New implantable cardiac monitor with three-lead ECG and active noise detection.

BACKGROUND: A new implantable cardiac monitor (BioMonitor, Biotronik) with a continuous remote monitoring option was prospectively implanted in patients with suspected arrhythmias or for therapy control after atrial fibrillation (AF) ablation. A three-lead ECG detection was intended to make the implantation more independent of the implantation site and the electrical heart axis. Because noise is a frequent problem in implantable cardiac monitors, an active noise detection algorithm was implemented. The aim of the trial was to evaluate the clinical performance of the device. METHODS: The device performance was evaluated in a prospective nonrandomized multicenter study with a follow-up of 12 months. Study endpoints were device-related serious adverse events at 3 months, appropriate QRS detection in direct comparison with synchronized Holter ECG recordings, sensitivity and positive predictive value of arrhythmia detection in comparison with Holter ECG and independent of it, and noise burden during the entire follow-up period. RESULTS: The implantation was successful in all 152 patients. Two device-related serious adverse events (pocket infections) occurred by 3 months. The mean QRS amplitude of 0.3 ± 0.2 mV at implantation remained stable over 12 months. QRS sensing performance indicated little over- and undersensing in most patients. More than 80 % of the patients had more than 22 h of noise-free monitoring per day. CONCLUSION: BioMonitor effectively detects patients with bradycardia, tachycardia, AF, or asystole. Active noise detection seems to reduce the transmission of meaningless data without diminishing the positive predictive value of the device.

Cardiac contractility modulation in non-responders to cardiac resynchronization therapy.

AIMS: Cardiac resynchronization therapy (CRT) has become a standard therapy in cases of heart failure and asynchrony. Unfortunately, 20-30% of patients were non-responsive (NR) to CRT. In this report we used cardiac contractility modulation (CCM) as an adjunctive measure in NR patients. METHODS AND RESULTS: Sixteen NR patients, mean age 65 +/- 9 years, mean ejection fraction 27.3 +/- 7.4%, and New York Heart Association (NYHA) class III (n = 9) or IV (n = 7) despite CRT plus optimized medical therapy, received an additional CCM-implantation contra-lateral to the existing CRT system (OPTIMIZER III, Impulse Dynamics, Orangeburg, NY, USA). Cardiac contractility modulation delivers non-excitatory high-energy stimulatory impulses during the absolute refractory period, thus improving contractility [left ventricular (LV) dp/dt)] by stimulating the septum with two screw-in leads and one additional atrial lead for triggering the impulses. Acute LV dp/dt changes induced by CCM stimulation were measured by 5F Millar catheters placed in the LV during the implantation procedure in 14 of 16 cases. Patients were followed prospectively. Left ventricular dp/dt increased from a mean of 568 +/- 153 to 646 +/- 147 mmHg/s (+14%, P < 0.001) in the acute intraoperative testing. We noted the following complications and events during a follow-up of an average of 147 +/- 80 days (range 68-326) after CCM: intraoperative ventricular flutter needing cardioversion (n = 1), atrial lead dislocation (n = 1), coronary sinus (CS) lead dislocation (n = 1), painful stimulation requiring repositioning of septal leads (n = 1), true defibrillator shocks (n = 3), cardiac decompensations (n = 3), atrial fibrillation (n = 4), renal failure (n = 1), and pneumonia (n = 2). NYHA class improved from 3.4 to 2.8 (P < 0.01), and the ejection fraction increased from 27.3 +/- 5 to 31.1 +/- 6 (P < 0.01). Three patients (19%) died suddenly presumably due to electromechanical dissociation after 318, 104, and 81 days. No electrical interference was observed between the CCM and CRT systems, and in particular, at no time was the CRT-implantable cardioverter-defibrillator found to be delivering inadequate shocks. CONCLUSION: The CCM method is feasible and could be applied with calculated risks as a possible useful adjunct in CRT-NR when no other options are available; however, mortality and event rates are high in this very sick population.

What can happen during coronary sinus lead implantation: dislocation, perforation and other catastrophes.

Cardiac resynchronization therapy (CRT) using coronary sinus (CS) leads is an established method for the therapy of congestive heart failure (CHF) in the case of asynchronous ventricular contractions. Successful therapy depends on the placement of left ventricular leads usually via the coronary sinus (CS), a technically more challenging procedure than regular pacemaker implantations. Without specific precautions CRT implantation can be the gateway to a time consuming nightmare. Therefore CS lead implantation methods, with a focus on complications, were reviewed according to the literature and own experience with approximately 500 procedures from 1999-2007.

Rhabdomyolysis after addition of digitoxin to chronic simvastatin and amiodarone therapy.

Rhabdomyolysis is a well known side effect of statin therapy. Several drugs may increase its risk by drug-drug interactions. In particular, patients with heart disease receive more and more different compounds to cope with all the pathomechanisms involved and may therefore be of high risk for side effects. We report a case of rhabdomyolysis in a patient with heart failure on a multi-drug regimen caused by a drug interaction between chronic statin therapy (simvastatin), amiodarone and newly administrated digitoxin. The patient recovered fully after cessation of simvastatin therapy, the other drugs were given continuously. Potential mechanisms of this event are discussed. Most interesting in this case is that rhabdomyolysis occurred only after starting digitoxin after long-term therapy with the statin.

Inappropriate shock during left ventricular threshold measurement in a patient with coexisting ICD and a biventricular pacemaker.

Cardiac resynchronization therapy (CRT) using coronary sinus (CS) leads for biventricular stimulation is an established method for the therapy of congestive heart failure (CHF) in the case of inter- or intraventricular conduction delays. There are some patients having two separate devices: an ICD and a biventricular pacemaker. This case report describes an unusual interaction of these systems: an inappropriate VVI defibrillator shock during left ventricular threshold measurement in a biventricular pacemaker implanted on the other side.

Analysis of terminal arrhythmias stored in the memory of pacemakers from patients dying suddenly.

AIMS: Stored electrograms or marker channels are available in most of modern cardiac pacemaker models. We sought to analyse these information to uncover terminal events of pacemaker patients dying suddenly. Method and results We made post-mortem pacemaker (PM) interrogations in 19 patients dying suddenly out of hospital between the years 1997 and 2005 (mean age 59 +/- 13 years, 90% males). The systems had activated arrhythmia monitoring algorithms. Indications of pacing were sick sinus syndrome in seven, AV-block in five, and heart failure due to asynchrony in seven cases. The interrogated pacemakers were CHORUS 7034 (n = 12), CONTAK TR (n = 2), and INSYNC III (n = 5). For interpretation stored marker channels and electrograms were analysed. The mean observation time after PM implantation prior death was 2.11 +/- 1.44 years, the mean left ventricular ejection fraction from the last available echo examination in the year prior death was 27.5 +/- 8%, mean age was 63 +/- 12 years. In 17/19 cases (89%), a tachycardia (most likely ventricular tachycardia) was found correlating to the time of death. The mean cycle length of the terminal arrhythmia was 307 +/- 144 (250-344) ms, corresponding to a heart rate of 195 +/- 95 (174-240) bpm. We found no evidence of specific pacemaker-related problems such as electronic failure, battery depletion, or undersensing. CONCLUSIONS: Post-mortem analysis of arrhythmia monitoring of pacemaker patients revealed tachycardias (most likely ventricular tachycardia) to be related to sudden death. These findings give some insight in mechanisms of terminal events in this group.

First experience with a new active fixation coronary sinus lead.

AIMS: Coronary sinus (CS) lead implantation is a technically challenging procedure owing to variable vein anatomies and a high dislocation rate. Therefore, CS lead technology has undergone evolutionary changes during the last 10 years. The mode of fixation has been a passive one up to now. We want to describe our first clinical experience with the newly available active fixation lead 4195 in terms of dislocation rate and stability of thresholds compared with conventional models. METHODS AND RESULTS: From 1999 to February 2007, we implanted 403 CS leads in 368 patients. Leads were categorized into three different groups on the basis of their fixation mechanism: straight (Easytrak I and Situs OTW; n = 54), curved (Attain 4193 and 4194, Corox, Aescula, Situs ULD; n = 308), and active (Attain 4195; n = 41). Operative and follow-up data were prospectively noted and checked for significance between groups during the first 3 months after implantation. Kaplan-Meier analysis of long-term lead function was also performed. Straight and curved CS leads suffered from significantly more dislocations compared with active fixation (P < 0.001). The active fixation lead (4195) has a stable threshold over time compared with a significant rise after 24 h and thereafter in straight (62%) and curved leads (20%). However, retraction of an active fixation CS lead may be a difficult issue as outlined in two cases requiring pullback of a 4195 lead owing to phrenic nerve stimulation (one unsuccessful despite vigorous traction). CONCLUSION: The active fixation lead 4195 using retention lobes yielded stable thresholds over time and seems to be superior to conventional leads in terms of dislocation. However, extraction may be a difficult or even impossible task.

Hemodynamic changes during cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is a new method for the correction of inter- and/or intraventricular conduction delays of patients with heart failure. The long-term impact of CRT on central hemodynamics is not fully characterized. We performed complete right heart catheterization studies in 31 patients receiving a CRT device pre and 6 months after implantation. Most of the patients improved in their NYHA stage, their LVEF, and in parallel showed reduced right atrial (RA) pulmonary artery (PA) and pulmonary capillary wedge (PCW) pressures and pulmonary vascular resistance both at rest and at 25 watts. In addition, we found a reduction in heart rate accompanied by an increased mean arterial pressure both at rest and at 25 watts. Accordingly, brain natriuretic peptide levels (BNP) were lowered. It was concluded that, besides other well-known effects on ventricular coordination, central hemodynamics after 6 months were improved during CRT.

Inappropriate ICD discharge induced by electrical interference from a physio-therapeutic muscle stimulation device.

This report illustrates the case of a patient with an implantable cardioverter defibrillator (ICD) who during physiotherapy with transcutaneous electrical stimulation of the lumbar musculature perceived a shock discharge by the ICD. Analysis of the stored electrogram showed inappropriate therapy due to electromagnetic interference with the external stimulation. Patients as well as physiotherapists should be informed about this potential interaction to avoid such iatrogenic, inappropriate ICD therapy.

Experience with coronary sinus lead implantations for cardiac resynchronization therapy in 244 patients.

INTRODUCTION: Cardiac resynchronization therapy (CRT) using coronary sinus (CS) leads is a new method for the therapy of congestive heart failure (CHF). Because the intervention is more complex than regular pacemaker implantations, information on the feasibility and side effects of this method are of interest. METHODS: From 1999 to June 2005, CRT implantations were attempted in 244 patients (pts; mean age 64+/-12 years, range 14-90 years), 82% were male, 44% had coronary artery disease, 29% were in atrial fibrillation, 71 had preexisting pacemakers. RESULTS: In 97% of the pts the intervention was successful (27% of the systems with defibrillation capabilities). In 285 interventions, 255 CS leads were positioned according to CS vein anatomy in 130 posterolateral, 97 anterolateral and 28 anterior side branches (16 patients received 2 CS leads). Over-the-wire leads were used in 88%, 71% were additionally preshaped. We observed no mortality but 37 complications (12.5%): CS dissection in 9, CS perforation in 1, ventricular fibrillation in 4, asystole in 5, pulmonary edema in 1, pneumothorax in 2, need for early CS lead revision in 19 (dislodgement n=7, phrenic nerve stimulation n=12) and infection with explantation in 2 cases. An improvement in NYHA functional class was found in 88% of pts (only 55% if anterior lead position). CONCLUSION: Perioperative complications during CS lead implantation occur in 10-15% of cases. Most patients responded well to CRT. Patients should be informed about the possible need for a reoperation. During implantation, immediate defibrillation and stimulation capabilities must be available. Anterior lead positions should be avoided.

Long-term hemodynamic benefit of biventricular pacing depending on coronary sinus lead position.

BACKGROUND: Acute studies in cardiac resynchronization therapy (CRT) showed that hemodynamic effects may depend on the coronary sinus (CS) lead position. However, there are no data on the longterm effect of CS lead position. METHODS: In 45 heart failure patients with left bundle branch block and QRS >150 ms (age 59+/-10 years, 17 dilative cardiomyopathy, 23 ischemic, 5 valvular), biventricular pacemakers were implanted. CS leads were positioned in posterior (P, n=15), lateral (L, n=19) or, if no other option available, anterior (A, n=11) side branches. Before and 6 months after implantation, clinical state, echocardiography, brain natriuretic peptide (BNP) and right heart catheterization were evaluated. RESULTS: Baseline parameters were similar between groups. After 6 months, there were 32/34 responders in groups P and L compared to 7/11 responders in group A (94 vs groups P and L: Arterial pressure +8 and +9% vs +2%; PCWP -23 and -15% vs -4%, pulmonary pressure -18 and -12% vs -3% (p<0.01 for A vs P+L); cardiac index +21 and +12% vs +11% (p=0.03 for A vs P). BNP was reduced by 55, 35, and 27% (p=0.05 for A vs P). Ejection fraction increased in P and L by 40 and 41%, respectively, but only by +19% in A (p<0.03 for A vs P+L). CONCLUSION: Chronic CRT improves ejection fraction, BNP and hemodynamic measurements predominantly in patients with lateral and posterior CS lead positions. Anterior lead positions should be avoided.

Heart transplantation in a patient with multiple sclerosis and mitoxantrone-induced cardiomyopathy.

We describe a 30-year-old man with end-stage heart failure after therapy with mitoxantrone for multiple sclerosis. A successful orthotopic heart transplantation was performed when intensified medical therapy failed to improve the patient's hemodynamics. In spite of the severe underlying disease he did well on dual immunosuppression with methylprednisone and cyclosporine. Neurologic symptoms remained stable throughout the procedure and, after 2 months, he resumed preoperative ambulatory status. Eight years after the operation, the patient is now in New York Heart Association (NYHA) Class I status. Using canes, he is able to walk short distances. Repeated urinary tract infections caused by Escherichia coli became a problem, but have been controlled by long-term oral antibiotic prophylaxis with trimethoprim.

[Excimer laser extraction of pacemaker and defibrillator leads]. / Excimer-Laser Extraktion von Schrittmacher- und Defibrillatorelektroden.

BACKGROUND: Pacemaker infection or some lead dysfunctions are an indication for removal of all foreign material. The use of laser energy is a new method for extraction of fixed leads that have been in place for a long time. There are only a few reports on results and complications of laser extraction in comparison to conventional methods. Therefore, this study compares results of laser lead extraction and conventional methods. METHODS: Since January 1999 we have made use of the laser lead extraction system of Spectranetics, Inc. Inner traction of the leads was performed using a "lead locking device" (LLD) and for laser application 12, 14 und 16 French "laser sheaths" were used. As the energy source, an excimer laser device was used (CVX-300). The intervention was performed under heart-lung machine backup. Results of the laser procedure in 24 patients and 45 leads (including 3 defibrillator leads) are compared to results of manual traction (23 patients, 53 leads), traction devices (24 patients, 38 leads), snare catheters (6 patients, 6 leads) and thoracotomy (5 patients, 9 leads) from the years 1995-1998. RESULTS: The mean operation time of the laser method (93 +/- 50 min) was not significantly different from manual traction (82 +/- 48 min,) or traction devices (100 +/- 45 min). The mean fluoroscopy time (9.4 +/- 50 min) was similar to traction devices (8.4 +/- 5 min, p < 0.05). In one patient a percardial tamponade developed with the need for urgent thoracotomy. This patient died on the fourth postoperative day due to cerebral hypoxia. The other 23 patients had an uneventful course. All but one lead could be removed without fragmentation, including a malpositioned lead in the left ventricle (success rate 96%). In 62 patients and 97 conventional extractions (53x manual, 38x device, 6x snare) from 1995-1998, one fatal (sepsis due to lead fragmentation) and four severe complications developed (pericardial tamponade, pulmonary abscess, pulmonary embolism, sepsis). In 15/62 patients with conventional methods, lead fragments remained (success rate 76%). Of five patients from 1995-1998, in whom leads with vegetations or tricuspid valve insufficiency were removed by thoracotomy and cardiopulmonary bypass, one patient died perioperatively. CONCLUSIONS: In contrast to conventional methods, excimer laser pacemaker or defibrillator lead extraction allows total removal of all foreign material. This prevents late complications from lead fragments left in place. However, life-threatening complications can occur with conventional as well as with the laser method. Therefore, this intervention should be done only in specialized centers using extended monitoring (invasive blood pressure, TEE).

Excimer laser-assisted extraction of an infected bipolar left ventricular pacing lead implanted 10 years ago.

Routine intraoperative transesophageal echocardiography (TEE) revealed a previously undiscovered ventricular positioning of an infected ventricular lead left in place for 10 years. This case report describes successful removal of this lead from the left ventricle by means of excimer laser and discusses some important aspects to be considered.

Combination therapy with carvedilol and amiodarone in patients with severe heart failure.

BACKGROUND: Carvedilol and at least in some studies, amiodarone have been shown to improve symptoms and prognosis of patients with heart failure. There are no reports on the outcome of combined treatment with both drugs on top of angiotensin-converting enzyme inhibitors (ACEI), diuretics and digitalis. METHODS AND RESULTS: In 109 patients with severe heart failure submitted for heart transplantation at one single center between the years 1996 and 1998 [left ventricular ejection fraction (LVEF) 24.6+/-11%, 85% males, 52% idiopathic dilated cardiomyopathy (DCM), mean observation time 1. 9+/-0.4 years] a therapy with low-dose amiodarone (1000 mg/week) plus titrated doses of carvedilol (target 50 mg/day) was instituted. In addition, patients received a prophylactic dual chamber pacemaker (PM) in order to protect from bradycardia and for continuous holter monitoring. The devices were programmed in back-up mode with a basal rate of 40 i.p.m. with a hysteresis of 25%. Significantly, more patients were in sinus rhythm after 1 year than at study entry (85% vs. 63%, P<0.01). In 47 patients, under therapy over at least 1 year, the resting heart rate fell from 90+/-19 to 59+/-5 b.p.m. (P<0.001). Ventricular premature contractions in 24-h holter ECGs were suppressed from 1.0+/-3 to 0.1+/-0.3%/24 h (P167 b.p.m. detected by the pacemaker (1.2+/-2.8 episodes/patient/3 months vs. 0.3+/-0.8 episodes/patient/3 months after 1 year (P<0.01). The LVEF increased from 26+/-10 to 39+/-13% (P<0.001). NYHA class improved from 3. 17+/-0.3 to 1.8+/-0.6 (P<0.001) as well as right heart catheterization data. From the total cohort, seven patients (6%) developed symptomatic documented bradycardic rhythm disturbances requiring reprogramming of their pacemakers to DDD(R)/VVI(R) mode with higher basic rates. Two of these patients developed AV block, four sinu-atrial blocks or sinus bradycardia and one patient had bradycardic atrial fibrillation. During the observation period five patients died (3 sudden, 1 due to heart failure and 1 due to mesenteric infarction). Two patients had undergone heart transplants. The 1-year survival rate (Kaplan-Meier) without transplantation was 89%. Compared to historic control patients with amiodarone only (n=154) or without either agent (n=283) this rate was 64 and 57% (P<0.01). CONCLUSIONS: Heart failure patients benefit from a combined therapy with carvedilol and amiodarone resulting in a markedly improved NYHA stage, an increase in LV ejection fraction, a stabilization of sinus rhythm, a significant reduction in heart rate, a delay of electrical signal conduction and a suppression of ventricular ectopies. Approximately 6% of patients under such a regime became pacemaker-dependent in the first year. Compared to historic controls prognosis was better and the need for heart transplantation was lower. The exact role of either agent in combination or alone should be clarified in larger randomized studies.