ERIGO: a possible strategy to treat orthostatic hypotension in progressive supranuclear palsy? A feasibility study.

Progressive supranuclear palsy (PSP) is a neurodegenerative disease of the central nervous system, presenting with different clinical phenotypes, all involving the extrapyramidal system. Orthostatic hypotension (OH) is a common symptom of cardiovascular autonomic dysfunction. OH is defined as a fall in systolic blood pressure of at least 20 mmHg and/or a fall in diastolic blood pressure of at least 10 mmHg on standing or head-up tilt. In this pilot study, we tested the feasibility and efficacy of the ERIGO® device in managing OH non-responsive to conventional treatments in a sample of patients with PSP. OH was chosen as the primary outcome, as the symptom is a serious complication in neurodegenerative disorders, challenging the rehabilitation treatment. Six patients received intensive training using ERIGO®, a robot- assisted tilt table with an integrated leg movement system that allows progressive verticalization of the patient, and application of functional electrical stimulation. In all the participants, OH improved after the training with the device, suggesting that robotic verticalization may be a feasible and effective tool in improving blood pressure stability in patients with PSP. Further studies in larger samples, also including patients with other neurodegenerative disorders associated with OH, are needed to confirm these promising results.

Atrioventricular nodal reentry tachycardia: slow pathway ablation using the transseptal approach.

Four hundred twenty consecutive patients with symptomatic slow/fast atrioventricular nodal reentry tachycardia had attempted slow pathway radiofrequency ablation. All patients had successful slow pathway ablation and no inducible tachycardia after ablation using the standard right-sided approach except for three patients. The three unsuccessful patients had inducible slow/fast atrioventricular nodal tachycardia after attempted right-sided posterior and inferoposterior anatomic ablative techniques and with slow pathway potential electrogram guidance. Lesions were also delivered linearly in the triangle of Koch and within the coronary sinus ostium. A transseptal puncture was performed and slow pathway ablation was obtained in each of these patients. Ablation was performed from the septal mitral valve annulus, anterior to the os of the coronary sinus and inferior to the His-bundle catheter with elimination of slow pathway conduction. Prior to the ablation, two of the three patients exhibited initiation of tachycardia with a double fast/slow antegrade response, and all three patients had long AH intervals (mean 378 ms) during slow pathway conduction. These electrophysiological findings may be consistent with a large area of slow pathway conduction that may include the left atrial septum not approachable by conventional right-sided ablative techniques. Slow pathway ablation to eliminate atrioventricular nodal reentry tachycardia at times may require a left atrial/transseptal approach when conventional right-sided techniques are ineffective.

The effect of ibutilide on retrograde accessory pathway conduction.

Ibutilide is a compound with Class III effects marketed for rapid conversion of atrial fibrillation and atrial flutter. The Class III effect is primarily mediated by blockade of the rapid component of the cardiac delayed rectifier of potassium current, Ikr. Ibutilide was used in three patients with concealed accessory pathways during electrophysiological evaluation for ablation of symptomatic atrioventricular reentry tachycardia. Each pathway (mid-septal, left posterior, and left lateral) exhibited a mean retrograde effective refractory period of 240 +/- 20 ms. Each patient had atrioventricular reentry tachycardia that consistently degenerated to recurrent sustained atrial fibrillation. One to two milligrams of intravenous ibutilide converted atrial fibrillation to sinus rhythm and maintained sinus rhythm throughout the procedure. Retrograde accessory pathway conduction was unchanged. Maintenance of sinus rhythm allowed for successful mapping and catheter ablation of the concealed accessory pathways. No direct current cardioversion was needed. In these patients, ibutilide was effective in converting and controlling atrial fibrillation induced by atrioventricular reentry tachycardia without masking retrograde pathway conduction. Antegrade accessory pathway conduction could not be assessed in this study.

Pediatric radiofrequency ablation for tachyarrhythmias: the Westchester Medical Center experience.

Radiofrequency ablation, first performed in the late 1980s, has become a standard therapeutic procedure for tachyarrhythmias in children and adults. This procedure can achieve a high degree of success with minimal complications. This report describes the pediatric radiofrequency ablation experience at Westchester Medical Center, including 89 consecutive children who have undergone 104 ablations of 96 arrhythmia substrates with an overall success rate of 95%. The series is analyzed in the context of previously published series of pediatric radiofrequency ablations. Unresolved issues in pediatric ablation related to anesthesia, learning curve, necessity for hospital admission, anticoagulation protocol, and technical aspects of the procedure are discussed.

Symptomatic atrioventricular dual pathway double responses: a role for slow pathway ablation.

Two patients with symptomatic fast/slow pathway double responses were evaluated with electrophysiology studies. Chronic palpitations were resistant or worsened by medical therapy. No reentry tachycardias were induced. A nonreentrant paroxysmal supraventricular tachycardia was documented. Radiofrequency ablation of the slow pathway was safely and successfully performed. Patients remain asymptomatic for 16-18 months. Ablation of the slow pathway for this substrate is a viable option.

Safety and efficacy of outpatient transseptal radiofrequency ablation of atrioventricular accessory pathways.

A retrospective analysis of 60 consecutive patients who underwent outpatient transseptal radiofrequency ablation of left sided accessory pathways at Westchester County Medical Center/New York Medical College from September 1994 to December 1997 was performed. Patients were followed for a mean duration of 22 months. No complications either local or related to the transseptal method were observed. All patients had successful ablation of the accessory pathway. One patient had a recurrence of symptoms. This study suggests transseptal radiofrequency ablation of the left sided accessory pathways to be safe, feasible and an effective procedure when performed in an outpatient setting. These results were obtained at a high volume center with experience using the transseptal technique.

Verapamil-sensitive left ventricular tachycardia in patients with coronary artery disease: clinical and electrophysiologic features consistent with triggered activity.

This is a retrospective review of three male patients with verapamil-sensitive left ventricular tachycardia, severe coronary artery disease, and past myocardial infarction. Each patient had severe left ventricular dysfunction (mean ejection fraction 34%). Each tachycardia had a right bundle branch block/left axis deviation morphology, which was sustained with isoproterenol. One patient had incessant tachycardia 3 days after coronary bypass surgery. Electrophysiology and clinical parameters were suggestive of triggered activity rather than reentry. Each tachycardia was terminated with verapamil but failed with adenosine, beta blockers, and class I/III antiarrhythmics. Prior cases of verapamil-sensitive ventricular tachycardia have been seen in patients without organic heart disease, and the putative mechanism appears to be reentry. These patients with ischemic coronary artery disease may exhibit a mechanism of triggered activity in the Purkinje system region, which is responsive to calcium channel blockade. Successful radiofrequency ablation was guided by Purkinje potentials.

Syncope and preexcitation: a case of a Kent and fasciculoventricular Mahaim fibers.

A case involving an 8-year-old girl with syncope and preexcitation on a surface electrocardiogram (ECG) that was suggestive of Wolff-Parkinson-White syndrome is presented. An intracardiac electrophysiologic study revealed a posteroseptal bidirectionally conducting Kent fiber. Radiofrequency ablation of the Kent fiber was successful, but the patient had a residual short His-ventricular (HV) interval and a new preexcitation pattern. Atrial extra stimuli and ventricular pacing revealed a fixed, preexcited QRS. Nodal block and loss of preexcitation was provoked with adenosine. The surface QRS and electrophysiologic features are consistent with a left septal fasciculoventricular Mahaim fiber.

Sudden cardiac death and coronary spasm: a case report.

A case involving a 55-year-old man with documented ventricular fibrillation is presented. Invasive evaluation revealed no inducible ventricular arrhythmia, and nonobstructive coronary disease. Ejection fraction and results of nuclear treadmill test and signal-averaged electrocardiogram were normal. An automatic cardiodefibrillator was implanted. In-hospital symptoms that replicated symptoms preceding sudden death revealed anterior ST segment elevations, which were treated with sublingual nitroglycerin. Follow-up after 27 months of calcium blocker and nitroglycerin therapy was uneventful and without device activity. Patients with unexplained sudden death may have unsuspected coronary spasm as the primary substrate. Combination drug and device therapy may be appropriate in such patients.

Radiofrequency catheter ablation: the first decade.

Radiofrequency catheter ablation (RFCA) has become a safe and effective procedure for treatment of supraventricular and ventricular arrhythmia in children and adults. Anatomic data and mapping experience obtained from surgical and direct current ablation procedures paved the way for radiofrequency ablation. Radiofrequency energy is a power source well suited to place focal catheterization lesions. A large variety of supraventricular tachycardias can be successfully cured with a high success rate with minimal complications. Also, a growing number of ventricular tachycardias can be cured or palliated with this procedure. Ongoing research may increase the scope of this procedure to provide primary cures for atrial fibrillation and ventricular tachycardia associated with coronary artery disease. These procedures are highly complex and should be performed in a high-volume center.

Heart rate variability and the outcome of head-up tilt in syncopal children.

Neurocardiogenic syncope may be caused by enhanced sympathetic activity evoking a vasodepressor-cardioinhibitory reflex. Heart rate variability (HRV) methods can be used to assess the modulation of sympathetic and parasympathetic activity. To determine whether HRV measurements are related to the outcome of head-up tilt testing (HUT), we studied 29 syncopal patients aged 7-19 y. After 30 min supine, patients were tilted to 80 degrees for 30 min or until syncope occurred. Sequential beats free from ectopy were analyzed. Time domain indices included SD (SDNN), root mean square successive differences (RMSSD), percent exceeding 50 ms (pNN50). An autoregressive model was used to calculate power spectra. Low frequency power (LFP, 0.05-0.15 Hz), high frequency power (HFP, 0.15-0.40 Hz), and total power (TP, 0.01-0.40 Hz) were compared before and after tilt. Data were obtained supine before tilt (baseline), within 5 min after HUT (early), 5-10 min after HUT (mid), and 15 min after HUT or presyncope (late). Seventeen patients fainted (HUT+), and 12 patients did not (HUT-). Variability indices were different for HUT- and HUT+ at baseline: SDNN was 123 +/- 17 versus 78 +/- 6, RMSSD was 127 +/- 23 versus 64 +/- 6 ms, pNN50 was 51 +/- 6 versus 31 +/- 4, respectively. Spectral data demonstrated decreased HFP and TP in HUT+ (834 +/- 133 and 2855 +/- 420 ms2) versus HUT- (3433 +/- 840 and 7062 +/- 1500). With tilt, SDNN, RMSSD, and pNN50 decreased proportionately in HUT- and HUT+. However, sympathovagal balance, measured by the ratio LFP/HFP and by normalized LFP, was markedly increased in HUT+ (2.2 +/- 0.7 and 0.43 +/- 0.03) compared with HUT- (0.8 +/- 0.2 and 0.31 +/- 0.02) at baseline and differences increased with tilt. With syncope, sympathetic activity decreased, and parasympathetic activity increased. Decreased RR variability with decreased parasympathetic activity and increased indices of sympathovagal balance before HUT predict a positive tilt test in children referred for evaluation of neurocardiogenic syncope.

Reversible late potentials due to ischemia.

The role of ischemia in the development of reversible late potentials was assessed in 19 patients undergoing percutaneous transluminal coronary angioplasty. Signal-averaged electrocardiograms were performed before angioplasty, during ischemia caused by balloon inflation and after angioplasty. Five of 19 patients developed late potentials that reverted to normal after angioplasty. Age, sex, ejection fraction, left ventricular end diastolic pressure, vessels involved, and extent of myocardium in jeopardy did not predict the development of late potentials. Patients with a prior history of myocardial infarction were more likely to develop late potentials. Therefore, patients with prior myocardial infarction appear more likely to develop the substrate for reentrant ventricular tachycardia during periods of ischemia.

Prospective evaluation of heart block complicating early Lyme disease.

Lyme disease is a recognized cause of heart block/carditis. The incidence of heart block complicating early Lyme disease has not been prospectively evaluated. In this study, 61 patients with early Lyme disease documented by the rash of erythema migrans were prospectively evaluated for carditis. Fifty five of 61 patients had a repeat examination 3 to 4 weeks after initiation of antibiotic therapy. Only one of 61 patients (1.6%) presented with heart block, which resolved with antibiotics. None of the 54 patients without heart block on initial presentation had a change in any measured electrocardiographic parameter or progressed to heart block after antibiotics. Therefore, early Lyme disease appears to be infrequently complicated by heart block. Early administration of antibiotics may prevent the development of heart block/carditis.

Acute reversible diffuse conduction system disease due to Lyme disease.

During the acute phase of Lyme disease, a 56-year-old man without previous heart disease developed complete heart block with alternating left and right bundle branch block pattern QRS complexes. Electrophysiological study performed in the acute phase revealed marked HV prolongation, although the level of heart block was at the atrioventricular node. The heart block was mildly symptomatic and resolved (as did the bundle branch block) with antibiotic therapy. Lyme disease may cause reversible His-Purkinje disease.