Dual-chamber pacing in the treatment of neurally mediated tilt-positive cardioinhibitory syncope : pacemaker versus no therapy: a multicenter randomized study. The Vasovagal Syncope International Study (VASIS) Investigators.

BACKGROUND-This study was performed to compare implantation of a DDI pacemaker with rate hysteresis with no implant in respect to syncopal recurrences in patients with severe cardioinhibitory tilt-positive neurally mediated syncope. METHODS AND RESULTS-Forty-two patients from 18 European centers were randomized to receive a DDI pacemaker programmed to 80 bpm with hysteresis of 45 bpm (19 patients) or no pacemaker (23 patients). Inclusion criteria were >/=3 syncopes over the last 2 years and a positive cardioinhibitory (Vasovagal Syncope International Study types 2A and 2B) response to tilt testing. The median number of previous syncopal episodes was 6; asystolic response to tilt testing was present in 36 patients (86%) (mean asystole, 13.9+/-10.2 seconds). All patients were followed up for a minimum of 1.0 years and a maximum of 6.7 years (mean, 3.7+/-2.2). One patient (5%) in the pacemaker arm experienced recurrence of syncope compared with 14 patients (61%) in the no-pacemaker arm (P=0.0006). In the no-pacemaker arm, the median time to first syncopal recurrence was 5 months, with a rate of 0.44 per year. On repeated tilt testing performed within 15 days after enrollment, positive responses were observed in 59% of patients with pacemakers and in 61% of patients without pacemakers (P=NS). CONCLUSIONS-In a limited, select group of patients with tilt-positive cardioinhibitory syncope, DDI pacing with hysteresis reduced the likelihood of syncope. The benefit of the therapy was maintained over the long term. Even in untreated patients, the syncopal recurrence burden was low. A negative result of tilt testing was not a useful means to evaluate therapy efficacy.

Role of autonomic reflexes in syncope associated with paroxysmal atrial fibrillation.

OBJECTIVES: The purpose of this study was to evaluate the role of autonomic reflexes in the genesis of syncope associated with the onset of paroxysmal atrial fibrillation. BACKGROUND: Syncope associated with paroxysmal atrial fibrillation has been interpreted as an ominous finding predictive of rapid ventricular rates. However, various mechanisms may be involved when heart rate is not particularly high. METHODS: Forty patients (age 60 +/- 14 years, 20 men, 20 women) with syncope and atrial fibrillation were compared with atrial fibrillation without syncope. Carotid sinus massage and head-up tilt testing (at 60 degrees for 60 min at baseline and during isoproterenol infusion) were performed during sinus rhythm. A positive response was defined as the induction of syncope. Atrial fibrillation was also induced on a tilt table at 60 degrees by means of short bursts of atrial pacing. RESULTS: Results of carotid sinus massage were positive in 15 (37%) of 40 patients but in no control subjects (p = 0.002). Head-up tilt test findings were positive in 25 (66%) of 38 patients and in 2 (12%) of 16 control subjects (p = 0.0004). The induction of atrial fibrillation in the upright position elicited syncope in 16 (42%) of 38 patients but in none of 16 control subjects (p = 0.001). At the beginning of atrial fibrillation, systolic blood pressure was lower in patients than in control subjects (88 +/- 32 vs. 127 +/- 32 mm Hg), whereas mean heart rate was similar (142 +/- 35 vs. 134 +/- 25 beats/min). The correlation between heart rate and systolic blood pressure was weak (r = 0.35), and in five patients syncope occurred at a heart rate < or = 130 beats/min. At the time of syncope, heart rate decreased (-12 +/- 21 beats/min) in patients with induced syncope, whereas it remained unchanged in patients without induced syncope (+1 +/- 17 beats/min, p = 0.04) or slightly increased in control subjects (+9 +/- 21 beats/min, p = 0.009). CONCLUSIONS: Patients with syncope associated with paroxysmal atrial fibrillation are predisposed to an abnormal neural response during both sinus rhythm and arrhythmia. In some patients the onset of atrial fibrillation triggers vasovagal syncope.

Diagnostic value of history in patients with syncope with or without heart disease.

OBJECTIVES: We sought to establish what historical findings are predictive of the cause of syncope. BACKGROUND: The clinical features of the various types of syncope have not been systematically investigated. METHODS: Three hundred forty-one patients with syncope were prospectively evaluated. Each patient was interviewed using a standard questionnaire. A cause of syncope was assigned using standardized diagnostic criteria. RESULTS: A cardiac cause of syncope was established in 23% of the patients, a neurally mediated cause in 58% and a neurologic or psychiatric cause in 1%, and in the remaining 18%, the cause of syncope remained unexplained. In a preliminary analysis including age, gender and the presence of suspected or certain heart disease after the initial evaluation, only heart disease was an independent predictor of a cardiac cause of syncope (odds ratio 16, p = 0.00001), with a sensitivity of 95% and a specificity of 45%. In contrast, the absence of heart disease allowed us to exclude a cardiac cause of syncope in 97% of the patients. In patients with certain or suspected heart disease, the most specific predictors of a cardiac cause were syncope in the supine position or during effort, blurred vision and convulsive syncope. Significant and specific predictors of a neurally mediated cause were time between the first and last syncopal episode >4 years, abdominal discomfort before the loss of consciousness and nausea and diaphoresis during the recovery phase. In the patients without heart disease, palpitation was the only significant predictor of a cardiac cause. CONCLUSIONS: The presence of suspected or certain heart disease after the initial evaluation is a strong predictor of a cardiac cause of syncope. A few historical findings are useful to predict cardiac and neurally mediated syncope in patients with and without heart disease.

Implantable cardioverter-defibrillator (ICD) indications in 1996: have they changed?

The recent progress in the technology of the implantable cardioverter-defibrillator (ICD) and the excellent clinical results achieved with ICD treatment in the prevention of sudden death have facilitated the wide-spread acceptance and diffusion of this therapeutic modality. However, ICD implantation is a costly therapy and its use is still associated with some important unresolved issues. In particular, owing to the absence of randomized controlled clinical trials, it is not yet known whether ICD really reduces overall mortality. Thus, at the present time, it appears logical to exercise restraint in expanding the use of ICDs as first-choice therapy in patients with life-threatening ventricular arrhythmias. ICD treatment should be restricted to those well-defined categories of high-risk patients who are most likely to benefit from device implantation in terms of life prolongation. Basically, this means patients with hemodynamically poorly tolerated ventricular tachycardia or ventricular fibrillation that are not inducible at electrophysiologic study and those who do not respond to, or do not tolerate, drug therapy with amiodarone, sotalol, or beta blockers. Patients with idiopathic ventricular fibrillation also seem to be suitable candidates for ICD implantation. Other indications for ICD therapy are, as yet, more controversial and should be carefully evaluated on a case-by-case basis.

Comparison of diagnostic accuracy of sublingual nitroglycerin test and low-dose isoproterenol test in patients with unexplained syncope.

Despite the widespread use of head-up tilt testing as a means for diagnosing vasovagal syncope, standardization of test methodology remains a controversial issue. The aim of this study was to compare the diagnostic value of head-up tilt testing potentiated with sublingual nitroglycerin with that of head-up tilt testing potentiated with low-dose isoproterenol. For this purpose, 71 patients with unexplained syncope (mean age 43 years) and 30 asymptomatic controls were studied. All underwent the sublingual nitroglycerin and low-dose isoproterenol tests on separate days in a randomized fashion. The protocol of the 2 tests was similar and consisted of 2 phases. Initially, subjects were tilted at 60 degrees for 20 minutes without medication; then, if syncope did not occur, patients and controls received sublingual nitroglycerin (300 microg) or low-dose intravenous isoproterenol (mean infusion rate 1.3 +/- 0.5 microg/min) and continued to be tilted at 60 degrees for a further 20 minutes. During the sublingual nitroglycerin test, a positive response (syncope associated with sudden hypotension and bradycardia) occurred in 35 patients (49%), a negative response in 36 (51%), and drug intolerance in none (0%). During the low-dose isoproterenol test, these percentages were 41%, 59%, and 6%, respectively. A concordant response was observed in 53 cases (75%). Among controls, 3 subjects (10%) had a positive response to the sublingual nitroglycerin test and 4 (13%) to the low-dose isoproterenol test. It is concluded that sublingual nitroglycerin and low-dose isoproterenol are equivalent tests for evaluating patients with unexplained syncope. The sublingual nitroglycerin test, however, is simpler, better tolerated, and safer than the low-dose isoproterenol test and, thus, more suitable for routine clinical use.

Reproducibility of head-up tilt testing potentiated with sublingual nitroglycerin in patients with unexplained syncope.

Head-up tilt testing (HUTT) potentiated with sublingual nitroglycerin has gained acceptance as means of diagnosing neurally mediated syncope. To evaluate the reproducibility of HUTT potentiated with sublingual nitroglycerin, 48 patients with unexplained syncope prospectively underwent 2 consecutive tests 1 to 28 days apart. The initial test ended in syncope in 34 patients (71%). In 9 patients (19%) the test was positive during the drug-free phase, whereas 25 patients (52%) had syncope after nitroglycerin administration. Of these 34 patients with an initial positive test result, 27 (79%) had a reproducible outcome on repeat testing. Of 12 patients (25%) with an initial negative test result, 10 (83%) had a reproducible outcome on repeat testing. Of 2 patients (4%) with a first test ending in exaggerated response, both had a negative repeat test response. The overall reproducibility of sublingual nitroglycerin tilt-table testing was 77%. In a group of 23 patients with both positive tests, 19 (83%) had the same response modality (2 vasodepressor, 4 cardioinhibitory, 13 mixed response). In the same group of patients, individual trough heart rates correlated well with each other between tests. Finally, in the 27 patients with both positive tests, intrapatient time of onset of symptoms did not significantly correlate between tests. Thus, in patients with syncope of unknown origin, HUTT potentiated with sublingual nitroglycerin provides an adequate reproducibility when repeated on different days.

Usefulness of head-up tilt test in evaluating patients with syncope of unknown origin and negative electrophysiologic study.

The vasovagal nature of syncope, which remained unexplained despite full clinical and electrophysiologic investigation, was evaluated by means of 60 degrees head-up tilt test for 60 minutes. Thirty patients (17 men and 13 women, mean age 65 years, 19 with and 11 without organic heart disease) with 1 to 28 (mean 5) episodes of syncope of unknown origin were studied. Head-up tilt test was considered positive if syncope developed in association with hypotension, bradycardia, or both. During baseline head-up tilt 15 patients (50%) had a positive response. Ten patients had a vasodepressor response (marked hypotension without marked bradycardia) and 5 had a mixed response (marked hypotension with marked bradycardia). None of 8 control subjects became symptomatic during the test. Baseline head-up tilt test was positively reproducible in 10 of 14 patients (71%). Nine of these 10 patients underwent serial head-up tilt tests after drug administration to determine the pathogenesis of vasovagal syncope. Atropine prevented tilt-induced syncope in 3 of 8 patients (37.5%), propranolol in 2 of 8 (25%) and etilephrine in 7 of 7 (100%). Seven patients received long-term drug treatment with drugs selected on the basis of acute drug testing. One responder to atropine received transdermal scopolamine and 6 received etilephrine. None of these 7 patients had syncopal recurrences or death during a mean follow-up of 12 months. Head-up tilt is a very sensitive and highly specific test to unmask susceptibility to vasovagal reaction in patients with syncope of unknown origin. Withdrawal of alpha-sympathetic stimulation is a principal mechanism responsible for vasodilation and syncope during head-up tilt.(ABSTRACT TRUNCATED AT 250 WORDS)

Value of head-up tilt testing potentiated with sublingual nitroglycerin to assess the origin of unexplained syncope.

This study was undertaken to assess the value of sublingual nitroglycerin administration during upright tilt as a simple practical test for the diagnosis of vasovagal syncope. To this purpose, 235 patients with syncope of unknown origin and no evidence of organic heart disease (110 men, mean age 52 +/- 20 years) and 35 asymptomatic control subjects underwent head-up tilt testing with nitroglycerin challenge. Patients and subjects were tilted at 60 degrees for 45 + 20 minutes; the initial 45 minutes were without medication and the final 20 minutes after 300 micrograms of sublingual nitroglycerin. During the drug-free phase of the test, 59 patients (25%) and no controls had a positive response. After drug administration, a positive response (syncope in association with sudden hypotension and bradycardia) occurred in 60 patients (26%) and in 2 controls (6%), whereas an exaggerated or false-positive response (minor or different symptoms in association with slowly increasing hypotension alone) was observed in 33 patients (14%) and in 5 controls (14%). We conclude that the sublingual nitroglycerin head-up tilt test is a useful tool to unmask the vasovagal origin of unexplained syncope in patients without organic heart disease. The addition of nitroglycerin to upright tilt allows the positive rate of passive tilting to be doubled (51% vs 25%) while maintaining a high specificity (94% vs 100%).

Which strategy is "best" after myocardial infarction? The Beta-blocker Strategy plus Implantable Cardioverter Defibrillator Trial: rationale and study design.

The Beta-blocker Strategy plus Implantable Cardioverter Defibrillator (BEST-ICD) Trial is a multicenter prospective randomized trial that started in June 1998, in 95 centers in Italy and Germany. The trial will test the hypothesis whether, in high-risk post myocardial infarction (MI) patients already treated with beta blockers, electrophysiologic study (EPS)-guided therapy (including the prophylactic implantation of implantable cardioverter defibrillator [ICD] in inducible patients) will improve survival compared with conventional therapy. Patients eligible for the study are survivors of recent MI (> or = 5 and < or = 21 days), aged < or = 80 years, with left ventricular ejection fraction < or = 35% and > or = 1 of the following additional risk factors: (1) ventricular premature beats > or = 10/hour; (2) decreased heart rate variability (standard deviation of unusual RR intervals < 70 msec); and (3) presence of ventricular late potentials. Furthermore, all enrolled patients must be able to tolerate at least 25 mg of metoprolol per day. These patients constitute about 9% of all patients with recent MI and are expected to have a 2-year all-cause mortality > 25% of which 50% is anticipated to be from sudden death. The main criteria of exclusion from the study are (1) a history of sustained ventricular arrhythmia; (2) documentation of nonsustained ventricular tachycardia during the screening phase; and (3) the need for myocardial revascularization and contraindications or intolerance to beta-blocker therapy. Eligible patients will be randomized to 2 different therapeutic strategies: conventional strategy or EPS/ICD strategy. Patients allocated to the EPS/ICD strategy will undergo further risk stratification, and electrophysiologically inducible patients (approximately 35%) will receive prophylactic ICDs, in addition to the conventional therapy, whereas noninducible patients will be only conventionally treated. The primary endpoint of the study will be death from all causes. By hypothesizing a 30% reduction in the 2-year mortality (from 20% to 14%) in the EPS/ICD group compared with conventionally treated patients, 1,200 patients will have to be included. A triangular, 2-sided sequential design with preset boundaries, for a 5% significance level and 90% power to detect a reduction in 2-year mortality from 20% to 14%, will be used to permit early termination of the trial if the strategy is found to be efficacious, no difference, or inefficacious.

Clinical usefulness of slow pathway ablation in patients with both paroxysmal atrioventricular nodal reentrant tachycardia and atrial fibrillation.

Some patients with atrioventricular (AV) node reentrant tachycardia (AVN RT) also presented with atrial fibrillation (AF). In this study we demonstrate that slow pathway ablation is able to suppress both AVN RT and AF in subjects without structural heart abnormalities, whereas in patients with structural heart abnormalities after ablation AF frequently recurs.

Importance of acquired systemic-to-pulmonary collaterals in the Fontan operation.

BACKGROUND: Children with chronic cyanotic heart disease often develop systemic-to-pulmonary collateral arteries that can be deleterious at the time of a Fontan procedure due to excessive pulmonary blood flow. We therefore occlude all significant collaterals during cardiac catheterization. METHODS: From June 1993 to May 1998, 93 children aged 1.5 to 15.8 years (median 2.5 years) underwent a fenestrated lateral tunnel Fontan procedure. Eighty-nine (96%) had a previous bidirectional Glenn anastomosis, including 31 (33%) with a Norwood procedure. RESULTS: Preoperatively, 33 children (35%) required occlusion of 1 to 11 (mean 3.6) collateral vessels. Two of the three perioperative deaths (operative survival 97%) were due to excessive pulmonary blood flow from unrecognized collaterals in one and uncontrollable collaterals in the other. Postoperatively, 19 children (20%) required coil occlusion of 1 to 21 (mean 5.6) collaterals for elevated pulmonary artery pressures, heart failure, or prolonged chest tube drainage. Duration of inotropic support, postoperative ventilation, intensive care unit stay, and postoperative hospitalization were all significantly longer in the patients who had postoperative occlusion of collaterals. On follow-up of 2 to 67 months (mean 35 months), there have been four late deaths (two infections, two heart failures); 6 patients underwent successful cardiac transplantation for refractory heart failure. All 8 patients with ventricular failure required occlusion of significant collaterals postoperatively. CONCLUSIONS: Hemodynamically significant collaterals are not uncommon in Fontan candidates, and aggressive control can result in good operative and medium-term survival. After the Fontan, significant collaterals may be a marker for eventual cardiac failure because 8 of 18 patients requiring postoperative coils went on to transplantation or died of heart failure.

Current results with pediatric heart transplantation.

BACKGROUND: Cardiac transplantation is an accepted treatment for children with end-stage heart failure or complex or inoperable congenital defects. METHODS: Since 1988, 95 transplants have been performed in 89 children aged 4 days to 18 years (median 6.9 years, 42 patients 0-5 years). Fifty-eight (61%) had congenital or acquired heart disease, 31 (33%) had idiopathic cardiomyopathy, and 6 (6%) were retransplants. Fifty-seven of the patients had prior cardiac surgery with a range of one to eight procedures (mean 3.4 procedures/patient). At the time of transplantation, 53 (56%) were United Network for Organ Sharing (UNOS) status I, including 23 children on mechanical ventilation and 4 with mechanical circulatory support. RESULTS: Thirty-day survival in this group was 96%. Posttransplant results showed a median time of ventilation of 1 day (mean 3.0+/-5.7 days), median duration of inotropic support of 2 days (mean 2.7+/-2.3 days), median intensive care unit (ICU) stay of 4 days (mean 6.9+/-9.6 days), and median hospitalization of 9 days (mean 14.3+/-13.9 days). Follow-up from 1 month to 10.3 years (mean 3.1 years) has demonstrated a 1-year actuarial survival of 79% and a 5-year actuarial survival of 69%. Rejection, both acute and chronic, accounted for the vast majority of deaths. CONCLUSIONS: Pediatric heart transplantation can be accomplished with excellent early survival despite multiple prior cardiac operations and relative severity of illness. Parameters such as postoperative ventilation, inotropic support, ICU stay, and hospitalization can be kept at reasonable levels with acceptable long-term results, although rejection remains a serious problem.

Extracardiac atrial pedicle conduit repair of partial anomalous pulmonary venous connection to the superior vena cava in children.

Between June, 1982, and July, 1983, 6 children with partial anomalous pulmonary venous connection to the middle or high segment of the superior vena cava (SVC) underwent repair of the anomaly by division of the SVC proximal to the site of entry of the anomalous pulmonary veins. Continuity between the cephalad end of the SVC and the right atrium was established by direct anastomosis to the right atrial (RA) appendage or by creation of a pedicle conduit of RA appendage, RA free wall, and pericardium. The anomalous pulmonary veins remained in situ on the lower segment of SVC, blood being directed to the left atrium through an atrial septal defect by a pericardial patch placed within the right atrium well away from the sinoatrial node, anomalous pulmonary veins, and cavoatrial junction. All children have survived, remain in normal sinus rhythm, and have no evidence of vena caval or pulmonary venous obstruction. Follow-up cardiac catheterizations, angiocardiograms, and Holter recordings support the efficacy of this technique as an alternative in the management of anomalous pulmonary veins joining the SVC well above the cavoatrial junction.

Saphenous vein homograft: a superior conduit for the systemic arterial shunt in the Norwood operation.

BACKGROUND: Excessive pulmonary blood flow increases ventricular volume work in the face of inadequate systemic cardiac output, low diastolic blood pressure, and inadequate coronary perfusion. Using the smallest available 3-mm polytetrafluoroethylene shunts have been successful, although catastrophic shunt thrombosis has occasionally been observed. To avoid thrombosis with a smaller conduit, saphenous vein homografts (SVG) were used to construct the modified Blalock-Taussig (BT) shunts. METHODS: From January 1998 to April 1999, 25 patients weighing 3.1 kg (3.0 kg or less, n = 9), at a mean age of 8.9 days, underwent stage I Norwood using an SVG BT shunt. Common heart defects were aortic atresia (n = 8), mitral atresia and double-outlet right ventricle (n = 5), and unbalanced AVC (n = 5). Mean BT shunt size was 3.2 mm, with 12 patients having shunts that were 3 mm or smaller. RESULTS: Thirty-day hospital mortality was 8% (2 of 25). No shunt thrombosis was seen, despite banding the BT shunt in 3 patients. One patient had BT revision because of an anatomic issue not directly related to the shunt material. CONCLUSIONS: Excellent results may be achieved using SVG BT shunts in the Norwood operation. This conduit seems less likely to thrombose, both acutely and chronically, allowing the use of appropriately smaller-sized shunts in small neonates.

Increased chromosome damage in pediatric heart catheterization patients after diagnostic fluoroscopy and cineangiography.

Chromosome damage (CD) and sister chromatid exchange (SCE) levels were studied in lymphocytes from 30 pediatric heart catheterization patients receiving radiation during diagnostic fluoroscopy and cineangiography procedures. Forty-eight-hour CD and 72-hr SCE cultures were prepared from sequential samples taken from each patient: samples 1-3 via the catheter the same day (1) before exposure, (2) after fluoroscopy, and (3) after cineangiography; and sample 4 by venipuncture the next morning. Significant increases in CD (dicentrics, rings, and fragments), but not SCE, were observed. From a mean base level of 0.4% cells with CD, the CD levels increased 2-3-fold in samples 3 and 4 (p = .001). Rings only occurred in samples 3 and 4. While increased CD levels also correlated with increasing age, body surface area, and weight, partial correlations controlling for these factors clearly indicate that the CD effects are principally attributable to the radiological procedures (p = .001). Increased CD levels correlated with both the roentgen dose of cineangiography exposure (p = .002) and the volume of contrast medium (p = .000); however, partial correlations, controlling for either factor, indicate that the contrast medium was the principal factor (p = .006).

Transesophageal echocardiographic evaluation of the morphologic and hemodynamic cardiac changes during ventricular fibrillation.

To analyze cardiac motion during ventricular fibrillation (VF), we used transesophageal echocardiography to study nine male subjects, aged 44 +/- 7 years, affected by heart disease who have poor left ventricular function, during implantation of an Implantable Cardioverter Defibrillator, when VF is induced several times to determine the defibrillation threshold. Wall and valvular motion, transmitral and transaortic blood flow, and blood echoreflectivity were evaluated in all patients. Moreover, in basal conditions, during VF, 1 and 5 minutes after restoration of basal rhythm, we calculated the left ventricular end-diastolic volume (EDLVV) and area (EDLVA), the left ventricular end-systolic volume and area, the ejection fraction, and the fractional area change with a four-chamber echocardiographic view. At the onset of VF, the myocardium and valves exhibited a chaotic motion. About 10 seconds later the oscillatory movement of the heart walls became more ample and regular; the mitral valve showed a cyclic closure and opening with a forward flow, and the aortic valve exhibited similar behavior, although at a lower intensity. A spontaneous echo contrast appeared inside the atrial and ventricular cavities, gradually becoming an incrt homogeneous mass that was completely flushed away with the restoration of the basal rhythm. When VF started, EDLVV (286 +/- 98 ml) and EDLVA (50 +/- 16.5 cm2) decreased abruptly (EDLVV = 182 +/- 65 ml, p < 0.02; EDLVA = 38 +/- 9.2 cm2,p < 0.05); so did ejection fraction (31.8% +/- 15% versus 11% +/- 5%; p < 0.003) and fractional area change (25.8% +/- 6.5% versus 7% +/- 3.4%; p < 0.001). When the basal rhythm was restored, the heart extended again and EDLVV, EDLVA, ejection fraction, and fractional area change after 1 and 5 minutes were similar to those calculated before induction of VF. This behavior was observed during both the first and last induced VF. Thus during VF, great variations of heart morphology and dynamics, as well as blood echoreflectivity, occur; the heart seems to make attempts to organize its dynamics during the arrhythmia. Repeated episodes of VF and defibrillation with low energies do not seem to worsen left ventricular dynamics even in impaired hearts.

Cardiovascular adaptations to endurance training and detraining in young and older athletes.

In order to evaluate the influence of aging on cardiovascular adaptations to endurance training and detraining, 12 young (range 19-25 years) and 12 older (range 50-65 years) male cyclists were examined during the training and after 2 months of detraining. Twelve young and 12 older healthy sedentary males matched for age and body surface area were used as control groups. Each subject underwent a maximal exercise test using a cycle-ergometer in order to measure maximum oxygen consumption, an M-mode and 2D echocardiography in order to assess left ventricle morphology and systolic function, and a Doppler echocardiography for evaluating the diastolic filling pattern. During the training period both groups of athletes showed higher values of maximum oxygen consumption, left ventricular wall thicknesses, end-diastolic diameter and volume, as well as left ventricular mass, than their control subjects; in the older subjects the adaptation of the heart to aerobic training seems to be obtained mainly through a higher increase in left ventricular diastolic filling. In both groups no significant modifications in the ejection fraction and diastolic function parameters were recorded. After the detraining period the wall thicknesses decreased only in young athletes, while left ventricular mass and end-diastolic diameter and volume reduced only in older athletes. In conclusion, training and detraining induced nearly similar left ventricular morphological modifications in the two age groups, even though greater in the older athletes with respect to the ventricular mass and volume. No relevant differences were observed in the Doppler filling pattern between athletes and sedentary controls.

Transhepatic vascular access in pediatric cardiology patients with occlusion of traditional central venous sites.

Central venous access in pediatric patients with complex congenital heart disease may be difficult. Percutaneous transhepatic access offers an alternative for patients with occlusion of traditional central venous sites. We reviewed our experience utilizing transhepatic access in 10 consecutive pediatric cardiology patients for central venous lines, cardiac catheterization and endomyocardial biopsy. We include 5 patients who have had multiple procedures via the transhepatic approach.

Long-term effects of spinal cord stimulation on myocardial ischemia and heart rate variability: results of a 48-hour ambulatory electrocardiographic monitoring.

BACKGROUND: Spinal cord stimulation (SCS) has analgesic properties and may be used to treat pain in patients with therapeutically refractory angina who are unsuitable for myocardial revascularization. Some studies have also demonstrated an anti-ischemic effect. The aim of this study was to evaluate the long-term persistence of the effects of SCS on myocardial ischemia and on heart rate variability. METHODS: Fifteen patients (9 males, 6 females, mean age 76 +/- 8 years, range 58-90 years) with severe refractory angina pectoris (Canadian class III-IV), on optimal pharmacological therapy, unsuitable for myocardial revascularization and treated with SCS for a mean follow-up of 39 +/- 27 months (range 9-92 months) were studied. Eleven patients had had a previous myocardial infarction and 5 a coronary artery bypass graft. The mean ejection fraction was 54 +/- 7% (range 36-65%). All patients underwent 48-hour ambulatory ECG monitoring and were randomly assigned to 24 hours without SCS (off period) and 24 hours with SCS (on period). The primary endpoints were: number of ischemic episodes, total duration of ischemic episodes (min), and total ischemic burden (mV*min). RESULTS: The heart rate was not statistically different during the off and on SCS periods (median 64 and 67 b/min respectively). The number of ischemic episodes decreased from a median of 6 (range 0-29) during the off period to 3 (range 0-24) during the on period (p < 0.05). The total duration of ischemic episodes decreased from a median of 29 min (range 0- 186 min) during the off period to 16 min (range 0-123 min) during the on period (p < 0.05). The total ischemic burden decreased from a median of 2.5 mV*min (range 0-19.5 mV*min) during the off period to 0.8 mV*min (range 0-13 mV*min) during the on period (p = NS). The heart rate variability parameters were similar during the on and off periods. CONCLUSIONS: SCS exerts long-term anti-ischemic effects.

[A new organization model for hemodynamic cardiology diagnosis and intervention cardiology]. / Un nuovo modello organizzativo per la diagnostica cardiologica emodinamica e la cardiologia interventistica.

In centers without hemodynamic laboratories the quality of medical care may be suboptimal since the unavailability of these technologies may reduce medical experience in the treatment of heart disease, mostly in acute coronary syndromes, and may increase the need for referring some patients to other hospitals. The problem will be of great relevance in the case of expansion of the aggressive approach in the treatment of acute ischemic syndromes such as acute myocardial infarction and unstable angina. The impelling need for small centers of improving medical care may promote the spontaneous and uncontrolled proliferation of hemodynamic laboratories. The high number of hemodynamic laboratories may lead to a low institutional volume and, as a consequence, may negatively influence the outcome of coronary intervention and increase health care costs. The experience of operators and the costs are probably more relevant as regards angioplasty than coronary angiography. Therefore we propose the implementation of departments of interventional hemodynamic laboratories including different hospitals: diagnostic laboratories will be allocated in hospitals with coronary care units, while interventional laboratories will be allocated in referring hospitals.