Jürg Schläpfer

Age at onset and gender of patients with different types of supraventricular tachycardias

Abstract Sex differences between certain types of arrhythmias have been reported. For example the Wolff-Parkinson- White syndrome is more frequent in male than female subjects. 1 Atrioventricular (AV) nodal tachycardia has been found to occur more frequently in female subjects. 2 Little is known about the age at onset of different types of supraventricular tachycardias. The purpose of this study was twofold: (1) to obtain insight into a possible relation between gender of patient and type of supraventricular tachycardia, and (2) to look for possible differences in age at the time of the first arrhythmic event in relation to the type of arrhythmia. The following 3 groups of patients were studied: those with atrial tachycardia, AV nodal tachycardia and tachycardias in the presence of an accessory AV pathway.

Acute Hemodynamic Effects of Atrioventricular Pacing at Differing Sites in the Right Ventricle Individually and Simultaneously

We hypothesized that pacing, which provided a rapid uniform contraction of the ventricles with a narrower QRS, would produce a better stroke volume and cardiac output (CO). We sought to study whether pacing simultaneously at two sites in the right ventricle (right ventricular apex and outflow tract) would provide a narrower QRS and improved CO in 11 patients undergoing elective electrophysiology studies. Patients were studied by transthoracic echocardiography measurement of CO using the Doppler flow velocity method in normal sinus rhythm, AOO pacing (rate 80), DOO pacing in the right ventricular apex (AV delay 100 ms). DOO pacing in the right ventricular outflow tract, and DOO pacing at both right ventricular sites simultaneously in random order. The COs were 5.42 ± 1.83, 5.61 ± 1.97. 5.67 ± 1.6. 5.84 ± 1.68. and 5.86 ± 1.52 L/min, respectively (no significant difference by repeated measures analysis of variance [ANOVA]). The QRS durations were 0.09 ± 0.02, 0.09 ± 0.02. 0.13 ± 0.027, 0.13 ± 0.03, and 0.11 ± 0.03 sees respectively. Repeated measures ANOVA showed that the QRS duration significantly increased with right ventricular apex or right ventricluar outflow tract pacing compared to sinus rhythm and AOO pacing (P < 0.001) but then diminished with pacing at both sites (P < 0.01). QRS duration was not correlated with CO, however the change in QRS duration correlated significantly with the change in CO when pacing was performed at the two right ventricular sites simultaneoasly. In conclusion, during DOO pacing, there was a trend for pacing in the right ventricular outflow tract or both sites to improve the CO compared to the right ventricular apex. With simultaneous pacing at both ventricular sites, the QRS narrowed. Further studies will be required to see if this approach has value in patients with poor left ventricular function or congestive heart failure.

Ten-Years Follow-Up of 20 Patients with Idiopathic Ventricular Tachycardia

The follow‐up and characteristics of 20 patients with ventricular tachycardia (VT) and no detectable heart disease is reported. These were 16 men and four women with a mean age of 44 years. Symptoms were present in 18 patients (eight had syncope and ten palpitations or dizziness), VT was sustained in 11 patients and a left bundle branch block morphology with inferior axis was found in 17 patients. In three patients, VT had a right bundle branch block morphology and left‐axis deviation. The VT was inducible in 13 patients during the electrophysiological testing (EP) and was sustained in five patients. Medical treatment was introduced in 19 patients. During a mean follow‐up of 10 years from the onset of the symptoms and 6 years from the EP testing, one patient died suddenly. He had stopped taking amiodarone 5 months before. In seven patients symptoms recurred and were due to discontinuation of therapy in two cases and inefftcacy of previous effective treatment in five patients. After modification of the treatment (three cases), implantation of a pacemaker (one case) and catheter ablation (one case), all patients became asymptomatic. Eleven patients became asymptomatic with the first administered antiarrhythmic therapy. One patient continues to be asymptomatic in spite of discontinuation of his medical therapy. We conclude that patients with VT and no detectable heart disease have a good long‐term prognosis and that appropriate therapy can be found in almost all patients.

The 12-lead electrocardiogram in midseptal, anteroseptal, posteroseptal and right free wall accessory pathways

The 12-lead electrocardiograms of 50 patients with 1 anterogradely conducting accessory pathway were analyzed to obtain characteristics of electrocardiographic findings in the midseptal, anteroseptal, true posteroseptal and right free wall accessory pathway locations. Locations were confirmed by surgery (33 patients) or radiofrequency catheter ablation (17 patients). This study analyzed (1) QRS in the frontal plane, (2) delta wave axis in the frontal plane, (3) the angle between QRS and delta wave axes, (4) the R/S ratio in lead III, (5) negativity of delta wave in inferior leads, and (6) the R/S ratio in precordial leads.(ABSTRACT TRUNCATED AT 250 WORDS)

Dual Chamber Pacing in Hypertrophic Obstructive Cardiomyopathy: Beneficial Effect of Atrioventricular Junction Ablation for Optimal Left Ventricular Capture and Filling

Clinical improvement with dual chamber pacing bas largely been reported in patients suffering from hypertrophic obstructive cardiomyopathy and mainly attributed to the reduction of the subaortic pressure gradient. To be effective, pacing must induce a permanent and complete capture of the LV. In two patients of our collective, symptoms (angina and dyspnea NYHA Class III and/or syncopes) persisted or relapsed despite pacing. This was related to the inability to obtain full LV capture due to a too‐short native PR interval. RF ablation of the AV junction was therefore performed in botb patients, resulting in permanent AV block in one and prolonged PR interval up to 310 ms in the second. Pacing was thereafter associated with an immediate and significant clinical improvement related to permanent LV capture, whatever the patients activity. After RF ablation, the AV delay was set up to induce the best LV filling, as assessed by Doppler analysis of mitral flow. Our observations suggest that RF ablation or modification of the AV junction can be a successful procedure in some patients with residual or recurrent symptoms, when the latter result from a loss of capture or from the inability to program an AV delay tbat does not compromise the active component to LV filling. Doppler echocardiography is a simple and effective mean to assess the hemodynamic effect of AV interval modulation in this setting.

Experience with a New Implantable Pacer-, Cardioverter-Defibrillator for the Therapy of Recurrent Sustained Ventricular Tachyarrhythmias: A Step Toward a Universal Ventricular Tachyarrhythmia Control Device

Ten consecutive patients (mean age 57.9 ± 7.6 years) were treated with an investigational tachyarrhythmia control device, the implantable Medtronic Pacer‐, Cardioverter‐, Defibrillator model 7216A or 72170. All patients had coronary artery disease with old myocardial infarctions and presented hemodynamically significant sustained ventricular tachyarrhythmias not suppressed by antiarrhythmic drug therapy and unrelated to acute myocardial infarction. In two patients a nonthoracotomy lead system was implanted. Lowest effective defibrillation energy ranged from 5 to 18 joules (mean 12.2 ± 4 joules) for the epicardial bielectrode systems and were 15 and 18 joules for the nonfhoracotomy lead system implants. The postoperative periods were unremarkable. Follow‐up ranged from 7 to 19 months (mean 13.8 ± 4.5 months). Spontaneous tachyarrhythmia episodes were detected and treated by the device in six patients, five of them received staged therapies. No deaths occurred and no hospital admissions were necessary for device related or ventricular tachyarrhythmia related complications. In conclusion, this integrated device represents a major step toward the development of a universal ventricular arrhythmia control device.

Clinical characteristics and electrophysiologic properties of atrioventricular accessory pathways : importance of the accessory pathway location

OBJECTIVES This study was designed to assess the influence of accessory atrioventricular (AV) pathway location on the clinical and electrophysiologic characteristics of 384 consecutive symptomatic patients having a single accessory pathway. METHODS Four locations were studied: left free wall (n = 270), posteroseptal (n = 52), anteroseptal (n = 29) and right free wall (n = 33). Ten clinical variables and 12 electrophysiologic variables were analyzed, including the effective refractory period of the accessory pathway and the different clinically occurring and inducible arrhythmias. RESULTS Only two clinical findings were associated with accessory pathway location: 1) later age at onset of symptoms in the left free wall versus other accessory pathway locations (24 +/- 12 vs. 20 +/- 11 years, p = 0.02), and 2) later age at the time of electrophysiologic study in the left free wall accessory pathway location (36 +/- 13 vs. 32 +/- 11 years, p = 0.01). Six electrophysiologic variables showed a correlation with the accessory pathway location: 1) retrograde conduction only was found less frequently in right free wall (9%) and anteroseptal (10%) than in left free wall (26%) and posteroseptal (29%) accessory pathway locations (p = 0.05); 2) the retrograde effective refractory period of the accessory pathway was shorter in anteroseptal (253 +/- 52 ms) and left free wall (270 +/- 72 ms) as compared with right free wall (296 +/- 101 ms) and posteroseptal (301 +/- 76 ms) locations (p = 0.05); 3) retrograde decremental conduction over the accessory pathway was present in the posteroseptal (17%) and left free wall (3%) but absent in the other locations (p less than 0.001); 4) anterograde decremental conduction was only seen in the right free wall location (12%) (p less than 0.001); 5) orthodromic reentrant tachycardia was induced less frequently in the right free wall than in other locations (70% vs. 93%, p less than 0.001); and 6) inducibility of atrial fibrillation was greater in anteroseptal (62%) than in right free wall (21%), left free wall (44%) and posteroseptal (36%) locations (p = 0.01). CONCLUSIONS The location of the accessory AV pathway is associated with specific electrophysiologic characteristics.

Effect of oral triiodothyronine during amiodarone treatment for ventricular premature complexes

Whether there is a link between the antiarrhythmic efficacy of amiodarone and its blocking effect on the peripheral conversion of tetraiodothyronine (T4) to triiodothyronine (T3) is uncertain. If such a link exists, oral intake of T3 during amiodarone treatment could reverse, at least partially, the antiarrhythmic efficacy of amiodarone. To assess the safety of oral intake of T3 during amiodarone treatment and gain further insight into the relation between the antiarrhythmic action of amiodarone and its metabolic effect on T4, 7 patients (aged 32 to 62 years) with multiple ventricular premature complexes (VPCs) but no underlying heart disease were studied. Antiarrhythmic treatment was indicated for symptomatic relief only. Each patient underwent a 48-hour ambulatory electrocardiographic recording, electrocardiography and thyroid function tests, including plasma T4, T3, reverse T3 (rT3), free T4, free T3 and thyroid-stimulating hormone without treatment (baseline) after 1 month of amiodarone therapy and after a second month of amiodarone therapy with increasing doses of oral T3 (up to 75 micrograms/day). Treatment with amiodarone resulted in a decrease in plasma T3 and free T3, an increase in plasma rT3, a marked diminution in the frequency of VPCs and a prolongation of the corrected QT interval (QTc). During treatment with amiodarone and T3, plasma T3 and free T3 increased and plasma T4, free T4 and rT3 levels decreased; the frequency of VPCs remained low despite shortening of the QTc to values not different from baseline. Thus, in patients with frequent VPCs and no underlying heart disease, oral intake of T3 during amiodarone treatment is safe and does not abolish the antiarrhythmic efficacy of amiodarone, despite a shortening of the QTc.(ABSTRACT TRUNCATED AT 250 WORDS)

BEZOLD-JARISCH-LIKE PHENOMENON INDUCED BY RADIOFREQUENCY ABLATION OF A LEFT POSTEROSEPTAL ACCESSORY PATHWAY VIA THE CORONARY SINUS

RF Ablation‐Induced Bezold‐Jarisch Phenomenon. We report a case of asystole induced by radiofrequency (RF) ablation via the coronary sinus in a 35‐year‐old man suffering from symptomatic left posteroseptal accessory pathway. RF application provoked progressive slowing of the sinus rhythm, disappearance of the preexcitation, and an 8‐second period of asystole followed by atrial fibrillation. The causal mechanism proposed is a strong stimulation of va‐gal afferent pathways linked with sensory endings of the inferoposterior myocardial wall leading to a Bezold‐Jarisch‐like phenomenon.

What risk should justify implantable cardioverter defibrillator therapy

Implantable cardioverter defibrillators (ICDs) were developed to prevent sudden cardiac death in patients with ventricular tachycardia (VT) or ventricular fibrillation (VF). Their safety and efficacy have been proved in multiple retrospective and prospective studies. Many of the published trials were directed at secondary prevention for patients who had already had a sudden cardiac death or a sustained VT. For primary prevention, the information available is limited, as only 2 trials have yet been published. Ongoing trials will probably allow us to broaden the indications for prophylactic ICD implantation. Justification of the risk will have to be evaluated against complexity of the implant, the latter including not only cost but quality of life and morbidity associated with an ICD. However, our efforts still have to be directed to improve risk stratification and to decrease the complexity of the procedure.