Assessment of the maximum voltage-guided technique for cavotricuspid isthmus ablation during ongoing atrial flutter.

OBJECTIVES: We aimed to test the maximum voltage-guided cavotricuspid isthmus (CTI) ablation technique during ongoing atrial flutter. BACKGROUND: Former pathological and electrophysiological studies clarified that the cavotricuspid isthmus is composed of distinct muscular bundles, which are responsible for the conduction of electrical activation. Based on this observation, a maximum voltage-guided ablation technique (MVGT) was developed. This technique was assessed during pacing from the coronary sinus and was reported to be a feasible method to reach bidirectional isthmus block without the need for a complete anatomic ablation line. METHODS: This was a prospective, randomized single center study. Twenty patients underwent CTI ablation during atrial flutter. In group I (10 pts) CTI ablation was performed with complete anatomical ablation line. In group II (10 pts) ablation was guided by the highest amplitude potentials on the CTI sequentially until bidirectional isthmus block was reached. The following parameters were compared: acute success rate, procedure time, fluoroscopy time, number of radiofrequency (RF) applications and total RF duration. RESULTS: In all patients, atrial flutter terminated during ablation. Bidirectional isthmus block could be achieved in all pts. Procedure time was shorter in group II (107 +/- 40 vs 68 +/- 19 min, p < 0.01). Significantly less fluoroscopy was used in group II (22.6 +/- 10.6 vs 12.1 +/- 3.8 min, p < 0.01). There were less RF applications in group II (27.1 +/- 21.5 vs 5.9 +/- 2.4, p < 0.001). CONCLUSIONS: (1) The major finding of this study is that MVGT is a feasible method even during ongoing atrial flutter. (2) Our data confirm that MVGT is an effective technique for CTI ablation with considerable decrease in procedure and fluoroscopy times.

[Pacemaker syndrome without a pacemaker]. / Pacemaker szindróma pacemaker nélkül.

Circulatory consequences of cardiac arrhythmias are not always evident. Proper interpretation of the clinical symptoms in certain cases requires assessment of the patients' other hemodynamic characteristics. The authors present the case of a patient with left ventricular hypertrophy, who developed severe circulatory failure at the time of artrioventricular dyssynchrony in association with junctional rhythm. Analogy between the circulatory consequences of the junctional rhythm and ventricular pacing was documented by hemodynamic measurements. The patient was subsequently treated by implanting an atrioventricular pacemaker.

Left atrial and left atrial appendage function in paroxysmal atrial fibrillation.

PURPOSE: In patients with paroxysmal atrial fibrillation (PAF) little information is available about left atrial (LA)function, and there is less information about LA appendage (LAA) function, and about their relations. METHODS AND RESULTS: 46 patients were selected for catheter ablation (CA) because of nonvalvular PAF.Transthoracic, tissue Doppler and transoesophageal echocardiography was performed before CA. LA volumes and volume index (LAVI) were calculated. LA function was assessed by LA filling fraction (LAFF), LA emptying fraction (LAEF), systolic fraction of pulmonary venous flow (PVSF) and late diastolic velocities of mitral annulus(Aa,, A5at) LAA function was assessed by peak LAA emptying flow velocity (PLAAEFV). Diastolic dysfunction(DD) was also assessed. Dilated LAVI in 32, LA dysfunction in 20, DD with elevated LV filling pressure in 19 patients was found. Aa,at and Aa,p correlated with LAFF (r:0.53; p<0.001 and r:0.43; p<0.05), LAEF (r:0.51;p<0.001 and r:0.63; p<0.001), PVSF (r:0.49; p<0.001 and r:0.46; p<0.005) and PLAAEFV (r:0.58; p<0.001 and r:0.45; p<0.01). CONCLUSIONS: In PAF patients Aa velocity is useful to assess LA function and correlates positively with other TTE derived LA functional parameters and LAA function by TEE derived PLAAEFV.

Trendelenburg positioning does not prevent a decrease in cardiac output after induction of anaesthesia with propofol in children.

BACKGROUND AND OBJECTIVE: Induction of anaesthesia may cause decreased cardiac output and blood pressure. Head-down tilt is often the first clinical step to treat hypotension. The objective of this randomized single centre study was to determine, with the use of impedance cardiography (ICG), whether Trendelenburg positioning modifies the haemodynamic response to propofol/fentanyl induction of anaesthesia in ASA I children. METHODS: Thirty ASA I children aged between 7 and 16 years scheduled for elective minor orthopaedic surgery were included. After intravenous induction with propofol and fentanyl in the head-down group (HDG, n = 15), 5 min of 20 degrees head-down tilt was applied. In the supine group (SG, n = 15), no change in the supine position was made. Heart rate (HR), mean arterial blood pressure (MABP), end-tidal carbon dioxide (ETCO(2)), stroke volume index (SVI), cardiac index (CI), systemic vascular resistance index (SVRI) and Heather index (HI) were recorded before (B), at 3 (A(3)), 5 (A(5)) and 8 (A(8)) minutes after induction in each group. RESULTS: After induction, a significant decrease in CI, MABP, HR and HI was recorded in both groups. In the study group, significantly lower values of HR (66 vs. 78 beat/min) and higher values of SVI (42.9 vs. 40.6 ml/min/m(2)) were measured at A(3) compared with the control group. After induction, no difference in CI and SVRI was found between the two groups. CONCLUSION: The present study shows that cardiac performance is not improved by Trendelenburg positioning after propofol/fentanyl induction of anaesthesia in children.