Remote postconditioning is more potent than classic postconditioning in reducing the infarct size in anesthetized rabbits.

PURPOSE: Postconditioning confers protection to the heart after a potentially lethal episode of prolonged ischemia. There is evidence that it may also be protective when applied at a distal artery. In the present study, we sought to determine whether remote postconditioning within the heart (local) or outside the heart (distal) is effective in salvaging the ischemic heart in vivo and to compare its effect with that of the classic postconditioning. METHODS: Twenty seven open chest New Zealand white anesthetized male rabbits were divided into four groups and were exposed to 30 min regional myocardial ischemia (isc), after ligation of a prominent coronary artery, followed by 3 h reperfusion (rep) after releasing the snare. Control group (n = 7) was subjected to no additional interventions, postC group (n = 6) was subjected to four cycles of 1 min isc/1 min rep of the same coronary artery at the beginning of reperfusion, remote local postC group (n = 7) to four cycles of 1 min isc/1 min rep of another coronary artery 30 s before the end of index isc and remote distal postC group (n = 7) to four cycles of 1 min isc/1 min rep of another (carotid) artery again 30 s before the end of index isc. Infarct size (I) and area at risk (R) were delineated with the aid of TTC staining and green fluorescent microspheres respectively and their ratio was expressed in percent (%I/R). RESULTS: Remote local and remote distal postC reduced the % I/R ratio (17.7 +/- 1.7% and 18.4 +/- 1.6%, respectively vs 47.0 +/- 2.5% in the control group, P < 0.01). Classic PostC had an intermediate protective effect (33.1 +/- 1.7%, P < 0.05 vs all the other groups). CONCLUSION: Remote postconditioning consisted of 1 min isc/1 min rep protects the ischemic rabbit heart in vivo, independently of the site of the remote artery. This intervention seems to confer a stronger protection than the classic postconditioning.

Evaluation of left atrial longitudinal function in patients with hypertrophic cardiomyopathy: a tissue Doppler imaging and two-dimensional strain study.

OBJECTIVE: We sought to quantify left atrial longitudinal function by tissue Doppler (TDI) and two-dimensional (2D) strain in patients with hypertrophic cardiomyopathy (HCM). DESIGN: Case-control study. SETTING: Tertiary university hospital. PATIENTS: 43 consecutive patients with familial HCM, aged 49 (SD 18) years, along with 21 patients with non-HCM left ventricular hypertrophy (LVH, aged 52 (12) years) and 27 healthy volunteers (aged 42 (13) years). INTERVENTIONS: Subjects were studied by both TDI and 2D left atrial strain during all three atrial phases (reservoir, conduit, contractile), as well as by left ventricular systolic strain; total atrial deformation (TAD) was defined as the sum of maximum positive and maximum negative strain during a cardiac cycle. MAIN OUTCOME MEASURES: Left atrial longitudinal function. RESULTS: Both TDI and 2D atrial strain and TAD were significantly reduced in HCM, compared to the other two groups in all atrial phases (p<0.001 in most cases); left ventricular systolic strain was also significantly reduced in HCM (p<0.001). Adding 2D contractile atrial strain to a model of conventional echo measurements (including left atrial diameter and volume index, interventricular septal thickness and E/A ratio and E/e' ratios) increased its prognostic value in differentiating HCM from non-HCM LVH (p value of the change <0.001), while addition of TDI atrial strain or left ventricular strain did not. A cut-off for 2D contractile strain of -10.82% discriminated HCM from non-HCM LVH with a sensitivity of 82% and a specificity of 81%. Intra-observer and inter-observer variabilities for atrial strain in HCM were 16% and 17.5% for TDI and 8% and 9.5% for 2D, respectively. Processing time per case in HCM was 12.5 (2.6) minutes for TDI versus 3.8 (1.2) minutes for 2D strain (p<0.001). CONCLUSION: Left atrial longitudinal function is reduced in HCM compared to non-HCM LVH and healthy controls. In addition, 2D atrial strain has an additive value in differentiating HCM from non-HCM LVH and it is more reproducible and less time consuming than TDI strain.

Clinical and prognostic implications of self-rating depression scales and plasma B-type natriuretic peptide in hospitalised patients with chronic heart failure.

BACKGROUND: Depression is common among patients with chronic heart failure (CHF) and has been independently associated with a poorer prognosis. PURPOSE: This study evaluated the clinical and prognostic value of depression scales (Beck Depression Inventory (BDI), Zung Self-rating Depression Scale (Zung SDS)) along with plasma B-type natriuretic peptide (BNP) in CHF. METHODS: 155 hospitalised CHF patients (ejection fraction 26.9% (SD 6.4%)) were studied by depression (BDI, Zung SDS) and functional questionnaires (Kansas City Cardiomyopathy Questionnaire (KCCQ), Duke Activity Status Index (DASI)), BNP and 6-minute walk test (6MWT). Patients were followed for 6 months for cardiovascular events, including death from any cause or rehospitalisation for CHF decompensation. RESULTS: Seventy-six (49%) patients with depressive symptoms, as estimated by both scales, had significantly lower DASI and KCCQ scores (13.2 (SD 9.9) vs 23.6 (SD 13.0) and 26.6 (SD 15.0) vs 45.0 (SD 17.0), respectively; p<0.001), higher BNP (921 (SD 889) vs 439 (SD 267) pg/ml, p = 0.001) and reduced 6MWT (270 (SD 130) vs 337 (SD 133); p<0.001). According to logistic regression analysis, Zung SDS and BNP were independently associated with adverse clinical outcomes; values of Zung SDS >or=40 and of BNP >or=290 pg/ml predicted future events with a sensitivity of 82% and 94% and a specificity of 45% and 46%, respectively. The combination of Zung SDS plus BNP had an additive prognostic value, predicting events with a sensitivity of 77% and a specificity of 70% (event-free survival: Zung <40 and BNP <290 pg/ml; 170 (SD 9) days; Zung >or=40 and BNP <290 pg/ml, 159 (SD 14) days; Zung <40 and BNP >or=290 pg/ml, 118 (SD 15) days; Zung >or=40 and BNP >or=290 pg/ml, 73 (SD 8) days, p<0.001). CONCLUSIONS: CHF patients with depressive symptoms have impaired physical activity, associated with excessive neurohormonal activation. Among the studied scales, Zung SDS seemed to independently predict clinical outcome, especially in patients with increased plasma BNP concentration. Hence, the combination of those two modalities provides a practical means for risk stratification in CHF.

Increased C reactive protein and cardiac enzyme levels after coronary stent implantation. Is there protection by remote ischaemic preconditioning?

AIM: To investigate whether remote ischaemic preconditioning (RIPC) can attenuate the inflammatory response and enzyme leakage that can occur after uncomplicated routine percutaneous coronary intervention (PCI). METHODS: 41 consecutive normotensive patients with stable angina and single-vessel disease were assigned to be exposed to RIPC (n = 20) or not (control group; n = 21) before elective PCI with stent implantation. RIPC was induced by three cycles of 5-min ischaemia-reperfusion of both upper limbs (inflation/deflation of blood pressure cuff). C reactive protein (CRP), creatine phosphokinase (CK), CK cardiac isoenzyme (CK-MB) and troponin I (TNI) were serially measured for 48 h. RESULTS: No difference in baseline values was observed between the groups. The CRP rose significantly (p<0.001) and at 48 h was similarly increased (>fourfold) in both groups (15.7 (2.6) v 14.0 (3.3) mg/l, RIPC v control; p = NS). However, sub-group analysis on the basis of statin use showed that the highest rise was in the group of patients with RIPC not taking statins and was significantly greater than in patients with RIPC taking statins (23.8 (3.71) v 11.4 (3.0) mg/l, respectively, p<0.01). Both CK-MB and TNI leakage were raised (slightly but significantly) after PCI in controls at 24 h compared with baseline values. However, this small rise was significantly worse after RIPC (CK-MB, 1.33 (0.27) v 3.57 (0.97) ng/ml, p<0.01; TNI, 0.255 (0.059) v 0.804 (0.232) ng/ml, p<0.05, respectively at 24 h). The increase was more marked in the RIPC subgroup not taking statins. CONCLUSIONS: RIPC does not reduce, but exacerbates, the enzyme and TNI release from the heart after single-vessel angioplasty with stent. Furthermore, the increased circulating CRP remains raised. It seems that there is an enhanced inflammatory response after RIPC in the absence of statin treatment.

Dobutamine echocardiographic study in patients with nonischemic dilated cardiomyopathy and prognostically borderline values of peak exercise oxygen consumption: 18-month follow-up study.

OBJECTIVES: We sought to study the prognostic value of dobutamine echocardiography in patients with nonischemic dilated cardiomyopathy (DCM) and prognostically borderline values of peak oxygen consumption (VO2max) during exercise. BACKGROUND: Changes in echocardiographic variables assessed by dobutamine echocardiography can be used to evaluate the functional status of patients with chronic heart failure (CHF) and DCM. METHODS: In 27 consecutive patients (mean age 55 +/- 15 years) with VO2max values between 10 and 14 ml/kg body weight per min, a low infusion rate (10 microg/kg per min) dobutamine echocardiographic test was performed. The induced changes in echocardiographic variables were measured, and an 18-month follow-up study was done. RESULTS: At the end of the protocol, 9 patients (group I) had died from cardiac reasons, whereas the remaining 18 patients (group II) survived. After dobutamine infusion, the left ventricular end-systolic diameter (LVESD) was smaller in group II (6.22 +/- 0.94 cm) than in group I (6.99 +/- 0.76 cm; p < 0.05), whereas end-systolic wall stress (ESWS) was higher in group I (1030.66 +/- 193.98 g/cm2) than in group II (691.57 +/- 297.06 g/cm2; p < 0.05). The changes in LVESD and ESWS were greater in group I (0.75 +/- 0.36 cm and 463.11 +/- 159.87 g/cm2, respectively) than in group II (-0.04 +/- 0.36 cm and 83.16 +/- 291.74 g/cm2, respectively; p < 0.01 for both). CONCLUSIONS: In the "gray" zone of VO2max, dobutamine echocardiography seems to be a valuable prognostic indicator in patients with CHF and DCM.

Serial evaluation of coronary flow reserve by transesophageal doppler echocardiography after angioplasty of proximal left anterior descending coronary artery: a 6-month follow-up study.

BACKGROUND: Coronary flow reserve can be estimated by transesophageal Doppler echocardiography (TDE). OBJECTIVE: To evaluate the coronary flow reserve by TDE, serially over 6 months' follow-up, after successful percutaneous transluminal coronary angioplasty (PTCA) of proximal left anterior descending coronary artery (LADA). METHODS AND RESULTS: We performed TDE examination of 30 patients (mean age 55 +/- 9 years) 72 h, 3 months, and 6 months after PTCA of LADA. Selective angiography of LADA was repeated 72 h and 6 months after PTCA of LADA. Velocity of flow in LADA was measured before and 2 min after cessation of intravenous infusion of dipyridamole (0.56 mg/kg in 4 min). The dipyridamole: rest mean diastolic velocity ratio was considered as an index of coronary flow reserve (CFR). For 20 of 21 patients with CFR > 2 there was no restenosis, whereas coronary angiography revealed restenosis in eight of nine patients with CFR < 2. The sensitivity was 88.9% and the specificity was 95.2%. For the 21 patients without restenosis mean CFR was 2.1 +/- 0.1 72 h after PTCA, had increased to 3.1 +/- 0.3 (P < 0.0001) 3 months after PTCA, and remained stable thereafter (3.0 +/- 0.9). CONCLUSION: CFR after PTCA of proximal LADA can be evaluated serially by transesophageal Doppler echocardiography. CFR of LADA in patients without restenosis is increased 3 months after PTCA and remains stable thereafter.

Assessment of the functional status of heart failure in non ischemic dilated cardiomyopathy: an echo-dobutamine study.

BACKGROUND: The functional status of heart failure (HF) is conventionally evaluated by peak exercise oxygen consumption (VO2 max). Dobutamine echocardiography can be used to evaluate myocardial reserve. The aim of this study was to estimate the functional status of chronic HF in patients with dilated cardiomyopathy, by investigating the changes in echo-variables, as assessed by echo-dobutamine, in relation with VO2 max. METHODS AND RESULTS: A low infusion rate echo-dobutamine test (10 micrograms/kg/min) was performed in 30 patients with dilated cardiomyopathy and 1 h later VO2 max was measured. VO2 max (ranging from 7.6 to 23 ml/kg/min, mean 14.06 +/- 0.64 ml/kg/min) was correlated with the changes (values obtained after inotropic stimulation minus those obtained at baseline) in left ventricular end-systolic diameter (r:0.80, p:0.001), in left ventricular end-systolic posterior wall thickness (r:0.73, p:0.001) and in left ventricular heart-rate corrected mean velocity of circumferential fiber shortening (Vcfc)/end-systolic meridional wall stress ratio (r:0.64, p:0.0001). A negative correlation was found between VO2 max and the changes in end-systolic meridional wall stress (r: -0.76, p:0.001). After dobutamine infusion Vcfc/systolic meridional wall stress ratio increased in patients with VO2 max > 14 ml/kg/min but decreased in patients with VO2 max < 14 ml/kg/min (0.0001 +/- 0.0001 vs -0.0002 +/- 0.0003 circ x cm2/g x s, p:0.0001). End-systolic meridional wall stress was decreased in patients with VO2 max > 14 ml/kg/min but increased in patients with VO2 max < 14 ml/kg/min (-126.97 +/- 34.24 vs 205.77 +/- 56.71 g/cm2, p:0.0001). CONCLUSION: The changes in echo-variables assessed by echo-dobutamine are well correlated with VO2 max and seem to be accurate for evaluating the functional status of chronic HF in patients with dilated cardiomyopathy.

Pulmonary vein flow analysis by transoesophageal echocardiogr phy in patients with chronic atrial fibrillation; 1 year follow-up after cardioversion.

AIMS: Left and right upper pulmonary vein flow can be adequately recorded by transoesophageal Doppler echocardiography. The aim of this study was to investigate whether analysis of the pulmonary venous flow velocity pattern can predict the long-term maintenance of sinus rhythm after successful cardioversion of chronic atrial fibrillation. METHODS AND RESULTS: Thirty-six consecutive patients, aged 53+/-9 years, with chronic atrial fibrillation of 5.33+/-2 months duration, were subjected to transoesophageal Doppler echocardiography to record left and right upper pulmonary venous flow, 24 h and 3 months following successful cardioversion. One year following cardioversion, 12 patients (33.3%) were in sinus rhythm (sinus rhythm group) while the remaining 24 patients were in atrial fibrillation (atrial fibrillation group). At 24 h following cardioversion, biphasic systolic forward flow in the left and/or right upper pulmonary venous flow velocity was detected in 10 patients of the sinus rhythm group and in four patients of the atrial fibrillation group (P<0001). The systolic fraction was significantly higher in the sinus rhythm group, 0.48+/-0.04 and 0.39+/-0.06, P<0.001 for the left upper pulmonary venous flow, and 0.52+/-0.05 and 0.41+/-0.04, P<0.001 for the right upper pulmonary venous flow, respectively. In patients who displayed a biphasic systolic forward flow and in whom the right upper pulmonary venous flow systolic fraction was higher than 0.50 at 24 h post-cardioversion, the probability of maintenance of sinus rhythm at 1 year exceeded 95%. CONCLUSION: The detection of a biphasic systolic forward flow in the pulmonary venous flow velocity, and of a right upper pulmonary vein systolic fraction higher than 0.50 as early as 24 h following cardioversion of chronic atrial fibrillation, identifies patients who will remain in sinus rhythm 1 year after cardioversion.

Prospective randomized trial of external versus internal transcatheter cardioversion in patients with chronic atrial fibrillation.

To evaluate the safety and long-term efficacy of internal transcatheter cardioversion, forty patients with chronic, lone atrial fibrillation were studied. The patients were randomised to internal transcatheter cardioversion or to conventional external cardioversion. In cases where the procedure was unsuccessful, cross-over to the alternate method was performed. Oral anticoagulation therapy was started three weeks prior to the procedure and was maintained for another three weeks following successful cardioversion. Sinus rhythm was restored in 16/18 patients (88%) in the internal cardioversion group, versus 9/22 patients (40%) in the external cardioversion group (p < 0.01). In addition, 8/13 (61%) patients who were crossed-over to internal cardioversion were successfully cardioverted to sinus rhythm. In contrast, both patients who were crossed-over to external cardioversion remained in atrial fibrillation. During a mean follow-up period of 23 months, 13 (39.3%) patients maintained sinus rhythm. Using the intention to treat principle, the recurrence rate was not statistically different between the two methods. It is concluded that internal cardioversion is more effective in acutely restoring sinus rhythm compared to external cardioversion. However, both methods have similar long-term recurrence rates.

Transesophageal Doppler evaluation of left anterior descending coronary artery angioplasty.

Transesophageal Doppler echocardiography can noninvasively evaluate the functional results of left anterior descending coronary artery angioplasty. Coronary flow reserve assessed by this technique is significantly increased only in those patients with less severe residual stenosis as detected by intravascular ultrasound, thus allowing a noninvasive assessment of the results of left anterior coronary artery angioplasty.

Coronary collateral blood-flow velocity improves with repeated coronary occlusions during angioplasty in patients with coronary artery disease and systemic hypertension.

BACKGROUND: Cardiac hypertrophy is associated with numerous alterations in the coronary circulation. OBJECTIVE: To test the hypothesis that, during angioplasty, the coronary collateral blood flow during repetitive coronary occlusions increases more in hypertensives than it does in normotensives. METHODS: We studied 34 patients (22 normotensives and 12 hypertensives) with stable angina and single-vessel disease undergoing coronary angioplasty during two similar balloon inflations. Each balloon inflation was maintained for 120 s. The coronary blood flow velocity was estimated using the Doppler-flow guide wire, which was positioned distally to the lesion. Flow velocities were recorded before balloon deflation. RESULTS: The average peak velocity increased by 29.0 +/- 14.7 mm/s in the hypertensives and decreased by 9.4 +/- 4.9 mm/s in the normotensives (P < 0.01) during the second balloon inflation, whereas the velocity-time integral increased by 33.1 +/- 19.2 mm and decreased by 14.3 +/- 11.3 mm (P < 0.05), respectively. The ST-segment elevation decreased by 1.13 +/- 1.27 and by 0.17 +/- 0.16 mV, respectively (P = 0.01). The increase in the average peak velocity which occurred during the second balloon inflation was related to the left ventricular mass (r = 0.47, P = 0.004). CONCLUSION: These results indicate that the coronary collateral blood flow velocity improves with repetitive coronary occlusions during angioplasty in patients with systemic hypertension and that this increase is correlated to the left ventricular mass.

Coronary flow reserve assessed by transesophageal echocardiography identifies early restenosis of the left anterior descending coronary artery angioplasty.

Although an increase in diastolic coronary flow velocity can be detected by transesophageal echocardiography 72 hours after both successful and unsuccessful left anterior coronary artery angioplasty, a significant improvement in coronary flow reserve is observed only in patients with a successful procedure. Transesophageal echocardiography-derived coronary flow reserve can identify early restenosis and thus serve as an index of the outcome of the procedure.

Decreased vasomotor effect of endothelin on the coronary arteries during angioplasty in hypertensive patients.

To investigate if the response of the contralateral artery during coronary angioplasty (PTCA) is different in hypertensive than in normotensive patients and whether this response is related to plasma levels of endothelin-1 (ET-1). We examined the change in ET-1 plasma levels and the reactivity of the left circumflex artery (LCx) during PTCA of the left anterior descending branch in 10 hypertensive and 23 normotensive patients. Peripheral vein blood samples were drawn for ET-1 estimation at baseline, after the end of the first balloon inflation, at the end of PTCA, and 4 h later. Angiograms of the LCx were obtained at baseline and during the 1st balloon inflation. The ET-1 level in hypertensives increased from 6.81 +/- 3.76 at baseline to 7.54 +/- 4.76 pmol/l (P = n.s.) at the end of PTCA, while in normotensives it increased from 8.21 +/- 3.73 to 11.56 +/- 5.04 pmol/l (F = 7.48, P = 0.0002) respectively. The LCx distal segment diameter increased from 1.29 to 1.50 mm during balloon inflation in hypertensive, and from 1.44 to 1.53 mm (F = 5.03, P = 0.03) in normotensives. The diameter increase was related to the baseline ET-1 level (r = -0.67, P = 0.005) in the normotensives, but not in the hypertensives. Thus ET-1 has a weaker vasomotion effect on the coronary vasculature in hypertensives than in normotensives during PTCA.

Protection from preconditioning can be reinstated at various reperfusion intervals.

The aim of this study was to evaluate the way in which short-term protection declines and is eventually lost in preconditioning and to determine the efficacy of a second preconditioning at various reperfusion intervals. Male rabbits were divided into six groups. Forty-five minutes (sustained) ischemia followed by 120 minutes reperfusion was applied 60, 65, 70, 75, and 80 minutes after a 5 minute preconditioning (groups A, B, C, D, and E) and in a control group (F) after no preconditioning. The infarct to risk ratio (I/R) was 38.3 +/- 3.5% in group A, 46.0 +/- 7.8% in B, 61.6 +/- 9.7% in C, 68.1 +/- 4.2% in D, 64.5 +/- 7.8% in E, and 61.0 +/- 7.7% in F. Group A had a smaller I/R compared with groups C, D, E, and F (p < 0.05). In another series, groups G, H, and I were exposed to two 5-minute preconditioning stimuli, separated, respectively, by 45, 60, and 75 minutes of reperfusion; 10 minutes after the last preconditioning, the animals were exposed to 45-minutes ischemia and 120 minutes reperfusion. Groups A and D (with the smaller and higher I/R ratio) were also incorporated into this protocol in order to compare the effect of the additional preconditioning with the single one. The I/R ratio was 25.4 +/- 8.5% in group G, 22.8 +/- 7.0% in group H, and 14.7 +/- 4.0% in group I (p = NS). Group D showed a higher I/R compared with groups G, A, and H (p < 0.01), and group I had a smaller I/R compared with groups A (p < 0.01) and D (p < 0.001). Cardioprotection after a first preconditioning declines gradually and is eventually lost. An additional preconditioning is always effective, and the longer the interval from the first preconditioning, the more potent is the effect.

Alterations in circulating cyclic guanosine monophosphate (c-GMP) during short and long ischemia in preconditioning.

The aim of this study was to investigate if levels of circulating cyclic guanosine monophosphate (c-GMP) alter in preconditioning. Twenty-eight rabbits were divided into four groups. In vivo hearts were preconditioned, either with 5 min (group A, n = 8) or with 1 min (group B, n = 8) ischemia, followed by 10 min reperfusion, while groups C (n = 7) and D (n = 5) had no interventions. Protection was determined by subjecting groups A, B and C (but not D) to 30 min regional ischemia which was followed (including group D) by 2 h reperfusion. Seven blood samples were collected for the assessment of circulating c-GMP at different points of time. All results were expressed in pmol/ml using radio-immunoassay and the infarcted to risk area in percent using fluorescent particles and tetrazolium chloride (TTC). Circulating c-GMP increased during long ischemia only in group A (baseline value 47 +/- 4, long ischemic values 60.5 +/- 4 and 60.4 +/- 4, p < 0.05). Circulating c-GMP in group A was significantly higher in the middle of the long ischemia in comparison to the groups B, C and D (60.5 +/- 4 vs 43.9 +/- 4, 45.8 +/- 5 and 43.6 +/- 4, p < 0.05). Infarcted to risk ratio was lower in group A than in groups B and C (12.2 +/- 4 vs 29.6 +/- 6 and 34.2 +/- 6 respectively, p < 0.05). Circulating c-GMP is increased in classically preconditioned in comparison to ineffectively preconditioned hearts or to control groups. This elevation may be related to the protective effect of this phenomenon.

Clinical, adrenergic and heart endocrine measures in chronic atrial fibrillation as predictors of conversion and maintenance of sinus rhythm after direct current cardioversion.

The aim of this study was to evaluate clinical, adrenergic and endocrine factors that could predict sinus rhythm maintenance after direct current cardioversion in chronic atrial fibrillation. Nineteen patients with chronic non-rheumatic atrial fibrillation (mean duration 6 +/- 5 months) were studied. They were exercised 24 h before cardioversion at maximum effort with the Naughton protocol. Heart rate and blood pressure at rest and exercise were recorded and blood samples were taken for the assessment of adrenergic activity, by measuring cyclic adenosine monophosphate, heart endocrine function, atrial natriuretic peptide and its second messenger, cyclic guanosine monophosphate. Fifteen of the 19 patients were initially converted to sinus rhythm (eight patients with external and seven patients with internal DC shocks). After 3 months eight patients remained in sinus rhythm and 11 had relapsed, most of them within the first month. On exercise the chronotropic response was lower in the group who remained in sinus rhythm than in the group in atrial fibrillation (peak heart rate 147 +/- 11 beats.min-1 vs 165 +/- 24 beats.min-1 P = 0.02). During exercise, the systolic blood pressure in the sinus group reached higher values than in the group who relapsed (192 +/- 17 mmHg vs 176 +/- 18 mmHg, P = 0.03). Cyclic adenosine monophosphate increased significantly from rest to peak exercise in the sinus rhythm group (from 23 +/- 9 pmol.ml-1 to 31 +/- 15 mol.ml-1, P = 0.02) while it remained unchanged in the atrial fibrillation group (25 +/- 10 pmol.ml-1 to 24 +/- 8 pmol.ml-1, P = 0.02). For all 19 patients the difference in cyclic adenosine monophosphate between rest and exercise was negatively correlated with maximum heart rate (r = 0.58, P = 0.009). Atrial natriuretic peptide increased from rest to peak exercise in the sinus rhythm group (from 129 +/- 58 fmol.ml-1 to 140 +/- 66 fmol.ml-1) while it remained unchanged in the group in which atrial fibrillation persisted or recurred (from 112 +/- 58 fmol.ml-1 to 111 +/- 53 fmol.ml-1, P = 0.002). A significant correlation between atrial natriuretic peptide and cyclic guanosine monophosphate levels at exercise before cardioversion was found for the sinus rhythm group only (r = 0.76, P = 0.02). In patients with non-rheumatic chronic atrial fibrillation evaluation of clinical parameters such as heart rate and blood pressure changes during maximal exercise can be useful in the choice of suitable therapy. An inadequate increase in plasma cyclic-adenosine monophosphate and atrial natriuretic peptide on exercise could predict patients with more severe underlying disease, where cardioversion should not be recommended.

Diastolic aortic pressure rise during percutaneous transluminal coronary angioplasty: an index of left ventricular systolic dysfunction.

OBJECTIVES: To investigate the relation between diastolic aortic pressure response and left ventricular systolic dysfunction during percutaneous transluminal coronary angioplasty. BACKGROUND: The abnormal diastolic blood pressure rise during exercise in patients with coronary artery disease probably reflects left ventricular systolic dysfunction rather than the number of stenosed coronary arteries. METHODS: Aortic blood pressures and left ventricular systolic function indices were estimated in 26 patients with single proximal stenosis of the left anterior descending coronary artery both before and during angioplasty. RESULTS: During coronary angioplasty all patients presented an increase in diastolic aortic pressure (P << 0.001), 8-12s before intracoronary electrocardiographic changes. During acute ischaemia there was a decrease in left ventricular ejection fraction (P << 0.001) and stroke volume (P << 0.001) and an increase in end systolic volume (P << 0.001) and left ventricular end diastolic pressure (P << 0.001). No statistically significant changes were observed in systolic blood pressure or heart rate. The aortic diastolic pressure increase was correlated with the decrease in ejection fraction (r = -0.95, P << 0.001) and with the increases in end systolic volume (r = 0.86, P << 0.001) and left ventricular end diastolic pressure (r = 0.85, P << 0.001). CONCLUSIONS: The rise in diastolic aortic pressure during percutaneous transluminal coronary angioplasty occurs earlier than intracoronary electrocardiographic changes and is related to ischaemic left ventricular systolic dysfunction.

Systolic functional response of normal older and younger adult left ventricles to beta-blockade during exercise.

There is controversy over the effects of beta-blockade on the left ventricular systolic response of the heart of the elderly to stress. In this study we compared the effects of acute beta-blockade in normal older and younger adult left ventricles during exercise. The study population consisted of 17 healthy elderly people, 67 +/- 3 years old, while 18 young normal subjects, 31 +/- 4 years old, served as controls. A symptom-limited exercise treadmill test was performed before and 15 minutes after intravenous administration of 0.12 mg propranolol/kg. M-mode echocardiographic studies were performed before and immediately after each test. Intravenous propranolol at rest decreased heart rate by 14 +/- 7 beats/min in the elderly and by 7.5 +/- 8 beats/min in the young (p = 0.02), decreased the double product by 2500 +/- 1200 mmHg/min and 1830 +/- 970 mmHg/min (p = 0.05), respectively; changed the left ventricular end-systolic dimension by +0.21 +/- 0.36 cm and +0.03 +/- 0.24 cm (p = 0.09), respectively; and changed the end-diastolic dimension by +0.22 +/- 0.46 cm in the elderly and by -0.02 +/- 0.32 cm in the young (p = 0.08). The change in fractional shortening was -1.22 +/- 4.17% in the elderly and -0.78 +/- 4.05% in the young (p > 0.05), and the decrease in the systolic blood pressure/end-systolic dimension ratio was 5.9 +/- 7 mmHg/cm and 4.3 +/- 3.8 mmHg/cm, respectively (p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The re-introduction of ischemic preconditioning is able to protect myocardium after repeated long reperfusion intervals.

Classic ischemic preconditioning confers protection to the vulnerable myocardium following brief periods of ischemia with short intermittent periods of reperfusion. The aims of this study were: (i) to ascertain the protection from preconditioning using a relatively long reperfusion interval; (ii) to see whether this protection exists if preconditioning and long reperfusion is repeated and (iii) to evaluate the effect that an additional preconditioning stimulus has if it is given immediately before the sustained ischemia. Following anesthesia, in-vivo hearts were preconditioned with a 5 minute coronary ligation followed by 10 minutes reperfusion (Group A). This was compared to groups that were preconditioned with 5 minutes ischemia and 1 hour reperfusion (Group B); or 5 minutes ischemia with 1 hour reperfusion, repeated twice (Group C); or 5 minutes ischemia with 1 hour reperfusion repeated twice and followed by 5 minutes ischemia and 10 minutes reperfusion (Group D). Protection was assessed by subjecting each of the above groups to a further 45 minutes of regional ischemia followed by 120 minutes reperfusion. This protocol without prior preconditioning served as a control (Group E). The ratio of the infarcted to risk area was 23.1 +/- 4.1% in group A, 38.3 +/- 3.5% in group B, 58.4 +/- 4.9% in group C, 10.4 +/- 3.1% in group D and 61.8 +/- 6.2% in the control group E. Group D was significantly different from all the other groups. Group B was not different in comparison to the control group E. When a relatively long reperfusion period (Group B) was introduced the preconditioning protection diminished. When this long reperfusion period was repeated (Group C) overall protection was lost. However, when preconditioning was re-introduced alter a long delay (Group D), the protection afforded by it not only returned but appeared to be potentiated.