Atrioatrial conduction after orthotopic heart transplantation.

OBJECTIVES: In two patients with orthotopic heart transplantation, the surface electrocardiogram suggested interaction between the donor right atrium and the recipient right atrium. An electrophysiologic investigation was performed to assess possible atrioatrial conduction. BACKGROUND: After orthotopic heart transplantation, both recipient and donor atrial activities are usually independent, but in humans they may synchronize for short periods during exercise. METHODS: Electrophysiologic recordings were made using standard techniques. The atrial electrode locations (anterior for the donor and posterior for the recipient right atria) were confirmed by fluoroscopy. Incremental and programmed donor and recipient right atrial pacing protocols were performed. RESULTS: Unidirectional conduction between native and graft atria occurred in both patients. This phenomenon was evident at rest, during normal sinus rhythm and at various pacing rates, resulting in frequent atrial bigeminy and trigeminy. CONCLUSIONS: Possible atrioatrial conduction after orthotopic heart transplantation may potentially be arrhythmogenic for the chamber where extrasystoles occur. This should be taken into account in attempting to devise new pacing modes if both atria are rendered electrically common.

Percutaneous transluminal balloon valvuloplasty of adult aortic stenosis: report of 92 cases.

Percutaneous transluminal balloon valvuloplasty was attempted in 92 adult patients with severe calcific aortic stenosis. The mean age was 75 +/- 11 years (range 38 to 91) and 35 patients were more than 80 years old. Most of the patients were severely disabled; 66 were in New York Heart Association functional class III or IV, 27 had syncopal attacks and 21 had severe angina pectoris. Because of unacceptably high surgical risk or contraindication to thoracic surgery, 42 patients could not be considered for valve replacement. Other patients either were in a category of high operative risk or refused the surgical intervention. Valvuloplasty was performed by way of the femoral route (82 patients) or the brachial route (10 patients). Catheters of size 15, 18 and 20 mm were successively placed across the aortic valve and three inflations were usually done with each of them, lasting 80 seconds on average, until a decrease in peak to peak systolic pressure gradient to 40 mm Hg or less was attained, a result considered satisfactory. The inflated balloons were not totally occlusive in most cases and clinical tolerance of inflation was good. Valvuloplasty resulted in a reduction of mean systolic gradient from 75 +/- 26 to 30 +/- 13 mm Hg (p less than 0.001); the final gradient was less than 40 mm Hg in 78 patients. Mean calculated aortic valve area increased from 0.49 +/- 0.17 to 0.93 +/- 0.36 cm2 (p less than 0.001). Immediately after the procedure, ejection fraction increased from 48 +/- 16 to 51 +/- 16% (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioscopic evaluation of rotational atherectomy followed by additional balloon angioplasty versus balloon angioplasty alone in coronary artery disease: a prospective, randomized study.

OBJECTIVES: This study sought to compare, by angioscopy, the morphologic changes induced by rotational atherectomy, followed by additional angioplasty, with those observed after balloon angioplasty alone. BACKGROUND: Rotational atherectomy and balloon angioplasty act by different mechanisms, which could explain the difference in morphologic changes induced by these two techniques. METHODS: The study group included 50 patients with 50 lesions who were randomly assigned to undergo rotational atherectomy (n = 24) or balloon angioplasty (n = 26). Rotational atherectomy with a single burr (approximately equal to 70% of coronary diameter) was systematically followed by additional balloon angioplasty. Angioscopy was performed immediately after the procedure. Abnormal angioscopic findings were 1) flaps, graded from 1 to 3 (1 = intimal flap; 2 = flap protruding into < 50% of the lumen; 3 = flap protruding into > or = 50% of the lumen); 2) thrombi, graded from 1 to 3 (1 = flat deposits; 2 = protruding but nonocclusive thrombus; 3 = occlusive thrombus); 3) subintimal hemorrhage; 4) longitudinal dissection. The two groups were comparable for clinical and angiographic baseline data. RESULTS: On angioscopy, flaps were observed less frequently after rotational atherectomy followed by additional balloon angioplasty (8 [33%] of 24 lesions) than after balloon angioplasty alone (14 [54%] of 26 lesions, p = 0.08) and were also less severe (grade 1 in 6 lesions, grade 2 in 2 and grade 3 in none vs. grade 1 in 4 lesions, grade 2 in 5 and grade 3 in 5). Longitudinal dissections were also significantly less frequent: one versus six (p = 0.05). There was no difference in the incidence of angioscopic thrombi (p = 0.16) or subintimal hemorrhage (p = 0.15), but the power to detect a significant difference was low for these variables (37% and 26%, respectively). CONCLUSIONS: Rotational atherectomy followed by additional balloon angioplasty leads to fewer angioscopic dissections and a trend toward fewer intimal flaps than balloon angioplasty alone. However, our angioscopic differences did not lead to an outcome difference between the two groups.

Improved myocardial ischemic response and enhanced collateral circulation with long repetitive coronary occlusion during angioplasty: a prospective study.

OBJECTIVES: The goal of the study was to evaluate the progressive increase in ischemic threshold with multiple sequential transient coronary occlusions and to assess the role of the collateral circulation in adaptation to ischemia. BACKGROUND: It has been observed that the duration of balloon inflations during coronary angioplasty can be gradually prolonged during subsequent dilations with a reduction in patient symptoms and diminished ischemic electrocardiographic (ECG) changes. Although the mechanism has not been fully explained, recruitment of coronary collateral circulation induced by repeated coronary occlusion has been reported. The stimuli for recruitment and the natural history of coronary collateral circulation are not understood. METHODS: Seventeen patients with isolated stenosis of the left anterior descending coronary artery and a normal left ventricle were enrolled. Angioplasty consisted of five successive prolonged inflations. Sequential changes in clinical, intracoronary ECG and left ventricular indexes of myocardial ischemia were examined. Coronary collateral channels were evaluated during balloon inflations by ipsilateral and contralateral injections of contrast medium and hemodynamically by occlusion pressure. RESULTS: An improved tolerance to myocardial ischemia with repetitive coronary occlusions was demonstrated by a significant reduction of angina, ST segment deviation, left ventricular filling pressure and less impairment of ejection fraction. Left ventricular wall motion abnormalities remained unchanged. Collateral angiographic grade did not change in 7 patients and increased in 10. CONCLUSIONS: This study confirms a progressive adaptation of myocardial ischemia to repetitive coronary occlusions and supports the concept that sequential episodes of myocardial ischemia are a stimulating factor for the recruitment of collateral channels in humans. These results also suggest that enhancement of recruitable collateral circulation might be an underlying mechanism of myocardial ischemic preconditioning.

Dobutamine stress echocardiography in orthotopic heart transplant recipients. VACOMED Research Group.

OBJECTIVES: This study sought to determine whether dobutamine stress echocardiography could accurately identify coronary artery disease after heart transplantation. BACKGROUND: After heart transplantation, coronary artery disease is related to either diffuse concentric intimal thickening or focal stenosis and may be underdiagnosed by coronary angiography. METHODS: We enrolled 41 patients, a mean (+/- SD) of 40 +/- 20 months after heart transplantation, at the time of their routine control coronary angiogram. Three patients were excluded because of poor echogenicity on the angiogram and one because of ventricular premature beats. Standard echocardiographic views were acquired at baseline and at incremental dobutamine infusion levels (from 5 to a maximal dose of 40 micrograms/kg body weight per min at 3-min intervals). Regional wall motion score was calculated from a 16-segment model, and each segment was graded from 1 (normal) to 4 (dyskinesia). Coronary angiography was performed 24 h after dobutamine stress echocardiography, and angiograms were analyzed in blinded manner. RESULTS: Twenty-three (62%) of 37 patients had normal coronary angiographic findings. Dobutamine stress echocardiography showed abnormalities in only 2 of 23 patients. Fourteen patients (38%) had abnormal angiographic findings, seven of whom had stenoses > 50%. Dobutamine stress echocardiography correctly identified the corresponding hypoperfused segments in these seven patients. More of interest were the other seven patients, of whom three had angiographic nonsignificant stenoses (< 50%), and four had minor diffuse coronary irregularities. Dobutamine stress echocardiography showed hypokinesia in five of these seven patients despite nonsignificant lesions at coronary angiography. The respective overall sensitivity and specificity of dobutamine stress echocardiography were 86% and 91%. At follow-up, 2 of the 37 patients had an acute myocardial infarction. Both had abnormal findings on dobutamine stress echocardiography: One had normal coronary angiographic results, and one had significant coronary lesions. CONCLUSIONS: Dobutamine stress echocardiography is a useful technique for the diagnosis of coronary artery disease after heart transplantation. These preliminary results indicate that dobutamine stress echocardiography may have a predictive value for further ischemic events in heart transplant recipients.

Insights on the mechanism of balloon valvuloplasty in aortic stenosis.

An analysis of the mechanisms of action of balloon valvuloplasty in adult aortic stenosis (AS), based on postmortem studies on fresh specimens and on clinical experience with 300 consecutive cases, is reported. When maximally inflated, a 20-mm diameter balloon (occupying a 3.14 cm2 cross-sectional area) significantly enlarges the stenosed valve orifice by 3 mechanisms: stretching of valve tissue, rupturing of commissural fusion and breaking of calcific deposits. These last 2 mechanisms are the most effective, in both tricuspid and bicuspid forms of AS, to render the cusps more flexible and able to open during systole and to close at the time of ventricular diastole. The marked increase in valve area obtained by the dilatation procedure was clearly demonstrated on fresh postmortem specimens and also on postmortem examination of cases that had had balloon valvuloplasty during life. Stretching alone may give only a temporary increase in valve area with an elastic return of the leaflets to their initial stenosing position and may explain, at least in part, the occurrence of restenosis. Inflation of the balloon is well tolerated with no deleterious decrease in blood pressure in two-thirds of the cases because the balloon opens the commissures, allowing blood ejection through these openings. It does not produce calcific emboli, probably because calcium deposits remain imbedded in the leaflets, covered by the endothelium. Finally, it very infrequently produces acute severe aortic regurgitation. Careful choice of balloon size is necessary to obtain on effective opening; most often a 20-mm diameter balloon but sometimes a balloon up to 23 mm is used.(ABSTRACT TRUNCATED AT 250 WORDS)

Results of percutaneous transluminal valvuloplasty in 218 adults with valvular aortic stenosis.

The results of balloon aortic valvuloplasty (BAV) in 218 adult patients with valvular aortic stenosis (AS) are reported. In most cases, 3 transcutaneously introduced balloons of successively increasing size were used. Tolerance was excellent in 64%, whereas a decrease in blood pressure below 60 mm Hg during inflation was observed in 36%. The left ventricular-aortic peak to peak gradient decreased from 72 +/- 25 to 29 +/- 14 mm Hg (p less than 0.001) and the aortic valve area increased from 0.52 +/- 0.18 to 0.93 +/- 0.33 cm2 (p less than 0.001). The final aortic valve area was greater than or equal to 1 cm2 in 69 patients (32%). In only 6 cases (3%) the aortic valve area did not change or increased by less than 10%. A clear improvement in the results was observed with gained experience and better catheters. There was 1 death and 1 stroke in the procedure room, and 3 strokes after BAV. Nine patients died shortly after the procedure. There were local complications (hematoma or thrombosis) at the femoral puncture site in 28 (13%) patients. Clinical follow-up was obtained for 144 patients (mean 8 months). There were 24 deaths. In the 120 remaining cases, symptomatic improvement was good in 84%, with decrease or disappearance of dyspnea, angina or both. This study demonstrates that BAV is feasible in adult AS at a low risk and is able to produce marked clinical improvement in most cases.

A multicenter double-blind comparative study of rilmenidine and clonidine in 333 hypertensive patients.

The efficacy and acceptability of rilmenidine were studied in a double-blind clonidine-controlled multicenter trial; after a 4-week placebo run-in period, patients with supine diastolic blood pressure (BP) between 95 and 115 mm Hg received as monotherapy either rilmenidine or clonidine over 6 weeks. The initial dose (rilmenidine 1 mg/day or clonidine 0.15 mg/day) was doubled (1 mg or 0.15 mg twice a day, respectively) after 2 weeks if diastolic BP remained greater than or equal to 90 mm Hg. Three hundred and thirty-three patients (mean age 57.8 +/- 0.7 years) with a systolic BP of 170.53 +/- 0.92 mm Hg and a diastolic BP of 101.57 +/- 0.30 mm Hg were randomly divided into 2 homogenous groups (rilmenidine, n = 162 and clonidine, n = 171). All patients taking rilmenidine completed the trial. Seventeen patients taking clonidine (10%, p less than 0.01 vs rilmenidine) were withdrawn because of severe side effects. Systolic and diastolic BP were significantly reduced in both groups at every examination (at 2, 4 and 6 weeks). The mean decreases in supine and erect BP were identical in both groups: systolic BP 19 mm Hg and diastolic BP 12 mm Hg after 6 weeks. BP was normalized (systolic BP less than 160 and diastolic BP less than or equal to 90 mm Hg) in 57% of patients taking rilmenidine and 56% of patients taking clonidine (60% of normalized patients had been taking the single dose in both groups).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of prolonged sequential balloon inflations on results of coronary angioplasty.

In percutaneous transluminal coronary angioplasty (PTCA), prolonged balloon inflations using perfusion balloon catheters have shown a higher procedural success rate and fewer in-hospital complications than short balloon inflations. However, perfusion balloons have well-recognized limits for routine use. This study assessed the effects of a prolonged cumulative occlusion time obtained with sequential balloon inflations using a routine balloon catheter, applicable to all lesions, and compared these results with those obtained with standard short balloon inflations. Three hundred ten lesions (in 289 patients) were randomized to either standard (3 to 5 inflations < or = 1 minute each; n = 161) or prolonged (3 to 5 inflations of 3 to 5 minutes each; n = 149) balloon inflations. Angiographic success (residual stenosis <50% and no dissection > or = D1) was assessed at the end of this "protocol" phase. Further dilatation was performed if required ("adjunctive" phase). Systematic repeat catheterization was scheduled 4 to 6 months later. Cumulative inflation time was 198 +/- 58 seconds in the "standard" group versus 782 +/- 303 seconds in the "prolonged" group. At the end of the protocol phase, the success rate was higher after prolonged than after standard dilatation (92% vs 80%; p <0.002), with less frequent dissections (14% vs 30%; p = 0.0009). At the end of the adjunctive phase, required for 12 patients in the prolonged group and 32 patients in the standard group (p = 0.003), results were comparable in the 2 groups and the restenosis rate was similar at 6 months. The prolonged cumulative occlusion time achieved with sequential balloon inflations using a routine balloon catheter improves the immediate results of PTCA. Repeat catheterization shows no effect of prolonged sequential inflations on the restenosis rate.

Intravenous anisoylated plasminogen streptokinase activator complex versus intravenous streptokinase in evolving myocardial infarction. Preliminary data from a randomised multicentre study.

The efficacy of a single intravenous bolus of anisoylated plasminogen streptokinase activator complex (APSAC 30U in 4 to 5 minutes) versus an intravenous infusion of streptokinase (1.5 X 10(6) U in 60 minutes) was assessed in 86 patients with evolving myocardial infarction of less than 6 hours duration in a cooperative randomised study. The patency of the infarct-related artery was assessed by coronary angiography at, on average, 90 minutes after therapy (mean time: APSAC 95 minutes, streptokinase 105 minutes). The treatment groups were similar with respect to sex, age, location of myocardial infarction and the delay from onset of pain to treatment. The 90-minute patency rate (grade 2 to 3) was 71.8% in the APSAC group and 55.8% in the streptokinase group; the difference was not statistically significant. There was no difference between the drop in fibrinogen concentrations in the 2 groups at 3 or 24 hours. The minimal concentration obtained at the first assessment was +/- 0.2 g/L in the streptokinase group and 0.5 g/L in the APSAC group. One patient in the APSAC group, who had a previous meningeal bleeding, had a non-fatal cerebrovascular accident. In a subgroup of 38 patients who had 3 control coronary angiograms at 90 minutes, 24 hours and 3 weeks, the patency rate was 63, 82 and 93%, respectively, in the APSAC group and 48, 88 and 92%, respectively, in the streptokinase group (the difference was not statistically significant). None of the patients in the APSAC group presented with reocclusion, whilst 3 patients in the streptokinase group had reocclusions.(ABSTRACT TRUNCATED AT 250 WORDS)