Florian Reinke

Occult Atrial Fibrillation in Cryptogenic Stroke Detection by 7-Day Electrocardiogram Versus Implantable Cardiac Monitors

Background and Purpose— A significant number of patients with cryptogenic stroke suffer from intermittent atrial fibrillation (iAF) which was not detected during the standard diagnostic procedures. We investigated whether implantation of an insertable cardiac monitor (ICM) is feasible in patients with cryptogenic stroke, and compared the iAF detection rate of the ICM with 7-day Holter monitoring. Methods— Sixty patients (median age 63; interquartile range, 48.5–72 years) with acute cryptogenic stroke were included. ICM was implanted 13 days (interquartile range; 10–65 days) after the qualifying event. Seven-day Holter was performed after the ICM was implanted. Results— The iAF was detected by the ICM in 10 patients (17%; 95% CI, 7% to 26%). Only 1 patient (1.7%; 95% CI, 0% to 5%) had iAF during 7-day Holter monitoring as well (P=0.0077). Episodes of iAF lasting 2 minutes or more were detected 64 (range, 1–556) days after implantation. There were no recurrent strokes during the observation period. The implantation procedure was well tolerated with no adverse events; the daily data transmission protocol was easy to handle by the patients. Conclusions— ICM implantation for the detection of iAF during outpatient follow-up is feasible in patients with cryptogenic stroke. ICMs offer a much higher diagnostic yield than 7-day Holter monitoring.

Implantation and follow-up of totally subcutaneous versus conventional implantable cardioverter-defibrillators: A multicenter case-control study

BACKGROUND The approval of an entirely subcutaneous implantable-cardioverter defibrillator (ICD) system (S-ICD) has raised attention about this promising technology. It was developed to overcome lead failure and infection problems of conventional transvenous ICD systems. Nevertheless, lead migration of the initial design and inappropriate shock rates have raised concerns regarding its reliability and safety. OBJECTIVE The purpose of this study was to report the largest multicenter series to date of patients with the new device in comparison with a matched conventional transvenous ICD collective with focus on perioperative complications, conversion of induced ventricular fibrillation (VF), and short-term follow-up. METHODS/RESULTS Sixty-nine patients (50 male and 19 female; mean age 45.7 ± 15.7 years) received an S-ICD in three German centers and were randomly assigned to 69 sex- and age-matched conventional ICD patients. The indication was primary prevention in 41 patients (59.4%) without difference between groups (34 control patients; P = .268). The predominant underlying heart disease was ischemic cardiomyopathy in 11 (15.9%), dilated cardiomyopathy in 25 (36.2%), and hypertrophic cardiomyopathy in 10 (14.5%) in the S-ICD group. Mean implantation time was 70.8 ± 27.9 minutes (P = .398). Conversion rates of induced VF were 89.5% for 65 J (15-J safety margin) and 95.5% including reversed shock polarity (15-J safety margin) in the study group. Termination of induced VF was successful in 90.8% (10-J safety margin, device dependent) of the control patients (P = .815). Procedural complications were similar between the 2 groups. Mean follow-up was 217 ± 138 days. During follow-up, 3 patients with S-ICD were appropriately treated for ventricular arrhythmias. Three inappropriate episodes (5.2%) occurred in 3 S-ICD patients due to T-wave oversensing, whereas atrial fibrillation with rapid conduction was the predominant reason for inappropriate therapy in conventional devices (P = .745). CONCLUSION The novel S-ICD system can be implanted safely with similar perioperative adverse events compared with standard transvenous devices. Our case-control study demonstrates a 10.4% failure of conversion of induced VF with the S-ICD set to standard polarity and 15-J safety margin and comparable inappropriate shock rates during short-term follow-up.

Supraventricular Premature Beats and Short Atrial Runs Predict Atrial Fibrillation in Continuously Monitored Patients With Cryptogenic Stroke

Background and Purpose— Supraventricular premature beats (SPBs) may help to assess the risk of atrial fibrillation (AF) in patients with cryptogenic stroke and therefore guide therapy. Methods— An internal loop recorder was implanted in consecutive patients with acute cryptogenic stroke. The occurrence and quantity of SPBs and short supraventricular runs (SVRs) in 24-hour ECG in patients with and without future AF were analyzed. We evaluated the relative risk of the upper quartile of SPB and SVR patients against the remainder and used binary logistic regression to evaluate a possible independent influence of SPBs and SVRs on AF occurrence. Results— Twelve of 70 included patients (mean age, 59±13 years) experienced development of AF during a mean monitoring duration of 536±212 days. Patients with AF had a median of 22.8 SPBs/h versus 1.2 SPBs/h (P<0.0001) in patients without AF and a median of 0.7 SVRs/h (AF) versus 0 SVR/h (non-AF). Patients in the upper quartile of SPBs (>14.1/h) and SVRs (>0.2/h) demonstrated a relative risk of 4.0 (95% confidence interval, 1.1–14.6; P=0.04) and 6.9 (95% confidence interval, 1.8–26.7; P=0.005) for future AF, respectively. In binary logistic regression, SPBs (P=0.02) and SVRs (P=0.05) remained significant independent predictors for occurrence of AF. Conclusions— Numerous SPBs and SVRs demonstrated a high risk for future AF in patients with cryptogenic stroke.

Diastolic filling pattern and left ventricular diameter predict response and prognosis after cardiac resynchronisation therapy

Objective: To investigate predisposing factors for cardiac resynchronisation therapy (CRT) response. Design: Single-centre study. Setting: University hospital in Germany. Patients: 122 consecutive patients with heart failure (mean (SD) age 65 (11) years; ischaemic/non-ischaemic 41%/55%; New York Heart Association (NYHA) class 3.1 (0.3); left ventricular ejection fraction 24.4 (8.1)%; QRS width 170 (32) ms, quality of life (QoL) 43.5 (19.2)) with an indication for CRT and demonstrated left ventricular dyssynchrony by echocardiography including tissue Doppler imaging. Interventions: Besides laboratory testing of clinical variables, results of ECG, echocardiography including tissue Doppler imaging, invasive haemodynamics, measures of QoL and of exercise capacity were obtained before CRT implantation and during follow-up. Main outcome measure: Responders were predefined as patients with improvement by one or more NYHA functional class or reduction of left ventricular end-systolic volume by 10% or more during follow-up. Mean (SD) follow-up was 418 (350) days. Results: Overall, 70.5% of patients responded to CRT. Responders had a significantly improved survival compared with non-responders (96.2% vs 45.5%, log-rank p<0.001). On univariate analysis, left ventricular end-diastolic diameter, left ventricular end-systolic diameter (LVESD), E/A ratio, a restrictive filling pattern, mean pulmonary artery pressure, pulmonary capillary pressure, N-terminal pro-brain natriuretic peptide and Vo2max were significant predictors of outcome. On multivariate analyses, LVESD (p = 0.009; F = 7.83), pulmonary capillary pressure (p = 0.015, F = 6.61) and a restrictive filling pattern (p = 0.026, F = 5.707) remained significant predictors of response. Conclusions: Despite treatment according to present guidelines nearly 30% of patients had no benefit from CRT treatment in a clinical setting. On multivariate analyses, patients with an increased left ventricular end-systolic diameter and concomitant diastolic dysfunction had a significantly worse outcome.

Successful treatment of catecholaminergic polymorphic ventricular tachycardia with flecainide: a case report and review of the current literature

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic disease that can cause sudden cardiac death due to ventricular fibrillation (VF). While pharmacological therapy with beta-blockers and/or Ca(2)(+) antagonists is often unreliable, a recent study has demonstrated that flecainide can effectively suppress arrhythmia in a murine model of CPVT as well as clinically in two human subjects suffering from CPVT. We here present the case of an 11-year-old boy suffering from CPVT-1 as well as a review of the current relevant literature. After resuscitation due to VF at age 9, an automated implantable cardioverter-defibrillator (ICD) was implanted in 2007. Under beta-blocker therapy, repeated shocks were delivered due to either fast ventricular tachycardia (VT) or VF. This persisted under additional therapy with verapamil. Implantable cardioverter-defibrillator routine interrogations showed frequent non-sustained VT with an average of 8.8 per day. Additionally, the patient suffered from impaired physical performance due to decreased chronotropic competence. In July 2009, flecainide was added to the beta-blocker/verapamil regimen, resulting in a plasma level of 0.20 mg/L. No ICD shock or sustained VT occurred until December 2010. Genetic testing revealed an RyR2 receptor mutation. The case demonstrates the challenge of diagnosis and management of CPVT. It furthermore supports recent experimental evidence that the class 1 antiarrhythmic drug flecainide can suppress CPVT. The presented case supports a novel strategy in treating CPVT with the class I antiarrhythmic agent flecainide.

[Current status and problems of the entirely subcutaneous ICD (S-ICD®)].

ZusammenfassungDie Prävention des plötzlichen Herztods ist eine der wichtigsten Aufgaben der Kardiologie. Transvenöse ICD-Systeme haben ihre Effektivität in zahlreichen randomisierten Studien eindrucksvoll belegt, aber sie haben ihre Grenzen durch häufige Komplikationen im Langzeitverlauf. Das seit wenigen Jahren verfügbare, rein subkutane ICD-System (S-ICD®, Boston Scientific, USA, zuvor Cameron Health, USA) scheint vielversprechend, obwohl prospektive, randomisierte Daten fehlen. Die Implantation des S-ICD® ist einfach, relevante Komplikationen sind wegen der rein subkutanen Lage selten. Die Erkennung und Therapie von lebensbedrohlichen Tachyarrhythmien scheint bislang sicher, obwohl Langzeitdaten noch fehlen und im Fall eines unzureichenden EKG-Screenings inadäquate Therapien ein häufiges Problem darstellen. Der S-ICD® ist wegen der begrenzten Programmiermöglichkeiten sowie der fehlenden Möglichkeit zur Stimulation keine Alternative zum transvenösen System, stellt aber eine interessante Ergänzung der ICD-Therapie dar.AbstractPrevention of sudden cardiac death is one of the most important tasks of cardiology. Transvenous ICD-systems have impressively proven their effectiveness in numerous randomized trials. Transvenous systems have their limitations due to frequent long-term lead complications. Having been available for a few years, the entirely subcutaneous ICD-system (S-ICD®, Boston Scientific, USA, former Cameron Health, USA) seems to be a promising alternative despite the lack of prospective data. The implantation of the S-ICD® can be performed easily; lead complications are rare because of the totally subcutaneous implantation. The detection and therapy of life-threatening tachyarrhythmias seems to be safe, although inappropriate therapies are a common problem in cases of insufficient ECG screening. S-ICD® is no alternative to the transvenous system due to limited programming options and the lack of stimulation, but it is an interesting supplement of ICD therapy.Prevention of sudden cardiac death is one of the most important tasks of cardiology. Transvenous ICD-systems have impressively proven their effectiveness in numerous randomized trials. Transvenous systems have their limitations due to frequent long-term lead complications. Having been available for a few years, the entirely subcutaneous ICD-system (S-ICD®, Boston Scientific, USA, former Cameron Health, USA) seems to be a promising alternative despite the lack of prospective data. The implantation of the SICD® can be performed easily; lead complications are rare because of the totally subcutaneous implantation. The detection and therapy of life-threatening tachyarrhythmias seems to be safe, although inappropriate therapies are a common problem in cases of insufficient ECG screening. S-ICD® is no alternative to the transvenous system due to limited programming options and the lack of stimulation, but it is an interesting supplement of ICD therapy.

Gegenwärtiger Stand und Probleme vollständig subkutaner ICD-Systeme (S-ICD®)

ZusammenfassungDie Prävention des plötzlichen Herztods ist eine der wichtigsten Aufgaben der Kardiologie. Transvenöse ICD-Systeme haben ihre Effektivität in zahlreichen randomisierten Studien eindrucksvoll belegt, aber sie haben ihre Grenzen durch häufige Komplikationen im Langzeitverlauf. Das seit wenigen Jahren verfügbare, rein subkutane ICD-System (S-ICD®, Boston Scientific, USA, zuvor Cameron Health, USA) scheint vielversprechend, obwohl prospektive, randomisierte Daten fehlen. Die Implantation des S-ICD® ist einfach, relevante Komplikationen sind wegen der rein subkutanen Lage selten. Die Erkennung und Therapie von lebensbedrohlichen Tachyarrhythmien scheint bislang sicher, obwohl Langzeitdaten noch fehlen und im Fall eines unzureichenden EKG-Screenings inadäquate Therapien ein häufiges Problem darstellen. Der S-ICD® ist wegen der begrenzten Programmiermöglichkeiten sowie der fehlenden Möglichkeit zur Stimulation keine Alternative zum transvenösen System, stellt aber eine interessante Ergänzung der ICD-Therapie dar.AbstractPrevention of sudden cardiac death is one of the most important tasks of cardiology. Transvenous ICD-systems have impressively proven their effectiveness in numerous randomized trials. Transvenous systems have their limitations due to frequent long-term lead complications. Having been available for a few years, the entirely subcutaneous ICD-system (S-ICD®, Boston Scientific, USA, former Cameron Health, USA) seems to be a promising alternative despite the lack of prospective data. The implantation of the S-ICD® can be performed easily; lead complications are rare because of the totally subcutaneous implantation. The detection and therapy of life-threatening tachyarrhythmias seems to be safe, although inappropriate therapies are a common problem in cases of insufficient ECG screening. S-ICD® is no alternative to the transvenous system due to limited programming options and the lack of stimulation, but it is an interesting supplement of ICD therapy.Prevention of sudden cardiac death is one of the most important tasks of cardiology. Transvenous ICD-systems have impressively proven their effectiveness in numerous randomized trials. Transvenous systems have their limitations due to frequent long-term lead complications. Having been available for a few years, the entirely subcutaneous ICD-system (S-ICD®, Boston Scientific, USA, former Cameron Health, USA) seems to be a promising alternative despite the lack of prospective data. The implantation of the SICD® can be performed easily; lead complications are rare because of the totally subcutaneous implantation. The detection and therapy of life-threatening tachyarrhythmias seems to be safe, although inappropriate therapies are a common problem in cases of insufficient ECG screening. S-ICD® is no alternative to the transvenous system due to limited programming options and the lack of stimulation, but it is an interesting supplement of ICD therapy.

Intraoperative Defibrillation Testing of Subcutaneous Implantable Cardioverter‐Defibrillator Systems—A Simple Issue?

Background The results of the recently published randomized SIMPLE trial question the role of routine intraoperative defibrillation testing. However, testing is still recommended during implantation of the entirely subcutaneous implantable cardioverter‐defibrillator (S‐ICD) system. To address the question of whether defibrillation testing in S‐ICD systems is still necessary, we analyzed the data of a large, standard‐of‐care prospective single‐center S‐ICD registry. Methods and Results In the present study, 102 consecutive patients received an S‐ICD for primary (n=50) or secondary prevention (n=52). Defibrillation testing was performed in all except 4 patients. In 74 (75%; 95% CI 0.66–0.83) of 98 patients, ventricular fibrillation was effectively terminated by the first programmed internal shock. In 24 (25%; 95% CI 0.22–0.44) of 98 patients, the first internal shock was ineffective and further internal or external shock deliveries were required. In these patients, programming to reversed shock polarity (n=14) or repositioning of the sensing lead (n=1) or the pulse generator (n=5) led to successful defibrillation. In 4 patients, a safety margin of <10 J was not attained. Nevertheless, in these 4 patients, ventricular arrhythmias were effectively terminated with an internal 80‐J shock. Conclusions Although it has been shown that defibrillation testing is not necessary in transvenous ICD systems, it seems particular important for S‐ICD systems, because in nearly 25% of the cases the primary intraoperative test was not successful. In most cases, a successful defibrillation could be achieved by changing shock polarity or by optimizing the shock vector caused by the pulse generator or lead repositioning.

Vernakalant in an experimental model of pacing-induced heart failure: lack of proarrhythmia despite prolongation of repolarization.

BACKGROUND The present ESC guidelines on atrial fibrillation have introduced vernakalant (VER) for pharmacologic cardioversion of atrial fibrillation. The aim of the present study was to investigate possible proarrhythmic effects of vernakalant in an experimental model of heart failure (HF). METHODS AND RESULTS In 12 female rabbits, HF was induced with the use of 4 weeks of rapid ventricular pacing. Twelve rabbits were sham operated. Isolated hearts demonstrated a significant prolongation of myocardial repolarization after induction of HF. Vernakalant caused a concentration-dependent (10 μmol/L and 30 μmol/L) increase of action potential duration (APD90) and QT interval without affecting spatial and temporal dispersion of repolarization. The increase in APD90 was accompanied by a greater increase in refractory period resulting in a significant increase in post-repolarization refractoriness. In control conditions, programmed ventricular stimulation and burst pacing led to ventricular fibrillation (VF) in 2 of the 12 sham (4 episodes) and in 3 of the 12 HF (24 episodes) subjects. In the presence of 30 μmol/L vernakalant, VF was no longer inducible in both groups (0 episodes). In the presence of low K+ concentration, neither sham nor HF vernakalant-treated subjects developed early after-depolarizations or ventricular tachyarrhythmias. CONCLUSION In the present study, application of vernakalant led to a significant prolongation of myocardial repolarization and increased post-repolarization refractoriness but did not induce early after-depolarization and therefore did not cause proarrhythmia in failing hearts.

Prospective evaluation of electrocardiographic parameters in cardiac resynchronization therapy: detecting nonresponders by left ventricular pacing.

BACKGROUND AND OBJECTIVE The purpose of this prospective evaluation of electrocardiographic (ECG) parameters was to identify predictive parameters for cardiac resynchronization therapy (CRT) response. METHODS One hundred two patients undergoing first CRT implantation were evaluated prospectively. Symptomatic response was defined as improvement in New York Heart Association functional class of at least 1 class within 3-month follow-up. Twelve-lead ECG of the intrinsic rhythm during biventricular (BIV), right ventricular (RV), and left ventricular (LV) pacing was obtained and analyzed in terms of QRS width and QRS axis (Datinf Measure Software, Datinf GmbH, Tübingen, Germany). In total, 77.5% (n = 79) of patients fulfilled the predefined clinical criterion for response. Patients with dilated cardiomyopathy were more likely to respond to CRT than were patients with ischemic cardiomyopathy (85% vs 71.8%, P = .034). A shorter QRS duration during LV pacing and, in particular, a shorter LV paced than RV paced QRS width were strong and independent predictors for response (-20.13 ± 33.2 ms in responders vs 6.05 ± 27.3 ms in nonresponders, P = .001). No statistically significant differences were found in RV and BIV paced QRS width or in QRS axis (P >.5). CONCLUSION This study describes novel and easily obtainable ECG measurements that can be performed during LV lead positioning to optimize clinical outcome of CRT in heart failure patients.