Spontaneous and induced vasodepressor/vasovagal syncope in hypertrophic cardiomyopathy

We describe a 47-year-old man affected with hypertrophic cardiomyopathy and frequent episodes of syncope. During ambulatory Holter monitoring and head-up tilt test, a syncopal attack was associated with sinus arrest and hypotension. This case suggests an additional mechanism of syncope in hypertrophic cardiomyopathy.     

56例肥厚型心肌病患者的临床分析

目的探讨肥厚型心肌病患者出现晕厥等严重临床症状的预测因素。方法回顾性分析56例肥厚型心肌病患者临床特征,按照有无晕厥的发生进行对照性研究。结果晕厥组中12例QT间期较非晕厥组延长更明显(452±20msvs429±25ms,p<0.01);且晕厥组中病例都出现心尖区3/6级以上收缩期杂音,而非晕厥组中心尖区杂音只有9%(4/44);另外,左室流出道梗阻在晕厥组中亦明显增多(p<0.05)。结论本研究发现对肥厚型心肌病患者发生晕厥等严重临床症状的危险性预测因素有:①QT间期延长;②心尖区3/6级以上收缩期杂音;③左室流出道梗阻。     

Programmed electrical stimulation in hypertrophic cardiomyopathy. Results in patients with and without cardiac arrest or syncope

Programmed electrical stimulation was performed in 54 consecutivepatients with hypertrophic cardiomyopathy. There were 11 ‘symptomatic’patients: three had a history of cardiac arrest due to ventriculartachyarrhythmias (group A), and eight had a history of syncopeof unknown origin (group B); 43 patients were ‘asymptomatic’,i.e. they had no documented or suspected symptomatic ventriculararrhythmias (group C). There were no differences among the groupswith respect to electrocardiographic, echocardiographic or hemodynamicdata. Ventricular arrhythmias were induced by atrial and rightand left ventricular stimulation with a maximum of two extrastimuliin 18 patients. Induced arrhythmias were repetitive ventricularresponse in six patients, nonsustained ventricular tachycardiain four, sustained ventricular tachycardia in five, and ventricularfibrillation in three patients. With one exception, ventriculartachycardia was always rapid (cycle lengths ranged from 180to 250 ms); it was polymorphic in six patients and monomorphicin three. Atrial stimulation induced rapid monomorphic ventriculartachycardia in one group A patient. The type and incidence ofinduced ventricular arrhythmias did not differ among the threegroups. It is concluded that programmed electrical stimulationinduces the same type of ventricular arrhythmia (rapid polymorphicventricular tachycardia or ventricular fibrillation) in ‘symptomatic’and ‘asymptomatic’ patients with hypertrophic cardiomyopathy,the incidence in the latter group being 19%. Induction by atrialstimulation of a rapid ventricular tachycardia may be a specificfinding to identify patients with hypertrophic cardiomyopathyat risk for exercise-induced ventricular fibrillation.     

Cardiovascular and hormonal responses to a meal in hypertrophic cardiomyopathy: A comparison of patients with and without postprandial exacerbation of symptoms

Some patients with hypertrophic cardiomyopathy experience postprandial exacerbation of symptoms. The aim of this study was to determine whether the hemodynamic and/or hormonal responses to a meal differ between patients with and without postprandial symptoms. Ten hypertrophic cardiomyopathy patients with postprandial symptoms, 10 patients without postprandial symptoms, and 10 normal subjects ate a 740 Kcal meal, following which heart rate, blood pressure, and echocardiographic and gastrointestinal hormone changes were compared among the three groups. Heart rate increased (p<0.001) and diastolic blood pressure fell (p < 0.001) to a similar degree in the three groups. Left ventricular outflow tract velocity increased (p< 0.01) and some patients had substantial increases in outflow tract pressure gradient; however, this was independent of the presence or absence of postprandial symptoms. The atrial contribution to filling increased in normal subjects and in both groups of hypertrophic cardiomyopathy patients. There was no significant difference in the gastrointestinal hormone changes in the three groups. In summary, there is no evidence for a distinctive hemodynamic or hormonal response to food in hypertrophic cardiomyopathy patients with postprandial symptoms. These symptoms more likely reflect differences in underlying cardiac disease characteristics and severity.     

Adverse effects of atrial fibrillation and syncope induced by calcium-channel blockers in hypertrophic cardiomyopathy

Calcium-channel blockers are useful for the treatment of hypertrophic cardiomyopathy (HCM), but, their adverse effects, especially, those of diltiazem, have not been of much concern. Forty patients with HCM were treated with calcium-channel blockers such as nifedipine, diltiazem, and verapamil. Atrial fibrillation was induced by diltiazem in two patients and verapamil induced syncope in one patient. The clinical and hemodynamic characteristics of the patients were as follows. All of them had the obstructive type of HCM (HOCM). One of them had a high pressure gradient of the left ventricular outflow tract and the others had earlier onset. In these patients, the left atrial overload seemed to be severe. The vasodilating action of calcium-channel blockers decreases the systemic pressure and in turn, may increase the pressure gradient and the left ventricular end-diastolic pressure. The elevated left ventricular end-diastolic pressure causes the left atrial overload which could be at risk of atrial fibrillation in patients with HCM. Therefore, calcium-channel blockers should be used carefully in peculiar cases of HOCM.     

肥厚性心肌病的心室造影特点

目的分析梗阻型肥厚性心肌病(HOCM)患者心室造影结果及形态学特征。方法纳入1995~2005年收治入院并接受心室造影和超声检查的74例确诊为肥厚型心肌病的患者。以左心室流出道与左心室压力差≥30 mmHg为梗阻型,30 mmHg为非梗阻型,将患者分为2组。比较其形态学和造影结果。结果 (1)入选74例患者,梗阻型14例(18.9%),其中收缩期前向运动6例(42.9%),冠心病3例(21.4%);非梗阻型60例(81.1%),其中11例合并冠心病(18.3%)。(2)超声显示室间隔增厚至(11.4±2.5)mm,左室后壁厚度(9.8±1.7)mm,左心室舒张末内径(48±5)mm,左心房内径(36±5)mm。(3)左室造影显示左室舒张末容积为(123±31)ml,左室收缩末容积为(27±11)ml,左心室射血分数(EF)为(78±6)%。(4)左心室造影形态学特征为梗阻型心室结构14例,其中正常5例;非梗阻型左心室结构60例,正常27例。结论非梗阻型肥厚性心肌病与HOCM左室舒张末内径、左室舒张末容积及左室收缩末容积、EF值,以及呈现正常形态的病例数等均无差异。     

Significant improvement of quality of life following atrioventricular synchronous pacing in patients with hypertrophic obstructive cardiomyopathy. Data from 1 year of follow-up. PIC study group. Pacing In Cardiomyopathy.

AIMS: Atrioventricular synchronous pacing exerts beneficial effects, including reduction of left ventricular outflow tract gradients, in patients with hypertrophic obstructive cardiomyopathy. The Pacing in Cardiomyopathy study was initiated to explore the effects of pacing in a double-blind randomized crossover fashion. The aims were to ascertain the beneficial effects of pacing in a controlled study and to rule out a placebo effect by pacing. This paper deals with the outcome of pacing on quality of life during 1 year of follow-up. METHODS: Quality of life was evaluated with the Karolinska questionnaire, validated for patients paced for bradyarrhythmias and ischaemic heart disease. Drug-refractory patients with hypertrophic obstructive cardiomyopathy were recruited for the study and after a temporary pacing procedure implanted with permanent pacemakers. Patients were randomized to two study arms defining the sequence of pacemaker programming. In one arm the pacemaker was inactive, in the other active. After 3 months the pacemaker was reprogrammed to the alternate mode and a further 3 months followed. After this period subsequent pacemaker programming corresponded to the mode preferred by the patient. A last assessment was made 1 year after baseline examinations. RESULTS: Eighty patients completed the first crossover period and 75 completed the full 1 year of follow-up. Active pacing induced significant quality of life improvements, in the order of 9-44%, regardless of programming sequence. Discontinuation of pacing after a first active period resulted in the return of symptoms. Fourteen patients requested early reprogramming after having been programmed to inactive pacing after a first period of active pacing. Seventy-six patients preferred active pacing after the crossover period. A further 6 months of pacing induced progressive improvement in symptoms already favourably influenced. CONCLUSION: Atrioventricular synchronous pacing has a profound beneficial effect on most domains of quality of life in patients with hypertrophic obstructive cardiomyopathy refractory to drug treatment.     

Clinical characteristics and outcomes of hypertrophic cardiomyopathy in Taiwan--a tertiary center experience

BACKGROUND: Most information concerning hypertrophic cardiomyopathy has been derived from western countries and Japan. HYPOTHESIS: Patients with hypertrophic cardiomyopathy in Taiwan may have a distinct morphology and clinical picture. METHODS: Information from 163 consecutive patients with hypertrophic cardiomyopathy at a medical center in Taiwan from 1990 through 2005 was retrospectively collected. The diagnosis of hypertrophic cardiomyopathy required echocardiographic demonstration of left ventricular hypertrophy (wall thickness >or= mm during diastole) in a specific region or with diffuse distribution. Follow-up information was obtained from medical records. RESULTS: Among 163 patients (male, 52%), the mean follow-up period was 5.3 +/- 4.1 years. Men had nearly a threefold increase in prevalence of apical hypertrophic cardiomyopathy (23.8% vs. 8.9%, p = 0.03), younger onset of initial evaluation (57.2 +/- 12.9 vs. 64.8 +/- 11.3, p < 0.001), and lower prevalence of hypertrophic obstructive cardiomyopathy (33.3% vs. 63.3%, p < 0.001) compared to women. Fifty-eight patients (35.6%) experienced cardiovascular events, of which pulmonary edema and paroxysmal atrial fibrillation were the most common (19.7% and 12.3%, respectively). The annual cardiovascular mortality rate was 0.8%. In multivariate analysis, left ventricular outflow obstruction [odds ratio (OR): 4.92, p = 0.001], atrial fibrillation (OR: 3.53, p = 0.014), and female gender (OR: 2.99, p = 0.043) were independent predictors of mortality. CONCLUSIONS: Hypertrophic cardiomyopathy did not significantly increase cardiovascular mortality rate, but over one-third of patients with hypertrophic cardiomyopathy experienced cardiovascular events. High prevalence of left ventricular outflow obstruction especially in elderly women was observed. Left ventricular outflow obstruction, atrial fibrillation, and female gender were predictors of mortality.     

Short- and long-term effects of nisoldipine on cardiac function and exercise tolerance in patients with hypertrophic cardiomyopathy

Nisoldipine is a second generation dihydropyridine calcium antagonist having characteristics of strong coronary artery dilating effect and less negative inotropic action. The purpose of this study was to evaluate the effect of nisoldipine on the cardiac function (systolic and diastolic) and the exercise tolerance in patients with hypertrophic cardiomyopathy (HCM).Subjects: Twenty-three patients with HCM were studied.Methods: We measured the following indices using M-mode and pulsed wave Doppler echocardiography before and after nisoldipine therapy; left ventricular fractional shortening (LVFS), isometric relaxation time (IRT), deceleration half-time (DHT) of early diastolic mitral (E) flow, late diastolic mitral (A) flow and A/E ratio. Symptomlimited treadmill exercise test was performed. Exercise tolerance (EX) time was measured. Nisoldipine of 10mg/day was orally administered. Same tests were repeated on day 14 and after 6 months.Results: 1) Short-term effects; LVFS did not change (55.9±5.9%57.0±7.4%, NS) after 2 weeks. However, LV diastolic function significantly improved (IRT; 92.1±7.7 ms85.2±11.6 ms, p<0.05, DHT; 70.7±16.2 ms63.3±3.7 ms, p<0.05). EX time increased (8.9±2.6 min 10.0±3.3 min, p<0.05). 2) Long-term effects; LV diastolic function had a tendency toward improvement, but is statistically not significant (IRT; 91.1±7.683.8±11.6 ms, DHT; 73.1±23.461.0±11.4 ms, A/E; 1.26±0.291.11±0.36) after 6 months. EX time was significantly increased (9.4±1.7 10.1±1.7 min, p<0.05).Conclusions: Nisoldipine improved LV diastolic dysfunction and exercise tolerance in patients with HCM. These effects were similar to the first generation calcium antagonists. LV diastolic dysfunction may be improved due to the reduction of intracellular calcium concentration and the relief of myocardial ischemia by strong coronary artery dilating effect. However, nisoldipine did not affect the LV systolic function because of its less negative inotropic effect.     

肥厚型心肌病患者心电图分析

目的探讨肥厚型心肌病住院患者的心电图特点。方法对1994年5月～2005年7月北京大学人民医院和北京世纪坛医院收治的经超声心动图诊断为肥厚型心肌病的住院患者76例,分析其心电图特点。结果按肥厚的部位分为单纯室间隔肥厚或室间隔肥厚为主组(46例)、单纯心尖肥厚组(14例)、单纯游离壁肥厚组(6例)和弥漫性肥厚组(10例)。间隔肥厚为主组患者中,23例(50.0%)存在病理性Q波,其中间隔厚度超过2.0cm者10例(42.5%);而在另23例无病理性Q波患者,间隔厚度超过2.0cm者仅5例(21.7%)。心尖肥厚组和单纯游离壁肥厚组均仅1例心电图存在病理性Q波。QRS波群宽度在各组无显著性差异(p>0.05)。76例患者中,心电图符合左室肥厚(SV1 RV5≥4.0mV)诊断标准的23例(30.3%),符合RV4>RV5>RV6(或RV3>RV4>RV5)者34例(44.7%),ST-T改变共71例(93.4%),ST段下移超过0.1mV者53例(69.7%),T波深倒置振幅超过0.5mV者30例(39.5%)。T波深倒置在心尖肥厚组多于间隔肥厚组(P=0.02),但T波倒置深度与心尖肥厚程度无明显相关(p=0.40)。间隔肥厚为主组中梗阻型和非梗阻型各项心电图指标无显著性差异(p>0.05)。结论病理性Q波多出现在室间隔肥厚为主型患者,T波深倒置在心尖肥厚组多于间隔肥厚组,但T波倒置深度与心尖肥厚程度无明显相关。     

肥厚型心肌病36例临床分析

目的:讨论通过临床症状体征、心电图、超声心电图等诊断肥厚型心肌病(HCM)的可行性及误诊原因。方法:对36例HCM患者的临床资料进行分析。结果:HCM临床表现多样,无特异性,容易被误诊。超声心动图检查可作为临床确诊和复查的首选方法。结论:应提高对HCM的认识,减少误诊,早期诊治。     

肥厚型心肌病伴心房颤动患者临床特点分析

目的分析32例肥厚型心肌病伴心房颤动患者的临床特点。方法选择1994-2005年在解放军总医院心脏中心就诊的肥厚型心肌病患者158例，平均随访（4．2±2．8）年，按病史、心电图、动态心电图是否记录到心房颤动分为房颤组和非房颤组，观察并比较2组患者的临床特点。结果（1）肥厚型心肌病伴房颤患者共32例，占全部肥厚型心肌病患者的20．3％，其中阵发性房颤14例（43．7％），持续性房颤18例（57．3％），无症状性房颤5例（15．6％）；（2）与非房颤组患者比较，房颤组患者平均年龄偏大（58±10．4vs46±12．6）岁（P〈0．01），左房直径大（42±3．5vs34±5．3）mm（P〈0．01）；（3）房颤组12例（心力衰竭8例，猝死4例）发生心血管事件，非房颤组9例（心力衰竭6例，猝死3例）发生心血管事件。房颤组患者中，房颤引发室颤1例（3％），脑栓塞2例（6．3％），下肢动脉栓塞2例（6．3％）。结论（1）20．3％肥厚型心肌病患者伴心房颤动，其中43．7％为阵发性房颤，57．3％为持续性房颤，15．6％为无症状性房颤；（2）与肥厚型心肌病不伴房颤患者相比，伴房颤患者年龄偏大，心血管事件发生率高。     

Successful treatment of end-stage hypertrophic cardiomyopathy with biventricular cardiac pacing.

The beneficial use of biventricular pacing is reported in a patient with end-stage hypertrophic cardiomyopathy, intraventricular conduction delay and echocardiographic evidence of intraventricular dyssyncrony. Marked improvement in clinical status, left ventricular ejection fraction and peak VO2 were observed. As far as we know, this is the first report of a beneficial effect of a biventricular device in this subset of patients, and may be worth further investigation.     

起搏治疗梗阻性肥厚型心肌病的长期疗效

目的 评价起搏治疗对梗阻性肥厚型心肌病（obstructive hypertrophic cardiomyopathy,OHCM）左心室流出道梗阻及临床症状的长期疗效。方法 25例OHCM患者接受起搏治疗,临床随访12个月,观察临床症状体征;采用超声心动图观察起搏前后室间隔厚度（interventricular septum thickness,IVS）、左心室后壁厚度（left ventricular posterior wall thickness,LVPW）、左心室舒张末内径（left ventricular end diastolic dimension,LVEDd）、左心室收缩末内径（left ventricular end systolic dimension,LVEDs）、左心房内径（left atrial dimension,LAD）、跨左心室流出道压力阶差（left ventricular outflow tract gradient,LVOTG）、及二尖瓣前向运动程度（mitral valve systolic anterior motion,SAM）、二尖瓣反流面积（mitral valve area,MVA）的变化。结果 OHCM 25例,植入双腔生理性起搏器（DDD）21例,占84%,单腔抑制频率调节起搏（SSIR）4例,占16%。起搏治疗12个月后,临床症状明显改善,15例晕厥发作术后症状完全消失,劳力性呼吸困难、胸痛改善分别占82.6%和75.0%,LVOTG显著下降,从术前（90±24）mmHg降至术后（37±13）mmHg（P〈0.01）,IVS、LAD、MVA减少,SAM运动明显改善,其他指标差异无统计学意义。结论 起搏治疗对OHCM长期临床效果满意。     

Coronary microvascular dysfunction in hypertrophic cardiomyopathy: Pathophysiology,assessment, and clinical impact

Myocardial ischemia constitutes one of the most important pathophysiological features in hypertrophic cardiomyopathy. Chronic and recurrent myocardial ischemia leads to fibrosis, which may culminate in myocardial dysfunction. Since the direct visualization of coronary microcirculation in vivo is not possible, its function must be studied indirectly. Invasive and noninvasive techniques allow microcirculatory dysfunction to be evaluated, including echocardiography, magnetic resonance, positron emission tomography, and cardiac catheterization. Blunted myocardial blood flow and coronary flow reserve have been suggested to associate with unfavorable prognosis. Microcirculatory dysfunction may be one additional important parameter to take into account for risk stratification beyond the conventional risk factors.     

Sudden cardiac death in patients with hypertrophic cardiomyopathy: From bench to bedside with an emphasis on genetic markers

Hypertrophic cardiomyopathy (HCM) is the most common cause of death in the young, particularly in young competitive athletes. Death often occurs suddenly in asymptomatic, apparently healthy individuals. Several clinical parameters as well as genetic factors have been characterized that can identify those HCM patients who are at high risk for sudden cardiac death (SCD). The clinical parameters that have some predictive values for SCD in HCM patients are the following: a prior history of SCD, a family history of SCD, history of syncope, symptomatic ventricular tachycardia on Holter monitoring, inducible ventricular tachycardia during electrophysiologic studies, and myocardial ischemia in children with HCM. Recent identification of mutations in the beta myosin heavy chain gene and genotype-phenotype correlation in HCM patients have shown that the beta myosin heavy chain mutations are also prognosticators in HCM families. Several mutations such as Arg⁴⁰³Gln and Arg⁷¹⁹Gln are associated with a high incidence of SCD, while Leu⁹⁰⁸Val mutation is associated with a benign course and a low incidence of SCD in HCM families. Additional genetic factors such as a polymorphism in angiotensin-converting enzyme I gene may also contribute to a high incidence of SCD in HCM families. Identification and characterization of HCM patients at high risk for SCD provide the opportunity to render prophylactic therapeutic interventions, such as implantation of defibrillators, in these individuals.     

Management of an asymptomatic patient with the apical variant of hypertrophic cardiomyopathy

Healthcare professionals are faced with challenging decisions regarding patient evaluation and management on a daily basis. Once a diagnosis is made, additional challenges include how to proceed with the management. Here, we present an eighty‐two‐year‐old female who was incidentally diagnosed with the apical variant of hypertrophic cardiomyopathy on a transthoracic echocardiogram. She was found to have newly diagnosed atrial fibrillation, but was otherwise asymptomatic from a cardiomyopathy standpoint. No specific guidelines exist for this patient population. Therefore, how does one proceed with the management of an asymptomatic patient with the apical variant of hypertrophic cardiomyopathy?     

Cardiopulmonary responses to exercise in patients with hypertrophic cardiomyopathy

Objective—To examine the submaximal and maximal indices of the exercise response of patients with hypertrophic cardiomyopathy.
Design and setting—Prospective examination of cardiopulmonary responses to ramp exercise test of a consecutive group of patients with hypertrophic cardiomyopathy attending a cardiomyopathy outpatient clinic.
Methods—50 patients aged 12 to 76 years (mean (SD) 35 (14)) with diagnosis of hypertrophic cardiomyopathy performed incremental cycle ergometry; 22 sedentary volunteers (seven female, 15 male) aged 14 to 58 years (mean (SD) 31 (12)) served as controls. Respiratory gas was continuously sampled from the mouthpiece, and its concentration profile phase aligned to the respired air flow signals. Following analogue to digital conversion, gas exchange variables were computed breath by breath and the data were averaged every 30 seconds for graphic display. A 12 lead ECG was monitored continuously and recorded every three minutes during the exercise.
Results—Both the peak oxygen uptake attained on the test (O₂ peak) and anaerobic threshold were reduced in patients with hypertrophic cardiomyopathy compared with the control group (p < 0.0001). In 29 patients (59%) the O₂ peak was less than 60% and only two patients achieved a peak above 80% of their predicted values. The anaerobic threshold was below 60% of the predicted value in 31 patients and above 80% in only three patients. The slope of oxygen uptake/work rate relation (ΔO₂/ΔWR) was decreased in 16 patients (32%). The maximum oxygen pulse (O₂/HR) was reduced as a percentage of the predicted value, and became flat at high work rates in 32 patients. There was a significant correlation between anaerobic threshold and O₂ peak (p < 0.0001), work efficiency (p < 0.0001), and maximum oxygen pulse (p < 0.0001). The slope of change in ventilation against change in carbon dioxide output (ΔE/ΔCO₂) for the subanaerobic threshold range was increased in 36 patients (72%) and was inversely correlated with anaerobic threshold (p < 0.0002).
Conclusions—There were severe abnormalities in maximal and submaximal indices of pulmonary gas exchange in a cohort of hypertrophic cardiomyopathy patients attending a referral cardiovascular clinic. The pattern of the abnormalities suggests that a reduced stroke volume response, ventilation/perfusion mismatch, and abnormal peripheral oxygen utilisation are the possible mechanisms of exercise intolerance.

Keywords: exercise tolerance;  work efficiency;  oxygen pulse;  hypertrophic cardiomyopathy     

Acute hemodynamic deterioration during rapid atrial pacing in patients with hypertrophic cardiomyopathy

Background and hypothesis: Supraventricular tachycardia and ventricular tachycardia are often observed in patients with hypertrophic cardiomyopathy (HCM) and they often alter the clinical features of HCM. We examine the influence of supra-ventricular tachycardia on cardiac function and assess the clinical characteristics of patients with HCM. Methods: We studied 32 patients with HCM and 8 normal volunteers using echocardiography under transesophageal rapid atrial pacing. Results: Presyncope-associated hypotension was observed during rapid atrial pacing in 8 HCM patients, but in none of the normal controls. During rapid atrial pacing (144 ± 8 beats/min in HCM, 146 ± 5 beats/min in controls), systolic blood pressure (SBP), the product of left ventricular filling volume (FV) and heart rate, and fractional shortening (%FS) in the HCM patients decreased significantly compared with the basal values (138 ± 19 mmHg vs. 99 ± 24 mmHg, 5.0 ± 1.21/min vs. 2.9 ± 0.91/min, 41.7 ± 6.2 % vs. 35.2 ± 6.0%, respectively), but these decreases were not observed in normal controls. The decrement of SBP during rapid atrial pacing in HCM patients with a history of syncope was more marked than that in those without such history. The decrement correlated positively with the indices of left ventricular hypertrophy (maximal wall thickness and wall thickness index) and with %FS, and correlated negatively with the endsystolic left ventricular diameter at rest. Conclusions: In some patients with HCM, supraventricular tachycardia causes marked hemodynamic deterioration that may be related to a history of syncope, marked hypertrophy, hyperkinesis, small cavity size, and small filling volume of the left ventricle.