Wolfram Grimm

Complications of implantable cardioverter defibrillator therapy in 440 consecutive patients.

Background: Although more than 150,000 implantable cardioverter defibrillators (ICDs) are implanted yearly worldwide, only few studies systematically examined complications of ICD therapy in large patient cohorts.

Electrophysiologic evaluation of sinus node function and atrioventricular conduction in patients with prolonged ventricular asystole during obstructive sleep apnea

In 15 patients with ventricular asystole of 8.5 +/- 3.5 seconds (range 5.0 to 16.8) occurring exclusively during obstructive sleep apnea, electrophysiologic study of sinus node function and atrioventricular conduction before and after administration of intravenous atropine (0.02 mg/kg) was performed. Electrophysiologic parameters of sinus node function were normal in 12 of 15 patients (80%) and atrioventricular (AV) nodal function was normal in 7 patients (47%). Almost all abnormal findings of sinus node function and AV nodal function were reversible by administration of atropine. The HisPurkinje system function was normal in 6 patients (40%). Prolonged HV intervals (57 to 73 ms) were found in 9 patients (60%). Intra- or infra-His block was not observed in any patient. In summary, electrophysiologic parameters of sinus node function and AV conduction were normal or only slightly abnormal in all 15 study patients, which suggests that prolonged ventricular asystole during obstructive sleep apnea is not due to fixed or anatomic disease of the sinus node or the AV conduction system.

Outcome of patients with sleep apnea–associated severe bradyarrhythmias after continuous positive airway pressure therapy

Twenty-nine patients in whom severe bradyarrhythmias occurred exclusively during obstructive sleep apnea and in whom advanced sinus node disease or atrioventricular conduction system dysfunction had been excluded by invasive electrophysiologic evaluation were prospectively followed on nasal continuous positive airway pressure. During 54 +/- 10 months follow-up, no syncope and no sudden deaths were observed, suggesting that patients with sleep apnea-associated bradyarrhythmias and a normal electrophysiologic study appear to have a favorable prognosis with continuous positive airway pressure.

The Six-Minute Walk—An Adequate Exercise Test for Pacemaker Patients?

LANGENFELD, H., ET AL.: The Six‐Minute Walk—An Adequate Exercise Test for Pacemaker Patients? In many pacemaker patients bicycle and treadmill ergometry are not practicable. As an alternative, we performed a 6‐minute walk on a 20‐m corridor in 97 pacemaker patients, who were asked to walk as far as possible determining their speed by themselves. Results were compared with those of bicycle ergometry in 42 of these patients and with treadmill exercise of a group of 92 other pacemaker patients. In the 6‐minute walk, performance and maximal heart rate were slightly lower (49 ± 18 W; 96 ± 23 beats/min) than in bicycle (57 ± 16 W; 110 ± 26 beats/min) and treadmill ergometry (50 ± 37 W; 102 ± 35 beats/min). A good correlation was found between walking and bicycling (r = 0.74) and in subgroups of patients with different pacemaker indications. All patients preferred the walk to bicycle ergometry considering it to be more related to daily physical activity. In conclusion, a 6‐minute walk is a simple and physiological exercise test for nearly all pacemaker patients with good correlation to other types of exercise. It seems to be preferable to other tests because of its better acceptance and practicability.

Symptoms, Cardiovascular Risk Profile and Spontaneous ECG in Paced Patients: A Five‐Year Follow‐Up Study

GRIMM, W., ET AL.: Symptoms, Cardiovascular Risk Profile and Spontaneous ECG in Paced Patients: A Five‐Year Follow‐Up Study. Only few data are available about the course of symptoms, cardiac diseases, and spontaneous rhythm in pacemaker patients. Therefore, we followed the course of 308 paced patients (age 72 ± 11 years) with a mean implantation time of 63 ± 45 months. Results: The symptom triad of syncope, dizziness, and dyspnea improved remarkably in 93% of patients. Thirty‐nine percent suffered from coronary heart disease. The risk factors of hypertension (47%), nicotine (37%), and diabetes mellitus (25%) were found significantly more often than in a normal population with the same age and sex profile. In VVI paced patients with sick sinus syndrome (SSS, n = 67) atrial fibrillation (AF) occurred significantly more often (42%) than in patients with AV block (n = 80, 23%, p < 0.05). Only one out of 41 DDD paced patients showed AF at follow‐up. VVI stimulation seems to favor AF due to retrograde conduction in SSS. Only 3% of patients with SSS developed second‐ or third‐degree AV block. Therefore, atrial pacing is preferable in most patients with SSS.

Atrial Fibrillation and Embolic Complications in Paced Patients

Atrial fibrillation (AF) and thromboembolism are discussed to he complications of the WI mode. We reinvestigated the spontaneous ECG and the anamnesis of 246 pacemaker patients with the indications second and third degree atrioventricular block (AV block, n = III), sick sinus syndrome (SSS, n ‐ 101) and other indications (n = 34), all had shown sinus rhythm at implantation. The mean implantation time was 63 ± 45 months (203 VVI and 43 dual chamber pacemkers). The results: (1) Atrial fibrillation was found in 63 patients (26%). Only one of them had a DDD pacemaker inserted, the implantation time of dual chamber devices being shorter, however, (2) The incidence of AF in patients with SSS (37%) was significantly higher (P < 0.01) than in patients with AV block (19%). (3) Three patients suffered from strokes or transitory ischemic attacks in the follow‐up, only one of them had AF at control. Conclusions: Our results confirm that VVI stimulation favors AF long‐term which is most likely due to irritation of the atrial rhythm by retrograde conduction. In our patients the incidence of thromboembolic complications was not higher in the group of patients with AF. However, from this study in surviving patients, we cannot exclude that we Jost some patients due to severe stroke.

Influence of D-Net (European GSM-Standard) Cellular Phones on Pacemaker Function in 50 Patients with Permanent Pacemakers

The widespread use of cellular phones in the last years has prompted some recant studies to suggest an interference of pacemaker function by cellular phone usage. To determine the risk of pacemaker patients using D‐net cellular phones, we tested 50 patients with permanent pacemakers after routine pacemaker check by short phone calls using a cellular phone (Ericsson, D‐net, frequency 890–915 MHz, digital information coding, equivalent to the European Croupe Systemes Mobiles standard). A six‐channel surface ECG was continuously recorded from each patient to detect any interactions between pacemakers and cellular phones. Phone calls were repeated during the following pacemaker settings: (1) preexisting setting; (2) minimum ventricular rate of 90 beats/min and preexisting sensitivity; and (3) minimum ventricular rate of 90 beats/min and maximum sensitivity without T wave oversensing. Only 2 (4%) of 50 patients repeatedly showed intermittent pacemaker inhibition during calls with the cellular phone. Both pacemakers had unipolar sensing. Therefore, although interactions between cellular phone use and pacemaker function appear to be rare in our study, pacemaker dependent patients in particular should avoid the use of cellular phones.

Arrhythmia risk stratification with regard to prophylactic implantable defibrillator therapy in patients with dilated cardiomyopathy. Results of MACAS, DEFINITE, and SCD-HeFT.

Abstract.To date, generally accepted indications for prophylactic defibrillator implantation in patients with dilated cardiomyopathy do not exist. Recently, the Marburg Cardiomyopathy Study (MACAS) revealed left ventricular ejection fraction to be the only significant arrhythmia risk predictor in a relatively large patient population with dilated cardiomyopathy. Meanwhile, the preliminary results of two prospective randomized trials evaluating prophylactic defibrillator therapy in dilated cardiomyopathy have been reported. The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation study (DEFINITE) randomized 458 patients with a history of symptomatic heart failure, a left ventricular ejection fraction ≤ 35% and arrhythmias on Holter to an ICD versus no ICD. As a result, ICD therapy was associated with a significant reduction of arrhythmic deaths, which failed to result in a significant decrease in total mortality due to an insufficient number of patients in DEFINITE. The Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) was a three-arm study comparing placebo to amiodarone to prophylactic ICD therapy in a total of 2,521 patients with ischemic cardiomyopathy (51%) or nonischemic dilated cardiomyopathy (49%). All patients in SCD-HeFT had a left ventricular ejection fraction ¡Ü 35% despite optimized medical heart failure therapy. SCD-HeFT showed a significant reduction of total mortality in the ICD group, whereas amiodarone did not improve survival.Zusammenfassung.Bis heute gibt es keine allgemein akzeptierten Indikationen zur prophylaktischen Defibrillatortherapie bei Patienten mit dilatativer Kardiomyopathie. Kürzlich zeigte die Marburger Kardiomyopathie-Studie (MACAS) die linksventrikuläre Ejektionsfraktion als einzigen signifikanten Parameter zur Arrhythmierisikovorhersage in einem relativ großen Patientengut mit dilatativer Kardiomyopathie. Zwischenzeitlich wurde über die vorläufigen Ergebnisse zweier randomisierter Studien zur prophylaktischen Defibrillatortherapie bei dilatativer Kardiomyopathie berichtet. Die DEFINITE-Studie (Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation) zeigte bei 458 Patienten mit symptomatischer Herzinsuffizienz, einer Ejektionsfraktion ¡Ü 35% und Arrhythmien im Langzeit-EKG eine signifikante Reduktion arrhythmiebedingter Todesfälle in der ICD-Gruppe, die aufgrund der zu niedrigen Fallzahl nicht zu einer signifikanten Reduktion der Gesamtmortalität führte. Bei der SCD-HeFT-Studie (Sudden Cardiac Death in Heart Failure) handelt es sich um eine dreiarmige Studie, in der 2 521 Patienten mit ischämischer Kardiomyopathie (51%) oder nichtischämischer Kardiomyopathie (49%) zu Plazebo, Amiodaron oder prophylaktischer ICD-Therapie randomisiert wurden. Alle Patienten in SCD-HeFT hatten eine Ejektionsfraktion ≤ 35% trotz optimierter medikamentöser Herzinsuffizienztherapie. SCD-HeFT zeigte eine signifikante Reduktion der Gesamtmortalität in der ICD-Gruppe, wogegen Amiodaron keinen Einfluss auf die Mortalität hatte.

Heart rate turbulence following ventricular premature beats in healthy controls.

Background: Heart rate turbulence (HRT) has recently been described as a strong, independent risk stratifier in postinfarct patients. To date, however, the incidence of false positive HRT findings in adults is unknown. Therefore, we performed a blinded, retrospective analysis of HRT in a prospectively collected database of 110 apparently healthy persons to determine the prevalence and clinical significance of abnormal HRT findings in healthy controls using previously published cut‐off values.

Epicardial Neodymium YAG Laser Photocoagulation of Ventricular Tachycardia Without Ventriculotomy in Patients After Myocardial Infarction

BACKGROUND Surgical ablation of ventricular tachycardia (VT) after myocardial infarction has been reported by different endocardial approaches. The ventriculotomy may increase mortality of the procedure. METHODS AND RESULTS We report on nine patients who suffered from recurrent VT in the late post-myocardial infarction period. Significant stenoses were detected in all patients. The mean left ventricular ejection fraction was 43.1 +/- 8.3%. Left ventricular scar (n = 9) was seen. The mean NYHA class was 2.2 +/- 0.4. Sustained VT (mean cycle length, 293 +/- 52 ms) occurred spontaneously (n = 9) and could be induced reproducibly. Catheter mapping detected a prematurity of -42 +/- 13 ms in six patients. Clinical VT was inducible during surgery in seven patients. Middiastolic potentials were detected from the epicardial surface (n = 3), and premature potentials were found (n = 8 with prematurity of -108 +/- 46 ms). Application of neodymium/yttrium/argon/ garnet (Nd:YAG) laser energy to early epicardial activation terminated the arrhythmia (n = 7). Ventriculotomy was not performed. Seven patients have been free of VT for a mean follow-up period of 17 +/- 11 months; one patient relapsed and was treated with an implantable cardioverter-defibrillator, as was a second patient with inducible VT after surgery. CONCLUSIONS Surgical Nd:YAG laser photocoagulation of VT on the epicardial surface of the heart in post-myocardial infarction patients without ventriculotomy is safe and has a high success rate. At the present time, this method is recommended in patients with sustained and tolerated VT who need bypass surgery. This is the first report on epicardial laser ablation of VT in post-myocardial infarction VT.