Nonpharmacological therapy of ventricular tachyarrhythmias: observations in 554 patients

[History of surgical treatment of cardiac arrhythmias in Germany : Surgical treatment of ventricular tachycardia and supraventricular tachycardia, especially pre-excitation syndromes (WPW)]

The history of surgical treatment of ventricular tachycardias (VT) is short, lasting from 1978 until 1993. "Indirect procedures" with infarct scar resection were performed without electrophysiologic studies, whereas "direct procedures" consisted of either complete endocardial incisions ("encircling endocardial ventriculotomy") or large endocardial resections ("endocardial peel-off" technique) after precise epicardial and endocardial mapping procedures. In Germany, the first to report on intra-operative electrophysiologic mapping for VT treatment were Ostermeyer, Breithardt and Seipel in 1979. In 1981, the Hannover group (Frank, Klein) published their first results of surgical treatment of VT. In 1984, Ostermeyer et al. demonstrated that a partial endocardial incision resulted in more beneficial results with less myocardial damage (8% versus 46%) than applying a complete encircling incision. In 1987, the Düsseldorf group reported treatment results of 93 patients. After 5 years, 77% had no VT recurrence, while total mortality after 1 year was 11% and after 5 years 30%. In 1992, the Hannover group reported results of 147 patients after endocardial resection for VT. Total mortality after 3 years was 27%; recurrence of VT events occurred in 18% of the surviving cohort.The history of surgical procedures for supraventricular tachycardia (SVT), in particular Wolff-Parkinson-White (WPW) syndrome, is even shorter than that of surgery for VT. As early as 1969, Sealy, Gallagher and Cox reported the first cases of surgical intervention for WPW syndrome via endocardial access in cardioplegic arrest. In 1984, Guiraudon and Klein reported on a new procedure with epicardial access to the accessory bundle without cardioplegia in laterally localised conduction pathways. In Germany, too, the groups in Düsseldorf (Ostermeyer, Seipel, Breithardt, Borggrefe) from 1980 and the Hannover group (Frank, Klein and Kallfelz) from 1981 performed surgical procedures for WPW syndrome. In 1987, Borggrefe reported on 18 patients with WPW syndrome and atrial fibrillation who had undergone surgery. After 2 years, 14 of 18 patients had no recurrences of tachycardia; in 1989, Frank, Klein and Kallfelz (Hannover) reported on 10 children (2-14 years) operated on using the cryoablation technique. Between 1984 and 1992, a total of 120 patients with SVT, mostly WPW syndrome, were operated on in Hannover; after 42 months, 12 patients had a recurrence of SVT. Two patients died during the reoperation.

[Short history of the DC-Catheter-Ablation]

Direct current (DC) catheter ablation in 5 patients aiming to interrupt rapid atrioventricular (AV) conduction with atrial fibrillation and subsequent pacemaker implantation was first published by M. M. Scheinman et al. (San Francisco, CA, USA) in 1982. In Germany, L. Seipel, G. Breithardt, and M. Borggrefe reported their first experience with DC catheter ablation in 1984, followed by the group in Bonn (M. Manz and B. Lüderitz) in 1985. The first international DC catheter ablation registry, which also included four German centers, reported DC catheter ablation results of 127 patients in 24 centers in 1984. Complete AV block was achieved in 71% patients. In 1992, the Hannover group (H‑J. Trappe, H. Klein and J. Huang) reported results of DC catheter ablation of AV conduction performed between 1983 and 1990 in 100 patients (86% with rapid atrial fibrillation, 14% with AV-node reentry tachycardias). The first successful DC catheter ablation in a patient with Wolff-Parkinson-White (WPW) syndrome was reported in 1985 by F. Morady et al. (San Francisco, CA, USA). In 1987, M. Borggrefe et al. were the first to report a switch from DC catheter ablation to a high-frequency (HF) catheter ablation procedure in a patient with WPW syndrome. The use of DC catheter ablation to treat ventricular tachycardia (VT) was described by G. O. Hartzler (Kansas City, MO, USA) in 3 patients in 1983. M. Borggrefe et al. (1989) reported on 24 patients who underwent DC catheter ablation for VT. Of those, 17 patients did not have VT recurrence within the following 14 months. In 1994, the Hannover group (H-J Trappe, H. Klein) published their 5‑year long-term results of DC catheter ablation of VT in 51 patients. VT recurrence occurred in 57% patients and overall mortality was also high (16%). A comparison of DC catheter ablation with HF catheter ablation for recurrent VT was reported in 1994 by G. Gonska et al. (Göttingen, Germany). After 2 years follow-up, success rates were not found to be significantly different.

Life Situation Related to The ICD Implantation; Self-Reported Uncertainty and Satisfaction in Swedish and US Samples

The aim of the study was to describe changes in the life situation related to the ICD implantation of Swedish and US samples with regard to uncertainty and satisfaction. The life situation was measured by reference to the uncertainty caused by the condition and satisfaction with the life situation. Inferential statistics were used to analyse changes within and between the Swedish and US samples. Uncertainty showed a statistically significant difference between the Swedish and US samples before as well as after the ICD implantation. A higher level of uncertainty was indicated for the US sample prior to the ICD implantation and for the Swedish sample following the implantation. In the Swedish sample, satisfaction with life showed a statistically significant difference within the socio-economic domain, indicating a higher degree of satisfaction 3 months after implantation. Satisfaction within the domains of health and functioning, socio-economics and psychological-spiritual showed a statistically significant difference between the Swedish and US samples both before and after ICD implantation, indicating a higher degree of satisfaction in the US sample. The previous study shows that the ICD-patient's life situation is changed after the implantation and that it is necessary to provide the patient with information and education based on their own preconditions. The fact that US sample was investigated at a later stage after ICD implantation than the Swedish sample may have influenced the results of the study.

Preventing sudden death after repair of tetralogy of Fallot: complex therapy for complex patients

Sudden arrhythmic death in patients with repaired tetralogy of Fallot or its variants has a variety of causes. Consequently, it can serve as a paradigm for management of potentially malignant arrhythmias in all pediatric patients, particularly with regard to the use of nonpharmacologic therapy for management. Five cases are presented as touchpoints for discussion and demonstrate a number of important issues concerning the assessment and reduction of sudden cardiac death risk in these patients. First, there are no clinical parameters that can be used to accurately assess risk. Second, pharmacologic agents alone rarely are adequate therapy. Third, catheter ablation and antitachycardia devices continue to play an ever increasing role in management of these patients, and, finally, additional data are necessary to establish clear management guidelines in patients with congenital heart disease at risk for arrhythmic death.

Single-chamber versus dual-chamber implantable cardioverter defibrillators: indications and clinical results

The clinical benefit of standard (single-chamber) implantable cardioverter defibrillator (ICD) therapy in elderly patients or in subjects with moderate or severe heart failure who had ventricular tachyarrhythmias has been debated. We studied the follow-up of 450 patients who underwent standard ICD implantation at our institution in relation to the functional status of heart failure (New York Heart Association Class) or patient's age. During a mean follow-up of 24 +/- 28 months (range, < 1-114 months), 90 patients (23%) died: 9 patients (2%) from sudden arrhythmic death and 5 patients (1%) suddenly, but probably not from arrhythmic causes; 55 patients (14%) died from congestive heart failure and/or myocardial reinfarction and 21 patients (5%) from noncardiac causes. We could clearly demonstrate that ICD therapy was able to prevent sudden cardiac death, both in patients with severely depressed left ventricular function and in patients aged > or = 65 years. An important step forward in ICD technology was the introduction of dual-chamber pacing possibilities to improve left ventricular dysfunction and to allow a more individualized ICD therapy. At our institution, we have implanted a dual-chamber ICD in 15 patients. Preliminary results showed that heart failure improved in 5 patients (33%) and remained unchanged in 10 patients (67%, p = not significant). There were no patients who had a lesser degree of heart failure after implant. Based on our experience so far, in addition to the hemodynamic benefits of dual-chamber ICDs, dual-chamber sensing and wave-form storage capabilities are very helpful and promising diagnostic tools for the detection and handling of inappropriate ICD therapies.

Large encircling cryoablation without mapping for ventricular tachycardia after anterior myocardial infarction: long-term outcome

OBJECTIVE

Map-guided procedures have been the accepted standard for ventricular tachycardia surgery. However, promising results of visually guided resections without mapping have been reported. The goal of this study was to evaluate the efficacy of large encircling cryoablation without mapping for ventricular tachycardia after anterior myocardial infarction.

METHODS

Between 1985 and 1996, this procedure, along with aneurysmectomy, was performed on 38 patients for malignant ventricular tachycardia. The mean interval between the operation and myocardial infarction was 59.2 months; 7 patients (18.4%) were operated on within 1 month of myocardial infarction. The mean patient age was 62.1 +/-7.3 years and the mean left ventricular ejection fraction was 29.0% +/-7.2%.

RESULTS

Hospital mortality was 2.6% (1 patient). The electrical success rate based on postoperative electrophysiologic studies was 94.5%. Overall electrical success rate was 89.1%. Freedom from ventricular tachycardia was 77% (95% CI 61%-94%) at both 5 and 7 years. Freedom from sudden cardiac death was 91% (95% CI 80%-100%) at both 5 and 7 years, with overall actuarial survivals at 5 and 7 years of 63% (95% CI 47%-80%) and 42% (95% CI 22%-63%), respectively. The main cause of late death was congestive heart failure in 62.6% of these patients.

CONCLUSIONS

One can achieve good results without intraoperative mapping in the treatment of patients with ventricular tachycardia after anterior myocardial infarction by using large encircling cryoablation.

Should patients with implantable cardioverter-defibrillators be allowed to drive? Observations in 291 patients from a single center over an 11-year period

Motor-vehicle driving restrictions for patients with implantable cardioverter-defibrillators (ICDs) vary widely throughout the world because safety concerns have never been adequately resolved in this patient population. To address this issue, we examined the driving behavior of 291 ICD patients to correlate the frequency of device therapy during driving, the occurrence of syncopal symptoms, and the incidence of traffic accidents. Fifty of the 291 patients had never driven. Of the remaining 241 patients, 171 (59%) continued driving postimplant and 70 (24%) elected to stop prior to (n = 30) or at the time of ICD implantation (n = 40). Patients were followed for a mean of 38 +/- 26 months (range < 1-124). During this period, no patients died while driving. Of 11 accidents involving 11 driving patients (6%), only 1 was caused by the driver, and none was related to syncopal symptoms or ICD therapy. Although 2 accidents (8%) occurred within 12 months postimplant, the majority (50%) took place after more than 36 months. ICD therapy was delivered in 8 patients (5%) while driving: 13% (1 episode) of the discharges occurred within the first year postimplant, 13% (1 episode) occurred between 1-2 years, and 74% (6 episodes) occurred > 2 years. None of these patients experienced syncope before or during these episodes. A multivariate analysis was unable to identify any variables that might predict increased risk of ICD therapy (with or without sudden death) while driving and consequent motor vehicle accidents. Our data suggest that such events occur only rarely.

[Cerebral hemodynamics during implantation of cardioverter-defibrillator systems]

OBJECTIVE

During ICD-implantation it is necessary to prove the function and to determine the optimal threshold by means of induced ventricular fibrillation (VF). Provoked cardiac arrests cause a circulator stop of the cerebral perfusion. Our aim was to examine the changes of cerebral blood flow velocity (CBFV(MCA)) after induced VF depending on the duration of fibrillation and prior values of CBFV(MCA).

PATIENTS AND METHODS

Sixty induced episodes of VF in 9 patients (mean age +/- SD 53.5 +/- 8 years) were examined during ICD-implantation. Beside the standardized anaesthesiological monitoring, transcranial Doppler sonography was used to record the cerebral blood flow velocity in the middle cerebri artery CBFV(MCA). The duration of the fibrillation-period and the range and duration of the CBFV increase during the post defibrillation-period were correlated. Additionally, we examined whether systematic differences existed between the episodes of each patient (time-trend) by means of 5 following episodes of a patient.

RESULTS

During all episodes of VF and hyperperfusion was present, that means a time interval showing increased values of CBFV(MCA), compared to the values present before VF. The duration of hyperperfusion depended significantly on the fibrillation time (r = 0.57; p < 0.001). The equation of regression is: hyperperfusion time = 11.1 + 1.22 x fibrillation time. The amount of hyperperfusion, that means the maximal CBFV after defibrillation, increase significantly with CBFV(MCA) before VF (correlation = 0.88; p < 0.001). The equations of regression is hyperperfusion height = 6.11 + 1.22 x CBFV(MCA) before VF. The duration of hyperperfusion is not influenced by the maximal CBFV(MCA) after defibrillation (r = 0.08; p = 0.52). In the examined patients no significant differences in the hyperperfusion time maximal CBFV(MCA) after defibrillation between the episodes were found.

CONCLUSION

After induced VF you always have to expect a reactive cerebral hyperperfusion. The amount of increase of CBFV after defibrillation depends on the prior values of CBFV before fibrillation and shows a nearly proportional relation to these. The duration of hyperperfusion shows a linear dependency on VF-times. This may show that we had VF-times, in which the cerebral autoregulation and other cerebral physiological reactions compensate the drop of the CBFV(MCA) during VF in the postfibrillation time. In further studies will be examined if there are similar changes in the cerebral metabolism as in CBFV(MCA).

Long-term follow up of patients with implantable cardioverter-defibrillators and mild, moderate, or severe impairment of left ventricular function

OBJECTIVE

To determine whether patients with life threatening ventricular tachyarrhythmias, impaired left ventricular function, and severe heart failure will benefit from implantable cardioverter-defibrillator (ICD) treatment.

DESIGN

410 patients were followed up after ICD implant. Left ventricular function was assessed by the New York Heart Association (NYHA) functional class of heart failure: 50 patients (12%) were in NYHA I-II, 151 (37%) in NYHA II, 117 (29%) in NYHA II-III, and 92 (22%) in NYHA III. Epicardial ICD implantation was performed in 209 patients (51%) and 201 patients (49%) received non-thoracotomy ICDs.

RESULTS

Perioperatively, 12 patients (3%) died, more often after epicardial ICD implant (11/209 patients, 5%) than after transvenous implant (1/201 patients, < 1%) (P < 0.05). During a mean (SD) follow up of 28 (24) months (range < 1 to 114 months), 90 patients (23%) died: nine (2%) died from sudden arrhythmia; five (1%) also died suddenly but probably not from arrhythmic causes; 55 (14%) died from cardiac causes (congestive heart failure, myocardial reinfarction); 21 (5%) died from non-cardiac causes. The three year, five year, and seven year survival was 92-96% for arrhythmic mortality in NYHA class I, II and III, compared to a three year survival of 94% and a five year and seven year survival of 84% for patients in NYHA class II-III. 338 patients (82%) received ICD shocks (21 (SD 43) shocks per patient); patients in NYHA class II (83%), class II-III (84%), and class III (90%) received ICD discharges more often than those in class I-II (64%) (P < 0.05). The mean (SD) time interval between ICD implant and the first ICD shock was shorter in NYHA class II (16 (17) months), class II-III (19 (27) months), and class III (16 (19) months) than in class 0-I (22 (24) months) (P < 0.05).

CONCLUSIONS

Patients with mild, moderate, and severe left ventricular dysfunction benefit from ICD treatment and these patients survive for a considerable time after the first shock. Survival is influenced by the degree of left ventricular dysfunction; aggressive treatment of heart failure is necessary as well as ICD therapy.

[Defibrillator therapy 1997. Prerequisites--results--prospects]

BACKGROUND

The first human cardioverter defibrillator implant was performed in 1980. Since then, significant technological improvement has been performed and today, ICDs with multiple diagnostic and therapeutic features are available. We report on 541 patients who underwent ICD implantation between January 1984 and March 1997. Epicardial ICD implant was performed in 209 patients (39%) and 332 patients (61%) received transvenous ICDs.

PATIENTS AND RESULTS

Perioperative mortality was 2% (13 patients), significantly more frequent after epicardial (12/209 patients, 6%) than after transvenous implantation (1/332 patients) (p < 0.01). During a mean follow-up of 28 +/- 23 months, 104 patients died (20%), 15 of them (3%) suddenly. 8407 arrhythmic episodes were observed and terminated by antitachycardia pacing in 6655 (79%). Infections occurred in 13 patients (2%), electrode complications in 43 patients (8%) and inappropriate shocks in 84 patients (16%).

CONCLUSION

The ICD is an effective approach to treat patients with life-threatening ventricular tachyarrhythmias leading to a low incidence of sudden death. Today, there is a low operative risk and modern ICDs have multiple diagnostic and therapeutic features that allow individual ICD therapy.

Transvenous defibrillation leads: is there an ideal position of the defibrillation anode?

A potential benefit of two-lead transvenous defibrillation systems is the ability to independently position the defibrillation electrodes, changing the vector field and possibly decreasing the DFT. Using the new two-lead transvenous TVL lead system, we studied whether DFT is influenced by SVC lead position and whether there is an optimal position. TVL leads and Cadence pulse generators were implanted in 24 patients. No intraoperative or perioperative complications were observed. In each patient, the DFTs were determined for three SVC electrode positions, which were tested in random order: the brachiocephalic vein, the mid-RA, and the RA-SVC junction. The mean DFTs in the three positions were not statistically different, nor was any single lead position consistently associated with lower DFTs. However, an optimal electrode position was identified in 83% of patients, and the DFT from the best lead position for each patient was significantly lower than for any one of the electrode positions (P < 0.01). The mean safety margin for the best SVC lead position was approximately 27 J. These results demonstrate the advantage of a two-lead system, as well as the importance of testing multiple SVC lead positions when the patient's condition permits. Both of these factors can decrease the DFT and maximize the defibrillation safety margin. This will become increasingly important as pulse generator capacitors become smaller (as part of the effort to decrease generator size) and the energy output of the generators consequently decreases.

First experience with a new nonthoracotomy defibrillation lead system

The clinical efficacy and safety of a new nonthoracotomy defibrillation lead system (TVL lead system, Ventritex, inc., Sunnyvale, Calif.) was studied in patients with ventricular tachycardia or fibrillation. Implantation of the TVL lead system and a Cadence pulse generator (Ventritex, Inc.) was attempted in 27 patients. A subcutaneous patch lead was added if required to achieve adequate defibrillation energy. Patients were monitored for an average of 6 +/- 4 months (range 1 week to 14 months). Implantation was successful in 26 patients (96%). Twenty-three of those patients (88%) were implanted in a lead-alone configuration; the remaining three (12%) required a subcutaneous patch lead. The mean defibrillation threshold was 401 +/- 120 V (12 +/- 7 J) at implantation, 467 +/- 134 V (15 +/- 8 J) at predischarge testing, and 452 +/- 151 V (14 +/- 9 J) at 4-month follow-up. The mean defibrillation threshold at 4 months was not significantly different from that at implant. No deaths, sensing anomalies, infections, lead fractures, or lead dislodgments occurred. One patient required addition of a subcutaneous patch 4 months after device implantation because of an elevated defibrillation threshold. Eight patients (31%) experienced 545 spontaneous arrhythmic episodes, and all episodes were successfully terminated by the device. In conclusion, the TVL lead system combined with Cadence tiered-therapy defibrillator has a high success rate and low complication rate, and it can be recommended for treatment of patients with life-threatening ventricular tachyarrhythmias.

Mechanisms and therapy of complex arrhythmias in pediatric patients

In recent years, the distinction between the diagnostic and therapeutic techniques used in the assessment and management of pediatric and adult patients with arrhythmias has gradually blurred. Nonetheless, arrhythmias in the pediatric patient are still often different from the adult patient in one of two important ways. First, a variety of arrhythmia mechanisms remain relatively unique to the pediatric population, some because of developmental issues and others because of early presentation of an incessant tachycardia. Second, the presentation and management of certain arrhythmias is sometimes markedly affected by patient age or the presence of structural congenital heart disease. A sampling from each of the above categories is reviewed and discussed.