An Experimental Study of Transvenous Defibrillation Using a Coronary Sinus Catheter

The efficacy of a transvenous defibrillating system, utilizing bipolar right ventricular and coronary sinus catheters was evaluated in 14 normal mongrel dogs. Two groups of seven animals each were studied. During all shocks, the right ventricular apex electrode served as the anode. In both groups, defibrillation was performed using the proximal pole of the right ventricular catheter (superior vena cava), as the cathode served as a control (configuration A). In group 1, a coronary sinus cathode (configuration B) was compared to control. The mean energy at which 50% or more of the shocks were successful was similar for configuration B (20.7 ± 7.9 joules) and for configuration A (18.8 ± 9.4 joules). In group 2, the superior vena cava and coronary sinus electrodes served as a common cathode (configuration C). Mean defibrillation energy at which 50% or more of the shocks was successful was 21.4 ± 9.0 joules for configuration C and 27.1 ± 9.5 joules for configuration A (P < 0.01). Leading edge voltage was similar for all three configurations, hut shock duration was longer for configuration A (11.3 ± 2.8 msec) than configuration B (6.6 ± 1.8 msec) or C (6.1 ± 1.5; P < 0.05). Nonsustained ventricular tachycardia and transient heart block were common, but no damage to the coronary sinus was noted despite the delivery of up to 38 shocks. Conclusions: (1) With the catheter system used, coronary sinus to right ventricular apex defibrillation system offered no advantages over a superior vena cava to right ventricular apex system; (2) A three-electrode system with the high right atrium and coronary sinus serving as the common cathode reduced defibrillation thresholds significantly without any severe short-term adverse consequences; and (3) Improvements in catheter design may make a coronary sinus catheter part of a feasible transvenous defibrillating system.     

Cardiac damage in dogs with chronically implanted automatic defibrillator electrode catheters and given four episodes of multiple shocks

In 14 dogs, a newly designed automatic defibrillator electrode catheter with paired ventricular and superior vena caval electrodes was implanted transvenously into the right ventricular (RV) apex for 26 weeks. Twelve dogs were given multiple (mean total = 21.3) near-threshold (mean delivered energy = 17.6 joules) shocks via the lead at 0, 5, 12, and 26 weeks after implantation. Two days after the last shocks, the dogs were killed and the cardiac alterations were evaluated at necropsy and by histopathology. The lead induced mild to moderate cardiac alterations of (1) endocardial fibrosis, either as flat or papillary lesions, and of (2) segments of smooth thin fibrous sheath formation over the lead with adhesions to the adjacent endocardium. Mild cardiac alterations were induced by the shocks including myocardial necrosis and calcification, concentrated in the ventricular septum and RV free wall adjacent to the ventricular electrodes, and foci of postnecrotic fibrosis. The chronically implanted lead was determined to be safe and effective in dogs.     

Superiority of biphasic shocks in the defibrillation of dogs by epicardial patches and catheter electrodes

Currently available internal cardiac defibrillators use a uniphasic, truncated exponential waveform morphology of about 6 msec in duration at an energy level of 23 to 33 joules. To determine if improved defibrillation could be achieved with a different waveform morphology, we implanted 4.5 cm2 titanium patches to the left and right ventricle of 28 dogs. After ventricular fibrillation was induced, defibrillation was attempted using 7, 12, 13, or 17 joules. A 5 msec rectangular uniphasic waveform morphology was compared with a 10 msec rectangular biphasic waveform with the lagging 5 msec pulse of half the amplitude of the leading 5 msec. In an additional seven dogs, a transvenous bipolar catheter was placed with the distal electrode in the right ventricular apex and the proximal electrode in the superior vena cava. Biphasic and uniphasic shocks were compared at 14 joules. In the patch-patch system, the biphasic waveform was superior to the uniphasic waveform at 7 joules (67% versus 35%, p less than 0.001) and at 12 joules (93% versus 78%, p less than 0.001). No statistically significant differences were achieved at 13 joules or 17 joules. In the catheter electrode system with a delivered energy of 14 joules, the biphasic waveform was more effective than the uniphasic waveform (87% versus 27%, p less than 0.001). Manufacturers of automatic implantable defibrillators should consider this information in the design of future automatic implantable defibrillators.     

Use of the automatic implantable cardioverter-defibrillator in the treatment of malignant ventricular tachyarrhythmias

Since February, 1980 nearly 200 automatic cardioverter - defibrillators have been implanted in patients with malignant ventricular arrhythmias. The currently-employed device weighs 298 grams and occupies a volume of 162 cm3. There are two defibrillation electrodes which also serve as sensors: one, an intravascular catheter placed in the superior vena cava at the level of the right atrium; the other, a flexible rectangular patch placed extrapericardially over the apex of the heart. Additionally, there is a bipolar right ventricular electrode for rate counting and R-wave synchronization which will eventually be used for pacing as well. The unit is powered by lithium batteries with a projected monitoring life of three years, or the capability of discharging approximately 100 times. The arrhythmia detector activates the cardioverter -defibrillator about 15 to 20 seconds after diagnosing a "treatable" arrhythmia, identified on the basis of a striking absence of isoelectric potential segments characteristic of ventricular fibrillation and many ventricular tachycardias. The diagnosis also requires fulfillment of individually-programmed heart rate criteria. If the initial discharge of 25 joules is ineffective, the device will recycle as many as three times with a final pulse of up to 42 joules. Of the twelve nonsurvivors among the initial 52 implantees who underwent implantation through September, 1982, only four deaths were unwitnessed and considered to be sudden and arrhythmic; the other eight deaths were due to heart failure or unrelated causes. Thus, from a predicted mortality of 48% in the same group of patients if the automatic defibrillator had not been implanted, the "sudden death" mortality was reduced to 8.5%.     

Comparison of defibrillation efficacy in humans using a new catheter and superior vena cava spring-left ventricular patch electrodes

The automatic implantable cardioverter-defibrillator currently utilizes an electrode system that requires a major operation for implantation. Effective defibrillation using an implantable cardioverter-defibrillator catheter positioned transvenously would eliminate the morbidity associated with such surgery. Fifteen patients undergoing defibrillator implantation were studied to compare the efficacy of the catheter with that of the superior vena cava spring (6.7 cm2, anode)-left ventricular patch (13.5 cm2, cathode) electrode system using truncated exponential waveforms with 60% tilt. The catheter is 11F in diameter and tripolar. A distal platinum-iridium tip used for pacing was separated by 4 mm from a middle 4.3 cm2 platinum electrode; these were positioned at the right ventricular apex. The proximal 8.5 cm2 platinum electrode was situated at the superior vena cava-right atrial junction. Defibrillation was performed using the middle (cathode) and proximal (anode) electrodes. Ventricular fibrillation was induced by alternating current six times, and defibrillation shocks of 1, 5, 10, 15, 20 or 25 J were given in random order, first using the catheter and then the spring-patch system. Rescue shocks of higher energy were given if there was failure. Although very low energy levels appeared to be slightly more efficacious when using the spring-patch system, there was no statistically significant difference between the electrode systems for any of the energies tested. Permanent implantation of the catheter would have been suitable in 45% of the patients, as compared with 54% of patients with the spring-patch system (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)     

Fulguration of atrial flutter in man. A pathological case

A 63 year old man with ischemic heart disease underwent two sessions of catheter ablation in the inferior right atrium for poorly tolerated resistant and recurrent atrial flutter. After endocavitary mapping and comparison with surface recordings of the f waves, a shock of 50 joules was delivered to the zone situated anteriorly to the inferior vena cava, under the orifice of the coronary sinus and behind the tricuspid valve. Early recurrence of the arrhythmia led to a second attempt and another 50 joules shock was administered to the same area. Another short term recurrence led to definitive nodohisian interruption with a 270 joules shock. Thirty months later, the patient died suddenly during an episode of cardiac failure. Macroscopic examination of the right atrium showed a zone of parietal congestion measuring 4 x 3 cm with a very thin, translucid, central zone measuring 3 x 1.5 cm, just anterior to the inferior vena cava in the right atrial free wall. Histological examination of this zone showed an intense, mutilating fibrosis dissociating the muscular fibres, of the pectinate muscle and even replacing the myocardium in certain regions. In the Eustachian valve, there were muscular fibres, probably representing the posterior internodal pathway, which were also fibrosed. These observations suggest that: 1) in view of the extreme thinness of the atrial wall at the site of ablation there is a high risk of perforation even when right endoatrial catheter ablation is performed with low energy shocks; 2) the posterior internodal pathway does not seem to be an essential component for atrial flutter.     

Clinical efficacy of dual electrode systems for endocardial cardioversion of ventricular tachycardia: a prospective randomized crossover trial

In order to eliminate the need for epicardial electrodes, two large transvenous catheter electrodes or one catheter and one extrathoracic patch electrode have been proposed as alternative electrode configurations for defibrillation and ventricular tachycardia cardioversion by implantable cardioverter/defibrillators. We compared the efficacy and safety of endocardial shocks delivered through these two electrode systems in man in a prospective randomized crossover study. Twelve patients with sustained ventricular tachycardia and heart disease undergoing electrophysiologic study were evaluated. A transvenous tripolar cardioversion electrode catheter with a large distal defibrillation electrode (surface area, 400 mm2) and proximal defibrillation electrode (surface area, 800 mm2) was positioned in the right ventricular apex with a cutaneous patch electrode placed on the cardiac apex. Sustained ventricular tachycardia was induced at electrophysiologic study. Shocks were delivered using two catheter electrodes only (right ventricular cathode and right atrial anode = method I), and one catheter electrode and cutaneous patch (right ventricular cathode and cutaneous apical patch anode = method II). Synchronized monophasic shocks were delivered using three preselected protocols based on ventricular tachycardia cycle length and morphology. Initial shock energies were 25 joules for polymorphic ventricular tachycardia and ventricular fibrillation, 15 joules for monomorphic rapid ventricular tachycardia (cycle length less than or equal to 300 msec), and 5 joules for monomorphic slow ventricular tachycardia (cycle length greater than 300 msec). Ventricular tachycardia was reinduced and shock energies titrated until cardioversion threshold was obtained. Identical ventricular tachycardia episodes were treated with both methods at each energy level.(ABSTRACT TRUNCATED AT 250 WORDS)     

心房颤动上腔静脉节段性电隔离方法及安全性评估

目的:分析心房颤动(房颤)上腔静脉节段性电隔离的具体手术方法,并评估其安全性.方法:入选2017年11月至2018年9月期间我院阵发性房颤患者50例,患者常规进行肺静脉隔离后,继续行上腔静脉隔离.消融前进行上腔静脉造影,显示上腔静脉与右心房解剖关系,并在CARTO系统运用PentaRay电极导管进行上腔静脉及右心房三维...     

The persistence of the left vena cava superior and the absence of the right vena cava superior: the implications in the implantation of a definitive pacemaker]

Persistent left superior vena cava and associated absence of the right superior vena cava is exceedingly rare. The authors present a case, diagnosed when a DDD pacemaker system was being implanted, and point out its rarity, possibility of diagnosis by non invasive methods and technical implications in transvenous electrode implantation.     

Evaluation of a new defibrillation pathway--the tongue-epigastric route. I. Experimental studies in dogs

The purpose of this study was to determine the efficacy of a tongue-epigastric defibrillation route in anesthetized dogs. Ventricular fibrillation was induced by rectangular pulses passed down a transvenous catheter into the right ventricle. Three groups of dogs were studied. Group I (15 dogs) received shocks from a 12 cm2 tongue electrode, a 50 cm2 circular, gelled self-adhesive electrode pad placed on the epigastrium and standard transthoracic defibrillator paddle electrodes. Shocks were given at energy levels of 50 to 460 joules (delivered energy, 50 ohm resistance). The success of the tongue-epigastric shocks in achieving defibrillation, and the resistance and current flow were determined at each energy level and compared with the same energy shocks from the standard transthoracic electrodes. In Group II (five dogs), comparisons were made between the 12 cm2 tongue electrode used in the first group of dogs and a larger tongue electrode of 40 cm2. In Group III (five dogs), intracardiac current flow (potential gradient) with tongue-epigastric and standard transthoracic electrodes was studied. In Group I, defibrillation success with the tongue-epigastric electrodes ranged from no success at 50 to 100 joules to 83% success at 460 joules. With standard transthoracic electrodes, success rates ranged from 65% at 50 joules to 100% at 300 joules. At all energies tested, the resistance was significantly higher and current significantly lower using tongue-epigastric compared with transthoracic electrodes. The higher tongue-epigastric resistance is probably related to the longer interelectrode distance; the correlation between interelectrode distance (x, in centimeters) and resistance (y, in ohms) in these dogs was y = 2.2x + 29.6, r = 0.78.(ABSTRACT TRUNCATED AT 250 WORDS)     

Azygos continuation of interrupted inferior vena cava in association with sick sinus syndrome

Various diagnostic and therapeutic procedures of the right side of the heart and the systemic venous system have increased the need for ready access to the inferior vena cava (IVC) through the transfemoral route. Anatomical variations or obstruction of the IVC can make these procedures difficult. The case of 47 year old woman with an interrupted infrahepatic IVC with azygos continuation accompanied by sick sinus syndrome and a structurally normal heart is reported. Negotiating a temporary pacing lead from the IVC to the right atrium was difficult. Ultimately, the lead took the course from the IVC to azygos vein to superior vena cava to right atrium to right ventricular apex. Permanent VVI pacing through the right subclavian route was uneventful, as the superior vena cava and its tributaries had a normal course. An awareness of the existence of these anomalies before pacing can lead to the use of an alternative route for pacing, which may avoid undue delay of an otherwise urgently needed procedure.     

Superior vena cava syndrome: Case report: A complication of permanent transvenous endocardial cardiac pacing requiring surgical correction

Superior vena cava syndrome developed in a patient in whom an endocardial transvenous pacemaker had been inserted five years previously. Venography demonstrated an obstructing lesion at the junction of the superior vena cava and right atrium. Balloon catheter dilatation failed to afford any relief from her progressive symptoms. Exploration of the area revealed a benign fibrotic lesion encircling the pacemaker lead within the right atrium. Excision of the lesion, removal of the lead, and patching the right atrium with pericardium resulted in rapid cure.     

An analysis of electrocardiographic,radiographic, and vectorcardiographic findings in patients with implanted cardiac pacemakers

In patients with implanted cardiac pacemakers, the radiological appearances, and the configuration of the 12-lead ECG have been conventionally used both to locate the site of the electrode implantation and to diagnose electrode placement errors. These techniques have limitations, and in the present study vectorcardiographic data derived from the pacemaker stimulus and the spread to ventricular depolarization has been added to improve accuracy. Three hundred patients with implanted cardiac pacemakers were studied. Unusual QRS complexes as determined from the 12-lead ECG were found in 37 (12%) and the position of the pacemaker electrodes determined from the lateral chest x-ray was outside normal (R.V. apex) in 61 patients (20.3%). A combined interpretation of the ECG, chest x-ray, and the vectorcardiogram agreed on positioning (correct or incorrect) in all but 17 patients (5.6%). Three patients had a perforated right ventricle, while further study of the other 14 suggested malpositioning of the catheter electrode in the right ventricle or in the coronary venous system. An analysis of the ECG patterns, x-ray appearances, and vectorcardiograms is presented with respect to the diagnosis of pacemaker electrode placement errors and a logical tree for establishing the position of the pacemaker is introduced.     

经永存左上腔静脉植入起搏电极体会

目的总结经永存左上腔静脉（PLSVC）植入起搏电极体会。方法总结4例PLSVC植入双腔起搏器的患者。患者出院前及出院后3个月、6个月进行随访,了解起搏器工作状态。结果4例患者术前均常规行经胸超声心动图检查,结果显示冠状静脉窦开口扩大,提示PLSVC存在可能。第1例患者因术前发现PLSVC可能,首先穿刺右侧锁骨下静脉;造影显示右上腔静脉缺如,右侧锁骨下静脉汇入PLSVC。第2、3例患者因双腔起搏器植入前反复出现心动过缓相关症状,在术前经右侧锁骨下静脉植人临时起搏器,术中造影显示PLSVC与右侧上腔静脉无交通。第4例患者在置入导丝时直接经PLSVC进入右心房。患者术后3个月、6个月常规行起搏器程控并调整起搏器出厂设置参数,此后每6—12个月行起搏器程控,程控时测量心房电极和心室电极的起搏阈值、感知和阻抗。均在满意范围。第1例患者两次随访时心律均为窦性心律,心房电极感知大于2mV,起搏阈值小于1V,阻抗小于1000Q。结论PLSVC能够顺利完成起搏电极植入。     

Nonthoracotomy internal defibrillation in dogs: threshold reduction using a subcutaneous chest wall electrode with a transvenous catheter electrode

The efficacy of truncated exponential waveform shocks using a cardioverter-defibrillator catheter with and without a 13.9 cm2 subcutaneous thoracic patch electrode was examined in 10 pentobarbital-anesthetized dogs. The cardioverter-defibrillator catheter was positioned through the external jugular vein with the distal 4 cm2 shocking electrode located in the right ventricular apex and the 8 cm2 proximal electrode located in the superior vena cava. Four electrode configurations were tested: 1) distal electrode (cathode) to proximal electrode and chest wall patch (common anodes), 2) distal electrode (cathode) to chest wall patch (anode), 3) distal electrode (cathode) to proximal electrode (anode), and 4) chest wall patch (cathode) to proximal electrode (anode). The lowest randomized energy resulting in termination of alternating current-induced ventricular fibrillation on four trials at that energy was 20.2, 21.3, 27.4 and greater than 40 J, respectively, for configurations 1 through 4. The energy requirements for configurations 1, 2 and 3 were significantly lower than for configuration 4 (p less than 0.001). Additionally, configurations incorporating the distal electrode and the patch electrode (configurations 1 and 2) were significantly better than the catheter alone (configuration 3; p less than 0.05). There was no significant difference between configurations 1 and 2. In conclusion, the addition of a subcutaneous chest wall electrode to the cardioverter-defibrillator catheter significantly lowered energy requirements for defibrillation, suggesting that a nonthoracotomy approach for the automatic implantable cardioverter-defibrillator is feasible.     

Development of the implantable transvenous cardioverter

The development of the transvenous cardioverter, from the initial animal studies, to the clinical studies using temporary leads, to the initial permanent implants is described. Shocks less than or equal to 2.0 joules synchronized to the QRS complex and delivered through a specially designed catheter electrode placed in the apex of the right ventricle successfully terminate most episodes of ventricular tachycardia in patients. The implanted unit which also serves as a demand ventricular pacemaker, can be used to perform programmed electrophysiologic studies. Future devices must be capable of defibrillation and more accurate arrhythmia detection.     

静脉畸形、迂曲、狭窄时永久起搏导线置入的方法探讨

经静脉造影或观察导丝走形证实 6例患者存在静脉畸形、迂曲、狭窄 ,其中 5例高龄患者置入永久起搏器时 ,其上腔静脉系统迂曲、狭窄 ,无法使用起搏器穿刺套装内的导丝及鞘管将导线送到起搏部位 ,另 1例为永存左上腔静脉合并有右上腔静脉缺如。试用 175cm 0 .0 35长导丝以及 6 8FINPUT鞘替代普通起搏器穿刺套装。结果 :使用175cm 0 .0 35长导丝以及 6 8FINPUT鞘顺利地将起搏导线送入右心房中下部 ,安全地完成置入手术 ,无并发症。结论 :一旦送入导线或导丝困难 ,应积极地进行血管造影 ,不应盲目的推送 ,使用 175cm长导丝增加支撑力 ,结合IN PUT鞘管通过狭窄或纡曲延长的血管段 ,给起搏导线提供一个光滑的通道 ,可顺利的将起搏导线送入心房及心室。     

Persistent left superior vena cava: multi-slice CT images and report of a case

Abnormalities of the vena cava system are usually asymptomatic and discovered incidentally during catheter placement or pacemaker implantation. Persistent left superior vena cava (PLSVC) is caused by failure of involution of the left anterior cardinal vein caudal to the left brachiocephalic vein during embryonic development. It is a benign condition, but becomes dangerous during pacemaker lead implantation, especially in emergency situations and when the right superior vena cava is absent. This is brought about by difficulty in pacemaker lead maneuvering into the right ventricle. A 64-cut multi-slice computed tomographic (MSCT) scan can show clear spatial relationship of the heart with its surrounding structures. We present a case of PLSVC discovered during pacemaker implantation, and viewed by 64-cut MSCT scan.     

Implantable cardioverter defibrillatory implantation in a patient with persistent left superior vena cava and right superior vena cava atresia

Persistence of a left superior vena cava has been observed in 0.3% of the general population as established by autopsy findings. In the adult population. it is an important anatomic finding if a left or right superior vena cava approach to the heart is considered for device implantation. We present a case with persistent left superior vena cava and right superior vena cava atresia in whom a dual chamber implantable cardioverter defibrillator was implanted and was technically challenging.     

导管射频右房线性消融治疗阵发性心房颤动

报道导管射频右房双线性消融临床试验性治疗阵发性心房颤动 (简称房颤 )的结果。10例特发性房颤的患者接受治疗 ,用 8mm大头电极温控导管完成下腔静脉口至三尖瓣口的线性消融 ,用连续 4个大头电极的温控导管完成从下腔静脉口经界嵴至上腔静脉口的线性消融。术中及术后无 1例发生并发症 ,术后恢复过程无异于一般的导管射频消融术。术后随访 1～ 10月 ,其中 6例无房颤发作、2例房颤发作次数明显减少 ;此 8例中 ,6例在术中诱发房颤时房颤是由 b型心房扑动转变而来。另 2例房颤发作次数无明显变化。初步结果表明 :导管射频右房双线性消融对 b型心房扑动启动的阵发性房颤有较好的治疗效果 ,但仍需积累更多病例和做更长时间的观察。