Atypical atrioventricular nodal reentry tachycardia with eccentric retrograde left-sided activation of coronary sinus.

BACKGROUND: Recent anatomical and electrophysiological studies have demonstrated that in the human atrioventricular node there are two main extensions, the rightward and leftward posterior nodal extension (LPNE). The occurrence of eccentric retrograde atrial activation has been demonstrated in several previous reports to be from 6 to 8% in patients with AVNRT. OBJECTIVES: The study was performed to confirm that standard right atrium ablation is effective and successful for atrioventricular node reentry tachycardia (AVNRT) with eccentric retrograde left-sided activation, masquerading as a tachycardia which looks like a tachycardia, using the left accessory pathway. METHODS AND RESULTS: During a 7 years period (from 2002 to 2008), 865 consecutive patients underwent electrophysiological study. In the group with atrioventricular node reentry tachycardia (AVNRT) there were 178 patients. In the group with typical fast-slow AVNRT (162 pts) there was concentric retrograde activation of both the atria. The 16 patients had atypical AVNRT (10 pts with slow-slow AVNRT and 6 pts with LPNE). The ablation was performed, in all patients in the Koch's triangle on the slow pathway of the atrioventricular node. The successful rate of ablation was 99.4% (177/178 pts). The incidence of AVNRT with eccentric retrograde activation was 3.4%. In the follow-up period (16±12 months), there was no recurrence of AVNRT in the group with LPNE. CONCLUSIONS: This study demonstrated the different electrophysiologic characteristics between the AVNRT patients with eccentric and concentric retrograde atrial activation. Standard ablation, but a little bit higher in the Koch's triangle, closer to the fast pathway, in the right atrium is effective and successful for AVNRT with retrograde left eccentric conduction in the coronary sinus.

Breast cancer risk assessments to barrier contraception exposure. A new approach.

(Full text is available at http://www.manu.edu.mk/prilozi). The risk prediction models for breast cancer remain unsatisfactory. The existing models of breast cancer risk assessment have failed to consider (calculate) the exposure to condom use, defined as the major risk factor of breast cancer. All the models, including the NCI-Gail model, are based on the so-called "known" breast cancer risk factors, such as, menarche, age at first birth, parity, OC pills, diet, physical activity, age at menopause, number of breast biopsies, family history, ethnicity (race), age and other. The commonest predictions of the models has been that "All women are at risk of breast cancer," which is deemed as a patently incorrect assessment. The risk assessments have served for identification and recruitment of women at "elevated risk" of breast cancer both for therapeutic randomized clinical trials (RCTs), and for implementing a possible clinical policy of "prophylactic" mastectomy and other prior surgical interventions. However, the models have raised questions lately about their adequacy and practical usefulness, because of the use of "weak" and inadequate risk factors. This study presents the results of a new approach and alternative model and results to the risk assessment of breast cancer, by calculating the exposure to barrier contraceptive practice (condom use and withdrawal practice) along with the factors of parity, age and other (non-barrier) birth-control methods, within a 5-year time period and the life span 20-54 years of age, by employing the Bayes' Probability Theorem. Key words: Breast cancer, Risk Assessment, New Approach, Bayes' Theorem, Parity, Condom Risk Factor, Primary prevention.

Cardiac memory (t-wave memory) after ablation of posteroseptal accessory pathway.

BACKGROUND: Cardiac memory is a phenomenon characterized by transient T-wave abnormalities occurring during normal sinus rhythm, after a period of altered ventricular depolarization, where the T-wave vector has the same direction as the vector of the previously altered QRS complex (T-wave inversion). It is a form of electrical remodelling of the ventricular, where the T-wave follows ("remembers") a previously altered QRS vector. METHODS AND RESULTS: Over a 5-year period (2002-2006), 525 consecutive patients underwent electrophysiological study. One hundred and one patients underwent ablation of the atrioventricular reentry tachycardia (AVRT) with an accessory pathway (AP). Forty-two of them were without delta wave on the electrocardiogram (concealed accessory pathway), and 58 patients had an open form of accessory pathways, with delta wave on EKG (Wolff-Parkinson-White syndrome) and only one patient had an accessory pathway between the right atrium and right bundle branch (Mahaim form). According to the location of the accessory pathway, 17 patients (29.3 %) had an accessory pathway in the right posteroseptal region. There was the highest percentage of the appearance of inversion of the T-wave in patients with this position of accessory pathway. T-wave changes were followed in the frontal plane (leads II, III, and aVF). Electrocardiogram (ECG) signs of cardiac memory were present in 16 of 17 (94.1 %) patients within one day after the ablation. The post-ablation T-wave vector had the same direction as the vector of the pre-excited QRS complex (and delta wave) creating inferior T-wave inversions. There was no correlation between the number or duration of energy applications and the extent of cardiac memory post ablation. A majority (90% of cases) of ECGs recorded 3 months after the procedure showed complete or almost complete normalization. None of the patients with T-wave inversion after ablation had a recurrence of preexcitation or tachycardia during the follow-up period of 12 +/- 4 months. CONCLUSIONS: T-wave inversion in leads II, III and aVF with the disappearance of the delta wave after ablation of the accessory pathway in patients with Wolff-Parkinson-White syndrome (accessory pathway in the right posteroseptal region of the heart), is the most powerful marker of successful ablation.

Dimensions of the triangle of Koch.

Dimensions of the triangle of Koch varied among the patients. The aim of this study was to present the dimensions of the triangle, and to compare the data obtained directly by post mortal measurement, using two different methods, and indirectly using mathematic formulas. The examination was performed in two independent groups consisting of 50 specimens each. Results showed that the mean value of area of the triangle of Koch obtained by the first type of post mortal measurement was significantly different from the mean value obtained using mathematic formulas (261.65 +/- 52.30 mm2 vs 116.74 +/- 13.20 mm2; p=0.00; p<0.05). But the mean value of the second type of the measurement was very similar to the mathematically obtained data (126.33 +/- 23.71 mm2 vs 116.74 +/- 13.20 mm2; p=0.278; p>0.05) (Fig. 1, Ref. 10).

Radiofrequency current catheter ablation of accessory atrioventricular pathways.

BACKGROUND: The purpose of this study was to evaluate the safety and efficacy of a radiofrequency catheter ablation in the patients with the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardia involving a concealed accessory atrio ventricular connection. METHODS AND RESULTS: During a 45 month period (1st January 2002 until 30th September 2005) 373 consecutive patients underwent electrophysiological study in our electrophysiological lab at the Institute for Heart Diseases. Of all the patients 171 (45.8%) were ablated for junction depend tachycardia. Ninety-five patients had undergone ablation of atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentry tachycardia (AVRT) with accessory pathway (AP) 76 patients. Ablation of the atrioventricular node (AVN) was performed in 59 patients, because of uncontrolled atrial fibrillation with implantation of pacemakers. Ablation was successful in 206 patients (89.3%), partial successful was achieved in 21 patient (9.4%), and no successful only in 3 patients (1.3%). Ablation successful outcome rate was 98.7% (without clinical supraventricular arrhythmia in the follow up period until September 2005). There was a need for performing a re-do ablation in 11 patients (4.8%). A complication occurred in 8 patients, 4.9% (only one major complication, complete atrioventricular block with narrow QRS complex in the AVNRT group). In the group with accessory pathways (atrio ventricular reentry tachycardia (AVRT), there were 76 patients, 28 without delta way on the electrocardiogram (concealed accessory pathways), 47 patients were with open form of accessory pathways, with delta way on EKG (Wolff-Parkinson-White syndrome) and only in one patient with accessory pathway between right atrio and right bundle branch (Mahaim form of concealed accessory pathway). In two patients with AVRT, another circle movement tachycardia was found after the ablation of the accessory pathways, bystander arrhythmia of AVNRT: CONCLUSIONS: The success and safety of catheter accessory pathway ablation is so great that we recommend this nonpharmacological approach as an initial option to any patient with AVRT who has recurrent symptomatic arrhythmias.

Variations of autonomic tone preceding onset of atrial fibrillation after coronary artery bypass grafting.

Assessment of autonomic tone preceding the onset of atrial fibrillation (AF) after coronary artery bypass grafting (CABG) with heart rate variability was examined in 64 patients scheduled for elective CABG (days 2 to 5). Ninety-six-hour Holter tapes were analyzed in each patient and all events labeled by an experienced technician. The hour preceding AF was divided into 4 quarters (heart rate variability calculated per quarter) and compared with similar time episodes from the group without AF. Twenty-six of 64 patients (40%) had a total of 35 episodes. Only increased age (68+/-5 vs 62+/-9 years) and lower ejection fraction (66+/-16% vs 73+/-8%) were associated with an increased risk for AF. Before onset, a greater number of atrial premature complexes was observed. The standard deviation of all RR intervals (SDNN) showed an increase in the group with AF in the last 15 minutes (significant vs controls and within the AF group). The low-frequency/high-frequency ratio was significantly lower in patients in the first 30 minutes, followed by an increase mainly because the high-frequency spectrum became less important. Thus, initiation of postoperative AF is influenced by autonomic tone variations. A shift in the autonomic balance with a loss of vagal tone and a moderate increase in sympathetic tone are observed before the onset of AF compared with those in controls.

Low-energy intracardiac shocks during atrial fibrillation: effects on cardiac rhythm.

The effect on ventricular rate of intracardiac shocks for atrial fibrillation was studied in 13 patients receiving 95 shocks. Shocks were synchronized to the R wave and were delivered after R-R intervals > 500 msec, with increasing strength (20 to 400 V). In 10 patients, conversion to sinus rhythm was achieved in this way. Noneffective shocks increased the mean first postshock R-R interval (compared with 20 V as baseline), for shocks > or = 140 V. The R-R prolongation correlated with the shock level (r = 0.936, p < 0.01). Subsequent R-R intervals were comparable to baseline. A similar trend toward longer first postshock intervals was observed for effective shocks. However, the maximal first R-R interval after noneffective shocks had no relation to the voltage. The number of pauses > 1500 msec tended to increase with voltage (noneffective shocks). Pauses > 2500 msec were exceptional (4 of 85 noneffective shocks). No symptomatic bradycardia occurred. In subsequent intervals (cycles 2 through 10) no pauses > 2500 msec were noted. It is concluded that atrial defibrillation attempts between the right atrium and coronary sinus prolong R-R intervals, in relation to administered energy, but without the need for backup pacing.