Obstructive sleep apnea and its management in patients with atrial fibrillation: An International Collaboration of Sleep Apnea Cardiovascular Trialists (INCOSACT) global survey of practicing cardiologists.

Background: Among international cardiologists it is unclear whether equipoise exists regarding the benefit of diagnosing and managing obstructive sleep apnea (OSA) to improve atrial fibrillation (AF) outcomes and whether clinical practice and equipoise are linked. Methods: Between January 2019 and June 2020 we distributed a web-based 12-question survey regarding OSA and AF management to practicing cardiologists in 16 countries. Results: The United States, Japan, Sweden, and Turkey accounted for two-thirds of responses. 863 cardiologists responded; half were general cardiologists, a quarter electrophysiologists. Responses regarding treating OSA with CPAP to improve AF endpoints were mixed. 33% of respondents referred AF patients for OSA screening. OSA was diagnosed in 48% of referred patients and continuous positive airway pressure (CPAP) was prescribed for 59% of them. Nearly 70% of respondents believed randomized controlled trials (RCTs) of OSA treatment in AF patients were necessary and indicated willingness to contribute to such trials. Conclusions: There was no clinical equipoise among surveyed cardiologists; a majority expressed certainty that combined OSA and AF treatment is superior to AF treatment alone for improving AF outcomes. However, a minority of surveyed cardiologists referred AF patients for OSA testing, and while half of screened AF patients had OSA, CPAP was prescribed in little more than half of them, reflecting the view that better clinical trial evidence is needed to support this practice. Our results underscore the need for larger, multi-national prospective studies of OSA treatment and AF outcomes to inform more uniform society guideline recommendations.

The impact of the distance between the atrial electrode and the atrial wall on atrial undersensing in patients with VDD pacemakers: long-term follow-up.

AIM: Atrial undersensing (AUS) in single-lead VDD pacemakers may be due to diminished P-wave amplitude secondary to local inflammation beneath the electrodes closer to atrial wall. The aim of this study was to assess the potential effect of distance between atrial electrode and atrial wall on immediate and long-term atrial sensing stability in VDD systems. METHODS: A total of 275 patients with normal sinus node function who received VDD pacemakers were enrolled into the study and were followed up for a median duration of 33 months. During each control visit, a standard 12-lead electrocardiogram (ECG) was obtained and standard pacemaker function assessment was performed including testing for pacing threshold and atrioventricular synchrony. The distance between atrial electrode and atrial wall was measured from chest X-ray. RESULTS: Of the 275 patients, AUS was detected in 59 patients. Univariate predictors of AUS were use of closely spaced bipolar ring atrial electrode (CSBR) (P = 0.01), wider atrial ring-spacing (P = 0.03), and atrial sensitivity programmed to a higher level (P = 0.001). Use of CSBR (P = 0.04) and atrial sensitivity > or =0.3 mV (P = 0.02) were observed to be the independent predictors for AUS. When the distance between atrial electrode and atrial wall was <7 mm, AUS was less with diagonally arranged bipolar ring electrodes (DABR) than it was with CSBRs (P = 0.02). CONCLUSIONS: The distance between atrial electrode and atrial wall does not appear to affect AUS incidence in VDD pacemakers. For VDD electrodes closer to atrial wall, AUS was significantly less likely in DABR-type electrodes.

Defibrillation testing and early neurologic outcome.

During implantable cardioverter-defibrillator (ICD) implantation, ventricular defibrillation testing (DFT) is considered a standard procedure. This procedure often requires multiple ventricular fibrillation (VF) inductions. These repeated short episodes of circulatory arrest with global cerebral ischemia may cause neurological damage. In the present study, patients undergoing initial ICD implantation and limited induction of VF for defibrillation safety margin testing were evaluated for pre- and postoperative cognitive and neurologic functions. In addition, the serum neuron specific enolase (NSE) level, which is a biochemical marker of cerebral injury, was evaluated. The study was performed on 16 patients undergoing initial elective transvenous insertion of an ICD. A neurologic examination and cognitive assessment tests were performed 24 to 48 hours before and after ICD. NSE was determined before (NSE 1) and at the end of the surgery (NSE 2), as well as 2 hours (NSE 3), 24 hours (NSE 4), and 48 hours (NSE 5) after implantation. A total of 29 internal shocks (average, 1.8 +/- 0.4) with energy ranging from 14 to 41 J (mean, 20 +/- 5; median, 20 J ) were delivered in the ICD group patients. In one patient, 3 external (50, 200 and 360 J) shocks were required for fast VT induced during ICD lead positioning. The mean duration of VF was 10 +/- 4 seconds and the mean cumulative time in VF was 16 +/- 5 seconds. The mean recovery time between VFs was 5.3 +/- 0.6 minutes. NSE levels were not different from the baseline at any time point in the patients of the group that completed the 48-hour observation period (P > 0.05). The patients did not report any new neurological symptoms after ICD implantation, and repeat examination after the procedure showed no abnormal findings other than those detected in the previous one. There were no statistically significant differences between the preoperative and postoperative scores obtained in the cognitive assessment. Single or two VF inductions and the brief arrest of cerebral circulation during ICD implantation are not associated with permanent neurological injury. However, further studies are needed to confirm this finding.

Acute pulmonary oedema during cardiac resynchronization therapy device implantation: management with the activation of intra-aortic balloon pump.

In this report, we present the case of two patients who experienced the development of acute pulmonary oedema during biventricular pacemaker implantation for cardiac resynchronization therapy. In both the cases, the activation of an intra-aortic balloon pump improved the clinical condition and the operation could be completed, which would otherwise have to be postponed.

Effect of transvenous cardiac resynchronization therapy device implantation on cardiac troponin I release.

BACKGROUND: Pacemaker and implantable cardioverter defibrillator (ICD) implantation increases cardiac troponin I (cTnI) levels which indicates myocardial injury. During implantation of a cardiac resynchronization therapy (CRT) device, balloon inflation for coronary sinus (CS) venogram, cannulation of CS side branch, and electrode advancement may interfere with CS drainage and, hence, may decrease the washout of toxic metabolites from the heart. Thus, CRT implantation may further increase cTnI levels. In this study, we investigated the effects of CRT implantation on cTnI release. METHODS: We included 10 patients (mean age = 57 +/- 15 years) in whom a successful transvenous CRT system was implanted (CRT group). Twenty patients (mean age = 65 +/- 10 years) who underwent a transvenous pacemaker or ICD implantation were included as the control group. Blood samples for cTnI were drawn at baseline and at six, 12, 18, and 24 hours thereafter. RESULTS: Baseline median cTnI levels were similar in CRT and control groups (0.03 ng/mL vs 0.02 ng/mL, respectively; P = 0.1). Postoperative cTnI levels during 24 hours were significantly higher in the CRT group (P < 0.05) by two-way repeated measures of analysis of variance. Post hoc analysis revealed that cTnI levels were higher at the 6th, 12th, 18th, and 24th hours compared to baseline levels (P < 0.001, P < 0.001, P < 0.01, and P < 0.01, respectively). There was a significant difference in the area under the curves (AUCs) of cTnI measurements (1.79 hr.ng/mL in the CRT group and 0.78 hr.ng/mL in the control group, P < 0.05). CONCLUSION: Postoperative cTnI levels were higher after CRT implantation than simple pacemaker/ICD implantation. This may be due to CS manipulation during CRT implantation.

Defibrillation threshold testing and neurologic outcome.

Implantable cardioverter defibrillator (ICD) implantation is a common approach in patients at high risk of sudden cardiac death. Verification of defibrillation efficacy by defibrillation threshold (DFT) testing during ICD implantation is the current standard. Traditionally, a safety margin of at least 10 J between the maximum output of the pulse generator and the energy needed for defibrillation has been used because early studies indicate that lower safety margins were associated with high rates of failed defibrillation and sudden cardiac death. Improvements in ICD and lead technology result in marked reductions in defibrillation thresholds and more stable thresholds long term. Despite these improvements, some patients still require system modification during implantation to obtain an adequate safety margin. During DFT testing multiple induction of ventricular fibrillation cause brief transient episodes of cerebral ischemia. These repeated short episodes of circulatory arrest with global cerebral ischemia have been associated with changes in cerebral oxygen uptake and cerebral electrical activity. In addition, minor neurologic injury can occur after ICD implantation and defibrillation testing. This finding needs to be examined in further research.

Appropriate ICD therapy in patients with idiopathic dilated cardiomyopathy: long term follow-up.

The implantable cardioverter defibrillator (ICD) has proved effective in preventing sudden death and decreasing mortality in randomised secondary prevention trials. Some nonrandomized studies have reported different incidences and predictors of appropriate ICD therapy in patients with idiopathic dilated cardiomyopathy (DCM). The antiarrhythmic and other medical therapies were different between the published studies and it was reported that not using beta-blockers was a predictor of appropriate ICD therapy. In the present study, we report on our long-term experience with ICD therapy in patients with DCM, the majority of whom were treated with beta-blockers and amiodarone. The study population consisted of 25 patients with DCM who underwent initial transvenous ICD implantation between December 1995 and May 2005. Indications for ICD implantation were monomorphic sustained ventricular tachycardia (VT) in 16 patients (64%), cardiac arrest in 8 patients (32%), and syncope plus inducible VT in one patient. Twenty-four patients underwent an electrophysiologic study (EPS). In 18 patients, the ICDs were programmed to only shocks and in 7 patients an additional antitachycardia pacing program was performed. One patient was lost to follow-up and 24 patients were followed-up primarily in our ICD pacemaker outpatient clinic. Appropriate ICD therapy was defined as antitachycardia pacing therapy or shock for tachyarrhythmia determined by evaluation of the clinical information and by device diagnostics to be either ventricular fibrillation or ventricular tachycardia. The mean follow-up was 39.29 +/- 30.59 months after ICD implantation. At follow-up, 17 patients were using a beta-blocker and 16 patients amiodarone. Appropriate ICD therapy was observed in 14 patients (58%). The detected arrhythmias were VT in 12 patients, ventricular fibrillation (VF) in one, and VT and VF in one patient. The time to first ICD therapy was 15.93 +/- 18.45 (range, 1-74) months. Using the Kaplan-Meier method, the percent survival free of appropriate ICD therapy was 82%, 72%, 66%, and 55% at 1, 2, 3, and 4 years follow-up, respectively. The clinical, echocardiographic, and electrophysiologic characteristics did not differ between those who did and did not receive appropriate ICD therapy. However, the mean QRS duration was significantly longer in patients who received appropriate ICD therapies. Cox regression analysis did not reveal any factors that predicted appropriate ICD therapy. Five patients (21%) died during follow-up. Four deaths were classified as cardiac and one as noncardiac. The cumulative survival from total death was 94%, 82%, 82%, and 69%, and the cumulative survival from cardiac death was 94%, 82%, 82%, and 76% during 1, 2, 3, and 4 years of follow-up, respectively. In summary, in this selected patient population with DCM, the majority of patients were unresponsive to beta-blocker and antiarrhythmic therapy. Most of these patients received appropriate ICD therapy during follow-up. Cox regression analysis did not identify any factors that predicted appropriate ICD therapy. Additional trials with larger patient populations are needed to detect the predictors of appropriate ICD therapy in patients with DCM.

Cardiac metastasis of malignant melanoma: a rare cause of complete atrioventricular block.

Malignant melanoma has an aggressive biological behaviour and a high rate of cardiac involvement. As shown from post-mortem studies, metastases of melanoma can involve any organ and cardiac metastases are frequent. This report describes a case of widespread malignant melanoma in a patient with clinical presentation of complete atrioventricular (AV) block. Thorax CT and transthoracic echocardiography revealed a mass involving the conduction system. By VDD permanent pacing (atrial synchronous ventricular pacing), haemodynamic stability was maintained and the patient remains under follow-up receiving chemo-immunotherapy. In the retrospective analysis of the patient's records, we realized that the AV conduction delay had been progressing for at least 7 months. Cardiac metastasis of malignant melanoma is a common finding and can proceed in the absence of overt clinical manifestations. Therefore, the clinician should be alert to the development of cardiac signs and symptoms in a metastatic melanoma patient and should perform a detailed cardiac examination to exclude cardiac metastasis of the tumour.

DDD pacemaker implantation in a patient with persistent left superior vena cava and absent right superior vena cava: a four-year follow-up report.

Persistent left superior vena cava coexisting with the absence of right superior vena cava is an uncommon anomaly, and sometimes requires permanent pacemaker implantation due to the relatively high incidence of conduction disturbances and arrhythmias. This anomaly makes the implantation of pacemaker leads more difficult; therefore, accurate preintervention diagnosis of this anomaly is valuable for the interventionalist. A patient in which the diagnosis of persistent left superior vena cava coexisting with absent right superior vena cava was made echocardiographically before permanent pacemaker implantation is presented. Acetylsalicylic acid was prescribed after pacemaker implantation to prevent a potentially fatal complication of coronary sinus thrombosis, and no complication occurred during the four-year follow-up. Some clues for the noninvasive diagnosis of this anomaly and techniques of pacemaker implantation are also described briefly.

Accessory pathway associated with an anomalous coronary sinus.

Congenital coronary sinus anomalies are unusual and they rarely coexist with accessory atrioventricular pathways. These anomalies are generally asymptomatic, however they can cause difficulty in mapping. The association between accessory pathway and coronary sinus anomalies may suggest an embryologic link. In this case, we report a male patient with permanent form of reciprocating tachycardia coexistent with anomalous coronary sinus.

A safe and simple method for management of frozen pacemaker leads.

The traction of frozen leads from the generator header is difficult in some patients. This report describes the authors' experience with frozen leads in which the lead pins were removed by pushing with the tip of screwdriver from the hole created with a scalpel blade at the closed end of the generator header.