Efficacy of the current of injury in envisaging the dislodgement of leads implanted in the right atrial septum or the right ventricular septum.

BACKGROUND: The implantation of leads in the right atrial septum (RAS) or the right ventricular septum (RVS) is technically challenging, and dislodgement occurs occasionally. This study aims to determine a predictor for the dislodgement of leads implanted in the RAS or RVS. METHODS: This retrospective cohort study enrolled 137 consecutive patients who underwent the cardiac implantable electronic devices implantation, using active fixation leads in the RAS and RVS. We compared the pacing threshold, R- or P-wave amplitude, slew rate, and presence of the current of injury (COI) between dislodged and nondislodged leads. RESULTS: We performed lead fixation for 74 and 125 times in the RAS and RVS, respectively. Atrial lead dislodgement occurred five times (6.8%) intraoperatively and five times (6.8%) postoperatively, whereas ventricular lead dislodgement occurred eight times (6.4%) intraoperatively and three times (2.4%) postoperatively. Although there were no lead parameters that showed a significant difference common to RAS lead and RVS lead, the presence of the COI was significantly different between nondislodged and dislodged leads in both the RAS and RVS (atrial leads: 57.8% vs 0%, P < 0.001; ventricular leads: 67.5% vs 9.1%, P < 0.001). The positive predictive value of COI presence for predicting no lead dislodgement was 100% and 98.7% in the RAS and RVS, respectively. CONCLUSION: Lead dislodgement is more likely when the COI is absent; documentation of COI should be pursued during lead implantation in challenging sites as the RAS and RVS.

Inappropriate automatic mode switching episodes: What's the mechanism?

We present a case series of five patients reporting abnormal automatic mode switching (AMS) episodes during routinary cardiac defibrillator (ICD) and pacemaker (PM) follow-up. This non-previously described phenomenon was reported to St. Jude Medical (Abbott) Technical Support that confirmed the inappropriate automatic mode switching.

Idiopathic isolated fibrotic atrial cardiomyopathy underlies unexplained scar-related atrial tachycardia in younger patients.

Aims: Unexplained scar-related atrial tachycardia (AT) has been frequently encountered in clinical practice. We hypothesized that idiopathic, isolated fibrotic atrial cardiomyopathy (ACM) underlies this rhythm disorder. This study was aimed to characterize the underlying substrate and to explore the aetiology of this unexplained scar-related AT. Methods and results: Twenty-six (11 men, aged 46 ± 13 years) of 52 non-surgical scar-related AT patients identified by three-dimensional voltage mapping were enrolled in this prospective observational study. Multimodality image examinations (echocardiography, cardiac magnetic resonance, 99Tc single-photon emission computed tomography), ventricular voltage mapping, and intracardiac pressure curve recording ruled out ventricular involvement. Catheter ablation was acutely successful for all the patients, and pacemaker implantation was performed in seven patients who presented sinus node dysfunction or atrial standstill after termination of the AT. In three patients with multiple AT recurrences, the diseased areas of the right atrium were resected and dechannelled via mini-invasive surgical interventions. Histological examinations revealed profound fibrosis without amyloidosis or adipose deposition. Viral and familial investigations yielded negative results. Fibrosis progression over a median of 45 (5-109) months of follow-up manifested as atrial arrhythmia recurrence in seven patients and atrial lead non-capture due to newly developed atrial standstill in two patients. Two patients suffered four ischaemic stroke events before receiving anticoagulation treatment. Conclusion: Isolated, fibrotic ACM may underlie the idiopathic scar-related ATs. This novel cardiomyopathy has unique clinical characteristics with high morbidity including stroke and warrants specific therapeutic strategies. Further investigations are required to determine the aetiology and mechanism.

Ozone therapy induced sinus arrest in a hypertensive patient with chronic kidney disease: A case report.

RATIONALE: Ozone autohemotherapy as an alternative treatment method has been applied to the treatment of several diseases. Here, we report a patient used ozone autohemotherapy to treat her hypertension and diabetes. Nevertheless, the patient occurred sudden dizziness and black haze due to hyperkalemia. PATIENT CONCERNS: A 54-year-old woman who was admitted to our emergency department complaining of sudden dizziness and black haze for 5 hours. DIAGNOSES: The blood potassium test showed hyperkalemia. Upon further inquiry of her medical history, the patient received ozone autohemotherapy to treat hypertension and diabetes for 9 days prior to admission. INTERVENTIONS: The ozone therapy had been asked to stop. Insulin, sodium bicarbonate, and sodium polystyrene sulfonate were administered to the patient. OUTCOMES: After treatment, blood potassium remained in the normal range. After 3 days of treatment, the 24-hour dynamic electrocardiogram revealed sinus rhythm with an average heart rate of 82 beats/min, occasional ventricular premature beats, occasional ventricular premature beats, and no ST segment depression. LESSONS: Although ozone therapy is widely used in the treatment of several diseases, adverse reactions should be given attention in clinical practice, especially in patients with chronic kidney disease.

Device malfunction caused by "auto-oversensing" of transthoracic impedance measurement test pulses in a modern minute ventilation dual-chamber pacemaker.

Oversensing of physiologic and non-physiologic electrical signals is a relevant cause of malfunctions in subjects with CIED. Physicians taking care of CIED patients must be aware of the potential causes of oversensing and their pattern in EGMs. The present case describes an uncommon source and unique underlying root cause for oversensing in a modern dual-chamber MV rate-adaptive pacemaker.

INFLUENCE OF PERMANENT PACING OF THE ATRIA FROM UPPER ANTERIOR AREA OF INTERCARDIAC SEPTA (AREA OF BAKHMAN'S FASCICLES) ON THE PART OF AMOTIVATIONAL VENTRICLE STIMULATION.

This research includes 74 patients with syndrome of the sinus node asthenia. The application of permanent bilocular pacing was indicated for these patients. An atrial electrode was located in the right atrial auricle in 37 patients and it was in the area of Bakhman's fascicles in other 37 patients. All the patients had a stimulated atrio-ventricular delay on 250 ms, but sensing delay was shorter on 20 ms. Given data were analyzed after operation in the periods of 6 and 12 months. Cumulative percent of ventricular stimulation was significantly less in the group with electrode in the area of Bakhman's fascicles (6%) as compared with the group where electrode installed in the right atrial auricle (41%) after 6 months. There were 4% in comparison with 43% after 12 months. The localization of atrial electrode in the area of Bakhman's fascicles led to reduction of cumulative percent of ventricular stimulation on 35% after 6 months and on 39% after 12 months. Permanent pacing in the area of Bakhman's fascicles could be an effective mode to decrease the part of amotivational stimulation of the right ventricle.

Atrial standstill in sinus node disease due to extensive atrial fibrosis: impact on dual chamber pacemaker implantation.

AIMS: Atrial standstill is characterized by the absence of atrial activity. We report about a series of cases, in which conventional atrial pacemaker lead implantation in patients with symptomatic sinus node disease failed due to lack of excitable right atrial tissue, thus, prompting the diagnosis of atrial standstill. We hypothesized that mapping of the atria with subsequent identification of myocardium still amenable to atrial pacing would allow dual chamber pacemaker implantation. METHODS AND RESULTS: In four patients, atrial lead implantation failed. In these patients, spontaneous or fibrillatory electrical activity was absent but the atria could not be captured despite high stimulation voltages at conventional atrial sites. We suspected partial or complete atrial standstill and subsequently confirmed this hypothesis by conventional (n = 1) or electroanatomical mapping (n = 3). Areas of fibrotic tissue were present in all patients as identified by lack of spontaneous electrical activity and inability of local electrical capture via the mapping catheter. Surviving atrial tissue, which could be electrically captured with subsequent conduction of activity to the atrioventricular (AV) node, was present in three patients. Successful targeted atrial lead implantation at these sites was achieved in all these patients. Isolated sinus node activity without conduction to the atria was found in one patient. CONCLUSION: Partial atrial standstill may be present and prevent atrial lead implantation in patients with sinus node disease. In these patients, recognition of partial atrial standstill and identification of surviving muscular islets with connection to the AV node by mapping studies may still allow synchronous AV sequential pacing.

Acute His-Bundle Injury Current during Permanent His-Bundle Pacing Predicts Excellent Pacing Outcomes.

INTRODUCTION: His-bundle (HB) pacing (P) is a physiological alternative to right ventricular pacing (RVP), but is technically challenging and limited by higher pacing thresholds. Myocardial injury current (IC) recorded during right ventricular lead placement implies good tissue contact and is associated with low-pacing thresholds. IC at the HB has not been previously described. We hypothesized that HBIC during permanent HBP may be associated with lower pacing thresholds. METHODS: Permanent HBP was performed using Medtronic Select Secure(tm) (Medtronic Inc., Minneapolis, MN, USA) delivered via a fixed-curve (C315 His) sheath. HB electrogram (EGM) was recorded in a unipolar fashion from the lead tip. Presence or absence of HBIC was documented. HBP threshold, sensing, and impedances were recorded at implant, 2 weeks, 2 months, and 1 year. RESULTS: Sixty patients (age 72 ± 15 years; male 55%, sick sinus syndrome 40%, atrioventricular block 60%, fluoroscopy duration 9.2 ± 3.7 minutes) underwent successful permanent HBP. HBIC was recorded in 22 (37%) patients (group I). HBEGM without IC was recorded in the remaining 38 (63%) patients (group II). Pacing threshold at implant, 2 weeks, 2 months, and 1 year were significantly lower in group I (1.16 ± 0.4 V; 1.18 ± 0.5 V; 1.23 ± 0.6 V; 1.3 ± 0.6 V @ 0.5 ms) compared to group II (1.75 ± 0.7 V; 1.82 ± 0.8 V; 1.93 ± 0.8 V; 1.98 ± 0.9 V @ 0.5 ms, P < 0.05), respectively. CONCLUSIONS: IC can be recorded at the HB during permanent HBP in 37% of patients. HBIC is associated with significantly lower pacing thresholds compared to patients in whom HBIC was not recorded. HBIC may be a marker for superior short-term HBP thresholds.

[Atrial mechanical and electrical dysfunction in patient with Emery-Dreifuss muscular dystrophy reason of change in electrotherapeutical approach: frequent result of rare disease]. / Elektryczna i mechaniczna dysfunkcja przedsionków u pacjenta z dystrofia miesniowa Emery-Dreifussa przyczyna zmiany wyboru optymalnej formy elektroterapii: czeste powiklanie rzadkiej choroby.

We present a case of a 35 year-old male patient with Emery-Dreifuss muscular dystrophy diagnosed in the age of 12 who was assigned to dual chamber pacing system due to bradycardia primarily recognised as sinus node insufficiency with the atrio-ventricular nodal rhythm. During the procedure permanent electrical atrial stand-still without atrial capture were detected and the mode of stimulation was change to VVIR.

A tale of early Reel syndrome caused by an over-enthusiastic masseuse.

Twiddler syndrome is a form of pacemaker lead dislocation caused by the coiling of the pacemaker leads due to pulse generator rotation on its long axis. Similar to Twiddler syndrome, Reel syndrome occurs due to rotation of the pulse generator on its transverse axis, leading to lead dislocation or fracture, followed by clinical symptoms of dislodged leads. We report a case of 75 years old woman with Reel syndrome presenting with syncope.

Management of central venous gradient using excimer laser lead extraction of chronic indwelling pacemaker leads in the setting of ipsilateral arteriovenous fistula.

Device therapy is becoming common in those patients with renal insufficiency. Coexisting need for arteriovenous (AV) fistula placement is often contemplated relative to device placement. We describe the excimer laser lead extraction of a malfunctioning chronic atrial pacemaker lead ipsilateral to an AV fistula.

Efficacy of low interatrial septum and right atrial appendage pacing for prevention of permanent atrial fibrillation in patients with sinus node disease: results from the electrophysiology-guided pacing site selection (EPASS) study.

BACKGROUND: The role of pacing sites and atrial electrophysiology on the progression of atrial fibrillation (AF) to the permanent form in patients with sinus node dysfunction (SND) has never been investigated. The aim of the study was to investigate the relationship between atrial electrophysiology and the efficacy of atrial pacing at the low interatrial septum (IAS) or at the right atrial appendage (RAA) to prevent persistent/permanent AF in patients with SND. METHODS AND RESULTS: The Electrophysiology-Guided Pacing Site Selection (EPASS) Study was a prospective, controlled, randomized study. Atrial refractoriness, basal and incremental conduction times from the RAA to the coronary sinus ostium were measured before implantation, and the difference (ΔCTos) was calculated. Patients with ΔCTos ≥ 50 ms (study group) and those with ΔCTos <50 ms (control group) were randomly assigned to RAA or IAS with algorithms for continuous atrial stimulation "on." The primary end point was time to development of permanent or persistent AF within a 2-year follow-up in the study group, IAS versus RAA. Data were analyzed by intention to treat. One hundred two patients (77 ± 7 years, 44 mol/L) were enrolled, 69 (68%) in the study group and 33 (32%) in the control group. Of these, 97 ended the study, respectively, randomly assigned: 29 IAS versus 36 RAA and 18 IAS versus 14 RAA. After a mean follow-up of 15 ± 7 (median, 17) months, 11 (16.6%) patients in the study group met the primary end point: 2 IAS versus 9 RAA (log rank=3.93, P=0.047). CONCLUSIONS: In patients with SND and intra-atrial conduction delay, low IAS pacing was superior to RAA pacing in preventing progression to persistent or permanent AF. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00239226.

Different strategies for performing pulmonary vein isolation in patients with pulmonary vein rhythm.

Pulmonary vein (PV) isolation was performed in atrial fibrillation (AF) patients whose cardiac rhythm was dominated by the ectopic beats originating from the PV. We herein report two cases with dominant PV ectopic rhythm that underwent catheter ablation for the treatment of paroxysmal AF. In one case, a permanent pacemaker implantation was required to treat a symptomatic long sinus pause after the isolation of all four PVs, while no AF was documented during the 5-year period after ablation. However, the isolation of all four PVs except for a PV with a dominant ectopic rhythm was performed in the other case. The latter case was free from both AF and symptomatic bradycardia following the procedure without the implantation of a pacemaker. Selective PV isolation therefore appears to be an effective therapy to both achieve the successful treatment of AF and to prevent the manifestation of sick sinus syndrome.

Severe venous and lymphatic obstruction after single-chamber pacemaker implantation in a patient with chest radiation therapy.

A 73-year-old woman with a history of paroxysmal atrial fibrillation, sinus node dysfunction, bilateral breast cancer, and extensive chest radiation developed progressive edema, dyspnea, and recurrent pleural effusions soon after single-chamber pacemaker implantation. Thoracentesis yielded a diagnosis of chylothorax, and progressive refractory anasarca developed. A computed tomography angiogram suggested obstruction of the superior vena cava and left subclavian vein despite outpatient therapeutic anticoagulation. Autopsy confirmed venous thrombosis, along with mediastinal fibrosis. The presumed etiology of the chylothorax and anasarca was obstruction of the atretic central venous structures following pacemaker implantation, critically impairing the already tenuous venous and lymphatic drainage. (PACE 2010; 520-524).

Accidental connection between the atrial and ventricular stylets during a stimulation threshold test for pacemaker implantation.

This report describes a case of atrioventricular crosstalk during a stimulation threshold test. This phenomenon was likely due to the accidental connection between the atrial and ventricular stylets. Electrocardiologists should recognize atrioventricular crosstalk during a stimulation threshold test to avoid repositioning the atrial lead unnecessarily or inducing ventricular arrhythmia.

Dual atrioventricular-nodal physiology, elicited by pacing and leading to a reversible cardiomyopathy.

Atrioventricular nodal re-entry tachycardia is the most common form of regular paroxysmal tachycardia in the adult population. This tachycardia is a re-entrant rhythm that uses the anatomic location of the atrioventricular node and its surrounding perinodal atrial tissue. The simplest concept regarding the atrioventricular nodal physiology that allows re-entry is founded upon the postulated existence of 2 atrioventricular nodal pathways with different conduction velocities and refractory periods. Herein, we present the case of a 64-year-old man who had a history of paroxysmal atrial fibrillation; he had a permanent pacemaker for sick-sinus syndrome. He developed a tachycardia-induced cardiomyopathy with a perpetual dual response to the pacemaker stimulus. The tachycardia displayed characteristic dual atrioventricular-nodal physiology that was suppressed by amiodarone therapy, leading to a reversal of the cardiomyopathy. We discuss the mechanisms that surround such phenomena.

Permanent direct his bundle pacing does not induce ventricular dyssynchrony unlike conventional right ventricular apical pacing. An intrapatient acute comparison study.

BACKGROUND: Benefits of A-V synchrony during right ventricular apical pacing are neutralized by induction of ventricular dyssynchrony. Only a few data are reported about direct His bundle pacing influence on ventricular synchronism. AIM: Was to assess the capability of direct His bundle pacing to prevent pacing-induced ventricular dyssynchrony comparing DDD- (or VVI- in case of Atrial Fibrillation) right ventricular apical pacing with DDD- (or VVI-) direct His bundle pacing in the same patients cohort. METHODS: 23 of 24 patients (mean age 75.1 +/- 6.4 years) with narrow QRS (HV < 65 ms) underwent permanent direct His bundle pacing for "brady-tachy syndrome" (11) or supra-Hisian II/III-degree AV Block (permanent atrial fibrillation 7, AV Node ablation 1). A 4.1 F screw-in lead was fixed in His position, guided by endocardial pacemapping and unipolar recordings. Additional permanent (13 patients) or temporary right ventricular apical pacing leads were also positioned. Inter- and left intra-ventricular dyssynchrony, mitral regurgitation and left systolic ventricular function Tei index were assessed during either direct His bundle pacing or right ventricular apical pacing. RESULTS: Permanent direct His bundle pacing was obtained in 23 of 24 patients. Indexes of ventricular dyssynchrony were drastically reduced, mitral regurgitation decreased and left systolic ventricular function Tei index improved during direct His bundle pacing (or His bundle and septum pacing) in comparison to apical pacing (p < 0.05). No statistically significant differences were observed between direct His bundle pacing and combined His bundle and septum pacing. CONCLUSION: Direct His bundle pacing (also fused with adjacent septum capture) prevents pacing-induced ventricular dyssynchrony.

Hyperkalemia induced failure of atrial and ventricular pacemaker capture.

Hyperkalemia is a life threatening metabolic condition. The common risk factors for hyperkalemia include renal insufficiency, use of angiotensin converting enzyme inhibitors, potassium supplementation and excessive consumption of potassium containing diet. A mild to moderate increase in serum potassium causes an increase in myocardial excitability, but further increase leads to impaired myocardial responsiveness, including that to pacing stimulation. Hyperkalemia has been reported to cause failure of atrial capture due to pacemaker exit block. We report a case where hyperkalemia resulted in failure of both the atrial and the ventricular pacemaker capture.