Archana Rao

A prospective longitudinal evaluation of the benefits of epicardial lead placement for cardiac resynchronization therapy

AIMS Cardiac resynchronization therapy (CRT) is a recognized treatment for appropriate patients. However, placement of the transvenous left ventricular lead is unsuccessful in 5-10% of patients and a further 20% fail to respond. For these groups, epicardial left ventricular lead placement is one alternative. We prospectively evaluated the effects of epicardial vs. transvenous placed CRT. METHODS AND RESULTS Twenty-three subjects with unsuccessful transvenous coronary sinus lead placement underwent epicardial implantation. The subjects underwent clinical evaluation, cardiopulmonary exercise testing, and echocardiography before 3 and 6 months after. The results were compared with a control group (n = 35) who had received transvenous CRT. In both groups, there were significant improvements in all measures at 3 and 6 months. The improvement in peak VO(2) was delayed in the epicardial group compared with the transvenous group. At 6 months, the improvements seen in all variables showed no difference between the groups. CONCLUSION Epicardial lead placement is a viable option for patients with unsuccessful coronary sinus lead placement. The improvements in most variables were of a similar magnitude and over a similar time scale compared with transvenous placement. Improvements in peak VO(2) were delayed in the epicardial group, probably as a result of a prolonged recovery time.

Thoracoscopic patch insulation to correct phrenic nerve stimulation secondary to cardiac resynchronization therapy

AIMS Cardiac resynchronization therapy is an established therapy for heart failure, improving quality of life and prognosis. Despite advances in technique, available leads and delivery systems, trans-venous left ventricular (LV) lead positioning remains dependent on the patients underlying venous anatomy. The left phrenic nerve courses over the surface of the pericardium laterally and may be stimulated by the LV pacing lead, causing uncomfortable diaphragmatic twitch. This paper describes a video-assisted thoracoscopic (VATS) procedure to correct phrenic nerve stimulation secondary to cardiac resynchronization therapy. METHODS AND RESULTS Most current ways of avoiding phrenic stimulation involve either electronic reprogramming to distance the phrenic nerve from the stimulation circuit or repositioning the lead. We describe a case where the phrenic nerve was surgically insulated from the stimulating current by insinuating a patch of bovine pericardium between the epicardium and native pericardium of the heart thus completely resolving previously intolerable and incessant diaphragmatic twitch. The procedure was performed under general anaesthesia with single-lung ventilation and minimal use of neuromuscular blocking agents. Surgical patch insulation of the phrenic nerve was performed using minimally invasive VATS surgery, as a short-stay procedure, with no complications. No diaphragmatic twitch occurred post-surgery and the patient continued to gain symptomatic benefit from cardiac synchronization therapy (New York Heart Association Class III to II), enabling return to work. CONCLUSIONS In cases where the trans-venous position of a LV lead is limited by troublesome phrenic nerve stimulation, thoracoscopic surgical patch insulation of the phrenic nerve could be considered to allow beneficial cardiac resynchronization therapy.

Cardiac pacing and device therapy

Cardiac pacing and device therapy / , Cardiac pacing and device therapy / , کتابخانه دیجیتال جندی شاپور اهواز

Pacemaker lead overcoiling: the overcoil–retraction phenomenon

The image (figure 1) shows the dangers of lead overcoiling. In the first post-implant image, a biventricular defibrillator is present with a St. Jude Quicksite left ventricular (LV) lead (SJM, Saint Paul, Minnesota, USA) positioned in a middle cardiac vein. On day 1 post-implant, loss of LV capture was noted. Repeat x-ray shows that the LV lead recoiled to the innominate vein (solid black …

081 A NOVEL STANDARD OF QUALITY EVALUATION IN BRADYARRHYTHMIA PACING

Introduction The annual implantation rate for bradyarrhythmia pacing devices continues to increase, due to the aging population fulfilling the indication criteria defined in national guidelines. Morbidity and mortality benefits conferred by pacemaker implantation, are well documented and evidence based. However, the complications arising from such invasive procedures are less well documented. The reported rates of complications are out of date and compounded by variation in complication definitions and the time scale of evaluation. Further confusion arises as a result of the denominator utilised to report complication rates for example, per procedure volume, or per number of leads deployed. The predominant focus on complication data has been peri-procedure and is thus insufficient to accurately represent patient morbidity. This study presents novel complication data reporting for de novo bradyarrhythmia pacing systems implanted at a high volume centre, with all complications and any form of re-operation tracked to 1-year post implant. Methodology A prospective review was performed following consecutive virgin pacemaker implants, between April 2008 and March 2011, at a tertiary cardiothoracic centre in the UK. All procedures were consultant led. Health records for each patient were reviewed independently by two clinicians, analysing the documentation pertaining to the primary procedure and all subsequent health care episodes within 1 year. Complications within this period were defined as follows; (1) radiographic evidence of a pneumothorax confirmed by a consultant radiologist, (2) pericardial effusion demonstrated on transthoracic echocardiogram indicated on clinical grounds and (3) any return to theatre within one calendar year post implant. Results Between April 2008 and March 2011, 1224 new bradyarrhythmia devices were implanted. Within 1 year of the index implant, 53 patients (4.3%) had one or more complications or re-operations. Cumulatively, 58 complications and re-operations were encountered (4.7%), with 5 patients sustaining two events. 6 pneumothoraces (0.5%) were identified, 1 haematoma mandating surgical evacuation (0.1%) and 1 pericardial effusion (0.1%). Regarding re-operation within the first year, 6 device extractions (0.5%) were performed, 30 procedures for either lead displacement or to refine pacing parameters (2.5%), 9 upgrades to cardiac resynchronisation therapy or implantable cardioverter defibrillator (0.7%) and 2 pocket revisions (0.2%). Conclusions For primary bradyarrhythmia pacemaker implantation at a high volume tertiary cardiothoracic centre, we report an overall 4.7% complication rate to 1 year post implant.

Troubleshooting After Device Implantation

Troubleshooting after pacemaker implantation is the task of both the cardiac physiologist and the cardiologist. It is a process which begins at the time of implantation and should be readdressed not only if the patient re-presents with ongoing or new symptoms post-implant, but also at every routine follow-up appointment. Adherence to these rules not only promotes safe and effective pacemaker function, but also serves to increase device longevity and reduce the adverse effects of unnecessary or inappropriate cardiac pacing.

Permanent Pacing: Current Overview

Today, approximately three million people worldwide have a pacemaker and more than 600,000 pacemakers are implanted annually.

Programmable Functions and Terminology

The rapid developments in technology and pacemaker research have enabled pacemakers and other implantable devices to be become more sophisticated. Devices have numerous programmable features and can store substantial amounts of diagnostic information related to device function, arrhythmia detection, cardiovascular hemodynamic parameters including transthoracic impedance and patient activity. Bi-directional telemetry using encoded and encrypted radiofrequency signals allows transmission of information to the implantable device from the programmer and to the programmer from the device. This process permits review of the programmed parameters and stored diagnostic data and reprogramming of device parameters to correct identified malfunctions and/or to optimize device function (Fig. 9.1).

Pacemaker and ICD Implantation in Children

The implantation and follow-up of pacemakers and ICDs in children poses unique challenges. Less than 1% of all pacemakers and ICDs are implanted in children and the numbers of implants taking place within individual centers are low. In a recent US survey, the mean annual number of new pacemaker implants per center was less than 25. A significant proportion of the pediatric population who require pacemaker and ICD implantation are survivors of palliative surgical procedures for complex congenital heart disease (CHD). Physicians are thus faced with the difficult situation of implanting few devices in complex patients and as a result sometimes adult cardiologists may be asked to implant devices in children. This chapter focuses on the key differences between adults and children in terms of pacemaker and ICD indications, implantation, and follow-up.

Predischarge Pacemaker Checks and Advice

The day after permanent pacemaker implantation (or just prior to discharge if “day-case” pacing is in operation), lead position should be checked by performing a PA and lateral chest X-ray (see Chap. 7). Pneumothorax and early lead displacement should be excluded. A 12-lead ECG should confirm satisfactory pacing in atrium, ventricle, or both depending on the type of pacemaker implanted, usually by application of the programmer head over the device to produce a “magnet ECG strip.” The pacing threshold should ideally be checked and the pacing parameters set appropriately by the clinical physiologist to ensure satisfactory pacing and sensing, if necessary by adjusting the pulse width (0.1–1.0 ms), output (2.5–7.5 V), and sensitivity (0.25–8 mV) settings (Figs. 8.1, 8.2, and 8.3). The pacemaker’s upper (100–180 bpm) and lower rate (30–100 bpm) limit, pacing mode (e.g., AAI, VVI, VVI, DDD), rate response, polarity (uni- or bipolar), refractory period (200–500 ms), and AVD delay (0–300 ms), etc., should also be confirmed by the clinical physiologist using the programmer and the settings documented in the case notes. For day cases, these checks will be made by the technician before the patient leaves the pacing theater.