A case of familial atrioventricular heart block affected by alteration of the autonomic nervous system.

Familial atrioventricular heart block affected by the autonomic nervous system has rarely been documented. We describe a 35-year-old man who had first-degree atrioventricular heart block with a PR interval of 0.46 s. He had a family history of 2 members with complete heart block and 1 with documented atrial standstill. The man's P-R interval was shortened by exercise and phenylephrine administration. In the electrophysiolgic study, a "split His" with an H-H' of 220 ms was recognized. Such a case of familial atrioventricular heart block with abnormal His-Purkinje conduction affected by the autonomic nervous system is very rare and worthy of description.

Ruptured mitral valve aneurysm in a patient with quadricuspid aortic valve.

Mitral aneurysm is commonly associated with infectious endocarditis of the aortic valve. In rare instances, it is associated with other underlying inflammatory or metabolic disorders. A 62-year-old man with mitral valve insufficiency with moderate aortic valve insufficiency underwent operation. Operative findings were the ruptured aneurysm of the mitral valve in association with the calcified quadricuspid aortic valve. There was no evidence of infection in the mitral valve and the aortic valve. The mitral valve was repaired, the aortic valve replaced, and Cox Maze procedure added. A rare combination of mitral and aortic valve lesions without endocarditis suggested that mechanical stress alone may induce mitral valve aneurysm.

[Effect of radiofrequency catheter ablation on autonomic tone in patients with common atrial flutter: difference depending on the site of ablation].

OBJECTIVES: Radiofrequency catheter ablation (RFCA) of the inferior vena cava-tricuspid annulus isthmus has become an effective procedure for radical treatment of common atrial flutter. This site is close to the right atrial posteroseptal region, so vagal denervation after slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia can also occur after the procedure. To confirm this hypothesis, we tested whether autonomic disturbance can occur after RFCA in 16 patients with common atrial flutter. METHODS: Parameters of the autonomic function were measured using several components of the time domain analyses and power spectra of heart rate variability calculated from Holter recordings and the baroreflex sensitivity. Patients were divided into 2 groups based on the location of the ablated area: the isthmus group (9 patients) with the ablated area of the exact isthmus, and the posteroseptal group (7 patients) with the ablated area slightly shifted toward the right atrial posteroseptal position. All values after RFCA were compared with those before RFCA, and the ratio (after/before) was compared between the groups. The correlation between the ratio and cumulative delivered energy was also studied for each parameter. RESULTS: After RFCA, the heart rate increased, and the SD, rMSSD and pNN50 decreased significantly in the posteroseptal group, whereas no significant changes occurred in the isthmus group. The high frequency of the power spectra decreased after RFCA only in the posteroseptal group, and the ratio was significantly smaller in the posteroseptal group compared to the isthmus group. A significant reverse correlation between the ratio of the high frequency and cumulative energy was observed only in the posteroseptal group. The baroreflex sensitivity tended to be diminished after RFCA only in the posteroseptal group. CONCLUSIONS: Vagal denervation can occur after RFCA of common atrial flutter when the ablation site is shifted toward the right atrial posteroseptal region.

Swallow syncope associated with complete atrioventricular block and vasovagal syncope.

A 21 year old man presented with multiple, recurrent episodes of complete atrioventricular (AV) block associated with swallowing. Electrophysiological study revealed an AV block with swallowing of carbonated beverages and balloon inflation in the lower oesophagus. Evaluation did not demonstrate any underlying oesophageal or cardiac disease, and the AV block was not induced after intravenous atropine administration. The AV block was probably caused by a hypersensitive vagotonic reflex triggered by mechanical receptors in the lower oesophagus, resulting in suppression of the AV node. Head up tilt test revealed an increase in the high frequency spectrum of heart rate variability before the onset of the syncope. These findings suggest that the amplitude of the continual fluctuations in response to a variety of stimuli and derangement from both intrinsic and extrinsic environments was greater in this patient than in normal subjects. Swallow syncope is an unusual but treatable disorder. These reflexes that become exaggerated to the point of causing illness are poorly understood.

Characteristics of intracardiac potentials at successful ablation sites in concealed Wolff-Parkinson-White syndrome.

The authors investigated bipolar electrograms recorded from the catheter tip at the actual successful ablation sites in 22 consecutive patients with concealed Wolff-Parkinson-White syndrome to clarify the characteristics of the potentials indicating the optimal site for catheter ablation. In all patients the retrograde transaortic approach to their left-sided accessory pathways, and a temperature-controlled (60 degrees C) energy delivery, were performed. The authors assumed that a shorter dissociation time (time from energy delivery to ventriculoatrial conduction dissociation) indicated more accurate catheter mapping. A significant negative correlation (r = 0.527, p < 0.05) between the AV ratio (ratio of the amplitudes of the atrial to ventricular potentials) recorded at the ablation catheter tip and the dissociation time was observed. When the AV ratio and the dissociation time were compared among the groups classified according to the corresponding Npeak (the number of positive potential peaks in the electrogram obtained from the ablation catheter tip during right ventricular apical pacing) value, they differed significantly (p < 0.05 and p < 0.01, respectively), ie, a higher AV ratio and a shorter dissociation time related to a multipeak electrogram from the ablation catheter tip. The authors conclude that the atrial insertion site of the accessory pathway, exhibiting a multipeak complex electrogram that may represent nonuniform anisotropic characteristics, is an adequate ablation site.

Clinical usefulness of 123I meta-iodobenzylguanidine imaging in predicting the effectiveness of beta blockers for patients with idiopathic dilated cardiomyopathy before and soon after treatment.

OBJECTIVE: To investigate the value of iodine-123 meta-iodobenzylguanidine (MIBG) myocardial imaging for defining high risk patients with idiopathic dilated cardiomyopathy from among candidates for beta blocker treatment, and for predicting functional improvement of the left ventricle in the early stages of treatment. METHODS: Echocardiographic indices, neurohormonal measurements, and myocardial MIBG distribution were assessed at baseline and after one month and three months of treatment in 27 patients with idiopathic dilated cardiomyopathy. Patients were classified into two groups, based on whether they reached a daily dose of > 20 mg of metoprolol without deterioration of heart failure at three months (group A, n = 20) or not (group B, n = 7). RESULTS: There were no significant differences in the echocardiographic indices or neurohormonal activity at baseline between the two groups, but MIBG uptake was higher, and the washout rate lower, in group A than in group B. After one month, though there were no significant changes in echocardiographic and neurohormonal variables, the heart to mediastinal (H/M) ratio on the delayed image was increased in group A but not in group B. In group A, the degree of increase in the H/M ratio on the delayed image after one month was also correlated with the degree of reduction in plasma concentrations of noradrenaline after three months. CONCLUSIONS: MIBG myocardial imaging may be useful for predicting the outcome of beta blocker treatment for heart failure patients with idiopathic dilated cardiomyopathy.

Use of iodine-123 metaiodobenzylguanidine myocardial imaging to predict the effectiveness of beta-blocker therapy in patients with dilated cardiomyopathy.

It is crucial to predict drug effectiveness in chronic disease, such as dilated cardiomyopathy (DCM), in which the left ventricular (LV) function might be improved by beta-blocker therapy. As the functional improvement effected by beta-blocker therapy takes more than 2 months, we investigated whether iodine-123 metaiodobenzylguanidine (123I-MIBG) imaging could be used to predict drug effectiveness. We studied 13 patients (11 men and two women; mean age, 43+/-13 years) with DCM and seven normal subjects (six men and one woman; mean age, 48+/-16 years). We obtained myocardial single-photon emission tomography (SPET) images 15 min and 4 h after administration of 123I-MIBG (111 MBq). Studies were performed in the patients with DCM before and 1 and 3 months after the administration of metoprolol and in the normal subjects. We calculated the regional 123I-MIBG washout rate (r-WR) in the SPET image, and the global 123I-MIBG washout rate (g-WR) and heart-mediastinum activity ratio (H/M) using the anterior planar image. We classified patients into those showing a >/=5% increase in LV ejection fraction (LVEF) at 3 months compared with LVEF values before the treatment (group I, n=7) and those showing a <5% increase in LVEF (group II, n=6). In group I, the r-WR values at pretreatment and at 1 month and 3 months of treatment, respectively, were 36%+/-19%, 29%+/-14%* and 25%+/-13%* in the anterior segment, 39%+/-17%, 33%+/- 17%** and 28%+/-17%* in the lateral segment, 36%+/- 16%, 31%+/-14%* and 22%+/-12%** in the septal segment and 40%+/-11%, 37%+/-19% and 31%+/-18%* in the inferior segment; the g-WR was 45%+/-11%, 43%+/-10% and 34%+/-9%*, respectively (* P<0.05, ** P<0.01 vs pretreatment). In group II, there were no significant changes in regional or global parameters during the 3-month period. In normal subjects, the r-WR values in each of the anterior, lateral, septal and inferior segments were significantly lower than those in groups I and II. These values were 18%+/-9%, 18%+/-15%, 20%+/-12% and 21%+/-15%, respectively. This study demonstrated that with regional assessment 123I-MIBG SPET imaging can be used to predict the functional improvement of LVEF at 1 month of beta-blocker therapy in patients with DCM.