[The long-term effects of dual-chamber stimulation in 8 patients with hypertrophic obstructive cardiomyopathy and symptoms refractory to medical therapy]. / Effetti a lungo termine della stimolazione bicamerale in otto pazienti portatori di cardiomiopatia ipertrofica ostruttiva con sintomi refrattari a terapia medica.

BACKGROUND: The issue of DDD pacing as a therapeutic option for patients with obstructive hypertrophic cardiomyopathy is still under debate. Moreover, some authors stress the concept of the placebo effect of electrical therapy in this particular setting. METHODS: We retrospectively evaluated 8 symptomatic patients with obstructive hypertrophic cardiomyopathy despite medical therapy, who underwent DDD pacemaker implantation as an adjunctive therapeutic strategy. All patients were evaluated with a two-dimensional/Doppler echocardiogram at baseline, shortly after the beginning of DDD pacing and at follow-up. In 3 patients dobutamine stimulation was necessary to elicit the intraventricular gradient. RESULTS: At follow-up (21 +/- 19 months, range 1-54 months) the peak gradient declined from 86 +/- 27 to 34 +/- 27 mmHg (55.2%). In 4 patients the peak gradient sharply declined after pacemaker implantation with active pacing and remained stable throughout the follow-up. In 2 patients we noted a continuous reduction in the peak gradient during the follow-up, while in 2 patients it returned to baseline values after 1 year and 1 month, respectively, despite an early reduction with DDD pacing. All patients experienced symptomatic amelioration throughout the follow-up. Two patients developed angina at the end of our observation together with an increase in the peak gradient. CONCLUSIONS: We believe that DDD pacing may be considered as a practical therapeutic option for patients with obstructive hypertrophic cardiomyopathy who would otherwise be regarded as candidates for surgery.

[Long-term clinical assessment of single-lead VDD electric stimulation]. / Valutazione clinica a lungo termine dell'elettrostimolazione VDD monocatetere.

BACKGROUND: During the last decade single lead VDD pacing has been progressively affirmed as an electrotherapy of choice in patients with advanced atrioventricular block without alterations of the sinus function. It combines the benefits of P-synchronous ventricular pacing with an easy implant procedure when compared to the conventional DDD approach. The aim of this study was to evaluate the validity of such an approach in a large population of patients, all implanted in a single center. METHODS: From 1987 up to now, 317 patients, all affected by advanced atrioventricular block and without sinus node dysfunction, were implanted in our center with a single lead VDD pacemaker. During follow-up the persistence of a proper atrioventricular synchronization was assessed and evaluated. RESULTS: The mean follow-up was 3.9 +/- 2.7 years/patient (range 6-138 months). The 94.6% of implanted systems maintained the normal VDD pacing function. Permanent reprogramming in VVI mode was necessary in 17 patients (5.36%); in 12 (3.78%) because of chronic atrial fibrillation and in 5 (1.63%) for loss of atrial sensing. The percentage of atrial synchronization was optimal (> 98%) and acceptable (> 95%) in 81% and 19% of patients, respectively. Episodes of paroxysmal atrial fibrillation occurred in 3 patients. Neither inhibition by myopotentials nor occurrence of sinus node disease was observed during follow-up. These results are in accordance with those reported by previous studies, performed on a smaller population or on a multicenter basis, and are comparable with the results reported for conventional DDD pacemaker. CONCLUSIONS: Our results confirm the high reliability of the single lead VDD pacing system concerning the long-term persistence of a proper atrioventricular synchronization. Data showed above enforce our opinion that this pacing approach should be considered the treatment of choice in patients with advanced atrioventricular block and preserved sinus node function.

Acute myocardial infarction shortly after a normal exercise stress test. Case reports.

The authors describe 3 cases of AMI occurring shortly after a negative bicycle ergometer stress test. These cases represent an unfortunate but extremely rare complication of a relatively safe diagnostic procedure. The authors also focus on the pathogenesis of the ischemic event, which may be attributed either to intraplaque hemorrhage or to platelet aggregation, both exercise-induced. The prevalence of AMI in this paper (0.06%) is similar to the data described in literature.

[Cardiovascular autonomic impairment in one case of acute pandysautonomia with recovery (author's transl)]. / Alterazioni del controllo autonomotropo cardiovascolare in un caso di pandisautonomia acuta con remissione clinica.

Pure acute Pandysautonomia (PAP), first described in 1969 by Young, is a rare but well defined clinical entity, in which the isolate involvement of Autonomic Nervous System (ANS) gives rise to a characteristic clinical admixture of symptoms and signs all due to the alteration of parasympathetic and sympathetic control of neurovegetative functions. The most prominent clinical features are: 1) postural hypotension without changes in heart rate leading to orthostatic syncopal or near-syncopal episodes, 2) abnormalities of intestinal tract and urinary bladder motility, leading to constipation alternating with diarrhea and urinary retention, 3) loss of sweating, 4) ocular abnormalities. We report a case of a 17 year old man with PAP, in whom almost complete resolution of clinical symptoms and signs of ANS involvement was observed within 9 months from the onset of illness. In our case, besides an accurate clinical and laboratory follow-up, particular attention was paid to investigate the cardiac responses to autonomic reflex tests and pharmacological interventions (atropine and beta-blocking drugs administration) during the entire course of illness. During the acute phase, complete vagal and almost complete beta-sympathetic "denervation" of the heart leading to disabling postural hypotension, fixed resting tachycardia and total unresponsiveness to Valsalva manoeuvre, were observed. PAP is a rare condition which must be known from cardiologists for a more complete knowledge of the etiology and pathophysiological mechanisms of postural syncopal attacks and must be distinguished from the less favourable progressive autonomic failure of the Shy-Drager syndrome.

Wenckebach second-degree A-V block in top-ranking athletes: an old problem revisited.

The occurrence of Wenckebach second-degree (Mobitz I) A-V block in apparently normal persons still provides a puzzle for the cardiologist, as the benign nature of this event has been recently questioned. This problem becomes more intriguing when Wenckebach A-V block is encountered in asymptomatic top-ranking athletes, because of medico-legal implications. We report 10 cases of highly-trained athletes, including three with mitral valve prolapse (MVP) features, with a spontaneous or induced Wenckebach second-degree A-V block. Previous ECGs of six subjects, dating from a maximum of 6 years to a minimum of 18 months, were available. Deterioration of A-V conduction has never been documented and all six cases have remained asymptomatic for the whole follow-up period. Athletes have been submitted to a protocol study consisting of ECG recording at rest, during, and after vagal and sympathetic reflex maneuvers, drug administration (isoproterenol and atropine), submaximal and maximal exercise. Nine subjects have been considered to have "normal" responses of the A-V node to provocative tests, since conduction disturbances were improved or normalized by reflex sympathetic stimulations and were completely normalized by autonomic drug administration and exercise. One athlete showed "abnormal" responses to tests. In order to give a conclusive prognostic and medico-legal assessment, we advised him to submit to an invasive electrophysiological investigation. Wenckebach second-degree A-V block in athletes may be a more common finding than so far described, especially when a systematic search is made. In our opinion, this event can still be considered a vagally-induced benign feature of athlete's heart, provided that an immediate improvement of A-V conduction is obtained in response to reflex sympathetic maneuvers, and that a complete normalization after sympathomimetic and vagolytic drug administration and physical exercise is observed. The clinical histories of our athletes and the observed complete disappearance of conduction disturbances after detraining, strongly support this opinion. Wenckebach second-degree A-V block in asymptomatic athletes with MVP features probably does not affect the prognosis if similar favorable responses to the aforesaid tests are observed.

T wave abnormalities in top-ranking athletes: effects of isoproterenol, atropine, and physical exercise.

Eight cases of top-ranking athletes with "repolarization disorders" are reported. All subjects were asymptomatic and were otherwise suited for excellent cardiovascular performances. Seven athletes did not show any evidence of heart disease. Seven had MVP (mitral valve prolapse). Umprompted variability of ECG tracings was observed in three cases. Both isoproterenol infusions (IS) and maximal physical effort (EX) normalized T wave (abnormalities in 100% of cases, while atropine (AT) was ineffective despite an increase in heart rate greater than that caused by IS. The authors emphasize the usefulness of combined use of the EX and IS tests in ascertaining the clinical significance of T wave changes in healthy athletes. A "neurogenic" mechanism is proposed by the authors for the pathogenesis of these T wave abnormalities. This hypothesis may explain the umprompted variability of ECG tracings and T wave normalization after maximal physical effort and isoproterenol infusion.