Implantable Cardioverter‐Defibrillator in Patients With Hypertrophic Cardiomyopathy: Efficacy and Complications of the Therapy in Long‐Term Follow‐up

ICD in Hypertrophic Cardiomyopathy Patients. Introduction: Although implantable cardioverter‐defibrillators (ICDs) are used in sudden cardiac death (SCD) prevention in high‐risk patients with hypertrophic cardiomyopathy (HCM), long‐term results as well as precise risk stratification are discussed in a limited number of reports. The aim of the study was to assess the incidence of ICD intervention in HCM patients with relation to clinical risk profile. Methods and Results: We studied 104 consecutive patients with HCM implanted in a single center. The mean age of study population was 35.6 (SD, 16.2) years with the average follow‐up of 4.6 (SD, 2.6) years. ICD was implanted for secondary (n = 26) and primary (n = 78) prevention of SCD. In the secondary prevention group, 14 patients (53.8%) experienced at least 1 appropriate device intervention (7.9%/year). In the primary prevention (PP) group appropriate ICD discharges occurred in 13 patients (16.7%) and intervention rate was 4.0%/year. Nonsustained VT was the only predictive risk factor (RF) for an appropriate ICD intervention in the PP (positive predictive value 22%, negative predictive value 96%). No significant difference was observed in the incidence of appropriate ICD discharges between PP patients with 1, 2, or more RF. Complications of the treatment included: inappropriate shocks (33.7%), lead dysfunction (12.5%), and infections: 4.8% of patients. Four patients died during follow‐up. Conclusion: ICD therapy is effective in SCD prevention in patients with HCM, although the complication rate is significant. Nonsustained ventricular tachycardia seems to be the most predictive RF for appropriate device discharges. Number of RF did not impact the incidence of appropriate ICD interventions. (J Cardiovasc Electrophysiol, Vol. 21, pp. 883‐889, August 2010)     

Atrial Electromechanical Sequence and Contraction Synchrony during Single- and Multisite Atrial Pacing in Patients with Brady-Tachycardia Syndrome

Objectives: Investigation of which atrial pacing modality provides atrial synchrony and the most physiological atrial contraction pattern in patients with brady-tachycardia syndrome.
Methods: Fifteen healthy subjects and 57 patients with sinus node dysfunction, atrial fibrillation recurrences, and prolonged P-wave on the electrocardiogram treated with multisite atrial (MSA) pacing were studied. One atrial lead was implanted in the coronary sinus (CS) ostium area, the other at the right atrial appendage (RAA): RAA+CS group (28 patients), or Bachmann's bundle (BB) region: BB+CS group (29). Sinus rhythm (SR) and CS, RAA, BB, RAA+CS, and BB+CS pacing modalities were evaluated. Electromechanical delay (EMD) in atrial walls was assessed by tissue Doppler echocardiography. Interatrial (ΔinterA), intra-right (ΔRA), and intra-left (ΔLA) atrial dyssynchrony were calculated.
Results: During SR, in the study group versus controls, important ΔinterA: 55 ± 23 versus 22 ± 11 ms (P < 0.01) and ΔLA: 47 ± 21 versus 21 ± 6 ms (P < 0.001) were present. Single-site BB and both MSA pacing modes restored ΔinterA and ΔLA (ΔinterA: 24 ± 16, 20 ± 13 and 14 ± 9 ms, ΔLA: 28 ± 18, 28 ± 13 and 20 ± 10 ms during BB, RAA+CS and BB+CS pacing, respectively). CS pacing prolonged lateral RA EMD, while RAA pacing LA walls EMD, which resulted in ΔinterA persistence. CS pacing induced ΔRA (50 ± 23 vs 16 ± 8 ms, P < 0.0001 vs controls). Atrial contraction sequence during BB pacing resembled that observed in controls.
Conclusions: (1) Single-site BB and both MSA pacing modes restored atrial synchrony. (2) Single-site RAA and CS ostium pacing retained interatrial dyssynchrony; moreover, CS pacing created RA dyssynchrony. (3) Single-site BB pacing provided physiological atrial contraction sequence.     

New N-terminal modified proctolin analogues

Five proctolin analogues modified in position 1 of the peptide chain by Cit (I), Lys (II), His (III), Phe(p-NH₂) (IV) and γ-Abu (V) were synthesized by conventional liquid phase method. Biological activity of the obtained peptides was investigated by the cardioexcitatory test on two insect species, cockroach, Periplaneta americana L. and yellow mealworm, Tenebrio molitor L.     

CYTOTOXIC FACTORS IN INHIBITION OF LYMPHOCYTE TRANSFORMATION IN LYMPHOMATA

SUMMARY.— Four patients with pemphigoid have been followed clinically and serologically for a sufficient period to indicate that pemphigoid antibody titre does not necessarily parallel the clinical activity of the disease. In contrast, for pemphigus, there does seem to be such a correlation.     

Peptides related to the active fragment of “proline rich polypeptide”, an immunoregulatory protein of the ovine colostrums

The preferred solution conformation of the PRP-hexapeptide (Tyr-Val-Pro-Leu-Phe-Pro) and of some of its structural analogues was investigated by NMR- spectroscopy, spectrofluorimetry and computer simulation technic. It was found that the preferred conformation is characterized by cis′-conformation of Pro³ and the γ-turn on the Leu⁴-residue: for Val² and Phe⁵ a β-structure seems to be privileged. In such a conformation Val² and Leu⁴ residues occupy exactly the same positions in space as residues i and i+ 3 in an α-helix. It suggests that the PRP-hexapeptide can interact with receptor protein inducing or stabilizing its helical conformation by “knobs into holes” packing.     

New Insight into Repolarization Abnormalities in Patients with Congenital Long QT Syndrome: the Increased Transmural Dispersion of Repoiarization

There is evidence from experimental studies that the time interval from the peak to the end of T-wave reflects the transmural dispersion in repolarization (electrical gradient) between myocardial "layers" (epicardial, M-cells, endocardial). Since Congenital Long QT Syndrome (LQTS) is considered to be classical disease or repolarisation abnormalities, we performed the present study to assess the transmtiral dispersion of repolarization in LQTS patients. The study group consisted of 17 patients: 7 LQTS pts and 10 pts from the control group. In each patient the 24-hour ECG recording was performed on magnetic tape. The interval from the peak to the end of the T-wave (TpTo) was automatically measured by Holter system during every hour as a measure of transmural dispersion of repolarisation. Thereafter the mean TpTo from 24-hours was calculated. In addition the spatial QT dispersion was measured from 12 lead ECG and 3 channel Holter tape as a difference between the shortest and the longest QT interval between leads. The values were compared between groups using the Anova test.
TpTo was 79,6±9,6 ms (72–92 ms) in LQTS group and 62,4±7,5 ms (51–70) in the control group (p< 0.001). In LQTS group TpTo was significantly longer at night hours 72,5±2 when compared to day hours 87,4±8 (p<0.01). The spatial QT dispersion was significantly higher in LQTS patients when compared to control, both in 12-lead standard and Holter ECG.
Congenital long QT syndrome is associated with increase in both transmural and spatial dispersion of repolarization. The extent of prolongation of the terminal portion of QT in patients with congenital long QT syndrome is greater at night sleep hours compared to daily activity.