotalol 2.2% (range 0.6% to 4.8%), quinidine 3.0% (range 1.7% to 4.7%), and control 1.1% (range 0.3% to 2.4%). Sotalol and quinidine are comparable in their ability to maintain sinus rhythm at 6 months (about 50%) and both agents are superior to control. There is a trend for both agents to increase mortality with long-term therapy. These data do not support choosing sotalol over quinidine as a safer alternative for preventing recurrences of chronic AF.

Twenty-year follow-up of the Hancock modified orifice porcine aortic valve

Background. The entire experience with the Hancock modified orifice porcine bioprosthetic aortic valve from 1976 to 1996 at the Brigham and Women’s Hospital has been reviewed. Eight hundred forty-three patients received this valve with a total follow-up of 61,114 months, and a mean follow-up of approximately 72.5 months. There were 490 men and 353 women, and the predominate lesion was aortic stenosis (636 of 843); 365 (43%) patients required a concomitant coronary artery bypass graft operation. Methods. Patients were followed prospectively in the Brigham Cardiac Valve Data Registry, and the data were analyzed by the SAS statistical package, using actuarial survival curves and incidence per patient-year of morbidity and mortality. Results. The overall operative mortality was 45 of 843 (5.3%) with 23 of 478 (4.8%) for isolated aortic valve replacement and 22 of 365 (6.0%) for aortic valve plus coronary artery bypass graft operation. The major morbidity of this valve was structural valve dysfunction, which was significantly related to the age of the patient in whom the valve was placed. Actuarial probability of freedom from structural valve degeneration at 5, 10, and 15 years overall was 99% ± 1%, 79% ± 3% and 57% ± 4%, at 15 years, respectively. In patients younger than 50 years, freedom from structural valve dysfunction was 16% ± 8%, whereas in the age group older than 70 years it was 87% ± 5% ( p = 0.0005). Thromboembolism at 10 and 15 years was 81% ± 3% overall, 84% ± 2% in patients in normal sinus rhythm, and 57% ± 13% in patients with chronic atrial fibrillation. Conclusions. The Hancock modified orifice aortic valve, despite its more complicated fabrication, has been a reliable porcine bioprosthetic valve and can be used reliably in patients older than 70 years because of its low structural valve degeneration rate, and protection from stroke and anticoagulant hemorrhage in those patients in sinus rhythm.

Two‐staged Biatrial Linear and Focal Ablation to Restore Sinus Rhythm in Patients with Refractory Chronic Atrial Fibrillation: Procedure Experience and Follow‐up Beyond 1 Year

Recent observations regarding the mechanisms of chronic atrial fibrillation (CAF) plus a few encouraging clinical reports have created a paradigm shift regarding treatment strategies and the potential for restoring normal sinus rhythm (NSR) utilizing available catheter-based ablation techniques. The initial and late follow-up clinical experience with a two-staged biatrial linear and focal radiofrequency ablation (BALF I, II) procedure to restore NSR in patients with CAF are described. Pre-BALF management included confirming drug refractoriness and optimizing anticoagulation therapy. BALF I and II were preceded by transesophageal echocardiography to exclude thrombus. Femoral venous catheters were placed in the left atrium and the right atrium with extensive left atrial mapping, ablation (linear and focal) and more limited right atrial ablation. Localized electrogram recordings demonstrated rapid, localized, stable focal driving rotors (FDRs) in the left atrium (nine patients) and in the right atrium (one patient). Atrial or intraatrial tachycardia (IAT) commonly recurred after BALF I. BALF II addresses these recurrences by repeat mapping and ablation techniques. There were no thromboembolic complications. Two patients developed pericardial tamponade that responded to medical management. Of the 11 patients with late follow-up data, 9 have NSR, atrial function, and are no longer experiencing CAF. Left atrial ablation lines decrease continuous electrogram activity, probably isolate portions of the atrium, and unmask FDRs. Focal and linear ablations appear helpful in transforming CAF to NSR. FDRs are commonly localized to pulmonary vein ostium, trabeculated portions of the atrium, and left atrial appendage.