Permanent radiofrequency ventricular pacing for management of drug-resistant ventricular tachycardia

Three patients with frequent episodes of symptomatic, sustained ventricular tachycardia that often required physician intervention were treated with a permanent patient-activated radiofrequency ventricular pacemaker for self-termination of ventricular tachycardia. Before pacemaker implantation, electrophysiologic testing revealed the tachycardia to be resistant to all approved and several investigational antiarrhythmic drugs. In all three patients, ventricular tachycardia was reliably and reproducibly terminated with brief bursts of rapid right ventricular apical pacing over several hundred trials. No patient had rapid ventricular pacing-induced acceleration of ventricular tachycardia or pacing-induced ventricular fibrillation. Since the implantation of a radiofrequency ventricular pacemaker an average of 13.7 months ago, all episodes of ventricular tachycardia (average 43/patient) have been terminated successfully by radiofrequency pacing, and no patient has required hospitalization for an arrhythmia-related problem.     

Surgical management of ventricular tachycardia

Surgical techniques that are used to treat VT have evolved into a sophisticated science over the past decade. Combining advanced electrophysiologic stimulation and study of the heart with innovative surgical approaches has been the key to successfully managing patients with recurrent VT. Several different surgical approaches have been developed. Endocardial excision and aneurysmectomy, which are combined with preoperative and intraoperative mapping, are the procedures currently used at HUP. Other institutions use simple ventriculotomy, endocardial encircling ventriculotomy, cryosurgery, and pacemaker therapy. The ability to successfully terminate VT has improved markedly from early attempts with use of these techniques. Long-term efficacy of these procedures and possible late complications remain to be established. Nursing management of the patient who undergoes surgery for VT is a challenging experience. It requires knowing basic principles of caring for the patient who will have open heart surgery. It also requires in-depth understanding of new and changing techniques and procedures to provide knowledgeable care to the patient.     

Surgical treatment of ventricular tachycardia

We present our clinical experience with 37 patients presenting with ventricular tachycardia who, between 1980 and 1986, underwent subendocardial resection, guided by per-operative mapping in 34 cases. An aneurysm of the left ventricle was present in 23 patients (62%), and an akinetic area in the remaining 14 patients. In every case the cause of ventricular tachycardia was an ischaemic heart disease. Prior to surgery, the global isotopic ejection fraction was 27 +/- 11% and the left ventricular end-diastolic pressure was 21 +/- 8 mmHg. The most common site of origin of the arrhythmia was the septum (26 cases, 77%). The mean area of resection was 26 +/- 16 cm2. Resection of a ventricular aneurysm was also performed in 23 cases, and 22 patients underwent coronary bypass. There were 4 early deaths (operative mortality rate : 10.8%) and 4 late deaths. The actuarial survival rate was 89 +/- 5% at 6 months and 72 +/- 9% at 24 months. One-half of the deaths was due to recurrence of the ventricular tachycardia. A post-operative electrophysiological study conducted in 30 patients proved negative in 28 (93%). Altogether, there were 6 immediate or late failures (16.2%) after a mean follow-up period of 18 months. The probability of a relapse-free, medication-free life or sudden death was 86 +/- 6% after 6 months and 82 +/- 7% after 24 months. The quality of life of the survivors war remarkable, since 86% of them (25/29 patients) remained in functional class 1 or 2 after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical treatment of non-ischemic ventricular tachycardia

The authors reviewed the results of 42 operations for non-ischemic ventricular tachycardias, tachycardia being arrested by laser ablation in 2 cases. Right and left ventricular tachycardias were seen in 26 and 14 patients, respectively. For diagnosis, preoperative electrophysiologic study, intraoperative epicardial mapping, and "delayed" potentials were used. In 38 of 40 patients who had undergone a direct operation, a positive result was obtained; in 31 patients, a complete disappearance without applying antiarrhythmics was observed. Four patients received drug therapy which proved to be ineffective before surgery. Two patients died after surgery due to recurrent tachycardia. Out of 38 survivals, 3 died of heart failure that was not caused by recurrent tachycardia.     

Surgical possibilities in the treatment of ventricular tachycardia

Medical therapy for recurrent sustained ventricular tachycardia is often disappointing. We report on the direct i.e. electrophysiologically guided surgical approach to 44 patients with sustained ventricular tachycardia. 43 patients had previous myocardial infarction, one patient had arrhythmogenic right ventricular dysplasia. During preoperative electrophysiologic study, sustained ventricular tachycardia was induced in 41 patients, three patients had an incessant sustained ventricular tachycardia. 30 patients underwent endocardial catheter mapping. In 28 of 30 cases, the earliest endocardial activation during ventricular tachycardia was detected. Intraoperative mapping was performed in 42 patients, in two cases surgical approach was guided by the result of endocardial catheter mapping. In 34 patients endocardial mapping revealed the earliest site of ventricular tachycardia, in eight patients the arrhythmogenic area was identified by mapping during sinus rhythm. An encircling endocardial ventriculotomy was performed in 14 patients, whereas 29 patients underwent a circumscribed endocardial resection. A cryosurgical technique was performed in the patient with arrhythmogenic right ventricular dysplasia. The hospital mortality rate was 16% (seven of 42 patients), in one patient the cause of death was ventricular fibrillation. The late mortality rate is 14% (five of 37 patients), one patient had sudden cardiac death. Two patients had a recurrence of ventricular tachycardia postoperatively. In one of these an antitachycardia pacemaker was implanted, the other was successfully reoperated with endocardial resection. Postoperatively, a sustained ventricular tachycardia was inducible by programmed stimulation in three patients. Complex ventricular ectopic activity was found in ten patients, all of these were administered antiarrhythmic drugs. With respect to the poor prognosis of medically refractory ventricular tachycardia, we conclude that the electrophysiologically guided surgical approach has become an acceptable therapeutical alternative.     

Mexiletine for control of drug-resistant ventricular tachycardia: Clinical and electrophysiologic results in 44 patients

The antiarrhythmic efficacy of mexiletine was evaluated in 44 patients with drug-resistant ventricular tachyarrhythmias. In 33 of these patients, the efficacy of mexiletine was assessed on the basis of the results of programmed ventricular stimulation. Mexiletine did not alter the ventricular effective refractory period, the Q-Tc interval, or the methods of tachyarrhythmia induction and termination during programmed stimulation. The mean cycle length of ventricular tachycardia (VT) increased from 270 ± 49 to 313 ± 80 ms in 21 patients in whom VT remained inducible on mexiletine alone (p < 0.002). Overall, VT remained inducible with methods similar to control (no drugs) inductions in 25 patients receiving mexiletine alone or in combination with a type I agent. VT induction was prevented in only 8 patients, 3 on mexiletine alone and 5 receiving mexiletine combined with another drug. Mexiletine alone (in 2 patients) or with another agent (in 3) suppressed clinical recurrence of VT in an additional 5 of 11 patients who did not undergo electrophysiologic study. These 13 patients were discharged on mexiletine alone (5 patients) or in combination with other drugs (8 patients), and remained arrhythmia-free over a mean follow-up period of 7.7 ± 4.1 months. Adverse effects occurred in 27 of 44 patients (61%) and were gastrointestinal in 17 and/or neurologic in 22. The drug was discontinued because of adverse effects in 6 patients (14%). Thus, mexiletine has limited efficacy when used alone, but when combined with other drugs it may be useful in up to 30% of patients with drug-resistant ventricular arrhythmias. Adverse effects are relatively common.     

Surgical treatment of ventricular allorhythmia and non-ischemic tachycardia]

The paper deals with the problems in the diagnosis and treatment of patients with the most malignant rhythm disturbances, i. e. ventricular arrhythmias. A great emphasis is laid on the so-called "primary" arrhythmias appearing without a manifest cardiac abnormality. The arrhythmias proceed unfavorably and are followed by profound morphofunctional myocardial changes occurring chiefly in the upper portions of the ventricular septum, more frequently on the right. Cryodestruction of arrhythmogenic areas is an effective method for surgical correction of arrhythmias having an unfavorable course.     

快速性恶性室性心律失常的发作方式及其临床干预

目的探讨快速性恶性室性心律失常的发作方式及其临床干预。方法对我院收治的快速性恶性室性心律失常56例(入院后至少发生1次以上),根据基础Q-T间期是否延长分为Q-T间期正常和长Q-T(U)间期,并按不同的发作方式临床干预治疗。结果基础心律Q-T间期正常(0.38±0.03s)33例,以室性心动过速或多形性室性心动过速多见,多数可用直流电复律。而Q-T间期延长(0.51±0.04s)23例,以尖端扭转型室性心动过速多见,多数经大剂量补钾、镁+异丙肾上腺素或阿托品静脉治疗。结论快速性恶性室性心律失常由不同形式的室性期前收缩诱发,应针对不同的临床、心电学特征,采取临床干预措施。     

Surgical therapy for drug-refractory ventricular tachycardia: results with mapping-guided subendocardial resection

Surgical therapy with mapping-guided subendocardial resection was used in 30 patients with drug-refractory ventricular tachycardia. Results of preoperative, intraoperative and postoperative electrophysiologic evaluation and long-term clinical follow-up are reported. Left ventricular aneurysm was located in the inferior wall in 8 patients and in the anterior wall in 22. Left ventricular mapping was performed in 15 patients preoperatively and in all 30 patients intraoperatively. Subendocardial resection was supplemented with cryoablation in 26 patients and with laser photocoagulation in 4. Coronary bypass surgery was performed in 27 patients. The surgical mortality rate was 10%; the three deaths were due to cardiogenic shock, pneumonia and sepsis, respectively. At postoperative electrophysiologic study, ventricular tachycardia was inducible in 8 (30%) of 27 patients. Previously ineffective antiarrhythmic drugs were effective in preventing the induction of ventricular tachycardia in four of these eight patients. Two of the remaining four patients received an automatic implantable cardioverterdefibrillator; the other two were treated with amiodarone. At a mean follow-up period of 18 +/- 17 months (range 1 to 52), there has been one sudden death and one nonfatal recurrence of ventricular tachycardia in the 18 patients without inducible arrhythmias postoperatively. Among the eight patients with inducible ventricular tachycardia after subendocardial resection, there has been one nonfatal ventricular tachycardia recurrence. Thus, among the 27 patients surviving surgery, 17 (63%) were cured with surgery alone, and another 7 (26%) had their ventricular tachycardia controlled with drugs (n = 5) or the defibrillator (n = 2). Inability to completely map the tachycardia, a clinical history of cardiac arrest requiring resuscitation and the presence of myocardial infarction within 2 months predicted postoperative arrhythmia inducibility and recurrence.     

Mapping for ventricular tachycardia

Mapping strategies for ventricular tachycardia (VT) have evolved significantly in the past 2 decades. This review discusses mapping techniques that can help in successful VT ablation. The electrocardiogram (ECG) remains a vital component of VT mapping and can help to identify the chamber of origin of VT. The ECG morphology of VT, however, is influenced by orientation of heart and location of the scar. Activation mapping during VT is an important technique that can help in further localization. Care has to be exercised to ensure that small signals are not ignored and far-field signals are recognized. Pace-mapping to mimic the VT is another way to map exit site for scar based reentrant VT or the site of origin of triggered and automatic VT in the absence of structural heart disease. For the latter group, this technique is widely used in determining the site of ablation. It is important to ensure a complete ECG match (12 out of 12 leads) of the pace-map to the clinical arrhythmia in these patients. In patients with structural heart disease, entrainment mapping remains the gold standard for defining the protected isthmus and other components of the VT circuit. Using this technique, successful ablation of reentrant VT can be achieved in 60–90% of patients. In order to perform entrainment mapping, the VT has to be hemodynamically tolerated; this is not the case in 25% of pts with scar based reentrant VT. The development of 3-dimensional mapping systems allows for more anatomically based linear ablation in patients with poorly tolerated uniform VT. Despite these advances, there are still about 10–20% VTs that cannot be ablated successfully with the above described techniques, especially in patients with structural heart disease. Other recent advances such as percutaneous closed chest epicardial mapping technique and cooled tip ablation catheter technology have the potential to enhance mapping and successful ablation of VT.     

Surgical treatment of ventricular tachycardia after epicardial mapping studies.

Two patients with intractable life-threatening ventricular tachycardias have been studied using intracardiac electrograms and programmed electrical stimulation of the heart. Both patients have shown to have an underlying re-entry mechanism in the ventricles as the basis for the tachycardias. Both patients underwent epicardial mapping studies at cardiac surgery, and the site of re-entry was established. In one patient the re-entry front was found to start in the posterobasal region of the left ventricle and in the other patient the re-entry front was found in the anterobasal region of the right ventricle. In both patients surgical interruption of the re-entry front was carried out. Both patients are alive and free from tachycardias at the time of writing.     

Surgical treatment of paroxysmal ventricular tachycardia (personal observations)

Five patients with recurrent VT/VF resistant to medical treatment were successfully treated surgically. In 3 patients excision of the altered endocardium by Harken's method (endocardial peeling) was done; in 2 of the patients it was preceded by intraoperative electrophysiological study. Two other patients were treated alternatively: a 45-year old patients with post-MI cardiomyopathy had a cardiac transplantation and a 57-year old patient with good left ventricular function an implantation of a automatic cardioverter-defibrillator (AICD). No patient had VT and/or VF during the 14-35 month follow-up. Exercise tolerance improved in all patients. Good short- and longterm results of surgical treatment show that these methods can be effective in treating patients with life-threatening arrhythmias resistant to pharmacological therapy.     

Tocainide for drug-resistant sustained ventricular tachyarrhythmias

Eighty-two patients with drug-resistant ventricular tachycardia or fibrillation were treated with oral tocainide. Treatment in 54 patients, all with inducible ventricular tachycardia or fibrillation at baseline electrophysiologic testing, was based on the results of invasive electrophysiologic testing. Twenty-eight additional patients with frequent spontaneous ventricular tachycardia or no inducible arrhythmia during electrophysiologic testing were treated on the basis of the findings of electrocardiographic (ECG) Holter monitoring. Tocainide was effective in 7 (13%) and partially effective in 5 (8%) of the 54 patients in the electrophysiologic study group and was effective in 17 (61%) of the 28 patients in the ECG monitoring group. History of previous myocardial infarction and failure of response to lidocaine correlated with failure to respond to tocainide. Side effects were common both during initial therapy and during long-term treatment and necessitated discontinuation of tocainide therapy in 17% of the patients. At a mean follow-up period of 14 months, 13 patients are still receiving tocainide and are arrhythmia-free. In conclusion, the usefulness of oral tocainide in the management of drug-refractory sustained ventricular tachycardia or fibrillation is limited because of its low effectiveness and frequent side effects.