Bidirectional ventricular tachycardia with myocardial infarction: a case report with insight on mechanism and treatment.

Bidirectional ventricular tachycardia (BVT) is a rare variety of tachycardia with morphologically distinct presentation: The QRS axis and/or morphology is alternating in the frontal plane leads. Since its original description in association with digitalis,(1) numerous cases of this fascinating tachycardia with disparate etiologies and mechanisms have been postulated. We report a patient with BVT in association with non-ST elevation myocardial infarction and severe cardiomyopathy in the absence of digoxin toxicity.

Spiked helmet sign: An under-recognized electrocardiogram finding in critically ill patients.

A 77-year-old male patient presented with rhabdomyolysis. He developed progressive respiratory failure and acute respiratory distress syndrome during his hospital stay requiring mechanical ventilation. An electrocardiogram during mechanical ventilation showed findings suggestive of ST elevation myocardial infarction. Closer review showed dome and spike findings that have been likened to a "spiked helmet." This finding has been associated with significant mortality. We discuss this under-recognized finding and the potential contributing mechanisms.

Comparison of endovascular versus epicardial lead placement for resynchronization therapy.

Cardiac resynchronization therapy (CRT) has been shown to improve survival and symptoms in patients with severe left ventricular (LV) dysfunction, congestive heart failure, and prolonged QRS duration. LV lead placement is achieved by placing the lead in the coronary sinus, an endovascular approach, or by a minimally invasive robotic-assisted thoracoscopic epicardial approach. There are no data directly comparing the 2 methods. Patients eligible for CRT were randomized to the endovascular and epicardial arms. Coronary sinus lead placement was achieved using the standard technique, and epicardial leads were placed using a minimally invasive robotic-assisted thoracoscopic approach. The primary end point was a decrease in LV end-systolic volume index at 6 months. The secondary end points included 30-day mortality rate, measures of clinical improvement, 1-year electrical lead performance, and 1-year survival rate. The relative improvement of LV end-systolic volume index from baseline to 6 months was similar between the arms (28.8% for the transvenous [n = 12] vs 30.5% for the epicardial (n = 9) arm, p = 0.93). There were no significant differences in the secondary end points between the 2 groups. In conclusion, there were no differences in echocardiographic and clinical outcomes comparing a conventional endovascular approach versus robotic-assisted surgical epicardial LV lead placement for CRT in patients with heart failure. Surgical approaches are still a viable alternative when a transvenous procedure has failed or is not technically feasible.

Effect of spironolactone on ventricular arrhythmias in patients with left ventricular systolic dysfunction and implantable cardioverter defibrillators.

AIMS/OBJECTIVES: Patients with implantable cardioverter defibrillators (ICD) often receive an adjunctive anti-arrhythmic therapy. We propose that an addition of spironolactone will reduce the number of clinically significant ventricular arrhythmias and ICD-related therapies. METHODS AND RESULTS: In a multicentre retrospective study, 64 patients with ischaemic and non-ischaemic dilated cardiomyopathy whose left ventricular ejection fraction (LVEF) was <35% and with ICD were selected. Amongst these patients, 28 patients were on spironolactone and 36 were not taking spironolactone. The ICD interrogation data were analysed for a maximum of 12 months. Wilcoxon Rank Sum test was used to compare the study and control groups. The outcomes were: (1) the number of shocks/anti-tachycardia pacing (ATP) episodes and (2) the number of episodes of ventricular tachycardia (VT) requiring ATP, non-sustained VT (NSVT), and ventricular fibrillation (VF) over the study period. The spironolactone group had fewer monthly, VTs (P=0.027) (requiring ATP). The two groups did not differ in the number of NSVT or VF per month. CONCLUSION: Addition of spironolactone as an adjunct to ICD therapy in patients with congestive heart failure (CHF) reduces VT requiring ATP, but does not affect NSVT or VF per month.

Clinical utility of a novel wireless implantable loop recorder in the evaluation of patients with unexplained syncope.

BACKGROUND: The implantable loop recorder (ILR) is particularly useful for monitoring patients with syncope, given the episodic nature and unpredictable pattern of recurrent episodes. Current practice guidelines advocate ILR implantation in select patients with unexplained syncope. OBJECTIVE: The purpose of this study was to evaluate the clinical utility and potential advantages of a novel wireless ILR in a consecutive cohort of patients with unexplained syncope. METHODS: Patients with unexplained syncope despite a comprehensive evaluation who underwent implantation of a Transoma Medical Sleuth ILR were examined. ILR implantation was considered in these patients if left ventricular function was ≥ 40% and if syncope was recurrent, associated with trauma, and/or associated with an abnormal ECG (e.g., bifascicular block). RESULTS: The Sleuth ILR was implanted in 50 patients. During mean follow-up 293 ± 211 days, 16 (32%) patients had recurrent near-syncope or syncope. Only half of the patients self-activated the ILR; in the other half, a diagnosis was established based on autoactivation-initiated storage of a significant arrhythmia event. Overall, there were 5 patients with complete heart block, 3 with sinus node dysfunction, 3 with supraventricular tachycardia, 2 with neurally mediated syncope, and 3 with a nonarrhythmic cause of syncope. The median time from an event to physician notification was 150 minutes (interquartile range 99, 297 min). Median time from ILR implantation to final diagnosis was 71 days (interquartile range 24, 143 days; range 3-683 days). CONCLUSION: A diagnosis of syncope was ultimately made in nearly one third of patients with unexplained syncope. Patients frequently did not activate their ILR at the time of recurrent syncope. However, the wireless ILR automatically transferred ECG data to a central monitoring station within minutes to hours of the arrhythmic event, virtually eliminating the possibility of data loss, thus greatly facilitating clinical decision making.

Pulmonary vein isolation alone in patients with persistent atrial fibrillation: an ablation strategy facilitated by antiarrhythmic drug induced reverse remodeling.

INTRODUCTION: Pulmonary vein isolation (PVI) alone has been thought to be insufficient in patients with persistent atrial fibrillation (PersAF). We hypothesized that preablation treatment of PersAF with a potent antiarrhythmic drug (AAD) would facilitate reverse atrial remodeling and result in high procedural efficacy after PVI alone. METHODS AND RESULTS: Seventy-one consecutive patients (59.4 ± 9.8 years) with PersAF and prior AAD failure were treated with oral dofetilide (768 ± 291 mcg/day) for a median of 85 days pre-PVI. P-wave duration (Pdur) on ECG was used to assess reverse atrial remodeling. Thirty-five patients with paroxysmal (P) AF not treated with an AAD served as controls. All patients underwent PVI alone; dofetilide was discontinued 1-3 mos postablation. In the PersAF patients, the Pdur decreased from 136.3 ± 21.7 ms (assessed postcardioversion on dofetilide) to 118.6 ± 20.4 ms (assessed immediately prior to PVI) (P < 0.001). In contrast, no change in Pdur (122.6 ± 11.5 ms vs. 121.3 ± 13.7 ms, P = NS) was observed in PAF patients. The 6 and 12 mos AAD-free response to ablation was 76% and 70%, respectively, in PersAF patients, similar to the 80% and 75%, response in PAF patients (P = NS). A decline in Pdur in response to dofetilide was the only predictor of long-term clinical response to PVI in patients with PersAF. CONCLUSIONS: Pre-treatment with AAD resulted in a decrease in Pdur suggesting reverse atrial electrical remodeling in PersAF patients. This may explain the excellent clinical outcomes using PVI alone, and may suggest an alternative ablation strategy for PersAF.

Long-term outcome of leads and patients following robotic epicardial left ventricular lead placement for cardiac resynchronization therapy.

INTRODUCTION: In cardiac resynchronization therapy (CRT), positive clinical response and reverse remodeling have been reported using robotically assisted left ventricular (LV) epicardial lead placement. However, the long-term performance of epicardial leads and long-term outcome of patients who undergo CRT via robotic assistance are unknown. In addition, since the LV lead placement is more invasive than a transvenous procedure, it is important to identify patients at higher risk of complications. METHODS: We evaluated 78 consecutive patients (70 ± 11 years, 50 male) who underwent robotic epicardial LV lead placement. The short- (<12 months) and long-term (≥ 12 months) lead performance was determined through device interrogations. Mortality data were determined by contact with the patient's family and referring physicians and confirmed using the Social Security Death Index. RESULTS: All patients had successful lead placement and were discharged in stable condition. When compared to the time of implantation, there was a significant increase in pacing threshold (1.0 ± 0.5 vs 2.14 ± 1.2; P < 0.001) and decrease in lead impedance (1010 ± 240 Ω vs 491 ± 209 Ω; P < 0.001) at short-term follow-up. The pacing threshold (2.3 ± 1.2 vs 2.14 ± 1.2; P = 0.30) and lead impedance (451 ± 157 Ω vs 491 ± 209 Ω; P = 0.10) remained stable during long-term follow-up when compared to short-term values. At a follow-up of 44 ± 21 months, there were 20 deaths (26%). These patients were older (77 ± 7 vs 67 ± 11 years; P = 0.001) and had a lower ejection fraction (EF) (13 ± 7% vs 18 ± 9%; P = 0.02) than surviving patients. CONCLUSION: Robotically implanted epicardial LV leads for CRT perform well over short- and long-term follow-up. Older patients with a very low EF are at higher risk of death. The risks and benefits of this procedure should be carefully considered in these patients.

How to Learn Epicardial Intervention Techniques in Electrophysiology.

This article outlines an approach to begin an epicardial ablation program in the electrophysiology laboratory. There are some logistical hurdles in getting this program up and running, so this is a good opportunity to review the indications, the risks that are inherent in the procedure, and the infrastructure necessary in the electrophysiology laboratory and institution to perform the procedure safely and effectively.