Background Noncompaction of ventricular myocardium （NVM） is a rare type of primary cardiomyopathy. The disease is caused by the disorder in the densification of the myocardium in the early stage of the embryo proces...Background Noncompaction of ventricular myocardium （NVM） is a rare type of primary cardiomyopathy. The disease is caused by the disorder in the densification of the myocardium in the early stage of the embryo process. The morphological characteristics are projecting trabeculation in the ventricle and the deep trabecular space interlinked with ventricular chamber. In recent years, many studies have found that the left ventricular growth associated genetic mutation is closely related to the occurrence of NVM. The most clinical manifestations such as heart failure, thromboembolism and arrhythmia are specific. Echocardiography is the most commonly used tech- nique for the diagnosis of NVM. Cardiac computed tomography （CT） scan, cardiac magnetic resonance imaging and left ventricular angiography are other important techniques for its diagnosis. The NVM patients have a long course of disease, poor prognosis and a high rate of misdiagnosis. This article reviews the research progress in the aspects of epidemiological characteristics, genetic characteristics, clinical manifestations, pathophysiology, diagnosis, treatment and so on, in order to provide the basis for the diagnosis and treatment of NVM.展开更多
Abstract Using histochemistry technique, the effects of radiofrequency catheter ablation (RFCA) on the activities of LDH, SDH, CCO, and Ca^2+ ATPase of guinea pig ventricular myocytes were examined. In the ...Abstract Using histochemistry technique, the effects of radiofrequency catheter ablation (RFCA) on the activities of LDH, SDH, CCO, and Ca^2+ ATPase of guinea pig ventricular myocytes were examined. In the meanwhile, the histological changes were observed as Department of Cardiology, Tongji Hospital, Tongji Medical University. Wuhan 430030, China (Wang YG, Lu ZY) Department of Anatomy, Tongji Medical University, Wuhan 430030, China (Xiong XK) control. Radiofreqency energy (500 kHz) delivered was 20W×10s. The resultes were as follows: RFCA resulted in significant impairments in all the four kinds of enzymses but without statistical differences among their areas involved in this energy level, and there are no statistical significant differences when compared with those of histological lesion area. These findings showed consistency in areas of the histological and histochemical lesions resulted from RFCA.展开更多
Background: Left ventricular noncompaction with multiple left ventricular thrombi can be revealed by echocardiography, and early diagnosis seems to be imperative to prevent significant embolic events. Case Report: A 5...Background: Left ventricular noncompaction with multiple left ventricular thrombi can be revealed by echocardiography, and early diagnosis seems to be imperative to prevent significant embolic events. Case Report: A 57-year-old woman presented with symptoms of heart failure. Two-dimensional transthoracic echocardiogram demonstrated a dilated and diffusely hypokinetic left ventricle with severe impaired left ventricular systolic function. Moreover, a markedly thickened endocardium at the left ventricular apex and middle segment with numerous, excessively prominent trabeculations and deep intertrabecular recesses were present. During systole, the ratio of the noncompacted to compacted myocardial layers at the site of the maximal wall thickness was above two, a characteristic finding in left ventricular non-compaction. Multiple mobile, homogeneous, echodense thrombi were identified in the left ventricle, with the largest one in the apical noncompacted segment (dimensions, 32 × 14 mm). Cardiac magnetic resonance imaging confirmed the diagnosis of noncompacted myocardium with the presence of multiple thrombi. After anticoagulant therapy, her symptoms improved and thrombi dissolved. Unexpectedly, she re-admitted to the cardiovascular unit with progressive dyspnea. Transthoracic echocardiogram showed new large right atrial thrombi, with the largest one was 43 × 38 mm compared to the echocardiogram done 11 months ago. The patient was anticoagulated with continuous heparin infusion for several days followed by oral Apixaban. After 4 weeks, the floating thrombi completely disappeared. After a 26-month follow-up, the patient’s condition was stable without embolic complications. Conclusion: Echocardiography was the cornerstone of diagnostic methods for early detecting left ventricular thrombi to eventually prevent embolic events.展开更多
Objectives To investigate the relation between hypertrophied myocardium and ventricular fibrillation threshold in spontaneously hypertensive rats （SHR）. Methods 20 male SHR were randomly divided into two groups： 10...Objectives To investigate the relation between hypertrophied myocardium and ventricular fibrillation threshold in spontaneously hypertensive rats （SHR）. Methods 20 male SHR were randomly divided into two groups： 10 week group （n= 10） and 18 week group （n=10）. 10 week male Wistar rats were controlled group （n=10）. The systolic blood pressure （SBP）, heart mass index （HMI）, ventricular effective refractory period （VERP） and ventricular fibrillation threshold（VFT） were measured respectively.① The SBP and HMI of SHR were significantly higher than those of Wistar rats（P 〈 0.001）. The VFT of SHR were significantly lower than that of Wistar rats （P 〈 0.001）.②In SHR, the SBP and HMI of 18 week SHR were significantly higher than those of 10 week SHR （P 〈 0.001）. The VFT of 18 week SHR were significantly lower than that of 10 week SHR （P 〈 0.001）. ③There were no significant difference of VERP among 10 week SHR, 18 week SHR and Wistar rats（P 〉 0.05）. ④There was no relationship between HMI and VFT or SBP in Wistar rats. There was significant relationship between HMI and VFT or SBP in different age spontaneously hypertensive rats. ⑤HMI, age and species of animal were the major influent factors of VFT. Conclusions The VFT of hypertrophied myocardium decreased. The higher the degree of hypertrophy of myocardium and the higher the systolic blood pressure were, the lower the ventricular fibrillation threshold was.展开更多
Objectives The long-term benefit of late reperfusion of infarct-related artery （IRA） after acute myocardial infarction （AMI） is controversial, and the benefit mechanisms remain uncertain. Low dose dobutamine stres...Objectives The long-term benefit of late reperfusion of infarct-related artery （IRA） after acute myocardial infarction （AMI） is controversial, and the benefit mechanisms remain uncertain. Low dose dobutamine stress echocardiography （LDSE） can identify viable myocardium and predict improvement of wall motion after revascularization. Methods Sixtynine patients with first AMI who did not received early reperfusion therapy were studied by LDSE at 5 to 10 days after AMI. Wall motion abnormality and left ventricular size were measured at the same time. Successful PCI were done in all patients at 10 to 21 days after AMI onset. Patients were divided in two groups based on the presence or absence of viable myocardium. Echocardiography was repeated six months later. Results There were 157 motion abnormality segments. 89 segments （57%） were viable during LDSE. 26 patients （38%） with viability and 43 （62%） without. In viable group, left ventricular ejection fraction （LVEF） was increased （P 〈 0.05）, and left ventricular end systolic volume index （LVESVI） and wall motion score （WMS） were decreased （P 〈 0.05 and P 〈 0.01） significantly at 6 months compared with baseline. But in patients without viability, LVEF was decreased （P 〈 0.01）, and LVESVI and left ventricular end diastolic volume index （LVEDVI） were increased （P 〈 0.05） significantly after 6 months, and the WMS did not changed （P 〉 0.05 ）. LVEF increased （P 〈 0.05 ） and WMS decreased （P 〈 0.05） on LDSE during acute phase in patients with viability, but they were not changed in the nonviable group. Conclusions Late revascularization of IRA in patients with presence of viable myocardium after AMI is associated with long-term preservation left ventricular function and less ventricular remodeling. Improvement of left ventricular systolic function on LDSE indicates late phase recovery of left ventricular function after late revascularization.展开更多
AIM To compare myocardial viability assessment accuracy of cardiac magnetic resonance imaging(CMR)compared to[^(18)F]-fluorodeoxyglucose(FDG)-positron emission tomography(PET)depending on left ventricular(LV)function....AIM To compare myocardial viability assessment accuracy of cardiac magnetic resonance imaging(CMR)compared to[^(18)F]-fluorodeoxyglucose(FDG)-positron emission tomography(PET)depending on left ventricular(LV)function.METHODS One-hundred-five patients with known obstructive coronary artery disease(CAD)and anticipated coronary revascularization were included in the study and examined by CMR on a 1.5T scanner.The CMR protocol consisted of cine-sequences for function analysis and late gadolinium enhancement(LGE)imaging for viability assessment in 8 mm long and contiguous short axis slices.All patients underwent PET using[^(18)F]-FDG.Myocardial scars were rated in both CMR and PET on a segmental basis by a 4-point-scale:Score 1=no LGE,normal FDG-uptake;score 2=LGE enhancement<50% of wall thickness,reduced FDG-uptake(≥50% of maximum);score 3=LGE≥50% ,reduced FDG-uptake(<50% of maximum);score 4=transmural LGE,no FDG-uptake.Segments with score 1 and 2 were categorized"viable",scores 3 and 4 were categorized as"non-viable".Patients were divided into three groups based on LV function as determined by CMR:Ejection fraction(EF),<30% :n=45;EF:30% -50% :n=44;EF>50% :n=16).On a segmental basis,the accuracy of CMR in detecting myocardial scar was compared to PET in the total collective and in the three different patient groups.RESULTS CMR and PET data of all 105 patients were sufficient for evaluation and 5508 segments were compared in total.In all patients,CMR detected significantly more scars(score 2-4)than PET:45% vs 40% of all segments(P<0.0001).In the different LV function groups,CMR found more scar segments than PET in subjects with EF<30% (55% vs 46% ;P<0.0001)and EF 30% -50% (44% vs 40% ;P<0.005).However,CMR revealed less scars than PET in patients with EF>50% (15% vs 23% ;P<0.0001).In terms of functional improvement estimation,i.e.,expected improvement after revascularization,CMR identified"viable"segments(score 1 and 2)in 72% of segments across all groups,PET in 80% (P<0.0001).Also in all LV function subgroups,CMR judged less segments viable than PET:EF<30% ,66% vs 75% ;EF=30% -50% ,72% vs 80% ;EF>50% ,91% vs 94% .CONCLUSION CMR and PET reveal different diagnostic accuracy in myocardial viability assessment depending on LV function state.CMR,in general,is less optimistic in functional recovery prediction.展开更多
The expression of stretch activated potassium channel TREK-1 mRNA and protein of hypertrophic myocardium was measured. Using a model of hypertrophy induced by coarctation of abdominal aorta in male Wistar rats, the ex...The expression of stretch activated potassium channel TREK-1 mRNA and protein of hypertrophic myocardium was measured. Using a model of hypertrophy induced by coarctation of abdominal aorta in male Wistar rats, the expression of TREK-1 mRNA and protein was detected by using semi quantitative RT-PCR and Western blot respectively. At 4th and 8th week after constriction of the abdominal aorta , rats developed significant left ventricular hypertrophy. As compared to sham-operated group, stretch-activated potassium channel TREK-1 mRNA was strongly expressed and protein was up regulated in operation groups （P〈0.05）. It was concluded that the expression of TREK-1 was up-regulated in hypertrophic myocardium induced by chronic pressure overload in Wistar rats.展开更多
The whole-cell patch-clamp technique was employed to obtain information about the voltage-dependence and kinetics of interaction of 7-chlor-benzylte-trahydropalmatine (7-Cl-BTHP) with cardiac sodium channels. 7-Cl-BTH...The whole-cell patch-clamp technique was employed to obtain information about the voltage-dependence and kinetics of interaction of 7-chlor-benzylte-trahydropalmatine (7-Cl-BTHP) with cardiac sodium channels. 7-Cl-BTHP (30 mol/L) significantly decreased the peak sodium current (from 7. 8±1. 8 nA to 5. 3±1. 4 nA, P<0. 01, n=5), without producing a shift of the current-voltage curve. It shifted the inactivation curves of sodium current to hyperpolarized potentials, and the V(0.5) was shifted from - (82. 5±2. 5) mV to - (95±2.4) mV (P <0. 05, n=4). 7-Cl-BTHP produced a significant use-dependent effect that was proportional to the duration of the voltage step. In addition, 7-Cl-BTHP slowed the recovery of sodium channel from inactivation, which could explain its use-dependent effects on sodium current. The characteristics of 7-Cl-BTHP blockage suggest that this agent binds preferentially to inactivated sodium channels.展开更多
The effects of amiodarone on transmural dispersion of ventricular effective refractory periods （ERPs） in the normal and hypertrophic canine heart were investigated in vivo. By using the programmed stimulation protoc...The effects of amiodarone on transmural dispersion of ventricular effective refractory periods （ERPs） in the normal and hypertrophic canine heart were investigated in vivo. By using the programmed stimulation protocol, the ERPs of epicardium （Epi）, midmyocardium （Mid） and endocardium （Endo） were measured by inserting specially-designed electrodes into the three myocardial layers before and after mainlining of amiodarone. No significant ERPs-dispersion was observed in the three layers before and after mainlining of amiodarone in the normal group. In contrast, ERPs of all the three layers were prolonged in the hypertrophic heart, while the ERPs-dispersion was reduced significantly after mainlining of amiodarone. The ERPs-dispersion was significantly increased in the hypertrophic heart but not in the normal heart using ＂long-short＂ and ＂short-long＂ interval stimulation technique. It was concluded that （1） the differences in ERPs-dispersion among the three layers were significant in hypertrophic heart, and differences were not significant in normal canine heart; （2） ERPs of each three-myocardial layers were significantly prolonged after using amioda- rone, but the ERPs-dispersion decreased in hypertrophic heart and （3） the programmed extrastimulus technique of ＂long-short＂ and ＂short-long＂ intervals increased the transmural ERPs-dispersion in the hypertrophic heart.展开更多
文摘Background Noncompaction of ventricular myocardium （NVM） is a rare type of primary cardiomyopathy. The disease is caused by the disorder in the densification of the myocardium in the early stage of the embryo process. The morphological characteristics are projecting trabeculation in the ventricle and the deep trabecular space interlinked with ventricular chamber. In recent years, many studies have found that the left ventricular growth associated genetic mutation is closely related to the occurrence of NVM. The most clinical manifestations such as heart failure, thromboembolism and arrhythmia are specific. Echocardiography is the most commonly used tech- nique for the diagnosis of NVM. Cardiac computed tomography （CT） scan, cardiac magnetic resonance imaging and left ventricular angiography are other important techniques for its diagnosis. The NVM patients have a long course of disease, poor prognosis and a high rate of misdiagnosis. This article reviews the research progress in the aspects of epidemiological characteristics, genetic characteristics, clinical manifestations, pathophysiology, diagnosis, treatment and so on, in order to provide the basis for the diagnosis and treatment of NVM.
文摘Abstract Using histochemistry technique, the effects of radiofrequency catheter ablation (RFCA) on the activities of LDH, SDH, CCO, and Ca^2+ ATPase of guinea pig ventricular myocytes were examined. In the meanwhile, the histological changes were observed as Department of Cardiology, Tongji Hospital, Tongji Medical University. Wuhan 430030, China (Wang YG, Lu ZY) Department of Anatomy, Tongji Medical University, Wuhan 430030, China (Xiong XK) control. Radiofreqency energy (500 kHz) delivered was 20W×10s. The resultes were as follows: RFCA resulted in significant impairments in all the four kinds of enzymses but without statistical differences among their areas involved in this energy level, and there are no statistical significant differences when compared with those of histological lesion area. These findings showed consistency in areas of the histological and histochemical lesions resulted from RFCA.
文摘Background: Left ventricular noncompaction with multiple left ventricular thrombi can be revealed by echocardiography, and early diagnosis seems to be imperative to prevent significant embolic events. Case Report: A 57-year-old woman presented with symptoms of heart failure. Two-dimensional transthoracic echocardiogram demonstrated a dilated and diffusely hypokinetic left ventricle with severe impaired left ventricular systolic function. Moreover, a markedly thickened endocardium at the left ventricular apex and middle segment with numerous, excessively prominent trabeculations and deep intertrabecular recesses were present. During systole, the ratio of the noncompacted to compacted myocardial layers at the site of the maximal wall thickness was above two, a characteristic finding in left ventricular non-compaction. Multiple mobile, homogeneous, echodense thrombi were identified in the left ventricle, with the largest one in the apical noncompacted segment (dimensions, 32 × 14 mm). Cardiac magnetic resonance imaging confirmed the diagnosis of noncompacted myocardium with the presence of multiple thrombi. After anticoagulant therapy, her symptoms improved and thrombi dissolved. Unexpectedly, she re-admitted to the cardiovascular unit with progressive dyspnea. Transthoracic echocardiogram showed new large right atrial thrombi, with the largest one was 43 × 38 mm compared to the echocardiogram done 11 months ago. The patient was anticoagulated with continuous heparin infusion for several days followed by oral Apixaban. After 4 weeks, the floating thrombi completely disappeared. After a 26-month follow-up, the patient’s condition was stable without embolic complications. Conclusion: Echocardiography was the cornerstone of diagnostic methods for early detecting left ventricular thrombi to eventually prevent embolic events.
文摘Objectives To investigate the relation between hypertrophied myocardium and ventricular fibrillation threshold in spontaneously hypertensive rats （SHR）. Methods 20 male SHR were randomly divided into two groups： 10 week group （n= 10） and 18 week group （n=10）. 10 week male Wistar rats were controlled group （n=10）. The systolic blood pressure （SBP）, heart mass index （HMI）, ventricular effective refractory period （VERP） and ventricular fibrillation threshold（VFT） were measured respectively.① The SBP and HMI of SHR were significantly higher than those of Wistar rats（P 〈 0.001）. The VFT of SHR were significantly lower than that of Wistar rats （P 〈 0.001）.②In SHR, the SBP and HMI of 18 week SHR were significantly higher than those of 10 week SHR （P 〈 0.001）. The VFT of 18 week SHR were significantly lower than that of 10 week SHR （P 〈 0.001）. ③There were no significant difference of VERP among 10 week SHR, 18 week SHR and Wistar rats（P 〉 0.05）. ④There was no relationship between HMI and VFT or SBP in Wistar rats. There was significant relationship between HMI and VFT or SBP in different age spontaneously hypertensive rats. ⑤HMI, age and species of animal were the major influent factors of VFT. Conclusions The VFT of hypertrophied myocardium decreased. The higher the degree of hypertrophy of myocardium and the higher the systolic blood pressure were, the lower the ventricular fibrillation threshold was.
文摘Objectives The long-term benefit of late reperfusion of infarct-related artery （IRA） after acute myocardial infarction （AMI） is controversial, and the benefit mechanisms remain uncertain. Low dose dobutamine stress echocardiography （LDSE） can identify viable myocardium and predict improvement of wall motion after revascularization. Methods Sixtynine patients with first AMI who did not received early reperfusion therapy were studied by LDSE at 5 to 10 days after AMI. Wall motion abnormality and left ventricular size were measured at the same time. Successful PCI were done in all patients at 10 to 21 days after AMI onset. Patients were divided in two groups based on the presence or absence of viable myocardium. Echocardiography was repeated six months later. Results There were 157 motion abnormality segments. 89 segments （57%） were viable during LDSE. 26 patients （38%） with viability and 43 （62%） without. In viable group, left ventricular ejection fraction （LVEF） was increased （P 〈 0.05）, and left ventricular end systolic volume index （LVESVI） and wall motion score （WMS） were decreased （P 〈 0.05 and P 〈 0.01） significantly at 6 months compared with baseline. But in patients without viability, LVEF was decreased （P 〈 0.01）, and LVESVI and left ventricular end diastolic volume index （LVEDVI） were increased （P 〈 0.05） significantly after 6 months, and the WMS did not changed （P 〉 0.05 ）. LVEF increased （P 〈 0.05 ） and WMS decreased （P 〈 0.05） on LDSE during acute phase in patients with viability, but they were not changed in the nonviable group. Conclusions Late revascularization of IRA in patients with presence of viable myocardium after AMI is associated with long-term preservation left ventricular function and less ventricular remodeling. Improvement of left ventricular systolic function on LDSE indicates late phase recovery of left ventricular function after late revascularization.
文摘AIM To compare myocardial viability assessment accuracy of cardiac magnetic resonance imaging(CMR)compared to[^(18)F]-fluorodeoxyglucose(FDG)-positron emission tomography(PET)depending on left ventricular(LV)function.METHODS One-hundred-five patients with known obstructive coronary artery disease(CAD)and anticipated coronary revascularization were included in the study and examined by CMR on a 1.5T scanner.The CMR protocol consisted of cine-sequences for function analysis and late gadolinium enhancement(LGE)imaging for viability assessment in 8 mm long and contiguous short axis slices.All patients underwent PET using[^(18)F]-FDG.Myocardial scars were rated in both CMR and PET on a segmental basis by a 4-point-scale:Score 1=no LGE,normal FDG-uptake;score 2=LGE enhancement<50% of wall thickness,reduced FDG-uptake(≥50% of maximum);score 3=LGE≥50% ,reduced FDG-uptake(<50% of maximum);score 4=transmural LGE,no FDG-uptake.Segments with score 1 and 2 were categorized"viable",scores 3 and 4 were categorized as"non-viable".Patients were divided into three groups based on LV function as determined by CMR:Ejection fraction(EF),<30% :n=45;EF:30% -50% :n=44;EF>50% :n=16).On a segmental basis,the accuracy of CMR in detecting myocardial scar was compared to PET in the total collective and in the three different patient groups.RESULTS CMR and PET data of all 105 patients were sufficient for evaluation and 5508 segments were compared in total.In all patients,CMR detected significantly more scars(score 2-4)than PET:45% vs 40% of all segments(P<0.0001).In the different LV function groups,CMR found more scar segments than PET in subjects with EF<30% (55% vs 46% ;P<0.0001)and EF 30% -50% (44% vs 40% ;P<0.005).However,CMR revealed less scars than PET in patients with EF>50% (15% vs 23% ;P<0.0001).In terms of functional improvement estimation,i.e.,expected improvement after revascularization,CMR identified"viable"segments(score 1 and 2)in 72% of segments across all groups,PET in 80% (P<0.0001).Also in all LV function subgroups,CMR judged less segments viable than PET:EF<30% ,66% vs 75% ;EF=30% -50% ,72% vs 80% ;EF>50% ,91% vs 94% .CONCLUSION CMR and PET reveal different diagnostic accuracy in myocardial viability assessment depending on LV function state.CMR,in general,is less optimistic in functional recovery prediction.
文摘The expression of stretch activated potassium channel TREK-1 mRNA and protein of hypertrophic myocardium was measured. Using a model of hypertrophy induced by coarctation of abdominal aorta in male Wistar rats, the expression of TREK-1 mRNA and protein was detected by using semi quantitative RT-PCR and Western blot respectively. At 4th and 8th week after constriction of the abdominal aorta , rats developed significant left ventricular hypertrophy. As compared to sham-operated group, stretch-activated potassium channel TREK-1 mRNA was strongly expressed and protein was up regulated in operation groups （P〈0.05）. It was concluded that the expression of TREK-1 was up-regulated in hypertrophic myocardium induced by chronic pressure overload in Wistar rats.
文摘The whole-cell patch-clamp technique was employed to obtain information about the voltage-dependence and kinetics of interaction of 7-chlor-benzylte-trahydropalmatine (7-Cl-BTHP) with cardiac sodium channels. 7-Cl-BTHP (30 mol/L) significantly decreased the peak sodium current (from 7. 8±1. 8 nA to 5. 3±1. 4 nA, P<0. 01, n=5), without producing a shift of the current-voltage curve. It shifted the inactivation curves of sodium current to hyperpolarized potentials, and the V(0.5) was shifted from - (82. 5±2. 5) mV to - (95±2.4) mV (P <0. 05, n=4). 7-Cl-BTHP produced a significant use-dependent effect that was proportional to the duration of the voltage step. In addition, 7-Cl-BTHP slowed the recovery of sodium channel from inactivation, which could explain its use-dependent effects on sodium current. The characteristics of 7-Cl-BTHP blockage suggest that this agent binds preferentially to inactivated sodium channels.
文摘The effects of amiodarone on transmural dispersion of ventricular effective refractory periods （ERPs） in the normal and hypertrophic canine heart were investigated in vivo. By using the programmed stimulation protocol, the ERPs of epicardium （Epi）, midmyocardium （Mid） and endocardium （Endo） were measured by inserting specially-designed electrodes into the three myocardial layers before and after mainlining of amiodarone. No significant ERPs-dispersion was observed in the three layers before and after mainlining of amiodarone in the normal group. In contrast, ERPs of all the three layers were prolonged in the hypertrophic heart, while the ERPs-dispersion was reduced significantly after mainlining of amiodarone. The ERPs-dispersion was significantly increased in the hypertrophic heart but not in the normal heart using ＂long-short＂ and ＂short-long＂ interval stimulation technique. It was concluded that （1） the differences in ERPs-dispersion among the three layers were significant in hypertrophic heart, and differences were not significant in normal canine heart; （2） ERPs of each three-myocardial layers were significantly prolonged after using amioda- rone, but the ERPs-dispersion decreased in hypertrophic heart and （3） the programmed extrastimulus technique of ＂long-short＂ and ＂short-long＂ intervals increased the transmural ERPs-dispersion in the hypertrophic heart.
