Shoaib Hamid

Invasive Acute Hemodynamic Response to Guide Left Ventricular Lead Implantation Predicts Chronic Remodeling in Patients Undergoing Cardiac Resynchronization Therapy

OBJECTIVES We evaluated the relationship between acute hemodynamic response (AHR) and reverse remodeling (RR) in cardiac resynchronization therapy (CRT). BACKGROUND CRT reduces mortality and morbidity in heart failure patients; however, up to 30% of patients do not derive symptomatic benefit. Higher proportions do not remodel. Multicenter trials have shown echocardiographic techniques are poor at improving response rates. We hypothesized the degree of AHR at implant can predict which patients remodel. METHODS Thirty-three patients undergoing CRT (21 dilated and 12 ischemic cardiomyopathy) were studied. Left ventricular (LV) volumes were assessed before and after CRT. The AHR (maximum rate of left ventricular pressure [LV-dP/dt(max)]) was assessed at implant with a pressure wire in the LV cavity. Largest percentage rise in LV-dP/dt(max) from baseline (atrial antibradycardia pacing or right ventricular pacing with atrial fibrillation) to dual-chamber pacing (DDD)-LV was used to determine optimal coronary sinus LV lead position. Reverse remodeling was defined as reduction in LV end systolic volume ≥15% at 6 months. RESULTS The LV-dP/dt(max) increased significantly from baseline (801 ± 194 mm Hg/s to 924 ± 203 mm Hg/s, p < 0.001) with DDD-LV pacing for the optimal LV lead position. The LV end systolic volume decreased from 186 ± 68 ml to 157 ± 68 ml (p < 0.001). Eighteen (56%) patients exhibited RR. There was a significant relationship between percentage rise in LV-dP/dt(max) and RR for DDD-LV pacing (p < 0.001). A similar relationship for AHR and RR in dilated cardiomyopathy and ischemic cardiomyopathy (p = 0.01 and p = 0.006) was seen. CONCLUSIONS Acute hemodynamic response to LV pacing is useful for predicting which patients are likely to remodel in response to CRT both for dilated cardiomyopathy and ischemic cardiomyopathy. Using AHR has the potential to guide LV lead positioning and improve response rates.

Extraction of cardiac rhythm devices: indications, techniques and outcomes for the removal of pacemaker and defibrillator leads

Cardiac rhythm management devices (pacemakers) are being increasingly implanted worldwide not only for symptomatic bradycardia, but also for the management of arrhythmia and heart failure. Their use in more elderly patients with significant comorbidities is rising steeply and consequently long‐term complications are increasingly arising. Such an increase in device therapy is being paralleled by an increase in the requirement for system extraction. Safe lead extraction is central to the management of much of the complications related to pacemakers. The most common indication for lead extraction is system infection Adhesions in chronically implanted leads can become major obstacles to safe lead extraction and life‐threatening bleeding and cardiac perforations may occur. Over the last 20 years, specific tools and techniques for transvenous lead extraction have been developed to assist in freeing the lead body from the adhesions. This article provides a comprehensive review of the indications, tools, techniques and outcomes for transvenous lead extraction. The success rate largely depends on the time from implant. Up to 12 months from implant, it is rare that traction alone will not suffice. For longer lead implant duration, no single technique is sufficient to address all extractions, but laser provides the best chance of extracting the entire lead. Operator experience is vital in determining success as familiarity of a wide array of techniques will increase the likelihood of uncomplicated extraction. Long implantation time, lack of operator experience, ICD lead type and female gender are risk factors for life‐threatening complications. Lead extraction should therefore, ideally be performed in high volume centres with experienced staff and on‐site support from a cardiothoracic surgical team able to deal with bleeding complications from cardiovascular perforation.

Pacemaker and Defibrillator Lead Extraction: Predictors of Mortality during Follow‐Up

Background: Extraction of cardiac implantable electric devices is an accepted procedure when systems become infected or malfunction. However, there is an associated morbidity and mortality. We report our 5‐year experience and identify predictors of mortality, and long‐term follow‐up.

Multi-site left ventricular pacing as a potential treatment for patients with postero-lateral scar: insights from cardiac magnetic resonance imaging and invasive haemodynamic assessment.

AIMS Multi-site left ventricular (LV) pacing may be superior to single-site stimulation in correcting dyssynchrony and avoiding areas of myocardial scar. We sought to characterize myocardial scar using cardiac magnetic resonance imaging (CMR). We aimed to quantify the acute haemodynamic response to single-site and multi-site LV stimulation and to relate this to the position of the LV leads in relation to myocardial scar. METHODS Twenty patients undergoing cardiac resynchronization therapy had implantation of two LV leads. One lead (LV1) was positioned in a postero-lateral vein, the second (LV2) in a separate coronary vein. LV dP/dtmax was recorded using a pressure wire during stimulation at LV1, LV2, and both sites simultaneously (LV1 + 2). Patients were deemed acute responders if ΔLV dP/dtmax was ≥ 10%. Cardiac magnetic resonance imaging was performed to assess dyssynchrony as well as location and burden of scar. Scar anatomy was registered with fluoroscopy to assess LV lead position in relation to scar. RESULTS LV dP/dtmax increased from 726 ± 161 mmHg/s in intrinsic rhythm to 912 ± 234 mmHg/s with LV1, 837 ± 188 mmHg/s with LV2, and 932 ± 201 mmHg/s with LV1 and LV2. Nine of 19 (47%) were acute responders with LV1 vs. 6/19 (32%) with LV2. Twelve of 19 (63%) were acute responders with simultaneous LV1 + 2. Two of three patients benefitting with multi-site pacing had the LV1 lead positioned in postero-lateral scar. CONCLUSION Multi-site LV pacing increased acute response by 16% vs. single-site pacing. This was particularly beneficial in patients with postero-lateral scar identified on CMR.

Extraction of chronic pacemaker and defibrillator leads from the coronary sinus: laser infrequently used but required

AIMS Cardiac resynchronization therapy is an accepted treatment for heart failure but it may be necessary to explant these systems along with their leads. The evidence base for coronary sinus (CS) lead extractions is limited. We aimed to evaluate the percutaneous removal of these leads and the utility of laser extraction when necessary. METHODS AND RESULTS Of 265 patients referred for lead extraction between January 2004 and June 2008, 32 (12.1%) involved CS leads (30 males, mean age 67 years). Mean implantation time was 26.5 +/- 28.7 months (range 1-116 months). Indications for extraction were pocket infection (34.4%), lead malfunction (43.8%), skin erosion (15.6%), and endocarditis (6.2%). Twenty-eight (87.5%) CS leads were removed with manual traction, with laser utilized in four cases (12.5%). No major complications of CS laceration, pericardial effusion, emergency surgery, or death occurred. CONCLUSION Our experience supports the percutaneous extraction of CS leads as a safe and effective procedure including the utility of laser when necessary.

Treatment of Inappropriate Sinus Tachycardia with Ivabradine in a Patient with Postural Orthostatic Tachycardia Syndrome and a Dual Chamber Pacemaker

We present the case of a 44‐year‐old woman with postural orthostatic tachycardia syndrome (POTS) and a dual chamber pacemaker. The patient suffered from inappropriate sinus tachycardia that had been resistant to treatment with traditional rate‐slowing medications. Ivabradine—the specific sinus node If current inhibitor—was used to successfully lower the heart rate. The patient had no evidence of POTS on repeat autonomic function testing, and there was a corresponding symptomatic benefit. We propose that this class of drugs, the use of which is established as antianginals, should be considered in patients with resistant inappropriate sinus tachycardia.

Trends, indications and outcomes of cardiac implantable device system extraction: a single UK centre experience over the last decade

Background:  The rising number of device implantation has seen a parallel in the rising numbers of lead extraction. Herein we have analysed our experience in cardiac device and lead extraction in a single tertiary centre over the last decade.

Laser lead extraction to facilitate cardiac implantable electronic device upgrade and revision in the presence of central venous obstruction

Aims The number of procedures involving upgrade or revision of cardiac implantable electronic devices (CIEDs) is increasing and the risks of adding additional leads are significant. Central venous occlusion in patients with pre-existing devices is often asymptomatic and optimal management of such patients in need of device revision/upgrade is not clear. We sought to assess our use of laser lead extraction in overcoming venous obstruction. Methods and results Patients in need of device upgrade/revision underwent pre-procedure venography to assess venous patency. In patients with venous occlusion or stenosis severe enough to preclude passage of a hydrophilic guide wire, laser lead extraction with retention of the outer sheath in the vasculature was performed with the aim of maintaining a patent channel through which new leads could be implanted. Data were recorded on a dedicated database and patient outcomes were assessed. Between July 2004 and April 2012, laser lead extractions were performed in 71 patients scheduled for device upgrade/revision who had occluded or functionally obstructed venous anatomy. New leads were successfully implanted across the obstruction in 67 (94%) cases. There were two major complications (infection) and four minor complications with no peri-procedural mortality. Device follow-up was satisfactory in 65 (92%) cases with mean follow-up up to 26 ± 19 months. Conclusion Laser lead extraction is a safe and effective option when managing patients with central venous obstruction in need of CIED revision or upgrade.

Percutaneous lead and system extraction in patients with cardiac resynchronization therapy (CRT) devices and coronary sinus leads.

Background:  Cardiac resynchronization therapy (CRT) device and coronary sinus (CS) lead extraction is required due to the occurrence of system infection, malfunction, or upgrade. Published series of CS lead extraction are limited by small sample sizes. We present a 10‐year experience of CRT device and CS lead extraction.

Relationship between intracardiac impedance and left ventricular contractility in patients undergoing cardiac resynchronization therapy

Aims Cardiac resynchronization therapy (CRT) has dramatically improved the symptoms and prognosis of patients with heart failure in large randomized clinical trials. Optimization of device settings may maximize benefit on an individual basis, although the best method for this is not yet established. We evaluated the use of cardiogenic impedance measurements (derived from intracardiac impedance signals) in CRT device optimization, using invasive left ventricular (LV) dP/dtmax as the reference. Methods and results Seventeen patients underwent invasive haemodynamic assessment using a pressure wire placed in the LV cavity at the time of CRT device implantation. Intracardiac impedance measurements were made at different atrioventricular (AV) and interventricular (VV) delays and compared with LV dP/dtmax. We assessed the performance of patient-specific and generic impedance-based models in predicting acute haemodynamic response to CRT. In two patients, LV catheterization with the pressure wire was unsuccessful and in two patients LV lead delivery was unsuccessful; therefore, data were acquired for 13 out of 17 patients. Left ventricular dP/dtmax was 919 ± 182 mmHg/s at baseline and this increased acutely (by 24%) to 1121 ± 226 mmHg/s as a result of CRT. The patient-specific impedance-based model correctly predicted the optimal haemodynamic response (to within 5% points) for AV and VV delays in 90 and 92% of patients, respectively. Conclusion Cardiogenic impedance measurements are capable of correctly identifying the maximum achievable LV dP/dtmax as measured by invasive haemodynamic assessment. This study suggests that cardiogenic impedance can potentially be used for CRT optimization and may have a role in ambulatory assessment of haemodynamics.