Supernormal ejection performance is isolated to the ipsilateral congenitally pressure-overloaded ventricle.

Congenital left ventricular pressure overload is associated with "excessive" hypertrophy that leads to subnormal afterload (wall stress), permitting enhanced ventricular ejection performance. Whether congenital right ventricular pressure overload is associated with a similar phenomenon is uncertain. It is also unknown whether supranormal ejection performance affects only the overloaded ventricle or is a general process affecting both ventricles. Conflicting data exist about whether the hypertrophic process associated with pressure overload is induced primarily by local loading conditions or by neuroendocrine influences. If the former postulate is true, the hypertrophic response should be confined to the overloaded ventricle; if the latter is true, one might predict that both ventricles would be affected by a less specific response to circulating catecholamines. To help resolve these issues, both right and left ventricular performance was examined in seven patients with isolated congenital pulmonary stenosis (average pulmonary pressure gradient 78 +/- 13 mm Hg), six patients with isolated congenital aortic stenosis (average gradient 80 +/- 10 mm Hg) and six normal subjects. Right ventricular ejection fraction was increased in patients with pulmonary stenosis (61 +/- 2%) compared with the value in normal subjects (53 +/- 2%, p less than 0.01) and in patients with aortic stenosis (50 +/- 3%, p = 0.007). Left ventricular ejection fraction was increased in patients with congenital aortic stenosis (84 +/- 4%) compared with the value in normal subjects (70 +/- 4%, p less than 0.01) and in patients with congenital pulmonary stenosis (65 +/- 2%, p less than 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of outcome for aortic valve replacement in patients with aortic regurgitation and left ventricular dysfunction: a change in the measuring stick.

Although left ventricular function is generally regarded as a key determinant of prognosis in aortic regurgitation, predictors of outcome of aortic valve replacement based on this factor have recently been questioned. This study was performed to examine the role of indexes of left ventricular function in predicting the outcome of surgery in patients with aortic regurgitation and left ventricular dysfunction. Fourteen patients with aortic regurgitation with a preoperative ejection fraction of less than 0.55 (average 0.45 +/- 0.02) who underwent aortic valve replacement were studied. The patients had 82 (58%) of a possible 140 predictors of negative outcome preoperatively, but 12 of the 14 patients had a decrease in symptoms and an increase in ejection fraction into the normal range after operation (average postoperative ejection fraction 0.59 +/- 0.04). Although improvement occurred despite the presence of many negative predictors of outcome, there was a significant correlation between postoperative ejection fraction and eight of the tested preoperative predictors. Preoperative end-systolic dimension correlated best (r = -0.91) with postoperative ejection fraction. An end-systolic dimension of 60 mm correlated with a postoperative ejection fraction of 0.55. The results indicate that preoperative ventricular function is still an important determinant of outcome of aortic valve replacement for aortic regurgitation. However, current medical and surgical techniques permit a better prognosis in the presence of reduced ventricular function than was previously considered possible.

Prosthetic valve endocarditis due to Cardiobacterium hominis occurring after upper gastrointestinal endoscopy.

Bacterial endocarditis secondary to endoscopic procedures has been convincingly documented in only four cases. We describe a case of prosthetic valve endocarditis due to Cardiobacterium hominis that developed after upper gastrointestinal endoscopy. Because of this, we recommend subacute bacterial endocarditis prophylaxis in patients who have a prior history of endocarditis or valve replacement.

Efficacy and safety of sustained-release diltiazem as replacement therapy for beta blockers and diuretics for stable angina pectoris and coexisting essential hypertension: a multicenter trial.

To determine if a sustained-release form of the calcium entry blocker diltiazem would be a satisfactory substitute for the combination of beta-adrenergic blocking agent and thiazide diuretic in the treatment of systemic hypertension and angina pectoris, 38 patients were studied in a 4-center trial. Blood pressure and heart rate were measured in the supine position, immediately after and 5 minutes after standing. Modified Bruce protocol treadmill tests were performed to determine the time to onset of 1 mm ST-segment depression, time to onset of chest pain and time to termination of exercise. Diltiazem monotherapy resulted in equivalent blood pressure control in 28 of 38 patients (74%). In the remaining patients, blood pressure control was achieved with resumption of the diuretic. Blood pressure with beta blocker plus diuretic compared with diltiazem were, in the supine position 137 +/- 22/82 +/- 7 (+/- 1 standard deviation) versus 139 +/- 22/82 +/- 8 mm Hg, immediately after standing 131 +/- 20/84 +/- 9 versus 133 +/- 21/82 +/- 10 mm Hg and after standing for 5 minutes 134 +/- 19/85 +/- 8 versus 137 +/- 18/85 +/- 9 mm Hg (difference not significant for each). The heart rate with diltiazem was higher supine (67 +/- 11 versus 60 +/- 11 beats/min), standing (73 +/- 13 versus 64 +/- 14 beats/min) and 5 minutes after standing (73 +/- 14 versus 63 +/- 14 beats/min, p less than 0.01 for each).(ABSTRACT TRUNCATED AT 250 WORDS)

Catheter-induced tricuspid regurgitation. Incidence and clinical significance.

The incidence and severity of catheter-induced tricuspid regurgitation has not been studied extensively. Given the frequency with which right heart catheters are employed to measure cardiac output, it is important to know whether the severity of catheter-induced tricuspid regurgitation is sufficient to invalidate the measurement of thermodilution cardiac output. Accordingly, the purpose of the present prospective study was to determine the incidence and severity of catheter-induced tricuspid regurgitation in 25 men (mean age, 58.1 +/- 1.4 years) using Doppler ultrasound. The tricuspid valve was interrogated from two orthogonal views using pulsed-wave and color flow Doppler, either in the presence or absence of a 7-French catheter across the tricuspid valve. The severity of catheter-induced tricuspid regurgitation was graded semiquantitatively using a validated scoring system. Pulsed-wave Doppler studies showed that the incidence of catheter-induced tricuspid regurgitation was 48 percent, and that the average tricuspid regurgitation score increased from 0.41 +/- 0.16 to 0.61 +/- 0.17 (p less than 0.01). Color flow Doppler studies showed similar findings. Further, the incidence of catheter-induced tricuspid regurgitation was not related to the patient's underlying hemodynamic status or right ventricular geometry. In conclusion, this study shows for the first time that the quantitative extent of catheter-induced tricuspid regurgitation is small, and is therefore unlikely to be important clinically, particularly with regard to the assessment of thermodilution cardiac output.

Cardiac pacing under hyperbaric conditions.

Temporary external pacemakers have been reported to fail under hyperbaric conditions. In this study we investigated cardiac pacing under hyperbaric conditions. Permanent hermetically sealed pacemakers were found to function well under hyperbaric conditions, while several models of temporary external pacemakers failed. The electrical characteristics of pacing leads did not change under hyperbaric conditions. External pacing under hyperbaric conditions may be accomplished safely by using a permanent pacemaker attached to the patient's temporary external leads.

Connections of the nucleus accumbens.

Reports from previous works has given different classifications for the nucleus accumbens. There also appears to be a general lack of information regarding the fiber connections of the nucleus. The present investigation was undertaken to clarify the connections of this structure. Silver impregnation methods were used to discern some of the afferent fibers of the nucleus, and autoradiographic techniques were used to locate target areas of efferent projections. Afferents were found to be predominately from the septum. Other sources of possible afferents were the mid cingulate gyrus and the ventral nucleus of the diagonal band. No argyrophilia was observed in the nucleus accumbens following transection of the fornix body, lesions of the anterior orbital frontal cortex or anterior cingulate gyrus. On the basis of grain counts made from autoradiographic studies, the nucleus accumbens projects predominately to the lateral hypothalamus. Counts above background were found in the cingulate gyrus, septum, ventral nucleus of the diagonal band, midline thalamic nuclei, habenula, caudate and substantia nigra. Thus, efferent projections appear to distribute to both limbic and extrapyramidal structures. Considering these connections and the functions reported by various workers the nucleus accumbens may serve as bridge between limbic and extrapyramidal motor systems effecting limbic influence in some movements.

The impact of device recall on patients and family members of patients with automatic implantable cardioverter defibrillators.

BACKGROUND: Patients often depend on life-saving technology as a permanent part of their lives. Sometimes these devices become defective and are recalled. OBJECTIVES: To investigate how the urgent device recall of three models of the Automatic Implantable Cardioverter Defibrillator (AICD) affected confidence in the device and the psychosocial responses of patients and their family member caregivers. METHODS: All patients (N = 31) and caregivers (N = 21) affected by the recall at one heart center completed a survey instrument consisting of a series of visual analog scales designed to measure confidence before and after learning of the recall, fear, anger, depression, anxiety, helplessness, loss of control, uncertainty, and confusion associated with having a recalled AICD. Surveys were completed immediately after being told of the recall and 1 month later. RESULTS: Confidence of patients decreased significantly from a mean of 87% to 74% when comparing perceptions of before learning of the recall to those immediately after (t30 = 3.65, p < 0.0005). For caregivers, mean confidence dropped from 92% to 73% (t19 = 5.0, p < 0.0005). Confidence remained significantly lower 1 month later. Caregiver scores were consistently, although not significantly, higher (less favorable) on the measures of emotional response than patient scores. Caregivers of patients who had received shocks from the AICD and those of patients who had the device for more than a year were generally more affected. CONCLUSIONS: Patient and caregiver confidence in the AICD was significantly reduced. Further research is needed to investigate the trends in the data from caregivers.

Radionuclide evaluation of dual chamber pacing: comparison between variable AV intervals and ventricular pacing.

We prospectively evaluated changes in left ventricular ejection fraction, end diastolic volume, and stroke volume via radionuclide multigated acquisition study. Comparison was made between ventricular pacing and dual chamber pacing with varying AV intervals. The volumes and changes in ejection fraction were determined at rest, at set increased pacing rates, and during physiological stress. AV sequential pacing shows overall improvement in cardiac function in the majority of patients regardless of left ventricular function. The shorter AV interval would be appropriate for the majority of patients who have an atrial tracking mechanism (adequate intrinsic sensed atrial activity followed by ventricular pacing) and who undergo significant physiological stress.

Permanent cardiac pacing in patients on chronic renal dialysis.

We reviewed the need for permanent pacemaker implantation in patients with chronic renal failure who were undergoing dialysis. During a 10-year span, there were seven patients undergoing dialysis in whom a permanent pacemaker was indicated; this was an incidence of 0.68%. During that same period, the general patient population of this hospital had an incidence of permanent pacemaker implantation of about 0.29%. The need for hemodialysis in the same hospital population was 0.51%. Of the seven patients, four had universal pacemakers. Cardiac function was evaluated via radionuclide angiography. Three of the four patients showed improvement with dual-chambered pacing over ventricular pacing. Permanent pacemaker implantation was often needed after initiation of dialysis from 6 to 51 months with a mean of 21 months. During the follow-up period, three patients died from 7 months to 6 years after the institution of permanent pacing; their deaths were secondary to renal disease.

Significant complications can occur with ischemic heart disease and tilt table testing.

We present an elderly patient who had syncope, with known coronary artery disease and a conduction abnormality. Because of a possible vasovagal reaction, the patient underwent a tilt table test prior to evaluation of ischemia or her LV function. During the tilt table test on isoproterenol, the patient developed ventricular fibrillation which was corrected immediately by cardioversion. Subsequently, the patient was found to have significant coronary artery disease which was treated with stenting and angioplasty. After treatment, there were no inducible arrhythmias on full dose isoproterenol. This case reports a significant complication that may occur when tilt table testing with isoproterenol and ischemia.

Limitations of the long-term clinical application of rate hysteresis.

Rate hysteresis is the ability of a pacemaker to pace at an automatic rate that is different from the escape rate. We reviewed our experience with this programmable feature and its utility. The long-term clinical application of rate hysteresis was limited due to the development of atrial fibrillation or to slowing of the intrinsic cardiac rhythm in 27.6% of the 29 patients. Since many patients with sick sinus syndrome have preserved AV conduction, one might expect that these patients would have an adequate intrinsic heart rate to allow successful use of rate hysteresis pacing mode. Sick sinus syndrome was the intrinsic rhythm disturbance in 63% of the group requiring discontinuation of rate hysteresis. These patients may represent a subgroup in whom any theoretical advantages provided by the rate hysteresis feature may be outweighed by the propensity for the development of atrial fibrillation or significant slowing of the intrinsic rhythm.

Comparison of lead dislodgment and pocket infection rates after pacemaker implantation in the operating room versus the catheterization laboratory.

To assess and compare the rates of lead dislodgment and pocket infection in patients having procedures performed in the operating room versus those performed in the cardiac catheterization laboratory, we reviewed the records of 85 adult patients who underwent 88 procedures, all performed by one surgical team and having complete follow-ups at our institution from October 8, 1979, through November 7, 1986. Forty-five patients underwent 46 procedures in the operating room, and 40 patients underwent 42 procedures in the cardiac catheterization laboratory. There was one instance of ventricular lead dislodgment noted among the 48 leads implanted in the operating room and one instance of ventricular lead dislodgment among the 58 leads implanted in the cardiac catheterization laboratory. No instances of atrial lead dislodgment were noted. No instances of pocket infection were noted among the 46 procedures performed in the operating room or in the 42 procedures performed in the cardiac catheterization laboratory. We conclude that pacemaker implantation can be performed with equivalent safety and effectiveness in the cardiac catheterization laboratory and in the operating room.

Pacemaker follow-up and adequacy of Medicare guidelines.

The time of occurrence of cardiac pacemaker problems after implantation was identified to assess the adequacy of published federal guidelines for clinic and transtelephonic follow-up. One hundred eighty-nine pacemaker patients' charts were examined retrospectively to identify pacemaker problems: inadequate sensing, non-capture, battery failure, myoinhibition, muscle stimulation, and inadequate threshold safety margin. Twenty-nine patients (15%) were identified as having pacemaker problems. A total of 41 problems were identified, of which 28 (68%) were corrected by reprogramming. Sixty-one percent of the problems were found during a clinic visit. Problems occurred more frequently during the first year in dual-chamber devices (62%) vs single-chamber devices (35%). During years 1 to 4, when few problems are expected, 30% of all problems of single-chamber devices occurred and 39% of all problems of dual-chamber devices occurred. This is a period of time that Medicare guidelines allow for one clinic visit per year for single- and two visits per year for dual-chamber devices. These data suggest: (1) Many pacemaker problems will be missed with transtelephonic follow-up alone. (2) The majority of problems involving dual-chamber devices occurred in the first year. (3) For both dual- and single-chamber devices, an unexpected significant percentage of problems occurred in 1 to 4 years. (4) Medicare guidelines may be inadequate for follow-up during this time period.

The potential utility of sensor-driven pacing in DDD pacemakers.

Sensor-driven pacemakers have clinically improved symptomatology over ventricular pacemakers. Adding rate responsiveness to DDD pacing would theoretically benefit patients with an inability to increase their atrial rate. We evaluated 20 patients who had long-term implanted DDD pacemakers as to the utility of an added effect of rate responsiveness. The pacemakers had been implanted for an average of 34 months. This patient group included 15 patients with atrioventricular (AV) block and five patients with sick sinus syndrome. All patients were exercised on the treadmill until they were fatigued and were monitored to determine their intrinsic heart rate response. A sensor-driven pacemaker was strapped to the patients and was connected to an ECG to measure its rate response. It was set to activity threshold of medium, with a rate response of 7. The 20 patients exercised for an average of 5.9 minutes, with a range of 1.7 to 10 minutes. The maximum intrinsic atrial response averaged 110 beats/min, ranging from 60 to 150 beats/min. The maximum achieved activity rate averaged 99 beats/min, ranging from 60 to 118 beats/min. In 7 of the 20 of patients (35%), the activity pacemaker reached a higher rate than the patient's intrinsic rate. Six had AV block and one had sick sinus syndrome. In these seven patients the peak activity rate response averaged 102 beats/min and their intrinsic activity averaged to 78 beats/min. There was an increase in rate by the addition of rate responsiveness in 35% of our DDD patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Driving with an internal defibrillator: legal, ethical, and quality-of-life issues.

Patients with internal cardioverter-defibrillators experience many issues after implantation. One issue is operating a motor vehicle. This issue has many ethical, legal and quality-of-life concerns that must be addressed by the patient, health care providers, and society. The legal and ethical issues surrounding patients with internal cardioverter-defibrillators will be explored using an ethically based theoretical framework.

Steroid treatment of the painful pacemaker pocket.

Chronic pain about a pacemaker secondary to sterile fibrotic contracture of the capsule is an uncommon but frustrating complication for both the physician and the patient. Three cases of this complication controlled by the late injection of triamcinolone are reported.

An argument for pacemaker reuse: pacemaker mortality in 169 patients over ten years.

Retrospective examination of 169 consecutive pacemaker patient deaths was done to test the hypothesis that early mortality would preclude full utilization of current battery longevity. We found a 58% mortality within two years of the last generator implant. Nineteen percent occurred within six months, and 38% occurred within a year. This compares to a current clinic of 246 patients where 43% have utilized these pacemakers for greater than 48 months. The age comparison shows that those who died were older than the living controls. The 58% 24-month mortality demonstrates that many patients underutilize expected battery life. The economic implications of pacemaker reuse can then be understood.

Driving safety among patients with automatic implantable cardioverter defibrillators.

OBJECTIVE: To determine the driving behavior of patients following the placement of automatic implantable cardioverter defibrillators (AICDs). SUBJECTS AND DESIGN: Forty patients with AICDs (33 men, seven women; mean age, 62.7 years) responded to a questionnaire designed to ascertain driving behavior after hospital discharge. RESULTS: Despite medical advice never to drive again, 28 patients (70%) resumed driving, with the majority doing so by 8 months after AICD implantation. Of these, 11 (40%) identified themselves as the primary driver in their household. Fourteen (50%) drove daily. Two (7%) were driving and continued to drive during discharge of their AICDs. Twenty-five (91%) reported that they felt comfortable and safe while driving. CONCLUSION: A majority of patients with AICDs continue to drive after a proscription of this activity by health care workers.