Experience with intracardiac recording of sinus node electrograms (SNE) in 27 patients is described. Under fluoroscopic monitoring the poles of a tri- or quadripolar catheter were positioned at the superior vena cava--right atrium junction. For recording, high amplification of 100 microV/cm and low-pass filters of 0.2-70 Hz were used. SNE was verified by simultaneously recording electrograms from two pairs of poles at the same filter setting and the application of carotid sinus massage. SNE was obtained in 17 patients (63%). It was recognized as a smooth, low-frequency upstroke slope before rapid atrial depolarization. Its amplitude range was 30-90 microV. Directly recorded sinoatrial conduction time (SACT) ranged from 55 to 120 ms (mean 88 +/- 20). In 4 patients with sick sinus syndrome SACT varied from 90 to 220 ms. SACTs calculated by the premature stimulation method and measured directly from SNE were in good correlation (r = 0.61, p less than 0.05).

• MeSH
• Child MeSH
• Adult MeSH
• Electrocardiography methods   MeSH
• Coronary Disease physiopathology   MeSH
• Humans MeSH
• Adolescent MeSH
• Heart Valve Diseases physiopathology   MeSH
• Sinoatrial Node physiopathology   MeSH
• Sinoatrial Block physiopathology   MeSH
• Arrhythmias, Cardiac physiopathology   MeSH
• Sick Sinus Syndrome physiopathology   MeSH
• Vena Cava, Superior MeSH
• Check Tag
• Child MeSH
• Adult MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

AIMS: In patients with severe neurally mediated syncope (NMS), radiofrequency catheter ablation (RFA) of ganglionic plexi (GP) has been proposed as a new therapeutic approach. Cardio-inhibitory response during NMS is usually related to the sinoatrial (SA) and less frequently to atrioventricular (AV) node. Differential effect of GP ablation on SA and AV node is poorly understood. METHODS AND RESULTS: We report a case of a 35-year-old female with frequent symptomatic episodes of advanced AV block treated by anatomically guided RFA at empirical sites of GPs. After RFA at the septal portion of the right atrium-superior vena cava junction, heart rate accelerated from 62 to 91 beats/min and PR interval prolonged from 213 to 344 ms. Sustained first-degree AV block allowed to observe directly the effects of subsequent RFA on the AV nodal properties. Subsequent RFA at right- and left-sided aspects of the inter-atrial septum had no further effect on heart rate and PR interval. Ablation at the inferior left GP was critical for restoration of normal AV conduction (final PR interval of 187 ms). No bradycardia episodes were observed by implantable loop recorder during the follow-up of 10 months and the patient was symptomatically improved. CONCLUSION: This is the first clinical case showing the differential effect of GP ablation on SA and AV nodal function, and critical importance of targeting the GP at the postero-inferior left atrium. The successful procedure corroborates clinical utility of ablation treatment instead of pacemaker implantation in selected patients with cardio-inhibitory NMS.

• Keywords
• Atrioventricular block, Autonomic regulations, Catheter ablation, Ganglionic plexi, Neurally mediated syncope,
• MeSH
• Action Potentials MeSH
• Atrioventricular Block diagnosis   physiopathology   surgery   MeSH
• Autonomic Denervation methods   MeSH
• Time Factors MeSH
• Adult MeSH
• Electrophysiologic Techniques, Cardiac MeSH
• Electrocardiography MeSH
• Ganglia, Autonomic physiopathology   surgery   MeSH
• Catheter Ablation * MeSH
• Humans MeSH
• Atrioventricular Node physiopathology   MeSH
• Sinoatrial Node physiopathology   MeSH
• Recurrence MeSH
• Heart Rate MeSH
• Severity of Illness Index MeSH
• Syncope, Vasovagal diagnosis   physiopathology   surgery   MeSH
• Treatment Outcome MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Case Reports MeSH