High impedance low energy pacing leads: long-term results with a very small surface area steroid-eluting lead compared to three conventional electrodes.

We evaluated the handling performance at implant, and the long-term atrial and ventricular electrical performance of a new generation using a very small surface area (1.2 mm2) steroid-eluting electrode (Medtronic CapSure Z). We compared the performance of CapSure Z to that of traditional passive fixation leads, with and without steroid elution. The study was conducted during 2 years of follow-up. We studied 188 patients (105 males and 83 females; mean age 71 +/- 7 years). All of the patients were implanted with a dual chamber pacemaker and the same type of lead in both chambers. Forty-one patients received CapSure Z leads, 25 patients received Target Tip leads (8-mm2 surface area; no steroid elution), 63 patients received CapSure leads (8-mm2 surface area; steroid elution), and 59 patients received CapSure SP leads (5.8-mm2 surface area; steroid elution). The four groups were homogeneous in regards to sex, age, cardiac disease, and reason for implant. At follow-up, the CapSure Z lead showed sensing values comparable to the other leads, with lower pacing thresholds and higher pacing impedance in both chambers. We evaluated the mean current drained from the pacemaker by the different types of leads when using safe, low energy output settings. We found that by using CapSure Z leads, the mean current was significantly lower than that of the other types of leads (0.42 microA for CapSure Z ventricular lead vs 0.85 for CapSure SP, 1.42 for CapSure, and 1.54 for Target Tip). Thus, the use of the CapSure Z lead, combined with low energy output programming, will increase pacemaker longevity compared to the use of traditional leads and standard output programming.

Intrapatient comparison of atrial and ventricular sensing, pacing threshold, and impedance: benefits with steroid-eluting leads.

We compared the atrial and ventricular bio-electrical effects relating to pacing threshold, pacing impedance, and pacing energy in each of 58 patients to determine the importance of pacing impedance in safe low energy stimulations. The study was conducted during 4 years of follow-up. Of the 58 patients in our study, 31 were stimulated in both chambers with steroid-eluting leads (Capsure 4503 and 4003) and 27 with platinum electrode catheters (Target Tip 4511 and 4011). The two groups were homogeneous in sex, age, cardiopathy, and reason for implant. At 6 months, the mean impedance values for the Target Tip were: 358 +/- 72 omega for the atrium and 443 +/- 72 omega for the ventricle (P < 0.00002); after 1 year, atrium = 386 +/- 77 omega, ventricle = 439 +/- 42 omega (P < 0.04); at 2 years, atrium = 409 +/- 86 omega, ventricle = 510 +/- 94 omega (P < 0.0001); at 3 years, atrium = 428 +/- 81 omega, ventricle = 494 +/- 67 omega (P < 0.02); and at 4 years, atrium = 424 +/- 71 omega and ventricle = 501 +/- 69 omega (P < 0.003). The mean impedance value (for the Capsure) was: atrium = 351 +/- 43 omega, ventricle = 431 +/- 81 omega at 6 months (P < 0.03); at 1 year, atrium = 359 +/- 38 omega, ventricle = 446 +/- 83 omega (P < 0.01); at 2 years, atrium = 304 +/- 124 omega, ventricle = 459 +/- 108 omega (P < 0.0003); at 3 years, atrium = 359 +/- 108 omega, ventricle = 461 +/- 89 omega (P < 0.02); and at 4 years, atrium = 419 +/- 133 omega and ventricle = 515 +/- 75 omega (P < 0.01). In view of the chronic threshold, low energy stimulation was used at follow-up. The mean low energy stimulation values programmed for Target Tip were: atrium = 2.5 V/0.35 ms, ventricle = 2.5 V/0.30 ms; for Capsure, atrium = 2.5 V/0.25 ms, ventricle = 2.5 V/0.25 ms. The mean stimulation energy value was 31% higher in the atrium than in the ventricle with Capsure leads, and 39% higher with Target Tip. Pacing impedance was lower in the atrium than in the ventricle with both leads. Energy consumption in the atrium is significantly greater than in the ventricle with both leads, particularly with Target Tip.

[Physiopathology of vasovagal syncope: review of the most endorsed theories and recent findings]. / Fisiopatologia della sincope vasovagale: revisione delle teorie più accreditate e recenti acquisizioni.

Vasovagal syncope is associated with an abnormal reflex and the physiopathological mechanisms of the phenomenon overall are only partially known. Experimental and clinical studies suggest that the main factor which triggers the syncope is the brusque interruption of the alpha-adrenergic tone with marked, sudden peripheral vasodilation. Although documented, vagal hypertony, with consequent bradycardia and asystolia, is only occasional and is almost always a secondary phenomenon. The most commonly suggested cause of vasovagal syncope is a Bezold-Jarish reflex starting from the cardiac receptors in the walls of the ventricle, mediated by the paradoxical activation of afferent vagal fibres. However, recent studies are suggesting that there may be other pathogenetic mechanisms such as the paradoxical activation of the venous-atrial baroceptors and other "extracardiac" vascular receptors. The neuro-endocrine aspect of the vasovagal reaction is very complex and in spite of the many studies carried out on the catecholamine, renal-angiotensive system, arginine-vasopressin, and b-endorphine trends, there are still many points awaiting clarification. The response of the autonomous nervous system linked to age also require further research.

Intrapatient comparison between chronic VVIR and DDD pacing in patients affected by high degree AV block without heart failure.

In patients affected by high degree AV block without preexisting congestive heart failure there is no definite demonstration that DDD pacing gives real clinical advantages in respect to VVIR pacing. We performed an intrapatient, long-term study between the two pacing modes in 14 high degree AV block patients, using the Medtronic Synergyst 7027 dual chamber pacemaker, who could be programmed alternatively in DDD or VVIR mode. After a 4-week run-in period following the pacemaker implant, patients completed a randomized, double-blind, cross-over study to compare the effect of 6-week period VVIR and DDD pacing on symptoms and cardiovascular parameters. A semiquantitative score scale was used to quantify the symptoms of general well-being, palpitations, dizziness, pulsating sensation in the neck or abdomen, shortness of breath at rest and during effort, chest pain, and NYHA classification. The sum of symptom scores was 10.4 +/- 6.7 in VVIR period and 4.6 +/- 2.7 in DDD period (P less than 0.001); five patients (36%) crossed over early from VVIR to DDD because of intolerable symptoms; overall, eight patients preferred the DDD mode and no one preferred the VVIR. Cardiac output at rest (echo-Doppler method) was 4.7 +/- 1.4 versus 5.7 +/- 1.6 liter/min (P less than 0.01), body weight was 65.9 +/- 6.6 versus 64.9 +/- 6.1 kg (P less than 0.02), atrial natriuretic peptide was 236 +/- 112 versus 198 +/- 110 pg/mL (P less than 0.01), respectively, during VVIR and DDD modes. Effort tolerance was similar with the two modes of pacing (68 +/- 15 vs 70 +/- 18 watts/min).(ABSTRACT TRUNCATED AT 250 WORDS)

[Primary angiosarcoma of the right atrium invading the pericardial cavity. Description of a case diagnosed by exploratory thoracotomy and surgically treated with success]. / Angiosarcoma primitivo dell'atrio destro ad espansione in cavità pericardica. Descrizione di un caso diagnosticato con toracotomia esplorativa e trattato chirurgicamente con successo.

The AA. report the case of a 43-year-old woman with an angiosarcoma arising from the right atrial wall and growing into the pericardial cavity. The patient presented with recurrent pericardial effusion initially responsive to medical therapy. The diagnosis was made at the exploratory thoracotomy. Repeated 2D-Echocardiograms did not help for the diagnosis in this particular case. The patient underwent surgical resection of the tumor, chemo- and radiotherapy. After 30 months there are no signs of recurrence or metastasis. In our opinion the frequent recurrence of pericardial effusion in the same patient should be regarded with special suspicion.