Santiago Nava

Electrocardiographic Recognition of the Epicardial Origin of Ventricular Tachycardias

Background—Some ventricular tachycardias (VTs) originating from the epicardium are not suitable for endocardial radiofrequency ablation and require an epicardial approach. The aim of this study was to define the ECG characteristics that may identify an epicardial origin of VTs. Methods and Results—We analyzed the 12-lead ECG recordings during epicardial and endocardial left ventricular pacing in 9 patients to verify the hypothesis that the epicardial origin of the ventricular activation widens the initial part of the QRS complex. Then, we analyzed the ECG pattern in 14 VTs successfully ablated from the epicardium after a failed endocardial approach (group A), in 27 VTs successfully ablated from the endocardium (group B), and in 28 additional VTs that could not be ablated from the endocardium (group C). Four distinct intervals of ventricular activation were defined and measured: (1) the pseudodelta wave, (2) the intrinsicoid deflection time in V2, (3) the shortest RS complex, and (4) the QRS complex. VTs from groups A and C showed a significantly longer pseudodelta wave, intrinsicoid deflection time, and RS complex duration compared with VTs of group B. There was no difference between groups A and C. A pseudodelta wave of ≥34 ms has a sensitivity of 83% and a specificity of 95%, an intrinsicoid deflection time of ≥85 ms has a sensitivity of 87% and a specificity of 90%, and an RS complex duration of ≥121 ms has a sensitivity of 76% and a specificity of 85% in identifying an epicardial origin of the VTs. Conclusions—ECG suggests VTs originating from the epicardium and those with an unsuccessful radiofrequency ablation from the endocardium.

Incidence of pulmonary vein stenosis in patients submitted to atrial fibrillation ablation: a comparison of the Selective Segmental Ostial Ablation vs the Circumferential Pulmonary Veins Ablation.

Introduction: Pulmonary vein (PV) stenosis is an important complication of the AF ablation and could be underestimated if their assessment is not systematically done. Selective Segmental Ostial Ablation (SSOA) and Circunferential Pulmonary Veins Ablation (CPVA) have demonstrated efficacy in atrial fibrillation (AF) treatment. In this study the real incidence of PV stenosis in patients (pts) submitted to both SSOA and CPVA was compared.Methods: Those pts with focal activity and normal left atrial size were submitted to SSOA, remaining pts were submitted to CPVA to treat refractory, symptomatic AF. Contrast enhanced magnetic resonance angiography (MRA) was routinely performed in all patients 4 months after the procedure.Results: A series of 73 consecutive patients (mean age of 51 ± 11 years; 75% male) were included. SSOA was performed in 32 patients, and the remaining 41 patients underwent to CPVA, obtaining similar efficacy rates (72% vs 76% arrythmia free probability at 12 months; log rank test p = NS). Six patients had a significant PV stenosis, all in SSOA group none in CPVA group (18.8% vs 0%; p = 0.005). All patients were asymptomatic and the stenosis was detected in routine MRA. No predictors of stenosis has been identified analysing patient procedure characteristics.Conclusion: PV stenosis is a potential complication of SSOA not seen in CPVA. The study confirms than MRA is useful for identifying patients with asymptomatic PV stenosis.

Long-term efficacy of low doses of quinidine on malignant arrhythmias in Brugada syndrome with an implantable cardioverter-defibrillator: A case series and literature review

BACKGROUND To prevent the recurrence of ventricular arrhythmias (VA) in Brugada syndrome (BrS), only quinidine has been consistently reported to have a beneficial effect. Recommended doses are ≥ 1 g/d. The efficacy of lower doses of quinidine has been suggested on the basis of a few isolated experiences. OBJECTIVES To describe the efficacy and safety of doses ≤ 600 mg/d of quinidine after cardioverter-defibrillator implantation in BrS at 2 referral centers and to compare those results with a comprehensive review of the literature. METHODS In a retrospective analysis of medical records from the 2 centers, 6 men with BrS who received ≤ 600 mg/d of quinidine sulfate or hydroquinidine after cardioverter-defibrillator implantation were identified. Quinidine was initiated after arrhythmic syncope or appropriate shocks, including arrhythmic storm in 4. A literature search was performed to find previous cases with symptomatic BrS reported as having received ≤ 600 mg/d of quinidine. RESULTS Quinidine prevented recurrence of VA in all patients from our series without side effects during a median follow-up of 4 years (from 2 to 8 years). In the literature review, 14 additional adults were found. With the exception of 3, quinidine effectively suppressed arrhythmic events in all of them. Four subjects who discontinued the medication experienced VA recurrence, successfully treated by restarting quinidine. CONCLUSIONS Low doses of quinidine were well tolerated and effective to prevent the recurrence of VA, including arrhythmic storm, in subjects with BrS with an implantable cardioverter-defibrillator. Effectiveness of quinidine or hydroquinidine in doses ≤ 600 mg/d is 85%.

Radiofrequency catheter ablation for arrhythmic storm in patients with an implantable cardioverter defibrillator.

The aim of the study was to analyze the usefulness of RFA in controlling arrhythmic storm due to hemodynamically stable VT in a cohort of patients with an ICD and to evaluate the incidence of arrhythmic storm among patients with an ICD. A group of 13 (3%) of 403 consecutive ICD recipients were submitted to RFA of VT during an arrhythmic storm. Two additional patients were referred from other institutions. Standard criteria were used for VT endocardial ablation. A transcatheter epicardial approach was required in three patients. A total of 18 procedures were performed in 15 patients. A mean of 13.2 ± 9.7 pulses of RF were delivered. Clinical tachycardia was successfully ablated in 12 (80%) patients. One patient died in incessant VT, 1 patient underwent heart transplant, and 1 was treated with direct current ablation. During a mean follow‐up of 12 ± 17 months, only two patients suffered a single episode of VT. Arrhythmic storm requiring VT ablation was uncommon among patients with an ICD and occurred late after ICD implantation. The arrhythmic episode was successfully controlled in the majority of patients with endocardial or epicardial RFA. (PACE 2004; 27:971–975)

Reuse of Pacemakers Comparison of Short and Long-term Performance

Background— In developing economies, there are patients in whom pacemaker implantation is delayed because they cannot afford one. Reused devices have been a solution. To address concerns about safety, a cohort of consecutive patients implanted with a reused pacemaker was compared with a control group. Methods and Results— A cohort of 603 consecutive patients from 2000 to 2010 was studied in an ambispective noninferiority study. The study group patients (n=307) received resterilized pacemakers, and the control group patients (n=296) received a new pacemaker. A combined end point of 3 major outcomes–unexpected battery depletion, infection, and device dysfunction–was analyzed. A total of 85 pacemakers had to be explanted, 31 in the control group (10.5%) and 54 in the study group (17.6%; relative risk, 1.68; 95% confidence interval, 1.1–2.5; P =0.02). Forty-three reached the primary end point, 16 in the control group (5.5%) and 27 in the study group (7.2%; relative risk, 1.3; 95% confidence interval, 0.70–2.45; P =0.794). In terms of individual outcomes, 5 new pacemakers (1.7%) and 11 resterilized pacemakers (3.6%) had unexpected battery depletion (relative risk, 2.12; 95% confidence interval, 0.75–6; P =0.116); 3.7% new pacemakers and 3.2% reused pacemakers had a procedure-related infection (relative risk, 0.87; 95% confidence interval, 0.38–2.03; P =0.46); and 1 pacemaker in the study group malfunctioned. Conclusions— Pacemaker reuse is feasible and safe and is a viable option for patient with bradyarrhythmias. Other than the expected shorter battery life, reuse of pacemaker generators is not inferior to the use of new devices. # Clinical Perspective {#article-title-25}Background— In developing economies, there are patients in whom pacemaker implantation is delayed because they cannot afford one. Reused devices have been a solution. To address concerns about safety, a cohort of consecutive patients implanted with a reused pacemaker was compared with a control group. Methods and Results— A cohort of 603 consecutive patients from 2000 to 2010 was studied in an ambispective noninferiority study. The study group patients (n=307) received resterilized pacemakers, and the control group patients (n=296) received a new pacemaker. A combined end point of 3 major outcomes–unexpected battery depletion, infection, and device dysfunction–was analyzed. A total of 85 pacemakers had to be explanted, 31 in the control group (10.5%) and 54 in the study group (17.6%; relative risk, 1.68; 95% confidence interval, 1.1–2.5; P=0.02). Forty-three reached the primary end point, 16 in the control group (5.5%) and 27 in the study group (7.2%; relative risk, 1.3; 95% confidence interval, 0.70–2.45; P=0.794). In terms of individual outcomes, 5 new pacemakers (1.7%) and 11 resterilized pacemakers (3.6%) had unexpected battery depletion (relative risk, 2.12; 95% confidence interval, 0.75–6; P=0.116); 3.7% new pacemakers and 3.2% reused pacemakers had a procedure-related infection (relative risk, 0.87; 95% confidence interval, 0.38–2.03; P=0.46); and 1 pacemaker in the study group malfunctioned. Conclusions— Pacemaker reuse is feasible and safe and is a viable option for patient with bradyarrhythmias. Other than the expected shorter battery life, reuse of pacemaker generators is not inferior to the use of new devices.

Short head-up tilt test potentiated with oral nitroglycerine: comparison with a conventional test using isoproterenol.

Conventional tilt test protocols are time consuming and there is no consensus regarding the optimal duration of the test and the provocative drug to be used. This study evaluated the diagnostic power of a short nitroglycerine test against a conventional isoproterenol protocol. A cohort of 128 patients with unexplained syncope was studied. A group of 64 consecutive patients were tilted with a short nitroglycerine test consisting of a passive phase of 15 minutes and if this proved negative, 400 μg of sublingual nitroglycerin spray for a further 15 minutes. The control group consisted of 64 patients tilted with a conventional isoproterenol protocol with a passive phase of 30 minutes and a drug‐challenge phase of 20 minutes. In the nitroglycerine protocol 39 (60.9%) patients showed a positive response versus 27(42.2%) in the isoproterenol group (P = 0.034). The duration of the protocol was 23.2 ± 7.2 minutes in the nitroglycerine group versus 41.1 ± 15.5 minutes with isoproterenol (P = 0.001). The time until syncope was 18.87 ± 6.1 versus 29 ± 18, respectively (P = 0.002). For evaluating unexplained syncope the short tilt test protocol with nitroglycerine is less time consuming, easier to perform, and has a higher rate of positive response than a conventional isoproterenol protocol.

Lack of efficacy of radiofrequency catheter ablation in Andersen–Tawil syndrome: are we targeting the right spot?

Andersen–Tawil syndrome (ATS) is associated with a high arrhythmic burden as demonstrated recently by Delannoy et al .1 in this Journal . Almost all subjects (91%) had very frequent ventricular arrhythmias [>10 000 premature ventricular contractions (PVCs)/day] including episodes of bigeminy and non-sustained ventricular tachycardia. As in other hereditary sudden cardiac death syndromes, it seems appropriate to eliminate these arrhythmias by means of radiofrequency catheter ablation (RFCA). To our knowledge, there is no publication …

The relevance of Looking for Right Bundle Branch Block in catheter ablation of Ebstein's anomaly

INTRODUCTION Ebsteins anomaly is the most commonly occurring congenital defect associated with the Wolff-Parkinson-White syndrome. In patients with Ebsteins anomaly and supraventricular tachycardia, the absence of right bundle branch block (RBBB) in sinus rhythm is a highly sensitive and specific indicator of the presence of an ipsilateral accessory AP. CASE We present an electrophysiology case of a patient with Ebsteins anomaly and 3 ipsilateral accessory pathways. After ablation was performed, RBBB was evident. CONCLUSION In patients with Ebsteins anomaly and supraventricular tachycardia, the absence of a RBBB pattern in the surface ECG after RFCA should raise suspicion for the presence of multiple accessory pathways.

Andersen–Tawil syndrome. A diagnostic challenge

Article history: Received 14 November 2015 Accepted 22 November 2015 Available online 26 November 2015 heart sounds by premature beats with compensatory pause. Holter monitoring reported corrected QT interval of 515 ms, and very frequent VPB (32,231/24 h), with multiple morphologies, couplets, bigeminy, and trigeminy. Cardiac Magnetic Resonance reported no structural heart disease. Genetic study was requested using massive sequencing sponsored

Simplified progressive approach for the ablation of scar related atrial macroreentrant tachycardias

INTRODUCTION Radiofrequency ablation of scar related right atrial flutter is challenging. Long procedures, prolonged fluoroscopic times and high percentages of recurrences are of concern. We present a simple and progressive approach based on a single electroanatomic map of the right atrium. METHODS Twenty-two consecutive patients with atrial flutter and history of cardiac surgery were included. An electrophysiologic study was performed to define localization (left or right) and cavo-tricuspid isthmus participation using entrainment mapping. After a critical isthmus was localized, ablation was performed with an external irrigated tip catheter with a power limit of 30 W. Potential ablation sites were confirmed by entrainment. RESULTS The predominant cardiopathy was atrial septal defect. All arrhythmias were localized in the right atrium; mean cycle length of the clinical flutter was 274 ± 31 ms. Only 40% had cavo-tricuspid isthmus participation. None of the patients with successful ablation had recurrences after 13 ± 9.4 months of follow-up. CONCLUSIONS A progressive approach with only one activation/voltage CARTO(®) map of the atrium and ablation of all potential circuits is a highly effective method for ablating scar related macroreentrant atrial arrhythmias.