Subcutaneous implantable cardioverter-defibrillator implantation in a patient with a left ventricular assist device already in place.

A 56-year-old man with ischemic cardiomyopathy, a biventricular implantable cardioverter-defibrillator (ICD), and a left ventricular assist device (LVAD) developed a pocket hematoma and infection after an ICD generator change. The biventricular ICD was extracted, and the patient was given a full course of antibiotics. Because he had no indications for bradycardia pacing or biventricular pacing, he was implanted with a subcutaneous ICD under full anticoagulation. There was no interference in sensing or shock delivery from the ICD. The LVAD readings were unchanged during and after the procedure. The patient had an uneventful postoperative course, and both devices were functioning normally. To our knowledge, this is the first reported case of the implantation of a subcutaneous ICD in the presence of an LVAD. This report illustrates that both devices can be implanted successfully in the same patient. In addition, the subcutaneous ICD minimizes the risk of bloodstream infections, which can be fatal in patients who have life-supporting devices such as an LVAD.

Feasibility of temporary biventricular pacing after off-pump coronary artery bypass grafting in patients with reduced left ventricular function.

In selected patients undergoing cardiac surgery, our research group previously showed that optimized temporary biventricular pacing can increase cardiac output one hour after weaning from cardiopulmonary bypass. Whether pacing is effective after beating-heart surgery is unknown. Accordingly, in this study we examined the feasibility of temporary biventricular pacing after off-pump coronary artery bypass grafting. The effects of optimized pacing on cardiac output were measured with an electromagnetic aortic flow probe at the conclusion of surgery in 5 patients with a preoperative mean left ventricular ejection fraction of 0.26 (range, 0.15-0.35). Atrioventricular (7) and interventricular (9) delay settings were optimized in randomized order. Cardiac output with optimized biventricular pacing was 4.2 ± 0.7 L/min; in sinus rhythm, it was 3.8 ± 0.5 L/min. Atrial pacing at a matched heart rate resulted in cardiac output intermediate to that of sinus rhythm and biventricular pacing (4 ± 0.6 L/min). Optimization of atrioventricular and interventricular delay, in comparison with nominal settings, trended toward increased flow. This study shows that temporary biventricular pacing is feasible in patients with preoperative left ventricular dysfunction who are undergoing off-pump coronary artery bypass grafting. Further study of the possible clinical benefits of this intervention is warranted.

Effects of right ventricular septal pacing modes on acute cardiac function and ventricular synchronization in dogs with heart failure / 中国医师杂志

Objective To evaluate effects of right ventricular septal pacing modes on treatment of heart failure.Methods Twelve dogs with heart failure were performed in every dog at random,and the pacing modes employed in the test included right atrium-right ventricular apex (RVA),right atrium-right ventricular septal(RVS),and right atrium-biventricular (Bi-V) ; The pacing frequency was 180 times per minute.The results were measured before pacing and after 15 minutes when the pacing became stable in Color Doppler echocardiography,including left ventricular end-diastolic diameter (LVEDd),left ventricular ejection fraction (LVEF),interventricular mechanical delay (IVMD),interventricular septum and left ventricular posterior wall motion delay (SPWMD),and left ventricular 12-segment peak time standard deviation (Ts-SD).Results Right ventricular septal pacing mode:(1)Compared with parameter before pacing and RVA pacing,LVEDd,IVMD,SPWMD,and Ts-SD decreased and LVEF increased,and the difference was significant(P ＜0.05).(2)Compared with Bi-V pacing,LVEDd,IVMD,and SPWMDandTs-SD increased and LVEF decreased,and the difference was significant (P ＜ 0.05).Conclusions Right ventricular septal pacing could improve ventricular synchrony and cardiac function partly,and the effect was better than right ventricular apical pacing but less than biventricular pacing,also could not be a alternative models of cardiac resynchronization therapy for heart failure.

Study on the effects of different pacing modes of cardiac resynchronization therapy on dogs with heart failure / 中国医师杂志

Objective To evaluate advantages and disadvantages of different pacing modes of cardiac resynchronization therapy (CRT).Methods Twelve dogs with heart failure were performed in every dog at random,and the pacing modes employed in the test included right atrium-different sites of ventricle,and ventricular sites included right ventricular bifocal (RV-Bi),biventricular (Bi-V),left ventricular (LV).The pacing frequency was 180 times per minute,and the results were measured before pacing and after 15 minutes when the pacing became stable in Color Doppler echocardiography,including left ventricular enddiastolic diameter (LVEDd),left ventricular ejection fraction (LVEF),interventricular mechanical delay (IVMD),interventricular septum and left ventricular posterior wall motion delay (SPWMD),left ventricular 12-segment peak time standard deviation (Ts-SD).Results (1)Compared with before pacing,at the RV-Bi,Bi-V,and LV pacing modes,LVEDd,IVMD,SPWMD,and Ts-SD decreased,LVEF increased,the difference was statistically significant [(42.42 ± 3.94) mm vs (34.00 ± 4.07) mm,(34.17 ± 3.95)mm,(33.75 ±4.18)mm; (28.08 ±4.01)mm vs (13.00 ±3.64) mm,(11.95 ±2.54)mm,(12.08 ±3.51) mm; (75.00 ± 10.22)mm vs (51.75 ±9.84) mm,(20.66 ±7.41) mm,(20.75 ±7.56) mm; (25.08±4.16)mm vs (14.91 ± 3.31)mm,(7.50 ±4.24) mm,(7.41 ±3.39)mm;(32.91 ±4.46)mm vs (41.50 ±4.16)mm,(42.00 ±4.63) mm,(42.41 ±4.99)mm,P ＜0.05].(2)Compared with RV-Bi pacing mode,at the Bi-V,LV pacing modes,SPWMD and Ts-SD decreased,the difference was statistically significant(P ＜ 0.05); there was no significant difference among LVEDd,IVMD,and LVEF (P ＞0.05).(3)There was no significant difference in LVEDd,IVMD,SPWMD,Ts-SD and LVEF between LV and Bi-V pacing (P ＞ 0.05).Conclusions The hemodynamic effects of RV-Bi and LV pacing modes were similar to that of Bi-V pacing,and they can be used as CRT biventricular pacing alternative modes; however,the mechanisms of improving ventricular synchronization are not identical in above pacing modes.

Marked attenuation of shock burden by the use of antitachycardia pacing therapy in a patient with an implanted cardioverter-defibrillator.

A 76-year-old man was admitted to our institution for elective exchange of his implanted cardioverter-defibrillator generator. Nine years earlier, he had been diagnosed with nonischemic cardiomyopathy and nonsustainable ventricular tachycardia. At that time, he had received a single-chamber implanted cardioverter-defibrillator, which was upgraded to a dual-chamber implanted cardioverter-defibrillator 3 years later. In the course of the current admission, routine device interrogation during exchange of the patient's implanted cardioverter-defibrillator generator revealed 150 episodes of ventricular tachycardia in the preceding 7 months, 137 of which had been successfully treated by antitachycardia pacing therapy without shock. These findings show the remarkable effectiveness of antitachycardia pacing in terminating ventricular tachycardia while preventing the delivery of shocks, minimizing patient discomfort, and avoiding implanted cardioverter-defibrillator battery depletion.

Use of an active-fixation coronary sinus lead to implant a biventricular pacemaker via the femoral vein.

Cardiac resynchronization therapy, which involves the placement of a pacing lead in the right atrium and in each ventricle, is effective in treating heart failure that is caused by left bundle branch block and cardiomyopathy. The left ventricular lead is usually placed into a lateral branch of the coronary sinus via the subclavian route. When the subclavian route is unavailable, insertion of a standard, passive-fixation coronary sinus lead via the femoral approach is feasible; however, the likelihood of subsequent dislodgment is high. Herein, we describe the placement of a novel, self-retaining, active-fixation coronary sinus lead--the Attain StarFix Model 4195 OTW Lead--in an elderly heart-failure patient, via the femoral approach. We believe that this is the 1st report of this procedure.

Cardiac resynchronization therapy as an adjunct to conventional surgical treatment for heart failure.

From March 2004 through October 2007, we prospectively evaluated the benefits of cardiac resynchronization therapy as an adjunct to conventional procedures in patients who were undergoing surgery for heart failure.Twenty severely symptomatic patients (14 men and 6 women, with a mean age of 70 +/- 8 years) who displayed advanced cardiomyopathy, QRS duration > or =130 ms, or mechanical dyssynchrony, underwent isolated or combined coronary artery revascularization and mitral valve overreduction. In all patients, an epicardial lead was secured to the left ventricular wall at the end of the procedure and its extremity was brought into a subclavian pocket. In 5 patients, a resynchronization device was implanted at the time of surgery; in 8, it was implanted at a later date; the remaining 7 patients are awaiting implantation. One patient died postoperatively of low-output syndrome. There was 1 noncardiac late death. Eighteen patients were alive at a mean postoperative follow-up of 21.6 +/- 15.2 months (range, 1-43 mo). There were no subsequent hospital admissions after discharge. New York Heart Association functional class and left ventricular performance were significantly and lastingly improved when cardiac resynchronization therapy was added to the surgical procedure. Despite the limitations inherent in the small number of patients and the relatively short duration of follow-up, this study suggests that patients with dilated cardiomyopathy and left ventricular dyssynchrony in whom surgical correction is indicated may benefit from cardiac resynchronization therapy using a resynchronization device connected to an epicardial lead secured to the left ventricle at the time of surgery.

Transvenous biventricular pacing for cardiac resynchronization therapy in patients with persistent left superior vena cava and right superior vena cava atresia.

Biventricular pacing for cardiac resynchronization therapy is an effective adjunctive therapy for the treatment of symptomatic moderate and severe congestive heart failure. However, experience with transvenous cardiac resynchronization therapy in patients who have both persistent left superior vena cava and right superior vena cava atresia is extremely limited. We successfully performed cardiac resynchronization therapy in 2 patients who had persistent left superior vena cava, right superior vena cava atresia, and congestive heart failure. Our 2 cases demonstrate the possibility of a total transvenous approach for left ventricular pacing despite the presence of serious cardiac venous anomalies. This approach enables clinicians to avoid the riskier epicardial lead placement, which requires a thoracotomy under general anesthesia.