Arnaud Savouré

Catheter ablation of typical atrial flutter: a randomized comparison of 2 methods for determining complete bidirectional isthmus block.

Background —Complete bidirectional isthmus conduction block (CBIB) was initially assessed by sequential detailed activation mapping at both sides of the ablation line during proximal coronary sinus and anteroinferior right atrium pacing. Mapping only the ablation line (“on-site” atrial potential analysis) was recently reported as a means of CBIB identification. The study was designed to compare these 2 techniques prospectively regarding the diagnosis of CBIB. Methods and Results —In 76 consecutive patients (mean age, 63.4±10.5 years), typical atrial flutter ablation was performed using either the activation mapping technique (group I) or on-site atrial potential analysis (group II). Criteria for CBIB using on-site atrial potential analysis was the recording of parallel, widely spaced double atrial potentials along the ablation line. The CBIB criterion was retrospectively searched using the alternative technique at the end of the procedure. In successful patients, the mean radiofrequency delivery duration was longer in group II (845±776 versus 534±363 s;P =0.03). On-site, clear-cut, widely spaced double atrial potentials and activation mapping suggesting CBIB were concomitantly observed in only 47 patients (54%), and ambiguous/atypical double potentials were recorded in 31 patients (39%). Conclusions —Although feasible, the on-site atrial potential analysis seemed to be inferior to the classic activation mapping technique, mainly because of the ambiguity of electrogram interpretation along the ablation line. However, when combined with the activation mapping technique, it provided additional information regarding isthmus conduction properties in some cases. Therefore, optimally, both methods should be used concomitantly.

A New Dual‐Chamber Pacing Mode to Minimize Ventricular Pacing

Despite the low long‐term incidence of high‐degree atrioventricular (AV) block and the known negative effects of ventricular pacing, programming of the AAI mode in patients with sinus node dysfunction (SND) remains exceptional. A new pacing mode was, therefore, designed to combine the advantages of AAI with the safety of DDD pacing. AAIsafeR behaves like the AAI mode in absence of AV block. First‐ and second‐degree AV blocks are tolerated up to a predetermined, programmable limit, and conversion to DDD takes place in case of high‐degree AV block. From DDD, the device may switch back to AAI, provided AV conduction has returned. The safety of AAIsafeR was examined in 43 recipients (70 ± 12‐year old, 24 men) of dual chamber pacemakers implanted for SND or paroxysmal AV block. All patients underwent 24‐hour ambulatory electrocardiographic recordings before hospital discharge and at 1 month of follow‐up with the AAIsafeR mode activated. No AAIsafeR‐related adverse event was observed. At 1 month, the device was functioning in AAIsafeR in 28 patients (65%), and the mean rate of ventricular pacing was 0.2%± 0.4%. Appropriate switches to DDD occurred in 15 patients (35%) for frequent, unexpected AV block. AAIsafeR mode was safe and preserved ventricular function during paroxysmal AV block, while maintaining a very low rate of ventricular pacing. The performance of this new pacing mode in the prevention of atrial fibrillation will be examined in a large, controlled study.

A comparison of anxiety, depression and quality of life between device shock and nonshock groups in implantable cardioverter defibrillator recipients

BACKGROUND Using standardized scales, we assessed the point prevalence, the severity of anxiety and depressive disorders, and the quality of life (QOL) in implantable cardioverter defibrillator (ICD) recipients who received a device shock. METHODS Forty research subjects with device shocks (Group 1) and 25 without shocks (Group 2) were interviewed after ICD implantation using the Mini International Neuropsychiatric Interview (MINI), the Hospital Anxiety and Depression Scale (HADS) and the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). RESULTS The point prevalence of anxiety disorders was higher in Group 1 (37.5%) than in Group 2 (8%) (P=.009). Depressive symptoms scores were higher in Group 1 (4.75) than in Group 2 (2.24) (P=.04)), but the prevalence of depressive disorders or the anxiety scores were not significantly different. A positive correlation was found between the number of shocks and the depressive symptoms scores (P=.05, r=0.24); there was a negative correlation between the mental health subscore of the SF-36 and the number of shocks (r=-0.36, P=.003). The point prevalence of depressive disorders was higher in the group with congenital cardiac diseases (50%) than in the valvular (8%) and ischemic groups (23%) (P=.04), and the mental health composite summary score of the SF-36 was lower in this group (46.34) than in those with valvular and ischemic disease (56.09 and 52.61, respectively) (P=.03). CONCLUSION Exposure to shocks may lead to an increased risk of anxiety and depressive symptoms. Research subjects receiving a high number of shocks and research subjects with congenital cardiovascular diseases were at higher risk of depressive symptoms or at higher risk of poorer psychological aspects of QOL.

Extreme bradycardia after first doses of sofosbuvir and daclatasvir in patients receiving amiodarone: 2 cases including a rechallenge.

Sofosbuvir and daclatasvir are direct-acting antiviral drugs used to treat chronic hepatitis C virus infection. In 2015, the Food and Drug Administration and European Medical Agency warned that bradycardia could occur when amiodarone was administered in combination with sofosbuvir, but no case reports had been published. We report extreme bradycardia within 2 hrs after intake of sofosbuvir and daclatasvir by 2 patients receiving amiodarone. The first patient had a cardiac asystole 30 min after receiving sofosbuvir and daclatasvir. Amiodarone, sofosbuvir, and daclatasvir treatment were stopped; after 10 days, the cardiac evaluation was normal and patient was discharged. The second patient was taking amiodarone and propranolol; 2 hrs after receiving sofosbuvir and daclatasvir, he had an extreme sinus node dysfunction (heart rate of 27beats/min). Amiodarone and propranolol were stopped, but the patient continued receiving sofosbuvir and daclatasvir for 3 days and sinus bradycardia was recorded each day, 2 hrs after intake of these drugs. When he stopped taking the drugs, no bradycardia was observed. Administration of sofosbuvir and daclatasvir on day 13 induced bradycardia 2 hrs after intake. However, no bradycardia occurred following a rechallenge 8 weeks after the patient stopped taking amiodarone. These observations indicate that patients treated with amiodarone should be continuously monitored within the first 48 hrs following the initiation of sofosbuvir and daclatasvir.

Implantable cardioverter-defibrillators in lamin A/C mutation carriers with cardiac conduction disorders.

BACKGROUND Sudden cardiac death is frequent in patients with lamin A/C gene (LMNA) mutations and may be related to ventricular arrhythmias (VA). OBJECTIVE To evaluate a strategy of prophylactic implantable cardioverter-defibrillator (ICD) implantation in LMNA mutation carriers with significant cardiac conduction disorders. METHODS Forty-seven consecutive patients (mean age 38 ± 11 years; 26 men) were prospectively enrolled between March 1999 and April 2009. Prophylactic ICD implantation was performed in patients with significant cardiac conduction disorders: patients requiring permanent pacing for bradycardia or already implanted with a pacemaker at the initial presentation, or patients with a PR interval of >0.24 seconds and either complete left bundle branch block or nonsustained ventricular tachycardia. RESULTS Twenty-one (45%) patients had significant conduction disorders and received a prophylactic ICD. Among ICD recipients, no patient died suddenly and 11 (52%) patients required appropriate ICD therapy during a median follow-up of 62 months. Left ventricular ejection fraction was ≥45% in 9 patients at the time of the event. Among the 10 patients without malignant VA, device memory recorded nonsustained ventricular tachycardia in 8 (80%). The presence of significant conduction disorders was the only factor related to the occurrence of malignant VA (hazard ratio 5.20; 95% confidence interval 1.14-23.53; P = .03). CONCLUSIONS Life-threatening VAs are common in patients with LMNA mutations and significant cardiac conduction disorders, even if left ventricular ejection fraction is preserved. ICD is an effective treatment and should be considered in this patient population.

Safety, feasibility, and outcome results of cardiac resynchronization with triple-site ventricular stimulation compared to conventional cardiac resynchronization

BACKGROUND The nonresponder rate to cardiac resynchronization therapy (CRT) may be due to incomplete resynchronization, with dyssynchrony persisting in approximately 30% of patients. We hypothesized that CRT with triple-site ventricular stimulation (TRIV) may improve resynchronization and its outcomes. OBJECTIVE The purpose of this study was to assess the feasibility and safety of TRIV and collected data on clinical outcomes to dimension future studies. METHODS Our pilot randomized trial was designed to assess the safety and feasibility of TRIV with 2 right ventricular leads and 1 left ventricular leads compared to conventional CRT. The primary end-point was the rate of severe adverse events at 6 months. Secondary end-points included functional improvement parameters, quality-of-life (QOL) score, and changes of echocardiographic indices at 6 and 12 months in a subset of patients. RESULTS Seventy-six patients were enrolled at 11 centers and randomized to control or TRIV arm. All implant procedures but one were successful. At 6 months, there was no statistical difference between proportions of patients with at least 1 severe adverse event in both groups (34.1% vs 25.7%, P = .425). There also was no difference between functional improvement parameters, 6-minute walking distances (P = .40), QOL scores (P = .27), and echographic indices. At 12 months, the proportions of patients with a left ventricular ejection fraction gain of more than 5%, 10%, or 15% were significantly superior with TRIV. CONCLUSION TRIV pacing is an effective and safe technique and may provide a greater benefit in ventricular remodeling than conventional CRT. Further studies are needed to assess its long-term benefit.

An atypical atrial flutter of focal origin: A study using a noncontact mapping system

We report a case of focal atrial tachycardia with appearance suggestive of atypical atrial flutter in a 57‐year‐old man. Based on ECG criteria, tachycardia was misclassified as atypical atrial flutter. The electrophysiological study using a noncontact mapping system revealed a focal activity within the left upper pulmonary vein ostium. This case highlights the limitations of standard electrocardiographic and electrophysiological classifications of regular atrial tachycardia. This report also shows the relevance of new mapping techniques in the successful mapping and ablation of these arrhythmias, even those arising within the left atrium. (PACE 2003; 26:1410–1412)

The left coronary cusp as an unusual location for accessory pathway ablation

Case report In a 26-year-old woman, 6 months pregnant, with a recent history of palpitations, the surface electrocardiogram (ECG) showed sinus rhythm with ventricular preexcitation. As seen in Figure 1B, the delta wave was isoelectric in lead V1 and positive in leads I, II, III, and aVF and in all precordial leads, suggesting the presence of a right anteroseptal AP. ECG could not be performed during palpitations, and therefore tachycardia could not be documented. Beta-blockers were introduced, and the patient was no longer symptomatic during pregnancy. After childbirth, a few weeks before programmed electrophysiology study, the patient was hospitalized because of intentional beta-blocker overdose. After discontinuing it for 5 days, the electrophysiology study was then rapidly performed. A decapolar catheter was advanced within the coronary sinus, and a quadripolar catheter was positioned at the His bundle (HB) area. At baseline, programmed atrial stimulation showed an anterograde accessory pathway refractory period of 350 ms. No atrioventricular (AV) nodal jump was recorded. There was no ventriculoatrial conduction during ventricular pacing at a pacing cycle length of 600 ms.

Clinical testing of a new pacemaker function to monitor ventricular capture.

Automatic beat‐by‐beat capture functions are designed to minimize the pacing energy delivered, while maintaining the highest safety by delivering an immediate back‐up stimulus in case of loss of capture. The objective of this study was to estimate the lowering of ventricular pacing amplitude allowed by such a function, compared to amplitudes usually set manually in routine practice. An automatic ventricular pacing threshold test is launched every 6 hours to measure the automatic capture threshold (AT). From AT the function calculates: (1) the“capture amplitude”(Vc) = AT + 0.5 V at a minimum output of 1 V and (2) the“safety amplitude” (Vs) = twice AT at a minimum output of 2.5 V. The function preferentially uses Vc and verifies capture after each paced beat. In case of loss of capture, a back‐up spike is delivered and Vs is implemented until the next threshold measurement. We estimated the ventricular amplitude delivered by the pacemaker from data stored in the pacemaker memory. We compared these values with the pacing amplitude typically programmed manually (MPA) by physicians at twice AT and a minimum of 2.5 V. Data from 57 recipients of Talent 3 DR pacemakers were analyzed. Complete data sets were available in 25 patients at 1 day, 28 at 1 month, and 39 between 1 day and 1 month. No loss of capture or ventricular pause was observed on 53 ambulatory electrocardiograms (ECG); and pulse amplitude automatically delivered by the device was significantly lower than the MPA at each of the three time points analyzed. This new beat‐by‐beat capture function allows a significant lowering of the pacing amplitude compared to manual settings, while preserving a 100% safety.

Effective Long‐Term Left Atrial Pacing Using Regular Screw‐In Leads Implanted Within the Coronary Sinus

Passive‐fixation leads positioned inside the coronary sinus (CS) have been found to be effective in LA pacing and sensing, but their use is limited by a high incidence of early and late dislodgment. Since anatomic studies have shown that the proximal part of the CS is surrounded by a relatively thick musculature, the feasibility, safety, and efficacy of acute and chronic coronary sinus pacing via regular screw‐in leads positioned within the first centimeters of the CS were evaluated as compared to passive‐fixation leads. Thirty‐three patients (21 men, age 62 ± 10 years) underwent dual chamber pacemaker implantation with LA pacing obtained via passive‐fixation leads (7 patients) or regular screw‐in leads (26 patients). The former approach was prematurely abandoned because of a high rate of acute and late lead dislodgment (42%). The chronic pacing threshold was 1.7 ± 1.0 V at 0.67‐ms pulse width and 1.47 ± 1.3 V at 0.5‐ms pulse width for passive‐ and active‐fixation leads, respectively. In the CS active‐fixation lead group, no postoperative pericardial effusion, CS lead dislodgment, nor diaphragmatic stimulation were observed. In this last group, steroid eluting leads (14 patients) have a statistically lower pacing threshold than noneluting steroid leads (12 patients) (0.88 ± 0.23 vs 2.29 ± 1.68 V, P = 0.011) at long‐term follow‐up. The use of regular screw‐in leads implanted within the CS allows effective and safe long‐term LA pacing without risk of dislodgment. (PACE 2003; 26:1873–1877)