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Publications and source records attributed to Andrea M Russo.
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INTRODUCTION: Radiofrequency catheter ablation can effectively treat patients with refractory atrial fibrillation (AF). Very late AF recurrence (> or = 12 months post-ablation) is uncommon and may represent a unique patient cohort. METHODS AND RESULTS: A nested case-control study was performed in the cohort who underwent AF ablation at the University of Pennsylvania to characterize patients who develop very late AF recurrence after ablation. The procedure consisted of isolation of pulmonary veins (PVs) demonstrating triggers and elimination of non-PV triggers initiating AF. Twenty-seven (7.9%) patients with very late recurrence were compared to 219 patients without recurrence and > or = 12 months of follow-up. The mean age was 54.6 +/- 11.3 years and 79% were men. Very late recurrence patients more likely weighed >200 lbs (70% vs 55%, P = 0.01); during initial ablation had fewer PVs isolated (2.8 +/- 1.1 vs 3.3 +/- 1.0, P = 0.03); and were less likely to have right inferior PV isolation (37% vs 61%, P = 0.02), less likely to have isolation of all PVs (30% vs 56%, P = 0.01), and more likely to have non-PV triggers (30% vs 11% OR 3.4(95% CI, 1.3-8.7), P = 0.01). PV reconnectivity and new triggers were found in the majority of patients with very late recurrence of AF who underwent repeat ablation. CONCLUSION: Very late recurrence of AF more likely occurred in patients >200 lbs who demonstrated non-PV triggers and did not undergo right inferior PV isolation. The majority of patients undergoing repeat ablation for very late recurrence demonstrated PV reconnectivity and new non-PV and PV triggers not observed during the initial ablation.
BACKGROUND: Catheter ablation procedures for treating atrial fibrillation (AF) have dramatically increased since triggers of AF were first described in 1998. OBJECTIVE: We explored changes in patient characteristics in patients referred for catheter ablation of AF over a seven-year period from 1999 through 2005. METHODS: Patient characteristics were examined for all patients undergoing AF ablation from 1999 through 2005 at the University of Pennsylvania Health System (UPHS). The gender of patients undergoing ablation was also compared with outpatients seen at UPHS with a primary diagnosis of AF. RESULTS: From 1999 to 2005 the number of patients undergoing ablation has increased steadily, from 29 patients in 1999 to 265 patients in 2005 (P < 0.01). Patients have become older (47 to 56 years; P < 0.01), with more persistent or permanent AF (17% to 45%; P < 0.01), larger left atrial size (4.0 to 4.4 cm; P < 0.01), and fewer antiarrhythmic drugs used prior to ablation (3.9 to 2.0 drugs; P < 0.01). Patients undergoing ablation have been predominantly male, with a significantly higher male prevalence than patients seen in the UPHS outpatient primary care clinic with AF (77% vs 59% male; P < 0.001). CONCLUSIONS: Patients undergoing AF ablation from 1999 to 2005 are older, with larger left atrial size, more persistent/permanent AF, and fewer prior antiarrhythmic agents used. Compared with the gender-specific rates of AF in the population, the majority of patients referred for ablation are men, suggesting a referral bias against this invasive procedure for women. These findings are important for interpreting the outcome of ablation in the current era, and for designing prospective randomized trials.
OBJECTIVE: To compare safety and efficacy of 8-mm versus cooled tip catheter in achieving electrical isolation (EI) of pulmonary veins (PV) for long-term control of atrial fibrillation (AF). BACKGROUND: There is paucity of studies comparing safety/efficacy of 8-mm and cooled tip catheters in patients undergoing AF ablation. METHODS AND RESULTS: This was a randomized and patient-blinded study. Subjects were followed by clinic visits (at 6 weeks and 6 months) and transtelephonic monitoring (3-week duration) done around each visit. Primary endpoints were: (1) long-term AF control (complete freedom and/or >90% reduction in AF burden on or off antiarrhythmic drugs at 6 months after a single ablation), and (2) occurrence of serious adverse events (cardiac tamponade, stroke, LA-esophageal fistula, and/or death). Eighty-two patients (age 56 +/- 9 years, 60 males, paroxysmal AF = 59) were randomized (42 patients to 8-mm tip and 40 patients to cooled tip). EI of PVs was achieved in shorter time by the 8-mm tip as compared with cooled tip catheter (40 +/- 23 minutes vs 50 +/- 30 minutes; P < 0.05) but long-term AF control was not different between the two (32 patients [78%] vs 28 patients [70%], respectively; P = NS). One serious adverse event occurred in each group (LA-esophageal fistula and stroke, respectively) and no significant PV stenosis was observed in either. CONCLUSION: EI of PVs using either 8-mm or cooled tip catheter results in long-term AF control in the majority after a single ablation procedure, with comparable efficacy and safety.
BACKGROUND: The biventricular implantable cardioverter-defibrillator (ICD) is an important therapy for select patients with severe heart failure. Given reported risk factors for elevated defibrillation thresholds (DFTs), patients undergoing biventricular ICD placement would be suspected of having a higher incidence of elevated DFT. OBJECTIVES: The purpose of this study was to examine the clinical predictors and mortality risk of elevated DFTs in patients receiving a biventricular ICD. METHODS: Characteristics of patients undergoing biventricular ICD placement with an elevated DFT were compared to those without an elevated DFT. RESULTS: An elevated DFT was found in 14 (12%) of 121 patients. Mean QRS duration was 210 +/- 50 ms in the elevated DFT group and 171 +/- 36 ms in the normal DFT group (P = .01). Patients with a QRS duration >or=200 ms were more likely to have an elevated DFT than those with a duration <200 ms (odds ratio 13.4, 95% confidence interval 3.1-66.7, P <.01). No other clinical characteristics were associated with an elevated DFT. More than 90% of patients with an elevated DFT achieved an adequate safety margin through system modification or manipulation of their drug regimen. An elevated DFT did not have an impact on 2-year mortality. CONCLUSION: Patients with a biventricular ICD had a 12% incidence of elevated DFT in our sequential patient cohort. QRS duration prior to biventricular ICD placement is the most powerful predictor of patients at risk for an elevated DFT. An elevated DFT does not have an impact on mortality, perhaps because of successful implementation of system modifications to ensure an adequate defibrillation safety margin.
Cardiac tamponade as a late complication of device placement is exceedingly rare, with only several case reports previously published. We sought to characterize our institution's experience with cardiac tamponade occurring >30 days after permanent pacemaker or implantable cardioverter-defibrillator placement. From January 2000 to June 2003, 2,535 patients received an implantable cardiac device at our institution. Four patients (0.17%) presented with cardiac tamponade>30 days after the procedure. A fifth patient who had undergone implantation at another institution but was referred to our group with tamponade was also included in the analysis. The baseline characteristics varied widely with respect to age, gender, device type, and anticoagulation status. Lead parameters were altered in 2 of 5 patients. Two patients were treated with pericardiocentesis, 1 patient had pericardiocentesis followed by lead extraction, and 2 patients required cardiac surgical intervention. Pericardial fluid culture and cytologic findings were negative in all patients. All patients had normal recovery and were well at a mean follow-up of 31 months. In conclusion, cardiac tamponade is a rare, but serious late complication of permanent pacemaker and implantable cardioverter-defibrillator placement. The patient characteristics and mode of presentation vary widely. Once tamponade is recognized and treated, these patients appear well at long-term follow-up, with no other device-related problems. A role for lead manipulation does not appear to exist in the standard treatment of these patients.
BACKGROUND: Atrial fibrillation (AF) ablation procedures typically involve isolation of all pulmonary veins (PVs) in addition to adjunctive linear lesions, yet the need for such an extensive ablation strategy in all patients is unclear. OBJECTIVES: The purpose of this study was to identify a subgroup of patients undergoing AF ablation with good clinical success after limited PV isolation. METHODS: Patients (N = 450) underwent trigger-guided segmental isolation of only arrhythmogenic PVs. We compared clinical characteristics of patients who required isolation of only one or two PVs to those in whom AF ablation required isolating > or = 3 PVs. RESULTS: For the group of patients undergoing isolation of < or = 2 PVs, AF freedom without antiarrhythmic drug use was achieved in 56 (58%) of 97 patients, and AF control was achieved in 66 (68%) of 97 patients after a single procedure. After additional procedures, 77 (79%) of 97 patients achieved complete AF freedom without antiarrhythmic drugs, and 82 (85%) of 97 patients achieved AF control. Younger age (odds ratio [OR] 1.05; confidence interval [CI] 1.01,1.09) and lack of persistent AF (OR 3.27; CI 1.0, 10.7) were each independent predictors of freedom from AF. In patients younger than 50 years with paroxysmal AF undergoing isolation of < or = 2 PVs (n = 44), AF freedom without antiarrhythmic drugs was achieved in 32 (73%) of 44 after a single ablation procedure. CONCLUSION: Targeted PV isolation has a good long-term (18-month) success rate in patients younger than 50 years with paroxysmal AF and < or = 2 PVs triggering AF.
OBJECTIVES: The purpose of this study was to (1) determine how often implantable cardioverter-defibrillator (ICD) system modifications were needed to obtain an adequate safety margin for defibrillation, (2) identify how often and for what indications defibrillation threshold (DFT) testing was not performed, and (3) identify factors predicting the need for modification. BACKGROUND: Ventricular fibrillation (VF) typically is induced at the time of ICD insertion. Although DFT testing often is minimized, a safety margin of 10 J has been utilized as a standard of care. However, current devices offer technology such as biphasic waveforms and high outputs, and the need for testing has been questioned. METHODS: We reviewed the records of the last 1,139 patients undergoing initial ICD placement, generator replacement, or revision. RESULTS: Seventy-one patients (6.2%) were identified as having an unacceptably high DFT (<10 J safety margin) requiring intervention, and some required >1 modification. Use of a high-output device alone was not enough to obtain an adequate DFT in 48% (34/71) of patients who required modifications (3% of the total population). No arrhythmia inductions were performed in 54 patients (4.7%) because of well-defined clinical conditions. Patients who required system modification had a lower ejection fraction, were younger, were less likely to have coronary artery disease, were more likely to be undergoing upgrade/generator replacement, and were more likely to be taking amiodarone. Long-term mortality was not different between the group of patients who required modification compared with those who did not (17% vs 20%, P = NS). CONCLUSIONS: Routine VF induction and documentation of effective defibrillation still remains a reasonable part of ICD placement because an inadequate safety margin may occur in >6% of patients. The incidence of patients who were inappropriate for testing based on well-defined clinical conditions is small (<5%) in this unselected large series. Although some clinical features may predict the need for system modification, additional studies are needed to better define "acceptable efficacy" of ICDs in preventing sudden death prior to altering these standards in selected patients.
BACKGROUND: A proarrhythmic consequence of pulmonary vein (PV) isolation can be a recurrent organized left atrial (LA) tachycardia after ablation. This arrhythmia is frequently referred to as "left atrial flutter," but the mechanism and best ablation strategy have not been determined. METHODS AND RESULTS: Isolation of arrhythmogenic PVs was initially performed by segmental ostial PV ablation guided by a circular mapping catheter in 341 patients. Patients whose predominant recurrent arrhythmia was a persistent organized tachycardia returned for mapping and ablation. Recurrent organized LA tachycardias (cycle length 253+/-33 ms, range 213 to 328 ms) occurred in 10 (2.9%) of 341 patients (age 59+/-9 years, 1 woman). Mapping was consistent with a focal origin in 8 patients and with macroreentry in 1 patient and was unclear in 1 patient owing to degeneration to atrial fibrillation. Focal tachycardias originated from reconnected segments of prior isolated PVs (6 patients), the posterior LA (1 patient), or the superior septum (1 patient). Focal atrial tachycardias were ablated with point lesions that targeted the earliest activation. All reconnected PVs were also reisolated. Reentrant LA flutter occurred around the left PVs in 1 patient. After 6.7+/-2.3 months of follow-up, 9 (90%) of 10 patients were arrhythmia free (4 of whom were taking antiarrhythmic drug therapy), and one was having recurrent atrial fibrillation. CONCLUSIONS: Recurrent organized LA tachycardia after PV isolation is uncommon and typically has a focal origin from reconnected PV ostia. Reisolation of the PV and ablation of non-PV foci are sufficient to treat this proarrhythmia. Linear lesions are only required when a macroreentrant mechanism is present.
OBJECTIVES: We postulated that the pattern of death would be nonrandom with respect to temporal variables. BACKGROUND: Previous studies have demonstrated increased sudden death is associated with periods of relative stress, and overall mortality is associated with temporal variables. METHODS: In the Antiarrhythmics Versus Implantable Defibrillators (AVID) registry, vital status was obtained for 4,450 patients (who had a recent episode of sustained ventricular arrhythmias or unexplained syncope and inducible ventricular tachycardia) through the National Death Index Service as of December 31, 1997 (follow-up 25.5 +/- 13.7 months). RESULTS: Mortality was not associated with the day of the week or with holidays but was associated with season (P = .033). Seasonal variation was present both in northern and southern sites. Mortality was higher during the winter months compared to the remaining months (111.2% in winter vs 96.5% in other months, P = .036). In addition, increased mortality was associated with a high-risk season variable defined (prior to evaluation of treatment arm associations) as spring in the north and winter in the south (P < .001). The hazard ratio for death associated with this "high-risk season" measured 1.25 (P = .001) compared to the other seasons in each region. A test of interaction between "high-risk" season and implantable cardioverter-defibrillator (ICD) status suggested that the group with ICDs experienced reduced mortality during the "high-risk season" compared to the group without ICDs (P = .047). CONCLUSIONS: Mortality was higher in the winter months and in the respective regional "high-risk" seasons. Furthermore, seasonal variation in mortality may have been due to variation in sudden arrhythmic death, and associated increases in mortality were reduced by ICD therapy.
INTRODUCTION: Previous studies have demonstrated gender differences in risk of sudden death in patients with ischemic heart disease. The Multicenter UnSustained Tachycardia Trial (MUSTT) evaluated the ability of therapy guided by electrophysiologic (EP) testing to reduce mortality in patients with coronary disease, ejection fraction < or =40%, and spontaneous nonsustained ventricular tachycardia. METHODS AND RESULTS: We analyzed the influence of gender on results of EP testing and outcome of patients enrolled in MUSTT. Women made up 14% of the overall MUSTT population and were less likely than men to have inducible sustained randomizable ventricular arrhythmias (24% vs 36%, P < 0.001). Baseline characteristics differed between men and women. In randomized patients, women were older, more likely to have had an infarction within 6 months, more likely to have a history of heart failure, and more likely to have recent angina prior to enrollment than men (P < 0.05). In the EP-guided therapy group, there was no difference in implantable cardioverter defibrillator implantation rate in men and women (45% vs 53%, P = 0.38). There also were no significant gender influences on risk of arrhythmic death or cardiac arrest (2-year event rate 9% in women and 12% in men, adjusted hazard ratio 0.88) or overall mortality (2-year event rate 32% in women vs 21% in men, adjusted hazard ratio 1.51). CONCLUSION: The outcome and benefit of EP-guided therapy in this trial did not appear to be influenced by gender. However, due to the small numbers of women in the trial, small differences in outcome may not be apparent. Plans for future primary prevention trials should include careful risk stratification of women who less often have inducible sustained ventricular arrhythmias and better left ventricular function despite more frequent heart failure.
Automatic Sensitivity Control, unique to St. Jude defibrillators, allows for programmable sensitivity threshold and refractory periods. However, inappropriate programming can lead to marked undersensing and potentially lethal complications. We report a case of complete failure to sense ventricular fibrillation with inappropriate sensitivity adjustments. Detailed review of the parameters with induction of ventricular fibrillation must be performed to assure adequate safety.
BACKGROUND: The Multicenter UnSustained Tachycardia Trial (MUSTT) demonstrated the benefit of implantable cardioverter-defibrillators (ICDs) in patients with coronary disease, asymptomatic nonsustained ventricular tachycardia, and reduced left ventricular function. Previous studies have shown racial differences in risk of sudden death in patients with ischemic heart disease. METHODS AND RESULTS: We analyzed the influence of race on results of MUSTT. Whites were more likely to have prior revascularization and inducible, randomizable sustained ventricular arrhythmias and less likely to have left ventricular hypertrophy than were blacks. Compared with blacks, whites randomly assigned to electrophysiologically (EP)-guided therapy had a lower risk of arrhythmic death/cardiac arrest (adjusted P=0.003) and lower total mortality rates (adjusted P=0.051). In contrast, there was no racial difference in the risk of arrhythmic death/cardiac arrest among patients randomly assigned to no EP-guided therapy (adjusted P=0.477). Among whites, EP-guided therapy resulted in a survival benefit compared with no EP-guided therapy. However, survival of blacks randomly assigned to no EP-guided therapy was better than blacks receiving EP-guided therapy. This difference is partially explained by a higher ICD implantation rate in whites versus blacks (50% versus 28%, P=0.034). Whites were more likely to remain inducible after serial EP-guided drug testing (67% versus 42%, P=0.011), making them more likely to become eligible for ICDs. CONCLUSIONS: The outcome in this trial and the benefit of EP-guided therapy appeared to be influenced by race. In addition to differences in ICD implantation rates, differences in arrhythmic substrates and proarrhythmic responses to antiarrhythmic drugs may have influenced outcome.
Primary prevention trials have demonstrated that patients with coronary disease, reduced left ventricular function, and nonsustained ventricular tachycardia (NSVT) have improved survival with implantable cardioverter defibrillator (ICD) therapy, presumably secondary to effective termination of life-threatening arrhythmias. However, stored intracardiac electrograms were not always available and specific arrhythmias leading to ICD therapy were not always known. We examined the occurrence of ICD events in 51 consecutive patients who match the described patient profile to determine the frequency of appropriate and inappropriate ICD therapy. ICD detections were noted in 18 (35%) patients during a median follow-up period of 13.1 months. Appropriate therapy for sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) occurred in 11 (22%) patients, with appropriate shocks in 8 (16%) patients and appropriate antitachycardia pacing (ATP) in 4 (8%) patients. The time to first appropriate therapy occurred at a mean of 17 +/- 12 months (median 18 months, range 3-36 months). Inappropriate therapy occurred in 5 (10%) patients with inappropriate shocks in 4 patients and inappropriate ATP in 2 patients. Inappropriate therapy was delivered for supraventricular arrhythmias (SVAs) in 4 patients and for T wave oversensing in 1 patient. The reason for shock therapy was unknown in 1 patient (2%) due to ICD malfunction. The mean arrhythmia rate leading to appropriate therapy for VT/VF was 232 +/- 72 beats/min (range 181-400 beats/min), and the mean rate leading to inappropriate therapy for SVT was 168 +/- 10 beats/min (range 160-180 beats/min). Patients with coronary disease and asymptomatic NSVT commonly receive appropriate defibrillator therapy. These results support the need for ICD implantation for primary prevention, with attention to careful programming of the detection rate to prevent inappropriate therapy.
Implantable cardioverter defibrillators (ICDs) have proven highly successful in the treatment of life-threatening ventricular arrhythmias. Despite the efficacy of the ICD in terminating ventricular arrhythmias, antiarrhythmic drugs remain an important adjunct to ICD therapy. The use of antiarrhythmic drug therapy in combination with the ICD is synergistic in terms of beneficial effects, but also has the potential for some adverse interactions. Knowledge and recognition of these potential interactions is important for any physician managing patients with an ICD. This review summarizes the benefits and adverse effects of ICD in combination with antiarrhythmic drug therapy, and provides guidelines to ensure safe application of this hybrid therapy.