[New methods of functional assessment in the catheterization room. Pressure wire, Doppler flow wire and echocontrastomyography]. / Nuove modalità di valutazione funzionale in sala di cateterismo. Pressure wire, Doppler flow wire ed ecocontrastomiografia.

Although coronary angiography has been used for many years in the evaluation of coronary artery disease the limitations of this technique are well known. The functional significance of individual coronary artery stenoses may not be easily determined particularly in patients with intermediate stenoses, lesions with irregular and complex morphology and in subjects with multivessel diffuse disease and/or prior myocardial infarction. In selected patients, the role of abnormalities of vasomotion and function at the microcirculatory level cannot be assessed with lone coronary angiography. The functional evaluation of the results of percutaneous coronary interventions usually requires adjunctive non-invasive testing. New techniques for physiological evaluation of coronary artery disease are now available in the catheterization laboratory. The intracoronary pressure wires and Doppler flow wires may provide for an accurate evaluation of the functional significance of the individual stenosis and of the vasodilatory capacity of the coronary bed. Disease of the coronary microcirculation and vasomotion abnormalities may be recognized. Several studies have indicated that these techniques may be helpful in the clinical decision-making process. The strategy of deferring or performing percutaneous coronary interventions may be guided by on-line functional evaluation of the target stenosis and the result of interventions may be evaluated. In addition, new imaging modalities such as myocardial contrast echocardiography with new sonicated agents for intracoronary use may represent a novel approach to the direct evaluation of regional myocardial perfusion and microvascular integrity. The application of these techniques is safe, useful and cost-effective. Unfortunately, physiologic evaluation of the coronary artery disease by means of these techniques still remains confined to few catheterization laboratories.

High energy transcatheter cardioversion for chronic, poorly tolerated atrial fibrillation.

Between August 1991 and May 1993, 14 patients affected by chronic, poorly tolerated atrial fibrillation (AF) were submitted to high energy transcatheter cardioversion. Mean duration of AF was 27.4 +/- 45.1 months. In nine patients (56%), AF lasted for > 1 year. All patients had underlying heart disease, with a mean LVEF of 45.2% +/- 11.8% and a NYHA Class > or = II. Previously, a mean of 2.9 +/- 1.3 patients failed external electrical cardioversion, with and without antiarrhythmics, have been attempted. Transcatheter conversion was performed by pulling the His-bundle catheter back in the right atrial cavity until no His bundle activity was recorded on distal poles, and then delivering the shock between a proximal electrode (cathode) and a back plate (anode). In all patients, transcatheter conversion restored sinus rhythm. Transient complete atrioventricular (AV) block was observed in four patients (28%), and treated by prophylactic temporary pacing. At 1 year, seven patients (50%) were still in sinus rhythm. In this series, only younger age could be related to AF recurrence (46.1 +/- 10.8 vs 63.4 +/- 6.8 years, P < or = 0.004), even if prophylaxis with amiodarone showed a positive trend versus sinus rhythm maintenance (71% vs 14%, P = NS). In conclusion, high energy transcatheter cardioversion is a safe and effective method of restoring sinus rhythm in patients with chronic, poorly tolerated AF. In these patients, high energy transcatheter cardioversion could be considered as an alternative to AV node ablation techniques, avoiding pacemaker implant and embolic risk. Larger studies are needed to determine better patient selection and delineate drug strategy after the procedure.

[Incessant ectopic atrial tachycardia in pregnancy: radiofrequency catheter ablation in immediate postpartum with disappearance of tachycardia-related dilated cardiomyopathy]. / Tachicardia atriale ectopica incessante in corso di gravidanza: ablazione transcatetere mediante radiofrequenza nell'immediato post-partum con risoluzione del relativo quadro di cardiomiopatia dilatativa.

A 29-year-old woman presented with incessant atrial tachycardia and tachycardia-related cardiomyopathy during the last weeks of pregnancy. At 40 weeks of gestation a healthy infant was delivered by Cesarean section. Various medical treatments and two attempts of electrical cardioversion were ineffective in restoring sinus rhythm. Electrophysiologic study with endocardial activation mapping confirmed the diagnosis and thereafter radiofrequency transcatheter ablation of the ectopic focus was successfully carried out and sinus rhythm was restored. Serial 24-h Holter monitoring at 1, 3, and 6 months showed the persistence of sinus rhythm. Echocardiographic examinations demonstrated a very rapid recovery of both left ventricular diameters and ejection fraction to normal limits within two weeks after ablation. In this case-report the potential role of pregnancy and recent advances in the understanding and treatment of ectopic atrial tachycardia are summarized. Although endocardial mapping is difficult, radiofrequency catheter ablation appears to be the elective technique for the treatment of this particular arrhythmia, often refractory to antiarrhythmic drugs. Moreover, this case highlights that tachycardia-related cardiomyopathy should be seriously considered in any patient with apparently end-stage dilated cardiomyopathy and persistent tachycardia.

Hemodialysis-associated cardiac arrhythmias: a lower risk with bicarbonate?

The role of hemodialysis (HD) as an arrhythmogenic event has recently been emphasized. We studied 18 patients by Holter monitoring, comparing the arrhythmogenic effect of acetate dialysis (AHD) and bicarbonate dialysis (BHD). The frequency of ventricular arrhythmias was 93 +/- 66/h in AHD and 32 +/- 26/h in BHD (p less than 0.005). According to the classification of Lown and Graboys, classes III and IV were more often to be found in AHD than in BHD and no patient on BHD was in class IVB and class V. Five patients affected with ischemic heart disease had more frequent and dangerous ventricular arrhythmias than the others; a significant difference between buffers was recorded in all cases but 1. Intradialytic changes in body weight, hematocrit, osmolarity, ionized calcium and potassium during AHD and BHD were similar. The two methods only differed in the quickness and degree of correction of acidosis, and this was related to a significant difference in intraerythrocytic potassium at the end of the session. The quicker and more regular correction of acidosis with BHD and the consequent difference in ionic flows between the intra- and extracellular spaces, as demonstrated by changes in intraerythrocytic potassium at the end of the session, could account for the seemingly less arrhythmogenic effect of BHD.