Abnormal heart rate recovery after exercise: a comparison with known indicators of increased mortality.

BACKGROUND: Abnormal heart rate (HR) recovery at 1 min after exercise (< or =12 beats) was recently suggested to be a predictor of all cause and cardiac mortality. AIM: This study aimed to (1) correlate HR recovery at 1 min after exercise with known exercise and myocardial perfusion markers of increased cardiac mortality, and (2) compare the known exercise and myocardial perfusion markers of increased cardiac mortality between patients with a normal and abnormal HR recovery at 1 min after exercise. METHODS: One hundred patients with known or suspected coronary artery disease referred for exercise stress testing (ETT) were prospectively enrolled. Percent, ETT time peak HR, HR reserve, summed stress score (SSS), extent of stress (SE%) and reversible perfusion abnormalities (RE%) were recorded in every patient. RESULTS: There was poor correlation with markers of myocardial ischemia or infarction [SSS (r = 0.15), SE% (r = 0.05), RE% (r = 0.12), all p = n.s.] but highly significant correlation between HR recovery at 1 min after exercise and chronotropic variables [ETT time (r = 0.56), peak HR (r = 0.65), HR reserve % (r = 0.64), all p < 0.001]. Patients on beta-blockers had significantly more incidence of an abnormal HR recovery at 1 min after exercise, compared to patients not on beta-blockers (88 vs. 56%, p < 0.01). CONCLUSION: Abnormal HR recovery at 1 min after exercise has no correlation with known myocardial perfusion markers of increased cardiac mortality. Patients with an abnormal HR recovery do not appear to have an increased incidence or more severe myocardial infarction or ischemia. However, there is a strong correlation between HR recovery at 1 min after exercise and the chronotropic variables during exercise.

Can pre-treatment with beta-agonists reduce stress test time and the use of atropine in dobutamine stress testing?

AIM: To determine whether the use of inhaled beta-agonists decreases the duration of dobutamine stress testing (DAS), reduces the amount of dobutamine infused and decreases the use of atropine. METHODS: 34 patients on beta-agonists (group A) (mean age 65 +/- 8 years) and 32 patients not on beta-agonists or beta-blockers (group B) (mean age 65 +/- 10 years) undergoing DAS with SPECT were enrolled. RESULTS: The time of infusion of dobutamine in group A was 6.41 +/- 1.58 min and in group B was 9.77 +/- 3.60 min (p < 0.001). The amount of dobutamine infused was 10.64 +/- 5 mg in group A and 19.20 +/- 8 mg in group B (p < 0.001). In group A, 2 of 34 patients and 18 of 32 patients in group B needed atropine to reach peak HR (p < 0.001). CONCLUSION: Patients on short acting beta-agonists require smaller amounts of dobutamine with a shorter infusion time during DAS, and lesser use of side-effect prone atropine.

Abnormal heart rate recovery after exercise as a reflection of an abnormal chronotropic response.

Abnormal decline in heart rate (HR) after exercise has been linked to increased cardiac mortality. This study compares the decrease in HR in different patient types, elucidates the relation between the increase and decrease of HR with exercise, and studies the role of beta blockers on the recovery of HR after exercise. One hundred patients with coronary artery disease (CAD), 50 subjects with a very low likelihood of CAD (normals), and 21 postcardiac transplant (Tx) patients underwent Bruce protocols. Peak HR, percent of peak HR achieved, HR reserve percent, and decline in HR at 1, 3, 5, and 8 minutes were obtained for all groups and also for subgroups based on the use of beta blockers. HR recovery at 1, 3, 5, and 8 minutes differed significantly between patients with CAD, normals, and Tx patients. HR recovery at 1, 3, 5, and 8 minutes also differed significantly within the groups (normal and CAD) based on the use of beta blockers. There was highly significant correlation between decrease in HR and peak HR, percent peak HR and HR reserve percent in normal and CAD groups. After correction of the HR recovery for dependence on peak HR and HR reserve percent, the difference in HR recovery between normal and CAD groups was markedly reduced. The difference in the decrease of HR within each group (normal and CAD), based on the use of beta blockers or not, was also markedly reduced. beta blockers have a significant impact on the decrease in HR due to its effect on chronotropism. HR recovery rate is highly dependent on the chronotropic response. Hence, the main portion of the abnormality in HR recovery after exercise can be explained by chronotropic incompetence.

Long-term follow-up of residual mediastinal-hilar Ga-67 uptake after treatment for Hodgkin's and non-Hodgkin's lymphomas: what degree of Ga-67 uptake is significant?

PURPOSE: Ga-67 planar and SPECT images of 85 patients after treatment for mediastinal-hilar (M-H) lymphoma were reviewed retrospectively. Forty-seven patients had Hodgkin's disease and 38 patients had non-Hodgkin's lymphoma. The entire period was 7 years after diagnosis. The main goal was visual assessment of the significance of mild (grades 1 or 2) Ga-67 uptake in the M-H area as compared with Ga-67 uptake in bone marrow. METHODS: Residual Ga-67 mediastinal uptake after a complete course of chemotherapy or other treatments was defined as normal (no residual) M-H uptake, borderline (M-H residual uptake with intensity less than that or equal to the sternum, spine, or both), and abnormal (M-H residual uptake with intensity greater than that of the sternum or spine). RESULTS: Among the 38 patients (45%) with no residual M-H uptake, four (one Hodgkin's disease and three non-Hodgkin's lymphoma) experienced recurrence: two in the mediastinum and two in the abdomen. Among the 45 patients (53%) with borderline M-H uptake, five experienced recurrence: two in the mediastinum and three in other sites. The two patients (2%) with abnormal (M-H) uptake never responded to treatment. No significant statistical difference in tumor recurrence was found between no residual and borderline uptake (P = 0.21). CONCLUSIONS: Visual assessment of M-H Ga-67 uptake (without quantification) could be useful to differentiate active residual tumor from nonactive residual uptake.

Intrinsic limitations to unilateral parathyroid exploration.

OBJECTIVE: To evaluate a method of limited parathyroid exploration for primary hyperparathyroidism. SUMMARY BACKGROUND DATA: Although preoperative localization of parathyroid adenomas has become sensitive enough for clinical practice, it has not achieved success as the basis for limited parathyroid exploration, because multiglandular disease is routinely underdiagnosed. The rapid intraoperative parathyroid hormone assay is sensitive for multiglandular disease, because hormone levels will not fall within 10 minutes of adenoma removal if additional abnormal tissue is present. A combination technique in which the exploration is limited according to the localization studies and the success is confirmed with the parathyroid hormone assay has promise for producing a high rate of curative limited parathyroid explorations. METHODS: Forty-eight consecutive patients with primary hyperparathyroidism and indications for surgery underwent preoperative localization. After tests, 45 patients underwent unilateral parathyroid exploration and confirmation of the success of unilateral exploration during surgery using the rapid parathyroid hormone assay. The intraoperative management of these patients and their follow-up to 3 months was recorded. RESULTS: Thirty-two of the 48 patients (67%) had successful unilateral exploration as gauged by a marked drop in parathyroid hormone levels during the procedure and by 3-month clinical follow-up. Of the 16 patients who ultimately underwent bilateral exploration, 7 had parathyroid hormone levels that did not fall after adenoma removal. Of these seven, five were found to have a second adenoma and two had slow metabolism of hormone with no additional abnormal tissue found. In 5 of the 16 patients, bilateral exploration was performed for erroneous localization. Four additional patients underwent bilateral exploration for improved exposure or negative results on localization tests. CONCLUSIONS: These results show that unilateral parathyroid exploration is limited by the intrinsic 15% rate of multiglandular primary hyperparathyroidism, combined with the imperfections of preoperative localizing techniques. Although an 85% rate of unilateral exploration can theoretically be obtained for unselected cases, the other vagaries of the technique make a 70% rate a more reasonable expectation.

Significance of increased right ventricular uptake on 99mTc-sestamibi SPECT in patients with coronary artery disease.

UNLABELLED: The significance of increased right ventricular (RV) tracer uptake in patients with coronary artery disease (CAD) without pulmonary or valvular heart disease is unclear. METHODS: Forty consecutive patients with increased RV uptake on SPECT myocardial perfusion imaging and right heart catheterization within 4 wk were studied prospectively. Thirty-five individuals with very low likelihood of CAD served as controls. Rest and stress SPECT myocardial perfusion data were obtained using a standard 99mTc-sestamibi 1-d imaging protocol. A quick and simple RV-to-left ventricular (LV) myocardial uptake ratio was calculated from the maximum counts per pixel detected in the right and left ventricles using the reconstructed coronal slices. RV end-systolic pressure (RV-ESP), mean pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure were obtained by standard techniques. RESULTS: The RV/LV uptake ratio in the controls was 0.31+/-0.05. Thirty-six of the 40 (90%) CAD patients with increased RV tracer uptake had increased RV-ESP, and 39 (97.5%) had increased PAP. Highly significant positive correlations between the RV/LV uptake ratio and RV-ESP and PAP were found (r = 0.45, P = 0.003; and r = 0.52, P < 0.001, respectively). CONCLUSION: Increased RV uptake, assessed from standard myocardial perfusion studies, can identify RV pressure overload among patients with CAD. In the absence of pulmonary or valvular heart disease, increased RV uptake (i.e., RV pressure overload) indicates significant backward failure, a variable with known significant negative prognostic implications.

Frequency of pulmonary embolism in patients with low-probability lung scan and negative lower extremity venous ultrasound.

STUDY OBJECTIVES: To define the prevalence of pulmonary embolism (PE) in patients who are undergoing pulmonary arteriography because of a high clinical suspicion for PE but who have had a low-probability lung scan and a negative lower extremity venous ultrasound examination. DESIGN: A retrospective review of the medical records of 365 consecutive patients who underwent pulmonary arteriograms for suspected PE was undertaken. RESULTS: Of the 365 pulmonary arteriograms, 62 were performed in patients with suspected PEs despite a low-probability lung scan and a negative lower extremity venous ultrasound examination. In the latter group, five patients (8%; 95% confidence interval, 2.7% to 18%) had PEs revealed on the arteriogram. CONCLUSIONS: In patients whose presentation provokes a high clinical suspicion for PE despite having had a low-probability lung scan, a negative lower extremity venous ultrasound examination is insufficient to preclude proceeding to pulmonary angiography.

Effects of therapy with nifedipine GITS or atenolol on mental stress-induced ischemic left ventricular dysfunction.

OBJECTIVES: We sought to determine the effect of nifedipine gastrointestinal therapeutic system (GITS) or atenolol on ischemic left ventricular dysfunction induced by mental stress. BACKGROUND: The efficacy of conventional antianginal therapy in preventing myocardial ischemia induced by mental stress is unknown. METHODS: Nifedipine GITS, atenolol and placebo were administered to 15 subjects with stable angina in a double-blind crossover trial. Subjects underwent a series of mental stressors at the end of each treatment. Radionuclide ventriculography was performed at baseline and at peak mental stress. Other measured variables included time to ischemia on exercise treadmill testing, ischemia on 48-h ambulatory electrocardiogram (ECG) monitoring, and resting and mental stress-induced levels of plasma catecholamines, tissue plasminogen activator antigen, plasminogen activator inhibitor-1 and platelet aggregability. RESULTS: Mental stress resulted in a significant increase in plasma epinephrine and norepinephrine levels during each treatment phase. Atenolol therapy was associated with lower baseline and postmental stress rate-pressure product compared with nifedipine or placebo. Therapy with either nifedipine GITS or atenolol prevented the development of wall-motion abnormalities and the decline in regional ejection fraction (EF) in the segment with the largest deterioration in wall motion during placebo therapy. Both medications prevented the decrease in global EF in subjects who demonstrated at least a 5% fall in global EF on placebo therapy. No therapy exerted a statistically significant benefit on exercise performance or frequency of ischemia during ambulatory ECG monitoring. CONCLUSIONS: Both nifedipine GITS and atenolol are effective at preventing mental stress-induced wall-motion abnormalities, although the mechanisms may be different.

Transmyocardial laser revascularization: results of a multicenter trial with transmyocardial laser revascularization used as sole therapy for end-stage coronary artery disease.

BACKGROUND: Transmyocardial laser revascularization was used as the sole therapy for patients with ischemic heart disease not amenable to percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. This technique uses a carbon dioxide laser to create transmyocardial channels for direct perfusion of the ischemic heart. METHODS: Since 1992, 200 patients, at eight hospitals in the United States, have undergone transmyocardial laser revascularization. The patients have a combined 1560 months of follow-up for an average of 10 +/- 3 months per patient. Their age was 63 +/- 10 years and their ejection fraction was 47% +/- 12%. Eighty-two percent had at least one previous bypass graft operation and 38% had a prior angioplasty. Preoperatively, the patients underwent nuclear single photon emission computed tomography perfusion scans to identify the extent and severity of their ischemia. These scans were repeated at 3, 6, and 12 months. Angina class, admissions for angina, and medications were recorded. RESULTS: The perioperative mortality was 9%. Angina class decreased significantly from before treatment to 3, 6, and 12 months (p < 0.001). Likewise, there was a significant decrease in the number of perfusion defects in the treated left ventricular free wall. Concomitantly, there was a significant decrease in the number of admissions for angina in the year after the procedure when compared with the year before treatment (2.5 vs 0.5 admissions per patient-year). CONCLUSION: These combined results indicate that transmyocardial laser revascularization provides angina relief, decreases hospital admissions, and improves perfusion in patients with severe coronary artery disease.

Transmyocardial laser revascularization: operative techniques and clinical results at two years.

OBJECTIVES: A new technique, transmyocardial laser revascularization, provides direct perfusion of ischemic myocardium via laser-created transmural channels. From 1993 to 1995, we have treated 20 patients (mean age 61 years, four women and 16 men) with transmyocardial laser revascularization. Preoperatively, the average angina class was 3.7. The patients were screened before the operation by a technetium sestamibi perfusion scan to identify the location and extent of their reversible ischemia. METHODS: Operative exposure is gained via a left anterior thoracotomy. With the use of a 850-watt carbon dioxide laser, an average of 21 +/- 4 channels were created in 22 minutes with a total operative time of less than 2 hours. RESULTS: The in-hospital mortality was two of 20 patients. Three additional patients died after discharge. After an accumulated 172 patient-months (mean follow-up 11 +/- 8 months, range 1 to 26 months), the mean angina class is I (p = 0.01). Postoperative sestamibi scans were obtained at 3, 6, and 12 months. Using the septum as a control and comparing the postoperative results with the preoperative baseline, we noted a significant improvement in perfusion particularly in the areas of reversible ischemia. CONCLUSION: These early results indicate that transmyocardial laser revascularization is a simple operative technique that may improve myocardial perfusion and provide angina relief for patients in whom standard methods of revascularization is contraindicated.

Mitral valve prosthetic implantation with preservation of native mitral valve apparatus.

To avoid postoperative morbidity and mortality often associated with left ventricular dysfunction after mitral valve replacement (MVR) for chronic mitral insufficiency, reconstruction or preservation of the native mitral valve apparatus may be attempted during mitral prosthetic implantation (MPI). The effects of mitral surgery on heart function, studied with echocardiography and radionuclide angiography, were compared in seven patients with MPI (study group) and five with MVR (control group) who underwent complete preoperative, early postoperative and 3-6 months follow-up examinations. Preoperatively there was significant intergroup difference only in right ventricular ejection fraction measured at radionuclide angiography, which was lower in the MPI group (p < 0.05). At follow-up the MPI group had improved as regards this fraction (p < 0.005) and stroke volume index (p < 0.05). The number of patients with improved NYHA class at follow-up was significantly greater in the MPI group. Our preliminary experience with preservation of the native mitral valve apparatus thus suggests that the method offers haemodynamic advantages for postoperative right ventricular function.

Gated SPECT with technetium-99m-sestamibi for assessment of myocardial perfusion abnormalities.

High counting statistics with 99mTc-sestamibi make gated SPECT imaging realistic. Information obtained with gated and nongated SPECT were compared in 83 subjects (20 normals, 63 patients) using a 1-day protocol (250 MBq [6 mCi] rest, 900 MBq [24 mCi] peak stress). Studies were acquired for eight frames/RR interval and formatted to a standard nongated study, a study consisting of diastolic (DIA) frames and dynamic functional studies. The right ventricle appeared more distinct in DIA than in nongated studies (p < 0.01). The left ventricular cavity was larger in DIA studies (p < 0.001), leading to more coronal slices with cavity (p < 0.001). A strong inverse relation between left ventricular cavity size in nongated studies and increase in cavity size and in number of coronal slices with cavity in DIA studies was found (r = -0.74 and -0.67, both p < 0.001). Severity (extent and degree) of perfusion abnormalities in rest and stress studies, assessed quantitatively in 50 patients (20 normals as reference), correlated highly in nongated and DIA studies (r = 0.98, p < 0.001). Severity of small and moderate sized perfusion defects showed a high degree of agreement in nongated and DIA studies, while severity of large defects was less pronounced in DIA studies (p < 0.05). In patients with subtle perfusion abnormalities, the results from DIA imaging agreed best with clinical data.

Surgery for chronic left ventricular aneurysm. Benefits and side effects.

Seventy patients who underwent elective resection of symptomatic postinfarction apico-anterior left ventricular (LV) aneurysm with or without coronary revascularization are reviewed. The early (< or = 30 day) mortality was 5.7%. Mural thrombosis occurred in 29 cases (41.4%), unrelated to the degree of preoperative LV impairment and predictable from preoperative LV angiography in only seven cases. The response to surgery comprised significant overall improvement of global LV ejection fraction (LVEF) during rest and of all variables in stress testing. This LVEF recovery correlated significantly with that of peak ejections rate, a variable of myocardial contractility. Contrastingly, right ventricular ejection fraction (RVEF) at rest decreased slightly but significantly without correlation to preoperative RVEF or LVEF. In comparisons between patients with congestive heart failure or angina at rest as dominant symptom, the former group showed greater depression of preoperative watt and LVEF but better postoperative recovery of these variables, while right ventricular deterioration was significant only in the latter. Postoperative recovery was best in patients with poor preoperative LV function (LVEF < or = 20%), even when surgery comprised only aneurysmectomy in isolated but ungraftable LAD disease (5 cases). The observed RV deterioration may be 'nonspecific', but it must be kept in mind as a side effect of the operation, as it detracts unpredictably from postoperative ventricular recovery. Patients with well preserved preoperative LVEF, small LV aneurysm and marginal expected post-aneurysmectomy changes according to LaPlace's law are probably at risk, and surgery should then instead be directed towards preserving the remaining viable myocardium by direct revascularization.

Dependence of shunt on cardiac output in unilobar oleic acid edema. Distribution of ventilation and perfusion.

OBJECTIVE: In acute respiratory failure, increased cardiac output (Qt) increases shunt (Qs/Qt). We have tested if this is caused by: 1) a redistribution of blood flow towards edematous regions, or 2) a decrease of regional ventilation in the edematous region. DESIGN: Oleic acid edema was induced in the left lower lobe (LLL) of 11 pigs. Qt was varied with bleeding and infusion of blood and dextran. Blood flow to the LLL was measured at low and high Qt with electromagnetic low probes in 6 animals and with a gamma camera in 5. In the gamma camera pigs regional ventilation was also measured. MEASUREMENTS AND RESULTS: Qt was increased by 45% (electromagnetic flow probes) and 73% (gamma camera). Qs/Qt increased from 24.9-31.3% (p < 0.05) and from 17.6-28.8% (p < 0.001) respectively. No change in fractional perfusion of LLL could be seen, neither with flow probes nor with gamma camera. A decrease in ventilation of LLL, 2.6%, was observed when Qt was increased (p < 0.05). CONCLUSION: Theoretically a small decrease in ventilation can explain the increase in shunt, if regions with low ventilation/perfusion (VA/Q) ratio are transformed to shunt. This is, however, unlikely since earlier studies have shown that blood flow is distributed either to regions with normal VA/Q ratio or to shunt regions. We conclude that the cardiac output dependent shunt is not caused by redistribution of blood flow between lobes or by decreased ventilation in the edematous region. We cannot exclude that blood flow is redistributed within the edematous lobe.

Pre- and postoperative CT and MR in pseudoaneurysms of the heart.

Pseudoaneurysms of the heart have a propensity to rupture and surgery is indicated. Usually in these cases diagnostic imaging is based on angiographic and/or echocardiographic studies. We have attempted to determine in pre- and postoperative studies the value of CT and ECG-gated MRI in patients with pseudoaneurysm. Seven patients with a pseudoaneurysm and/or dyskinesia of the posterolateral or diaphragmatic wall of the left ventricle were investigated with CT and/or ECG-gated MR studies, in addition to angiography, echocardiography, and radionuclide studies, prior to cardiac surgery. Postoperative follow-up studies with CT in six and MR in five patients were also carried out. Both CT and ECG-gated MRI allowed us to visualize the neck and CT also confirmed the communication between the cavities with or without demonstrating the conduit. In addition, disruption of the epicardial fat layer by the pseudoaneurysm was seen on both CT and MR, and the presence of intrapericardial adhesions was visualized on MR. Finally, CT and MRI, in postoperative follow-up studies, may indicate a myocardial discontinuity adjacent to the surgical patch.

Left ventricular aneurysmectomy in patients with poor left ventricular function.

Physical performance and left ventricular (LV) function in the resting state were assessed in 22 patients with postinfarction anterior-apical left ventricular aneurysm (LVA) and global ejection fraction less than or equal to 20% who subsequently underwent radical LVA resection. The basic findings in the 20 survivors of surgery were significant improvement of global systolic LV function and more or less complete recovery of regional ejection fraction in the predominantly viable low and high lateral LV wall. This improvement was evident in patients with concomitant bypass grafting as well as in those with isolated and ungraftable lesions of the left anterior descending (LAD) coronary artery. We conclude that postinfarction anterior-apical LVA in a poorly functioning LV is suitable for surgical treatment, which can be accomplished with acceptable risk. All graftable stenotic major coronary arteries should be bypassed, in addition to the LVA resection, but a minority of patients with isolated, ungraftable LAD disease are likely to benefit from aneurysmectomy alone.

Coronary artery vasoregulation and left ventricular function in patients with angina pectoris-like pain and normal coronary angiograms.

Twenty patients with angina pectoris-like pain, normal coronary angiography and abnormal exercise 201Tl scans were investigated by means of haemodynamic, coronary sinus blood flow and lactate determinations before and after cold provocation, pacing and dipyridamole infusion. Radionuclide angiography, a new exercise 201Tl scan and noninvasive hyperventilation and ergonovine tests were performed. Intracoronary infusions of acetylcholine were given in increasing doses and a second coronary angiogram in combination with a 201Tl scintigram was performed. Despite a previously pathological 201Tl scintigram, with reversible perfusion defects, only ten of the patients had reversible perfusion defects at the second investigation. Hyperventilation and ergonovine tests did not result in ECG signs indicative of coronary spasm. Intracoronary infusion of acetylcholine resulted in a diffuse coronary constriction in 3 of 14 patients, and in one patient a perfusion defect was observed on thallium scintigram. In conclusion, although most of the common methods for inducing coronary vasospasm were used, no consistent pattern of reaction was found to explain the chest pains experienced in this group of patients.

Mucociliary transport with and without the use of a heat and moisture exchanger. An animal study.

The importance to mucociliary transport (MCT) and the condition of the mucus of using a heat and moisture exchanger (HME) was investigated. A high tracheotomy was performed on 10 young pigs. The animals were ventilated using a non-breathing system. In five animals an HME was used; the other five were connected directly to the ventilator circuit. After 6 h the trachea was inspected via a flexible bronchoscope. Mucociliary transport velocity was measured using Tc-99-marked macrospheres and a gamma camera. In the control group the tracheal mucus membrane was desiccated at half the distance from the tube tip to the bifurcation. In the HME group the entire trachea was well moistened, but two cases showed large amounts of abnormally thin and foamy secretion. Mucus quality differed significantly between the two groups. Maximum MCT velocities were 8.3 +/- 4.6 and 4.9 +/- 3.0 mm/min for the HME- and the control groups, respectively. The marker had moved 49 +/- 32 and 35 +/- 21 mm during 24 min. Neither of these differences was statistically significant. In the control group there was no transport over desiccated areas. We conclude: 1) the quality of tracheal secretion differed significantly between the two groups, and 2) a heat and moisture exchanger may retain too much water in the airway.