VVI Pacemaker Research Articles

Jugular pacing lead extraction with laser sheath: a case report

Over the past 20 years, the number of patients with pacemakers (PM) or implantable cardioverter defibrillators has risen markedly; consequently, an increasing number of lead-removal procedures have become necessary. A 64-year-old woman presenting with an infected device pocket and positive bacterial cultures (Staphylococcus aureus) was admitted to our department for lead removal; in 1991, she underwent VVI PM implantation for atrioventricular II degree Mobitz 1 block, and a unipolar lead was introduced via the left jugular vein. The procedure was performed in our Electrophysiology Lab with a cardiac surgeon on standby, using an excimer laser system emitting the energy at the tip of a flexible, fibre-optic 12 F sheath, developed by Spectranetics, Inc., Colorado Springs, CO, USA.

Cardiac Resynchronization Therapy for Left Ventricular Dysfunction Induced by Chronic Right Ventricular Pacing in a Child

Cardiac resynchronization therapy (CRT) has been proven its value in adult patients with congestive heart failure of low ejection fraction and wide QRS duration. Contrast to adult patients, CRT has been rarely applied for young patients. We report on a 9-yr-old boy with progressive left ventricular (LV) dilatation and dysfunction following chronic VVI pacemaker therapy for congenital complete atrioventricular block associated with maternal anti-SSA/Ro and SSB/La antibody. His LV dysfunction was improved after epicardially established CRT.

An alternative approach for endocardial pacemaker lead implantation in patient with persistent left superior vena cava

Persistent left superior vena cava represents a congenital vascular defect of the venous system, which often makes standard 58 cm endocardial lead placement impossible. A right chamber approach by the left cephalic vein was tried. This was impossible because standard endocardial lead (SJM Isoflex 5 1646T, bipolar lead, 58 cm in length, body diameter 7 French) was too short for this patient. A unipolar lead for coronary sinus (Medtronic ATTEIN 4193-88), 88 cm in length, body diameter 4 French, was placed in the posterior branch of the coronary sinus. With such positioning of the lead, a VVI pacemaker pacing was enabled. The operation lasted for 48 minutes, and the time of total X-ray exposure was 9.6 minutes. The values that were achieved were: threshold 0.3 V, pulse width 0.37 ms, maximum R 22.55 mV. Ten months after the implantation, the values were: threshold 0.3 V, maximum R 28.8 mV. Persistent left superior vena cava in some cases makes standard 58 cm endocardial lead placement impossible due to its joining to the right atrium over the dilated coronary sinus. Coronary sinus lead placement in the posterior or lateral coronary sinus branch represents an acceptable alternative approach for pacemaker lead placement in these patients.

Obligatory external quality control: a mandatory demand in device therapy

Cardiac pacing has developed into a technically reliable and efficient treatment for patients with bradycardic heart diseases. Randomized controlled trials have been done documenting the efficacy of this treatment with respect to improvement in quality of life and reduction in morbidity as well as to which pacing mode to select. However, in each centre performing pacemaker implantations, a continuous work still should be done aiming at improvement of treatment quality and at reducing side effects and complications. For this purpose, the regular feedback from obligatory well-organized quality control programmes is invaluable. Nowak et al. 1 present a study of the effect of patient gender on pacemaker implantation based upon analysis of pre- and peri-operative data from a cohort of 17 800 consecutive patients undergoing primary pacemaker implantation and reported as part of an obligatory external quality control programme. Some very interesting findings regarding pacing mode selection and complications of pacemaker treatment appeared in this analysis. A surprisingly high percentage of patients received a single-lead ventricular (VVI) pacemaker system instead of a physiological pacemaker system that preserves synchrony between the atria and the ventricles. More women than men were treated with VVI pacing. Restricting the analysis to patients treated in small centres performing less than 20 pacemaker implantations per year, the gender differences were extreme, with 60% of women receiving VVI devices vs. 45% of men, but still in the remaining larger centres as many as 39% of women and 33% of men were treated with VVI devices. In the elderly population, significantly more women than men received VVI pacemaker systems, both in … *Corresponding author. Tel: +45 89 49 55 66, Fax: +45 89 49 60 02, Email: jenniels{at}rm.dk

Abnormal Atrioventricular Node Conduction and Atrioventricular Nodal Reentrant Tachycardia in Patients Older Versus Younger Than 65 Years of Age

We examined the possible role of atrioventricular node (AVN) conduction abnormalities as a cause of AVN reentrant tachycardia (RT) in patients >65 years of age. Slow pathway radiofrequency catheter ablation (RFCA) was performed in 104 patients. Patients in group 1 (n = 14) were >65 years of age and had AV conduction abnormalities associated with structural heart disease. Patients in group 2 (n = 90) were <65 years of age and had lone AVNRT. Patients in group 1 versus group 2 (66% vs. 46% men) had a first episode of tachycardia at an older age than in group 2 (68 +/- 16.8 vs 32.5 +/- 18.8 years, P = 0.007). The history of arrhythmia was shorter in group 1 (5.4 +/- 3.8 vs 17.5 +/- 14, P = 0.05) and was associated with a higher proportion of patients with underlying heart disease than in group 2 (79% vs 3%, P < 0.001). The electrophysiological measurements were significantly shorter in group 2: atrial-His interval (74 +/- 17 vs 144 +/- 44 ms, P = 0.005), His-ventricular (HV) interval (41 +/- 5 vs 57 +/- 7 ms, P = 0.001), Wenckebach cycle length (329 +/- 38 vs 436 +/- 90 ms, P = 0.001), slow pathway effective refractory period (268 +/- 7 vs 344 +/- 94 ms, P = 0.005), and tachycardia cycle length (332 +/- 53 vs 426 +/- 56 ms, P = 0.001). The ventriculoatrial block cycle length was similar in both groups. The immediate procedural success rate was 100% in both groups, and no complication was observed in either group. One patient in group 2 had recurrence of AVNRT. One patient with a 98-ms HV interval underwent permanent VVI pacemaker implantation before RFCA procedure. In patients undergoing RFCA for AVNRT at >65 years of age had a shorter history of tachycardia-related symptoms than patients with lone AVNRT. The longer AVN conduction intervals and refractory period might explain the late development of AVNRT in group 1.

Implantable Cardioverter-Defibrillator Implantation in a Patient with Atrial Standstill

We report a 55-year-old female patient who presented with no P waves but with a wide QRS complex escape rhythm at 44 beats/min and prolonged QTc of 0.55 seconds on ECG. The patient had recurrence of ventricular fibrillations and loss of consciousness, and underwent defibrillation and cardiopulmonary resuscitation (CPR) several times because of cardiac arrest. The transthoracic echocardiography showed dilated cardiomyopathy and enlargement of both atria. The Doppler echocardiography documented the absence of A wave in the tricuspid and mitral valve flow. An electrophysiologic study demonstrated electrical inactivity in the right and left atria. Atrial pacing with maximum output did not capture the atria. These findings together with her electrocardiographic finding indicated atrial standstill. Sudden cardiac death was her first clinical manifestation of ventricular arrhythmia. The patient remained asymptomatic after receiving a single chamber implantable cardioverter-defibrillator (ICD) with VVI pacemaker function.

Pectus Excavatum Deforming Right Heart Causing Difficult Right Ventricular Pacing

A 93-year-old female was admitted to our emergency medicine department with syncope. Her ECG showed AF with complete heart block. She was haemodynamically stable so was transferred to the coronary care unit. Her echocardiogram identified an abnormally shaped right ventricle due to external compression. Her condition deteriorated due to prolonged periods of asystole. External pacing paddles were applied whilst she was transferred to the pacing room. A single pacing wire was passed towards the right ventricle. The tricuspid valve was navigated easily, but with some difficulty the wire was eventually placed in the right ventricle with a threshold of 1.3 volts. A thoracic CT scan identified a congenital pectus excavatum deformity compressing the right ventricle (see image), obstructing the passage of the pacing wire. The patient was transferred for insertion of VVI pacemaker. This was also reported as being difficult requiring a ventricular screw-in lead at the apex. CASE REPORT A 93-year-old female was admitted to our emergency medicine department with syncope. She had a history of ischaemic heart disease, but no known arrhythmia. Her ECG showed atrial fibrillation with AV dissociation and a wide complex ventricular escape rhythm with a rate of 50 bpm. She was haemodynamically stable so was transferred to the coronary care unit. Her peak troponin T reached 0.77. All electrolyte abnormalities and thyroid dysfunction were ruled out. Her chest x-ray showed pulmonary oedema. Her portable echocardiogram showed well preserved left ventricular function and identified an abnormally shaped right ventricle due to external compression. Her condition deteriorated due to prolonged periods of asystole up to 20 seconds. External pacing paddles were applied whilst she was transferred to the pacing room. The right internal jugular vein was cannulated under ultrasound guidance and a single pacing wire passed towards the right ventricle. The tricuspid valve was navigated easily, but some difficulty was experienced in securing the lead in place. The wire was eventually placed in the right ventricle with a threshold of 1.3 volts. The patient remained unstable throughout the procedure and external pacing was required intermittently. A thoracic CT scan identified a congenital pectus excavatum deformity compressing the right ventricle (see image), obstructing the passage of the pacing wire. The patient remained stable and was transferred for insertion of permanent VVI pacemaker. This was also reported as being a difficult procedure requiring a ventricular screw-in lead at the apex. She was well at follow up 4 months later. Figure 1 Figure 1 Image A: Transthoracic apical 4 chamber echocardiogram highlighting external compression of the right heart. Image B: Axial computed tomograph scan showing right atrial and ventricular compression by pectus excavatum. Image C: Saggital computed tomography revealing sternal Pectus Excavatum Deforming Right Heart Causing Difficult Right Ventricular Pacing 2 of 3 compression of the right heart. Image D: Chest X-Ray following temporary pacing wire insertion. Image E: Reconstructed 3D computed tomograph demonstrating compression of the right heart structures from the (digitally removed) sternum.

Cardiac strangulation: a rare, but devastating complication of epicardial pacing causing progressive myocardial ischaemia

A female infant with a history of prematurity (gestational age: 29 weeks) and congenital complete heart block caused by maternal lupus erythematodes underwent implantation of epicardial VVI pacemaker at the age of 3 months followed by surgical closure of an atrial septal defect, implantation of an atrial epicardial electrode, …

Cardiac involvement in adults with Pompe disease

Glycogen storage disease type II or Pompe disease is a neuromuscular disorder caused by deficiency of lysosomal acid alpha- glucosidase. Classic infantile Pompe disease results in massive left ventricular (LV) hypertrophy and failure. Although Pompe disease is often included in the differential diagnosis of LV hypertrophy the true frequency of cardiac involvement in adults with Pompe disease is not known. Forty-six consecutive adult patients (mean age 48 +/- 12, 22 men) with Pompe disease were included. Each patient underwent a clinical examination, electrocardiography, and rest and low-dose dobutamine (in 20 patients) two-dimensional echocardiography including contrast and tissue Doppler imaging. All patients had limited exercise tolerance; a rollator walking aid was used in seven patients (15%), a wheelchair in 13 patients (28%), and assisted ventilation in 14 patients (30%). Prior to this study, one patient was known with permanent atrial fibrillation, His-bundle ablation and a VVI pacemaker and another patient was known with fluid retention. The first patient had increased LV end-diastolic diameter, impaired LV ejection fraction, low systolic mitral annular velocities and diastolic dysfunction grade II. The patient with fluid retention was wheelchair bound and dependent on 24-h assisted ventilation and showed right ventricular and LV hypertrophy (septum 16 mm, posterior wall 15 mm). LV hypertrophy was not seen in any of the other patients. One woman of advanced age had isolated low systolic mitral annular velocities. Mean global systolic LV function, including contractile reserve, was not decreased in patients with Pompe disease. Eight patients (17%) had mild diastolic dysfunction grade I, related to hypertension in four and advanced age in seven. In adult patients with Pompe disease without objective signs of cardiac affection by 12-leads electrocardiography or physical examination, echocardiographic screening for LV hypertrophy seems not effective.

Spontaneous baroreflex sensitivity and heart rate turbulence parameters: parallel responses to orthostasis

Premature ventricular contractions (PVC-s) induce baroreflex mediated arterial pressure and heart rate fluctuations. PVC-related RR interval fluctuations detected on Holter ECG recordings could be characterized by the heart rate turbulence (HRT) parameters, including early post-extrasystolic acceleration, described by turbulence onset, and late deceleration, described by turbulence slope (TS). We have determined the increasing and decreasing spontaneous baroreflex sequence sensitivity (up- and down-BRS) parameters in supine and in upright position in 12 patients with VVI pacemaker while in sinus rhythm. Five-five premature ventricular pacemaker extrastmuli were also applied in both body positions and HRT parameters were calculated. Up- and down-BRS values showed a very close relationship with TS both in the supine (R = 0.94, P < 0.001 and R = 0.92, P < 0.001, respectively), and upright position (R = 0.96, P < 0.001, and R = 0.94, P < 0.001, respectively). The BRS indices decreased significantly upon tilting, which was paralleled by a significant decrease in TS (from 21.6 to 13.9 ms/cycle, P = 0.02). Our findings confirm the close association between TS and spontaneous BRS indices. The relationship is further supported by the similar postural behavior of these parameters. Our results suggest that the confounding effect of posture should be considered when analyzing Holter recordings.

The Acute Effect of Cardiac Pacing Mode on Endothelial Vasodilation: Prospective, Double‐Blind, Cross‐Over, Comparative Clinical Study

Compared to atrioventricular sequential pacing, ventricular demand pacing is known to have somewhat more deleterious hemodynamic effects, which probably arise from increased sympathetic tonus and inappropriate baroreceptor activation. Endothelial function is affected by various local and systemic factors including baroreceptor activity. The aim of this study was to explore whether cardiac pacing would have any effect on endothelial functions. Twelve patients (six male, mean age: 75 +/- 9 years) with previously implanted DDD or VDDcardiac pacemakers were included. All patients had stable atrial rhythms during the study. Patients were randomized to either atrial-based pacing mode (VDD or DDD) or ventricular demand pacing mode (VVI) first, and then cross-over was performed with the other pacing mode. Endothelial function was assessed by brachial artery ultrasonography. Basal diameter of the brachial artery, and both flow-mediated dilation (FMD) and endothelium-independent vasodilation with nitroglycerin were measured 1 hour after each pacing mode. Compared to atrial-based pacing mode, ventricular demand pacing was associated with a significantly worse FMD both as absolute and percentage values (0.17 +/- 0.09 mm vs 0.28 +/- 0.11 mm, P = 0.015 and 4.84 +/- 2.37 % vs 7.00 +/- 2.88 %, P = 0.028, respectively). However, there was no significant difference in nitroglycerin-mediated vasodilation values between the two pacing sessions. Acute ventricular demand pacing (VVI pacing) is clearly associated with attenuation of FMD in patients with atrial-based pacing systems. The attenuation of endothelial vasodilation might have a role in hemodynamic and clinical deterioration in patients with VVI pacemakers.

Upgrading from right ventricular pacing to biventricular pacing in pacemaker patients with chronic heart failure

Cardiac resynchronisation therapy (CRT) is now a recommended treatment in patients with advanced heart failure despite optimal drug treatment, left ventricular systolic dysfunction, enlarged left ventricle, and cardiac dyssynchrony defined...

P1-59 EFFECT OF SHORT-TERM VENTRICULAR PACING ON ATRIAL ELECTRICAL REMODELING

P1-59 EFFECT OF SHORT-TERM VENTRICULAR PACING ON ATRIAL ELECTRICAL REMODELING

New‐Onset Heart Failure After Permanent Right Ventricular Apical Pacing in Patients with Acquired High‐Grade Atrioventricular Block and Normal Left Ventricular Function

Emerging data have suggested that right ventricular (RV) apical pacing results in progressive left ventricular (LV) dysfunction and contributes to the development of heart failure (HF). This study aimed to investigate the prevalence and clinical predictors for the development of new-onset HF after long-term RV apical pacing in patients with acquired atrioventricular (AV) block who require permanent pacing. We studied the clinical outcomes after long-term RV apical pacing for acquired AV block in 304 patients without a prior history of HF. All patients had >90% ventricular pacing as determined by device diagnostic data. After a median follow-up of 7.8 years, 79 patients (26.0%) developed new-onset HF after RV apical pacing. Univariate Cox-regression analysis revealed that older age at the time of pacemaker implantation (P < 0.001), the presence of coronary artery disease (CAD) (P < 0.001) or atrial fibrillation (P = 0.03), VVI pacemaker (P < 0.001), wider paced QRS duration (P < 0.001), and new-onset myocardial infarction (P < 0.001) were predictors for HF. Multivariate analysis revealed that older age at implantation (Hazard ratio [HR] 1.06, 95% confidential interval [CI] 1.04-1.09, P < 0.001), CAD (HR 1.98, 95% CI 1.12-3.50, P < 0.05), and a wider paced QRS duration (HR 1.27 for each 10 ms increment, 95% CI 1.11-1.45, P = 0.001) were independent predictors of HF. Furthermore, cardiovascular mortality was significantly increased in those with HF (36.7% vs. 2.7%, P < 0.001). After a median follow-up of 7.8 years, permanent RV apical pacing was associated with HF in 26% of patients. Elderly age at the time of implant, a wider paced QRS duration and the presence of CAD independently predicted new-onset HF. More importantly, HF after RV apical pacing was associated with a higher cardiovascular mortality.

Prolonged Transient Atrial Electrical Silence Following Termination of Chronic Atrial Tachyarrhythmias

Atrial standstill is a rare heterogeneous arrhythmia characterized by electrical and mechanical standstill and electrical inexcitability. A long-lasting progressive form is seen with cardiac and neuromuscular diseases, and a familial or idiopathic form may have a genetic basis. A transient form was described secondary to drug intoxication, electrolyte imbalance, cardiac inflammation, and ischemia. We investigated three patients with long-standing atrial tachyarrhythmia (AT) (atrial flutter in two, and focal atrial tachycardia in one). All patients underwent a complete electrophysiological study with mapping of right and left atrial activity and radiofrequency ablation (RF Abl) of AT. Following RF Abl of AT, all three patients manifested transient atrial electrical silence in the absence of known reversible causes. Atrial electrical silence was observed when, following AT termination, an escape atrioventricular (AV) junctional rhythm (in two patients) and an escape VVI pacemaker rhythm (in one patient) showed transient ventriculo-atrial (VA) conduction block (up to 30 seconds). A dominant sinus rhythm was observed to return 30 minutes, 90 minutes, and 12 hours, respectively, in the three patients. Two patients received a dual chamber pacemaker and a decision was made not to upgrade the patient with VVI pacemaker. The present report expands the spectrum of the syndrome of atrial standstill and raises interesting questions regarding possible electrophysiologic mechanism(s) of prolonged post overdrive atrial standstill. The report suggests that chronic overdrive of sinus and subsidiary atrial pacemakers may result in calcium overloading of cardiac cells, which is known to cause suppression of pacemaker activity as well as increased intracellular resistance. These mechanisms can possibly result in either prolonged suppression of sinus and atrial pacemaker activity and/or pacemaker exit block.

Pacemaker Longevity: The World's Longest‐Lasting VVI Pacemaker

To describe VVI-pacemaker longevity by model type at our institution and report on a long-lasting model and the longest-lasting pacemaker to be described in the literature. Cardiac pacemakers are becoming increasingly common in the United States. Presently their batteries are expected to last up to 12 years. Pacemaker generator change is associated with increased cost to the health care system and is inconvenient for patients. After identifying a group of very long-lasting CPI Microlith 605 VVI pulse generators, we reviewed records on all patients who had either Guidant or Medtronic pulse generator explantation at our institution over a 10-year period. Average longevities were calculated for all VVI pacemakers, four common VVI models, and the CPI Microlith 605. A total of 105 VVI-programmed pacemakers were identified. Their average longevity was 7.2 years. The two most common Medtronic VVI-programmed pacemakers explanted were the Thera (7.1 years) and Kappa (7.3 years). The two most common Guidant/CPI models were the Vigor (4.2 years) and Discovery (5.7 years). The CPI Microlith 605 (19.2 years) lasted more than 26 years in one patient before being explanted. At a time when pacemakers are being used more frequently, pacemaker longevity may decrease as a result of the use of dual-chamber pacing systems. In our study, the CPI Microlith 605 had an average longevity more than twice that of all other VVI pacemakers. We also report on a pulse generator that lasted 26.3 years.

Superior vena cava syndrome: an increasingly frequent complication of cardiac procedures

A 29-year-old woman presented with chest pressure, progressive dyspnea, fatigue, and swelling of her face, neck and upper extremities. Four days earlier, she had undergone a procedure for treatment of inappropriate sinus tachycardia, during which atrioventricular node ablation and implantation of a single-lead VVI pacemaker had been performed following an unsuccessful attempt at sinus node modification. Physical examination, contrast-enhanced CT of the chest, Doppler ultrasonography of the upper extremities, venography, coagulation studies, echocardiography. Superior vena cava syndrome due to thrombotic obstruction-a complication of a cardiac procedure. Anticoagulation, catheter-directed thrombolytic therapy, mechanical thrombectomy, pericardiocentesis.

Rib Perforation From a Right Ventricular Pacemaker Lead

A 50-year-old man was admitted to a community hospital for high fever. Seven years earlier, he had been in a motor vehicle accident and a cervical spine injury had resulted in quadriplegia and ventilator dependence. During that hospitalization, he was noted to have long sinus pauses that were thought to be vagally mediated, and a single-chamber pacemaker was implanted to hasten his recovery, with an active fixation pacing lead placed at the right ventricular apex (Figure 1A through 1C). His bradycardia spells subsequently disappeared, and minimal pacing was needed. Figure 1. Serial chest radiographs showing the pacemaker lead position at the time of implantation (A), at initial hospital discharge (B), 7 months after implantation (C), and at the current admission (D). The position of the lead tip is designated by an arrow, and the lead tip is clearly located outside the rib cage (D). Because of spiking fevers, leukocytosis, and methicillin-resistent Staphylococcus aureus growing from blood cultures; a …

Ventricular capture by anodal pacemaker stimulation

This report describes the case of an 86-year-old male with syncopal paroxysmal 2:1 atrioventricular block and a single chamber VVI pacemaker programmed to bipolar sensing and unipolar pacing. After recurrence of syncope, a complete loss of ventricular capture with regular ventricular sensing was observed on ECG; fluoroscopic examination suggested perforation of the right ventricle by the helix of the implanted screw-in lead. Reprogramming the pacemaker to bipolar pacing/sensing resulted in regular ventricular capture and sensing, suggesting effective anodal stimulation from the ring electrode permitting complete non-invasive palliation.

A Case of Acute Ventricular Capture Threshold Rise Associated with Flecainide Acetate

Antiarrhythmic agents may increase capture threshold, but this is rarely of clinical significance. Flecainide acetate, a class IC agent, is reported to have a significant effect on the myocardial capture threshold. In this presentation, we report the case of a 72-year-old male, with a previously implanted VVI pacemaker due to sick sinus syndrome, who was treated with flecainide acetate for paroxysmal atrial arrhythmia control. During the fifteenth day of treatment, an abrupt rise in the ventricular capture threshold with ventricular pacing failure was noted. The capture threshold decreased two days after discontinuation of flecainide acetate.