The natural history of left ventricular hypertrophy in hypertrophic cardiomyopathy: an electrocardiographic study

ICD Therapy for Primary Prevention in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common and heterogeneous disorder that increases an individual's risk of sudden cardiac death (SCD). This review article discusses the relevant factors that are involved in the challenge of preventing SCD in patients with HCM. The epidemiology of SCD in patients is reviewed as well as the structural and genetic basis behind ventricular arrhythmias in HCM. The primary prevention of SCD with implantable cardioverter-defibrillator (ICD) therapy is the cornerstone of modern treatment for individuals at high risk of SCD. The focus here is on the current and emerging predictors of SCD as well as risk stratification recommendations from both North American and European guidelines. Issues related to ICD implantation, such as programming, complications and inappropriate therapies, are discussed. The emerging role of the fully subcutaneous ICD and the data regarding its implantation are reviewed.

Electrocardiographic evolution in patients with hypertrophic cardiomyopathy who develop a left ventricular apical aneurysm

INTRODUCTION

Hypertrophic cardiomyopathy (HCM) patients with apical aneurysm have a largely unfavourable clinical course, and are often unrecognised because echocardiography is limited in the assessment of the left ventricular (LV) apex. The aim of this study is the identification of electrocardiographic (ECG) abnormalities associated with the development of apical aneurysm in HCM patients.

MATERIALS AND METHODS

Electrocardiographic features were assessed in 14 HCM patients who had a good-quality baseline ECG recorded before and after the diagnosis of apical aneurysm.

RESULTS

During follow-up (8.8±7.5years), the following ECG changes were observed: increase in QRS-complex duration (87±12ms to 118±34ms, p=0.006), QRS-complex fragmentation, decrease in QRS-complex amplitude (SV1+RV5-6, from 41±18mm to 26±11mm, p=0.015), ST-segment elevation in V4-V6 (J-point in V5, from -0.9±1.3mm to +0.7±1.3, p=0.003), positivisation of negative T waves in V3-V6 (T-wave depth in V5, from -3.4±6.6 to +3.1±4.1, p=0.005).

CONCLUSIONS

HCM patients who develop LV apical aneurysm exhibit distinctive ECG changes along with apical remodelling. Suggestive ECGs should lead the physician to study LV apex by nonstandard echocardiographic views, and perform MRI.

Beyond the cardiac myofilament: hypertrophic cardiomyopathy- associated mutations in genes that encode calcium-handling proteins

Traditionally regarded as a genetic disease of the cardiac sarcomere, hypertrophic cardiomyopathy (HCM) is the most common inherited cardiovascular disease and a significant cause of sudden cardiac death. While the most common etiologies of this phenotypically diverse disease lie in a handful of genes encoding critical contractile myofilament proteins, approximately 50% of patients diagnosed with HCM worldwide do not host sarcomeric gene mutations. Recently, mutations in genes encoding calcium-sensitive and calcium-handling proteins have been implicated in the pathogenesis of HCM. Among these are mutations in TNNC1- encoded cardiac troponin C, PLN-encoded phospholamban, and JPH2-encoded junctophilin 2 which have each been associated with HCM in multiple studies. In addition, mutations in RYR2-encoded ryanodine receptor 2, CASQ2-encoded calsequestrin 2, CALR3-encoded calreticulin 3, and SRI-encoded sorcin have been associated with HCM, although more studies are required to validate initial findings. While a relatively uncommon cause of HCM, mutations in genes that encode calcium-handling proteins represent an emerging genetic subset of HCM. Furthermore, these naturally occurring disease-associated mutations have provided useful molecular tools for uncovering novel mechanisms of disease pathogenesis, increasing our understanding of basic cardiac physiology, and dissecting important structure-function relationships within these proteins.

Junctophilin-2 expression silencing causes cardiocyte hypertrophy and abnormal intracellular calcium-handling

BACKGROUND

Junctophilin-2 (JPH2), a protein expressed in the junctional membrane complex, is necessary for proper intracellular calcium (Ca(2+)) signaling in cardiac myocytes. Downregulation of JPH2 expression in a model of cardiac hypertrophy was recently associated with defective coupling between plasmalemmal L-type Ca(2+) channels and sarcoplasmic reticular ryanodine receptors. However, it remains unclear whether JPH2 expression is altered in patients with hypertrophic cardiomyopathy (HCM). In addition, the effects of downregulation of JPH2 expression on intracellular Ca(2+) handling are presently poorly understood. We sought to determine whether loss of JPH2 expression is noted among patients with HCM and whether expression silencing might perturb Ca(2+) handling in a prohypertrophic manner.

METHODS AND RESULTS

JPH2 expression was reduced in flash-frozen human cardiac tissue procured from patients with HCM compared with ostensibly healthy traumatic death victims. Partial silencing of JPH2 expression in HL-1 cells by a small interfering RNA probe targeted to murine JPH2 mRNA (shJPH2) resulted in myocyte hypertrophy and increased expression of known markers of cardiac hypertrophy. Whereas expression levels of major Ca(2+)-handling proteins were unchanged, shJPH2 cells demonstrated depressed maximal Ca(2+) transient amplitudes that were insensitive to L-type Ca(2+) channel activation with JPH2 knockdown. Further, reduced caffeine-triggered sarcoplasmic reticulum store Ca(2+) levels were observed with potentially increased total Ca(2+) stores. Spontaneous Ca(2+) oscillations were elicited at a higher extracellular [Ca(2+)] and with decreased frequency in JPH2 knockdown cells.

CONCLUSIONS

Our results show that JPH2 levels are reduced in patients with HCM. Reduced JPH2 expression results in reduced excitation-contraction coupling gain as well as altered Ca(2+) homeostasis, which may be associated with prohypertrophic remodeling.

Relation of QRS duration to mortality in a community-based cohort with hypertrophic cardiomyopathy

A prolonged QRS duration on the standard electrocardiogram is associated with an increased risk of cardiovascular death in cardiomyopathies of different origin. However, the relation between QRS duration and prognosis in hypertrophic cardiomyopathy (HC) remains undefined. We assessed the relation between QRS duration and cardiovascular death in 241 consecutive patients with HC. The study cohort was divided into 2 groups according to QRS duration: <120 and > or =120 ms. Of the 241 patients, 191 (79%) had a QRS duration <120 ms and 50 (21%) a QRS duration > or =120 ms. During a mean follow-up of 7.9 +/- 5.1 years, 35 patients died of cardiovascular causes related to HC. Of these 35 patients, 13 (6%) had a QRS duration <120 ms and 22 (43%) had a QRS duration > or =120 ms (p <0.01). Risk of cardiovascular death was significantly higher in patients with a QRS duration > or =120 ms than in those with a QRS duration <120 ms (relative risk 5.2, p <0.0001). At 8-year follow-up, cumulative risks of HC-related death were 7.1% in patients with a QRS duration <120 ms and 55% in those with a QRS duration > or =120 ms. Multivariate analysis confirmed that a QRS duration > or =120 ms was independently associated with an increased risk of cardiovascular death (hazard ratio 3.2, p = 0.007). New York Heart Association functional class III/IV was the only other clinical variable significantly and independently associated with an increased risk of cardiovascular death. In conclusion, in patients with HC, QRS duration on standard electrocardiogram is directly related to cardiovascular mortality, and a QRS duration > or =120 ms is a strong and independent predictor of prognosis.

Electrocardiographic markers of sudden death

The 12-lead ECG has limited utility to predict the risk for sudden cardiac death in common cardiac diseases such as coronary artery disease and idiopathic dilated cardiomyopathy. However, it is quite useful in diagnosing less common cardiac conditions that are associated with an increased risk for sudden death.

The value of changes in QRS width and in ST-T segment during exercise test in hypertrophic cardiomyopathy for identification of associated coronary artery disease

OBJECTIVES

Non-invasive methods cannot reliably predict the presence of coronary artery disease (CAD) in hypertrophic cardiomyopathy (HCM). This study aims to define the accuracy of QRS width changes versus standard ST-T criteria for recognition of associated ischemic CAD in patients with HCM undergoing exercise testing (ET).

METHODS

A retrospective study including patients with HCM. HCM was defined by left ventricular hypertrophy (LVH) of unknown etiology of at least 15 mm. Coronary angiography was performed as a gold standard for definition of CAD (> or =70% obstruction in at least one major artery). QRS width duration was measured at peak ET by a computerized method employing an optical scanner. No changes in QRS width or shortening during ET were considered normal; QRS width prolongation of more than 3 ms was defined as abnormal.

RESULTS

68 patients (56/12 M/F) aged 60+/-12 y were studied. During ET, abnormal QRS response was found in 40 (58.8%) and Ischemic ST-T changes in 52 (76.5%) patients. CAD in at least one artery was diagnosed in 31 patients (45.5%). The sensitivity of QRS width versus ST-T changes during ET for associated CAD was 82% and 28%, respectively. Specificity was 75% and 48%, respectively. Positive and negative predictive values were 88%; 68% for QRS width and 67%; 59% for ST-T changes respectively.

CONCLUSIONS

In patients with HCM undergoing ET, the association with CAD was more accurately predicted by an increase in QRS complex width than by standard criteria of ST-T segment changes. Thus, its use should be encouraged, especially in patients with HCM.

[Value of Doppler-echocardiography in the prognosis and follow up of hypertrophic myocardiopathy]

INTRODUCTION AND OBJECTIVES

The aim of this study was to assess the value of Doppler-echocardiogram for the prognosis and follow up of a hospital-based series of adult patients with hypertrophic cardiomyopathy (HC).

METHODS

One-hundred nineteen consecutive patients with HC (52 +/- 12 years, 60 women) were studied over a follow up period of 9.7 +/- 6.7 years. Echocardiographic evolution was analyzed in 104 patients (67 with dynamic obstruction) who had, at least, two echocardiograms performed within an interval of 3.7 +/- 3 years (1 to 7 years).

RESULTS

Seven patients died during follow up and 31 patients developed severe complications (7 deaths, 15 syncopes, 4 class IV angina, 3 class IV dyspnea and 2 acute myocardial infarctions). The presence of mitral insufficiency (p = 0.001) and dynamic gradient > 50 mmHg (p = 0.02) were predictive of mortality and a left atrial index > 25 mm/m2 was predictive (p = 0.028) of severe complications. Fifteen percent of the patients without dynamic obstruction in the first Doppler-echo showed a gradient > 25 mmHg in the last echo. A greater number of patients with mitral insufficiency (80% vs 66%; p = 0.01) and an increase in its severity (p = 0.038) was observed during follow up.

CONCLUSIONS

Mitral insufficiency, a dynamic gradient > 50 mmHg and a left atrial index > 25 mm/m2 are variables of a bad prognosis in adult patients with HC. An evolution to obstructive HC was observed in 15% of non obstructive HC, and a tendency to increased severity of mitral insufficiency was observed during follow up.

Persistent ST segment elevation: a new ECG finding in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is a primary disease of myocardium resulting in myocardial hypertrophy without any inciting pressure or volume overload. The typical triad of symptoms includes exertional angina, syncope, and shortness of breath. Sudden cardiac death, the most dreadful complication of this disorder, can be the first manifestation of the disease and is more common in young patients. Elderly patients, on the other hand, may have a relatively benign course with normal or near-normal life span. The electrocardiogram (ECG) and echocardiography are the two most useful measures to diagnose hypertrophic cardiomyopathy. The electrocardiographic features of hypertrophic cardiomyopathy are numerous, including ST segment elevation that may simulate other ST segment elevation syndromes, including acute myocardial infarction, variant angina pectoria, acute pericarditis, bundle branch blocks, ventricular paced rhythm, dyskinetic ventricular segment, ventricular aneurysm, left ventricular hypertrophy, Wolff-Parkinson-White syndrome, and early repolarization syndrome. This report describes a case of an asymptomatic patient who presented with ST segment elevation of acute injury type and, therefore, was admitted to rule out silent myocardial infarction. Myocardial infarction was ruled out by cardiac enzyme levels, but ST segment elevation remained persistent in all of the subsequent ECGs. Echocardiography was performed, which clearly showed hypertrophic cardiomyopathy with left ventricular outflow tract obstruction and a high intracavity pressure gradient. Subsequently, retrieval of old ECGs showed a similar type of ST segment elevation in the patient's previous ECGs.

Reversible ischaemia in hypertrophic cardiomyopathy

Atypical and typical chest pains are common symptoms in patients with hypertrophic cardiomyopathy. Some of these chest pains seem to be caused by ischaemia. It is difficult to objectively demonstrate ischaemia in hypertrophic cardiomyopathy. The first line treatment for chest pain considered to be ischaemic in patients with hypertrophic cardiomyopathy is the use of either a beta blocker or calcium blocker. Septal myectomy can be effective in patients with symptoms refractory to conventional treatment but is associated with significant morbidity and mortality. Recently dual chamber pacing has been advocated in such patients. In some cases dual chamber pacing alleviates chest pain in hypertrophic cardiomyopathy by an anti-ischaemic action, presumably by reducing the left ventricular outflow tract gradient and perhaps by causing an associated decrease in left ventricular outflow tract gradient and perhaps by causing an associated decrease in left ventricular end diastolic pressure.

Percutaneous radiofrequency ablation of the left bundle branch: an alternative modality of treatment for patients with hypertrophic obstructive cardiomyopathy

Hypertrophic obstructive cardiomyopathy (HOCM), which is characterized by asymmetric septal and ventricular obstructive hypertrophy, is currently palliated with a number of pharmacological, electrical and surgical interventions. Although none of the methods have been successful in reducing the incidence of sudden death, most of the patients have shown significant symptomatic improvement. Currently, pacemaker implantation and surgical procedures have been offered only to those patients who do not respond to a medical line of treatment. Since obstructive pressure gradients correlate fairly well with the clinical condition of a patient, the principal aim of surgical or pacemaker therapy has been to reduce the left ventricular pressure gradient. Surgical procedure achieves this objective by septal myotomy and myectomy whereas pacemakers attain it by altering the sequence of electrical stimulation of the ventricles. A right ventricular pacing, which behaves like a left bundle branch block, is known to alter the pattern of interventricular septal contraction and hence delay the onset of mitral leaflet-septal contact. The latter has been implicated in the pathogenesis of subvalvar dynamic left ventricular outflow tract obstruction, which is the hallmark of this condition. Currently, radiofrequency ablation of the left bundle branch has been successfully carried out for patients with resistant macrore-entry ventricular tachycardia, I, therefore, propose that radiofrequency ablation of the left bundle branch be used as a palliative procedure of choice for patients with HOCM who are resistant to a medical line of treatment. This would result in left bundle branch block which in turn would cause an altered pattern of septal contraction resulting in the reduction or elimination of left ventricular outflow tract obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Antihypertensive therapy

Choosing antihypertensive agents that protect patients against cardiovascular and other complications is a growing trend in the treatment of mild to moderate hypertension. Calcium channel blockers and angiotensin-converting enzyme (ACE) inhibitors are favored because they have neutral or positive effects on lipid levels and insulin resistance. The alpha 1 blockers, especially doxazosin mesylate (Cardura), are enjoying a resurgence in popularity because they have a beneficial effect on lipid levels. In terms of preserving patients' quality of life, the ACE inhibitors in particular have been shown to have a positive impact. It has been shown that systolic hypertension in elderly patients should definitely be treated, but the most appropriate agent has yet to be defined. Therapy should be tailored to the individual. The following questions should be considered when choosing an antihypertensive agent: (1) What are its side effects (especially metabolic ones)? (2) Does it require only once- or twice-a-day dosing? (3) Does it cause regression of left ventricular hypertrophy? (4) Does it prevent death from coronary artery disease? (5) How will it affect quality of life? (6) How much does it cost? The goal of therapy should be to provide adequate blood pressure control throughout the day, enhance compliance, and protect the heart, brain, and kidneys without adversely affecting metabolic state.

Long-term course and cardiac sympathetic nerve activity in patients with hypertrophic cardiomyopathy

OBJECTIVE

To investigate the relation between regional myocardial sympathetic nerve activity and the electrocardiographic and cardiac functional changes in hypertrophic cardiomyopathy.

DESIGN

A retrospective study to compare the findings of myocardial scintigraphy with iodine-123 metaiodobenzylguanidine (MIBG) and the serial electrocardiographic changes.

SETTING

Myocardial scintigraphy was performed with iodine-123 MIBG and thallium-201 and single photon emission computed tomography (SPECT) in the division of nuclear medicine of Kanazawa University Hospital. Both SPECT studies were performed within a week.

PATIENTS

22 patients with hypertrophic cardiomyopathy classified according to their serial electrocardiographic changes--namely, 15 patients with an increase in or the appearance of a negative T wave (group A) and seven patients with a conduction disturbance or a decrease in or disappearance of the negative T wave (group B). The mean follow up period was 45 (range 12-143) months.

RESULTS

Group B showed a high rate of decreased activity or defects in MIBG uptake compared with group A (p less than 0.005). The areas of decreased activity or defects corresponded with the hypertrophied portion of the left ventricular wall. Although the early myocardial uptake (MIBG: thallium ratio) was similar in both groups, the mean (SD) MIBG clearance rate was significantly higher (p less than 0.05) in group B (0.25 (0.17)) than in group A (0.10 (0.15)).

CONCLUSION

Abnormalities of regional myocardial sympathetic nerve activity may be important in patients with hypertrophic cardiomyopathy and suspected progression of myocardial damage.

Evolution of the electrocardiographic changes in patients with hypertrophic cardiomyopathy

In 75 patients with hypertrophic cardiomopathy (HCM) followed for a mean period of 5.5 years (range 2-20 years), evolution of the electrocardiographic (EKG) changes was assessed. Progression of EKG abnormalities occurred in 35 patients (47%). It was manifested by an increase in precordial QRS voltage in 33 patients, development of new P-wave mitral in 11 patients, and development or disappearance of pathologic Q waves in 14 patients. With follow-up times greater than 5 years, 5-8 years, and greater than 8 years, EKG progression was present in 27, 41, and 80% of patients, respectively. Age less than 30 years at the beginning of study and left ventricular outflow obstruction predisposed to EKG progression within 5-8 years. Patients with progressive EKG changes were more prone to experience clinical deterioration than those without EKG progression (63 vs. 15%, p less than 0.001). With chronic verapamil administration, progression of EKG abnormalities occurred insignificantly less often than with propranolol treatment (35 vs. 64%, p = 0.20). It is concluded that with long-term follow-up, HCM tends to progress in a significant proportion of adult patients.

Hypertension with concomitant conditions: the changing role of beta-adrenoceptor blockade

Hypertension often is associated with concomitant conditions such as chronic obstructive lung disease, diabetes mellitus, ischemic heart disease, and peripheral vascular disease. Moreover, other cardiovascular risk factors, including dyslipidemias and abnormalities of glucose and insulin metabolism, are common in patients with hypertension. Conventional beta-blockers used for antihypertensive therapy can have adverse effects in patients with airway disease, diabetes, and peripheral vascular disease, and can exaggerate the other risk factors. Newer beta-blockers such as celiprolol, which have selective partial agonist activity expressed at beta 2-receptors, appear to avoid these problems. Celiprolol exhibits antianginal and antihypertensive efficacy without adversely effecting left ventricular systolic function or exercise performance. It also may cause regression of left ventricular hypertrophy. The stimulatory action of celiprolol on vascular beta 2-receptors enhances regional flow and may increase walking distance in patients with claudication. The reduction in renal vascular resistance demonstrated by this drug is associated with preservation of renal blood flow and function. Spirometric measurements of airway function are unchanged during celiprolol treatment. Similarly, there are no adverse effects on lipid or glucose concentrations. These new developments in beta-blocker pharmacology indicate that this class of agents could be used in patients with hypertension with concomitant diseases or risk factors other than high blood pressure.

Q waves in hypertrophic cardiomyopathy in relation to the distribution and severity of right and left ventricular hypertrophy

The cause of abnormal Q waves in hypertrophic cardiomyopathy remains unclear. Myocardial wall thickness was assessed by two-dimensional echocardiography at 8 left ventricular and 10 right ventricular sites in 67 patients (mean age 40 years) with hypertrophic cardiomyopathy and the findings were analyzed in relation to the presence of abnormal Q waves on the 12 lead rest electrocardiogram (ECG). Nineteen (28%) of the 67 patients had abnormal Q waves. Right ventricular hypertrophy was significantly more common in patients without abnormal Q waves (25 [52%] of 48 versus 2 [11%] of 19, p less than 0.001). With univariate analysis, there were six measurements that were significantly associated with abnormal Q waves: an increase in upper anterior septal thickness (p less than 0.005) and maximal left ventricular wall thickness (p less than 0.02), a decrease in mean and maximal right ventricular wall thickness (both p less than 0.005) and an increase in the ratio of both upper anterior septal to mean right ventricular wall thickness (p less than 0.005) and upper anterior septal to upper posterior wall thickness (p less than 0.005). With multivariate analysis, only the ratios of upper anterior septal to mean right ventricular wall thickness (p less than 0.005) and to upper posterior wall thickness (p less than 0.05) were significantly related to the presence of abnormal Q waves and predicted Q wave location with a sensitivity, specificity and predictive accuracy of 90%, 88% and 89%, respectively. In hypertrophic cardiomyopathy, the presence of abnormal Q waves on the 12 lead ECG is primarily a function of the relation of right ventricular wall thickness and upper anterior septal thickness.

Electrocardiographic findings in patients with hypertrophic cardiomyopathy. Relation to presenting features and prognosis

The relation of ECG findings to presenting features and prognosis was evaluated in 125 consecutive patients with hypertrophic cardiomyopathy (HC). Seventy-nine men and 46 women (mean age, 34 +/- 7 years) were studied since 1970. Most ECG features were similar in patients with and without a left ventricular outflow tract gradient. Those with obstruction had a higher prevalence of left ventricular hypertrophy according to ECG voltage criteria (54% vs. 28%, p less than 0.01), whereas higher grade ventricular arrhythmias were more common in patients without an outflow gradient (20% vs. 7%, p less than 0.05). The prevalence of ECG abnormalities was also similar in younger (less than or equal to 14 years) and older patients (greater than 14 years), and only repolarization abnormalities were more frequently detected in the older age group (56% vs. 32%, p less than 0.025). Stratification of patients according to the clinical state revealed that those who had moderate to severe functional limitation had a higher prevalence of atrial fibrillation than asymptomatic or mildly symptomatic patients (24% vs. 1%, p less than 0.001). There were no significant differences in most hemodynamic variables among patients dichotomized according to any specific ECG abnormality. Only patients with atrial fibrillation had significantly higher right ventricular end-diastolic pressure (10 +/- 7 vs. 6 +/- 4 mmHg, p less than 0.01), lower systolic index (22 +/- 8 vs. 37 +/- 15 ml/m2; beat, p less than 0.02) and lower ejection fraction (53 +/- 8 vs. 64 +/- 10%, p less than 0.001) than those in sinus rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Diurnal change of giant negative T wave in patients with hypertrophic cardiomyopathy

To examine the diurnal change of negative T wave (deeper than 10 mm in precordial leads) in apical hypertrophic cardiomyopathy and the mechanism of giant negative T wave, 24-h ambulatory electrocardiographic monitoring was performed in 8 patients with apical hypertrophic cardiomyopathy, and effect of atropine on electrocardiogram was studied. The mean depth of negative T wave at 1, 2, and 3 P.M. was 9.3 +/- 3.0 mm, and that at 1, 2, and 3 A.M. was 12.6 +/- 4.8 mm. The mean R-R interval at 1, 2, and 3 P.M. was 792 +/- 113 ms and that at 1, 2, and 3 A.M. was 1055 +/- 94 ms. In seven patients (88%), negative T wave was deeper during the night than during the daytime. There was a positive correlation between R-R interval and depth of negative T wave in 6 patients (75%). Despite significant shortening of R-R interval (879 +/- 116 to 804 +/- 110 ms, p less than 0.05), atropine did not significantly change the depth of negative T wave (14 +/- 5 to 14 +/- 5 mm). In conclusion, negative T wave is not fixed, but is variable, diurnally, probably due to the change of sympathetic tone.

Severity of arrhythmias and extent of hypertrophy in hypertrophic cardiomyopathy

To evaluate the relationship between the extent of left ventricular hypertrophy and ventricular or atrial arrhythmias, 77 patients with hypertrophic cardiomyopathy underwent two-dimensional echocardiography and 24-hour Holter monitoring. Antiarrhythmic treatment was discontinued before the study. Hypertrophy was septal in 33 patients, "extensive" (i.e., involving the septum and free wall) in 38 patients, and predominantly apical in six patients. Lown grade I and II ventricular arrhythmias were detected in 37% of patients, grade III in 21%, and grade IV in 29%. Atrial extrasystoles were seen in 52% of patients and chronic atrial fibrillation in 13%. More serious ventricular arrhythmias (Lown grades III and IV) occurred significantly more frequently in patients with extensive than in those with only septal hypertrophy (22/38 vs 11/33; p less than 0.001); similarly, chronic atrial fibrillation occurred more commonly in those with extensive hypertrophy (9/38 vs 1/33; p less than 0.01). During a mean follow-up period of 2.6 years, three patients died. All had a pattern of extensive hypertrophy. Two of them had ventricular tachycardia and the third had chronic atrial fibrillation. Results of this study suggest that an echocardiographic finding of extensive hypertrophy represents a useful marker for detecting patients at increased risk for serious ventricular and atrial arrhythmias.

Clinical sustained uniform ventricular tachycardia in hypertrophic cardiomyopathy: association with left ventricular apical aneurysm

Of 51 patients with hypertrophic cardiomyopathy who had episodes of ventricular tachycardia detected during ambulatory electrocardiographic monitoring only two had clinical sustained uniform ventricular tachycardia that required medical treatment because of worsening symptoms. In both patients the arrhythmia was associated with the uncommon finding of an apical aneurysm with angiographically normal coronary arteries.

The resting surface electrocardiogram as a predictor of future hypertension

Resting supine and post-provocation (dynamic exercise, isometric exercise and cold pressor) levels of blood pressure were measured in 80 normotensive offspring of normotensive parents (control) and 55 normotensive offspring of parents with essential hypertension. The surface electrocardiogram (including conventional twelve leads, posterior chest leads, right-sided chest leads and bipolar precordial leads) was also recorded in all subjects. Twenty-eight offspring of parents with essential hypertension had their resting and/or post-provocation blood pressure above the upper limit of standard deviation in age- and sex-matched control group. Flat or upright T waves, with either S waves less than 0.2 mV, or S/R ratio less than 2, or T waves equal to or higher than the accompanying R waves in lead V4R, could identify these potential hypertensives with nearly 90% specificity and nearly 75% sensitivity. The criterion had been derived, however, by analysis of the data achieved retrospectively. Therefore, the exact discriminating value of this criterion can be assessed only by a long-term prospective study.

Hypertrophic cardiomyopathy with extreme increase in left ventricular wall thickness: functional and morphologic features and clinical significance

Clinical and morphologic features of 34 patients with hypertrophic cardiomyopathy and particularly marked left ventricular hypertrophy were analyzed. Only patients with a ventricular septal thickness of at least 35 mm (range to 52 mm) were selected for the study; 31 (90%) had a diffuse pattern of hypertrophy also involving substantial portions of the left ventricular free wall. Despite similar left ventricular morphology, these patients exhibited a broad spectrum of clinical findings and natural history. Ten patients (29%) had hemodynamic or echocardiographic evidence of basal subaortic obstruction (average gradient, 63 mm Hg); however, the majority (24 [71%]) had no evidence of obstruction at rest, despite substantial hypertrophy of the basal anterior portions of septum and free wall. Although the electrocardiograms of most patients (76%) showed patterns of left ventricular hypertrophy, the magnitude of precordial QRS complexes was not markedly increased (S wave in lead V1 or V2, 27 +/- 15 mm; R wave in lead V5 or V6, 21 +/- 9 mm). The clinical course was variable in 30 patients who were followed up for at least 1 year (mean 6 years). Although no patient died, nine (30%) have exhibited clinical deterioration, including two who spontaneously developed complete heart block and one who collapsed with ventricular fibrillation but survived. However, the clinical condition of the majority of patients (21 [70%]) remained unchanged or improved. At the most recent evaluation, 20 (67%) of the 30 patients were asymptomatic or only mildly symptomatic, including 7 who remained without symptoms throughout the period of follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Asymmetric apical hypertrophy: ten years experience

This paper reports 10 years experience of 31 patients with asymmetric apical hypertrophy, in whom left ventricular hypertrophy involved the apex exclusively and giant T wave inversion in the left precordial leads was the characteristic finding. This type of hypertrophic cardiomyopathy was observed predominantly in men over 40 years of age. Family history was negative and patients usually had no complaints. Left ventricular hypertrophy was evident by physical examination as in other forms of hypertrophic cardiomyopathy, but a systolic murmur was faint or absent and the second heart sound was frequently split. Electrocardiographic signs may fluctuate, and occasionally progression or regression occurs. Echocardiography including the two-dimensional method was essential for the diagnosis and left ventriculography was helpful for confirmation. To date complications have been infrequent and the prognosis seems good. The relation of asymmetric apical hypertrophy to other forms of hypertrophic cardiomyopathy is under investigation.

Development of severe left ventricular outflow tract obstruction over the course of 14 years: an unusual natural history of hypertrophic obstructive cardiomyopathy

A patient with hypertrophic obstructive cardiomyopathy who when first seen had a normal physial examination, chest x-ray, and electrocardiogram, and no provokable gradient with isoproterenol at cardiac catheterization, was re-evaluated after 14 years. At the time of re-evaluation, she was found to have a typical systolic ejection murmur, cardiomegaly, left ventricular hypertrophy, a pseudoinfarction pattern on electrocardiography, and a significant subaortic gradient both by catheterization and by doppler. This case demonstrates that hypertrophic obstructive cardiomyopathy can be a progressive disease and that patients with this condition warrant careful follow-up. Echocardiography with doppler may provide an excellent noninvasive method of following these patients.

Cardiomyopathies and their role in sudden death

Frequent ventricular premature complexes, complex ventricular ectopic activity and asymptomatic ventricular tachycardia are common to both hypertrophic and dilated cardiomyopathy; in both conditions, sudden death is a common occurrence. Asymptomatic young patients with hypertrophic cardiomyopathy who have a family history and a high incidence of ventricular arrhythmias have a particularly high incidence of sudden death. In patients with hypertrophic cardiomyopathy, efforts to attribute sudden death to the cardiac index, left ventricular end-diastolic pressure, left ventricular outflow obstruction, ejection fraction, age, symptomatic state and septal thickness have been unrewarding. Myocardial hypertrophy and disordered myocardial cell arrangement are the likely substrates for the development of ventricular arrhythmias in hypertrophic cardiomyopathy. Ventricular fibrillation preceded by ventricular tachycardia appears to be the terminal event in most patients who die suddenly. In some patients, cardiac asystole is the terminal event. Additional factors playing a role in the development of the substrate for sudden death in patients with hypertrophic cardiomyopathy vary in importance on an individual basis. These factors include narrowing of septal arteries and the artery to the atrioventricular node, preservation of fetal anatomy with dispersion in the atrioventricular node and His bundle, fibrosis of the sinus node, clefts in the septum, multiple atrioventricular pathways and massive myocardial infarction. Patients with dilated cardiomyopathy appear to have the highest incidence of ventricular arrhythmias of any disease yet studied. The substrate for the development of ventricular arrhythmias in these patients appears to be myocardial hypertrophy and myocardial fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Progression of hypertrophic cardiomyopathy. A cross sectional echocardiographic study

The progression of hypertrophy was studied in 39 patients with hypertrophic cardiomyopathy by echocardiography at follow up from January 1979 to September 1983 (mean follow up 42 months). Thirty two patients were treated medically and 11 had had a septal myotomy-myectomy. Progression of the hypertrophy was noted in four patients treated with propranolol. An additional region in the left ventricular long axis plane was affected in two, extending to the apical region in one and to the basal region in the other, and an additional segment in the left ventricular short axis plane in two extending from the septum into the free wall. The electrocardiograms of these four patients showed a significant increase in QRS voltages (Sokolow-Lyon index increase greater than 10 mm) and of the Romhilt-Estes score (increase greater than or equal to 3 points) in two, development of a left bundle branch block in one, and no change in one. Progression of hypertrophy was seen in none of the 11 patients treated with myotomy-myectomy. Thus echocardiography accurately detects the progression of hypertrophy in patients with hypertrophic cardiomyopathy, which may be prevented by septal myotomy-myectomy.

Chronic verapamil therapy in pediatric and young adult patients with hypertrophic cardiomyopathy

Oral verapamil, 5.2 +/- 1.1 mg/kg/day (range 2.8 to 7), was administered to 13 pediatric patients with hypertrophic cardiomyopathy for 13 +/- 6 months (range 2 to 20). The patients had significant symptomatic improvement on verapamil therapy. Murmur intensity diminished in 6 patients during therapy and left ventricular (LV) electromotive forces on the electrocardiogram diminished in 4, increased in 5 and did not change in 4. Exercise endurance increased from 8.4 +/- 3.9 to 10.9 +/- 2.8 minutes (p less than 0.01). Seven patients had ST-segment depression (0.38 +/- 0.28 mV) before verapamil therapy, which improved after verapamil therapy in 5 (0.24 +/- 0.17 mV, p less than 0.02). Of 4 patients with exercise-induced ventricular ectopic activity, 3 had diminution or abolishment of ectopy following verapamil. By echocardiography, the patients had an increase in LV end-diastolic dimension from 3.4 +/- 0.7 to 3.9 +/- 0.8 cm (p less than 0.01), with no significant change in shortening fraction (46.1 +/- 8.0% vs 44.6 +/- 8.0%). When adjusted for body size and age there was a significant decrease in LV septal thickness (from 106 +/- 70 to 45 +/- 52% of predicted normal values, p less than 0.05) and LV posterior wall thickness (from 40 +/- 45 to 5 +/- 26% of predicted normal values p = 0.05) after verapamil. Isovolumic relaxation time decreased from 69 +/- 26 to 42 +/- 19 ms after verapamil (p less than 0.01). Systolic anterior motion of the anterior mitral leaflet disappeared in 5 of 8 patients and midsystolic closure of the aortic valve was no longer present in 4 of 8.(ABSTRACT TRUNCATED AT 250 WORDS)

Development and regression of left ventricular hypertrophy

Left ventricular hypertrophy is an important adaptive response to chronic pressure or volume overload of the left ventricle. The different types and the pathophysiologic mechanisms of the development of left ventricular hypertrophy in various disease states are reviewed. Detection of left ventricular hypertrophy may be accomplished by electrocardiography and cardiac angiography. Echocardiography, however, is the most accurate noninvasive method to detect the presence and estimate the severity of increased left ventricular mass. The clinical significance of left ventricular hypertrophy and its prognostic implications in several cardiac diseases associated with hypertrophy are discussed. The critical transition stage from adaptive, compensatory and reversible left ventricular hypertrophy to "pathologic" hypertrophy with impaired left ventricular contractility and irreversible myocardial damage is yet unknown. Recent data are presented that provide evidence of regression of left ventricular hypertrophy after medical treatment of patients with hypertension and after aortic valve replacement in patients with aortic valve disease. The clinical importance of regression of hypertrophy and its effects on long-term prognosis remain to be determined.