Christian G. Wollmann

Implantable Cardioverter/Defibrillator Therapy in Arrhythmogenic Right Ventricular Cardiomyopathy Single-Center Experience of Long-Term Follow-Up and Complications in 60 Patients

Background—Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a major cause of ventricular tachycardia (VT) and cardiac arrest in young patients. We hypothesized that treatment with implantable cardioverter/defibrillators (ICDs) is safe and improves the long-term prognosis of ARVC patients at high risk of sudden death. Methods and Results—Sixty patients with ARVC (aged 43±16 years) were treated with transvenous ICD systems. Despite a higher number of right ventricular sites tested for adequate lead positions (P <0.05), lower R-wave amplitudes (P <0.001) were achieved in ARVC patients compared with other entities. During follow-up of 80±43 months (396 patient-years), event-free survival was 49%, 30%, 26%, and 26% for appropriate ICD therapies and 79%, 64%, 59%, and 56% for potentially fatal VT (>240 bpm) after 1, 3, 5, and 7 years, respectively. Multivariate analysis identified extensive right ventricular dysfunction as an independent predictor of appropriate ICD discharge. Fifty-three adverse events occurred in 37 patients during the perioperative (n=10) or follow-up (n=43) period, mainly related to the leads (n=31 in 21 patients). No lead perforation was observed. Freedom from adverse events was 90%, 78%, 56%, and 42% and freedom from lead-related complications was 95%, 85%, 74%, and 63% after 1, 3, 5, and 7 years, respectively. Conclusions—These results strongly suggest an improvement in long-term prognosis by ICD therapy in high-risk patients with ARVC. However, meticulous placement and long-term observation of transvenous lead performance with focus on sensing function are required for the prevention and/or early recognition of disease progression and lead-related morbidity during long-term follow-up of ICD therapy in ARVC.

Incidence of Complications in Patients with Implantable Cardioverter/Defibrillator Who Receive Additional Transvenous Pace/Sense Leads

Background: Implantation of an additional pace/sense (P/S) lead is commonly used in patients with implantable cardioverter/defibrillators (ICDs) to overcome P/S defects of integrated defibrillation leads (HV‐P/S leads). No information is available about the clinical outcome and the incidence of complications in these patients.

Cardiac Sympathetic Dysfunction in Genotyped Patients with Arrhythmogenic Right Ventricular Cardiomyopathy and Risk of Recurrent Ventricular Tachyarrhythmias

Patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) typically present with ventricular tachyarrhythmias preferentially triggered by an elevated sympathetic tone. Previous studies demonstrated an impairment of the presynaptic catecholamine reuptake as assessed by 123I-labeled norepinephrine analog on metaiodobenzylguanidine (123I-MIBG) SPECT. Mutations in the gene encoding for plakophilin-2 (PKP-2) are the most common cause of autosomal dominant ARVC (ARVC-9). In this study, we investigated the potential role of adrenergic dysfunction on the arrhythmia profile in patients with ARVC and correlated these findings with the causative genotype. Methods: 123I-MIBG SPECT was performed for 42 patients with definite ARVC (10 women, 32 men; mean age ± SD, 43 ± 14 y). Images were acquired at 4 h after injection and analyzed for regional 123I-MIBG uptake in a standardized 33-segment polar map. Results were compared with those obtained from 10 control subjects (5 women, 5 men; mean age ± SD, 43 ± 12 y). Results: An abnormal tracer uptake was detected in 25 patients with ARVC (59%). The extents of right ventricular dilation and regional wall motion abnormalities as well as electrocardiographic markers of de- or repolarization were not significantly different between patients with normal and abnormal 123I-MIBG SPECT findings. However, during long-term follow-up of 11.9 ± 4.1 y, patients with abnormal 123I-MIBG SPECT findings experienced life-threatening ventricular tachyarrhythmias significantly more often (22/25 patients [88%]) and independent of the extent of right ventricular dysfunction than those with a normal sympathetic innervation (6/17 patients [35%]; P < 0.0005). Mutations in PKP-2 were identified in 17 patients (40%) but were not correlated with the degree of adrenergic dysfunction. Conclusion: In patients with ARVC, an impairment of adrenergic innervation independent of the underlying genotype is associated with a higher incidence for future recurrences of ventricular tachyarrhythmias. This finding may suggest a potential role of 123I-MIBG SPECT for individualized risk stratification in ARVC patients and asymptomatic PKP-2 mutation carriers alike.

Two Different Therapeutic Strategies in ICD Lead Defects: Additional Combined LeadVersus Replacement of the Lead

Objectives: Implantation of an additional HV‐P/S lead versus extraction of the defective HV‐P/S lead and implantation of a new one is one possible therapeutic approach in cases of a defective high‐voltage pace/sense lead (HV‐P/S). No information is available on potential differences in clinical outcome in these different approaches.

Safe Performance of Magnetic Resonance Imaging on a Patient with an ICD

This is a report on a patient with an implanted cardioverter defibrillator (ICD) who intentionally underwent magnetic resonance imaging (MRI) of a malignant brain tumor. To avoid inadequate detection of ventricular tachycardia (VT) or ventricular fibrillation (VF), the ICD was inactivated by programming the VT‐detection and VT/VF‐therapy status off. The patient came through the protocol safely and without any difficulty or discomfort. There was no arrhythmic event. MRI affected neither programmed data nor the function of the ICD system.

Monocenter feasibility study of the MRI compatibility of the Evia pacemaker in combination with Safio S pacemaker lead.

BackgroundThe purpose of this study was to evaluate the feasibility of the magnetic resonance (MR) conditional pacemaker (PM) system (Evia SR-T and DR-T with Safio S leads) under MR conditions.MethodsPatients with standard PM indications and Evia PM were eligible for enrollment in this single center prospective non-randomized pilot study. Patients underwent MR of the brain and lower lumbar spine at 1.5 Tesla. Atrial (RA) und ventricular (RV) lead parameters (sensing, pacing threshold [PTH], pacing impedance) were assessed immediately before (baseline follow-up [FU]) and immediately after MRI (1st FU), after 1 month (2nd FU) and 3 months (3rd FU). The effect of MR on serious adverse device effect (SADE) free-rate, on atrial and ventricular sensing (AS/VS; mV) and atrial (RA) and ventricular (RV) pacing thresholds (PTH; V/0.4 ms) were investigated between baseline and 2nd FU. Continuous variables are expressed as mean ± SD and were compared using paired Student’s t-test. A p < 0.05 was considered significant.ResultsThirty-one patients were enrolled. One patient had to be excluded because of an enrollment violation. Therefore, data of 30 patients (female 12 [40%], age 73 ± 12 years, dual chamber PM 15 [50%]) were included in this analysis. No MR related SADE occurred. Lead measurements were not statistically different between the baseline FU and the 2nd FU (AS/VS at baseline 3.2 ± 2.1/15.0 ± 6.0, at 2nd FU 3.2 ± 2.1/14.9 ± 6.5; p = ns. RA-PTH/RV-PTH at baseline 0.68 ± 0.18/0.78 ± 0.22, at 2nd FU 0.71 ± 0.24/0.78 ± 0.22; p = ns). The presence of the permanent pacemakers led to MR imaging artifacts on diffusion weighted sequences of the brain, but did not affect other sequences (e.g. FLAIR and T2 weighted spin-echo images).ConclusionThe use of the MR conditional Evia PM in a MR environment under predefined conditions is feasible. No MR related SADEs nor clinically relevant changes in device functions occurred.

Benefit of immediate beta-blocker therapy on mortality in patients with ST-segment elevation myocardial infarction.

Objectives:Despite the recommendations to initiate &bgr;-blockade to all patients with an ST-segment elevation myocardial infarction, data concerning the timing of the administration of &bgr;-blockers are controversially discussed. In view of these controversies, we analyzed the effect of immediate vs. delayed &bgr;-blockade on all-cause mortality of patients with ST-segment elevation myocardial infarction in the Lower Austrian Myocardial Infarction Network. Design:Nonrandomized, prospective observational cohort study. Setting:Myocardial infarction network including the out-of-hospital emergency services, five primary-care hospitals and a percutaneous coronary intervention-capable hospital in the western part of Lower Austria. Patients:The data of all patients with ST-segment elevation myocardial infarction defined according to the American Heart Association criteria and treated according to the treatment protocol of the network were consecutively collected. For the purpose of survival analyses, the baseline survival time was set to 48 hours after the first electrocardiogram, and in all patients with recurrent MI within the observational period, only the first MI was regarded. Interventions:The treatment protocol recommended either the immediate oral administration of 2.5 mg bisoprolol (within 30 min after the first electrocardiogram) or 24 hours after acute myocardial infarction (delayed &bgr;-blockade). Measurements and Main Results:In total, out of the 664 patients with ST-segment elevation myocardial infarction, 343 (n = 52%) received immediate &bgr;-blockade and 321 (48%) received delayed &bgr;-blockade. The probability of any death (baseline survival time: 48 hours after first electrocardiogram; 640 patients) was 19.2% in the delayed treatment group and 10.7% in the immediate treatment group (p = 0.0022). Also the probability of cardiovascular mortality was significantly lower in the immediate &bgr;-blocker treatment group (immediate treatment group: 9 (5.2%); delayed treatment group: 30 (13.4%); p = 0.0002). Multivariable Cox regression analysis identified immediate &bgr;-blocker therapy to be independently protective against death of any cause (odds ratio: 0.55, p = 0.033). Conclusion:Immediate &bgr;-blocker administration in the emergency setting is associated with a reduction of all-cause and cardiovascular mortality in patients with ST-segment elevation myocardial infarction and seems to be superior to a delayed &bgr;-blockade in our patient cohort.

Evaluation of a Dual Chamber Implantable Cardioverter Defibrillator for the Treatment of Atrial and Ventricular Arrhythmias

BORIANI, G., et al.: Evaluation of a Dual Chamber Implantable Cardioverter Defibrillator for the Treatment of Atrial and Ventricular Arrhythmias. Eighty‐nine patients with a documented history of atrial tachyarrhythmias or fibrillation (AF) received a cardioverter defibrillator designed to selectively differentiate and treat atrial and ventricular arrhythmias. Twenty‐two patients received a coronary sinus lead and, therefore, could use a separate shock vector for selective treatment of atrial tachyarrhythmias/AF. The device is designed to treat tachyarrhythmias with antitachycardia pacing (ATP) and/or shock therapy using an atrial and/or a ventricular shock vector. Patients underwent induction and shock termination of atrial or dual tachyarrhythmias (AF/VF) to verify proper device function and to measure the arrhythmia detection time with enhancements and preventive algorithms programmed On and Off, respectively. Detection time for 329 VF inductions was 2.41 ± 0.64  seconds with enhancements On and 2.29 ± 0.47 with enhancements Off (NS). At implant or predischarge, 283 AF and/or AF/VF (121 atrial and 162 atrial/ventricular fibrillation) were induced. Shock conversion efficacy was 89.8% with AF conversion energies ranging from 0.9 to 27 J. Thirteen of the 23 patients had atrial shock conversions using the separate shock vector with an average conversion energy of 1.9 ± 1.4  J . (range 0.5–5 J). During follow‐up the efficacy of ATP on atrial tachyarrhythmias was 59% and the efficacy of delivered shocks on AF was 85%. This new dual chamber cardioverter defibrillator appropriately detected and classified atrial arrhythmias, and shock therapy for AF was highly effective. The detection algorithm differentiated atrial tachyarrhythmia/AF and did not delay VF detection. The separate shock vector converted induced AF with energies ranging from 0.6 to 5 J. (PACE 2003; 26[Pt. II]:461–465)

Implantable Dual-Chamber Defibrillator for the Selective Treatment of Spontaneous Atrial and Ventricular Arrhythmias: Arrhythmia Incidence and Device Performance

Introduction: Atrial tachyarrhythmias are a common co-morbidity in patients with an ICD indication. Recently introduced ICD’s are equipped to independently detect and treat atrial and ventricular tachyarrhythmias. The purpose of this prospective study was to evaluate the incidence and termination of spontaneous atrial and ventricular tachyarrythmias in patients with a history of atrial tachyarrhythmias.Methods and Results: Ninety patients, 70% male with an ICD indication and history of atrial tachyarrhythmia (LVEF 45 ± 6%, [AT/AF indication 55 ± 10, AT/VT 45 ± 16], 46% CAD) were enrolled and 89 were implanted with a VENTAK PRIZM AVT (Guidant). Spontaneous atrial and ventricular tachyarrhythmias were printed and evaluated during an average follow-up period of 272 ± 72 days utilizing the stored intracardial electrogram function of the device. Nineteen patients (21%) presented had only atrial tachyarrhythmias, 32 patients (36%) had both atrial and ventricular tachyarrhythmias and 18 patients (20%) had only ventricular tachyarrhythmias. Patients with only atrial tachyarrhythmias had a total of 3274 atrial episodes; 2002 terminated spontaneously, 1264 were treated with ATP and 8 with shock therapy. ATP was successful in 735 (58%) of 1264 episodes. Patients with both atrial and ventricular tachyarrhythmias had 7277 documented atrial tachyarrhythmias, 5231 terminated spontaneously, 1153 of 2009 were terminated by ATP (57.4%) and 37 by shock therapy (20 patient controlled). Atrial tachyarrhythmias identified as atrial flutter (AT) by the atrial rhythm classification (ARC) algorithm had a higher ATP conversion success rate than episodes identified as atrial fibrillation (AF); 66.7% for AT and 26.4% for AF. Patients with only ventricular tachyarrhythmias had 690 documented episodes, 401 terminated spontaneously, 248 (85.8%) were terminated by ATP and 41 by shock.Conclusion: Seventy-seven percent of patients with an ICD indication had spontaneous atrial and/or ventricular tachyharrhythmias within the first 6 months after ICD implantation. ATP therapy terminated 58% of all atrial tachyarrhytmias and 66.7% of the atrial flutters. The dual chamber ICD detected, classified and terminated all ventricular tacharrhythmias appropriately.

A 2-year survey of treatment of acute atrial fibrillation in an ED ☆

OBJECTIVE Pharmacologic cardioversion of atrial fibrillation (AF) is a reasonable mode of treatment if the arrhythmia is of recent onset. Results concerning the response rates of different drugs, respectively, in daily clinical practice and data with regard to the parameters associated with successful cardioversion are not very prevalent. METHODS Three-hundred seventy-six patients who were admitted to the emergency department with acute AF and a duration of shorter than 48 hours were enrolled into the AF registry. RESULTS The most effective drugs were flecainide and ibutilide (95% and 76%). Low response rates were observed with amiodarone (36%) and the individual use of digoxin or diltiazem (19% and 18%). Factors associated with a successful cardioversion were a lower blood pressure on admission (P = .002), a shorter time interval between the onset of AF and admission to the ED (P = .003), and adherence to treatment guidelines (P < .0001). CONCLUSION The use of flecainide and ibutilide is associated with a much higher rate of cardioversion than other drugs we studied.