Device complications and inappropriate implantable cardioverter defibrillator shocks in patients with hypertrophic cardiomyopathy.

BACKGROUND: Although the benefit of implantable cardioverter defibrillator (ICD) therapy in patients with hypertrophic cardiomyopathy (HCM) at risk for sudden cardiac arrest is well established, there may be a higher risk for device complications and inappropriate shocks. OBJECTIVES: To determine the incidence of inappropriate ICD shocks and device complications in HCM patients and the impact of young age at ICD implant and atrial fibrillation. METHODS: HCM patients who underwent ICD implantation between January 1988 and December 2005 were included. The frequency of device complications, including pneumothorax, pericardial effusion, haematoma, lead revisions, infection and rate of inappropriate shocks, was determined. ICD shocks were characterised as inappropriate if triggered by sinus tachycardia, atrial fibrillation or device malfunction. RESULTS: A total of 181 patients were included (mean age 44 (SD 17) years; 62% males). During a mean follow-up of 59 (42) months (4.92 years; 830.75 patient-years), 65 patients (36%) had a total of 88 device complications, including 42 (23%) patients with inappropriate shocks. The rate of inappropriate shocks was 5.3% per year (vs 4% risk of appropriate shocks), and the likelihood of inappropriate ICD shocks per 100 patient-years was 5.1. Younger age and atrial fibrillation were associated with an increased risk of inappropriate ICD discharges. CONCLUSIONS: The rate of inappropriate ICD shocks and frequency of device complications in HCM patients are not insignificant and are most common in younger patients and those with atrial fibrillation. Inappropriate ICD shocks are the most common device complication and should be accounted for when counselling high-risk HCM patients for ICD implantation.

Acute myocardial infarction: an unusual culmination of rheumatic pancarditis and antiphospholipid antibody syndrome.

A 29-year-old man with history of antiphospholipid antibody syndrome (APS) and two prior episodes of acute rheumatic fever developed a third episode of acute rheumatic fever. This was complicated by acute myocardial infarction due to spontaneous arterial thrombosis of the left anterior descending and right coronary arteries. We postulate that rheumatic pancarditis created an inflammatory, thrombogenic environment that facilitated coronary artery thrombosis secondary to APS, a novel association. Our patient was left with significant left ventricular dysfunction at a young age, and cases such as this emphasize the need for early recognition and proper treatment of APS. Further, the pathogenesis of thrombosis in APS is incompletely understood, and the cellular and molecular basis for this, including the role of 'second hits', are areas needing further investigation.

Comparison of ethanol septal reduction therapy with surgical myectomy for the treatment of hypertrophic obstructive cardiomyopathy.

OBJECTIVES: This study was designed to compare the hemodynamic efficacy of nonsurgical septal reduction therapy (NSRT) by intracoronary ethanol with standard therapy (surgical myectomy) for the treatment of hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Nonsurgical septal reduction therapy has gained interest as a new treatment modality for patients with drug-refractory symptoms of HOCM; however, its benefits in comparison to surgery are unknown. METHODS: Forty-one consecutive NSRT patients at Baylor College of Medicine with one-year follow-up were compared with age- and gradient-matched septal myectomy patients at the Mayo Clinic. All patients had left ventricular outflow obstruction with a resting gradient > or =40 mm Hg and none had concomitant procedures. RESULTS: There were no baseline differences in New York Heart Association class, severity of mitral regurgitation, use of cardiac medications or exercise capacity. One death occurred during NSRT because of dissection of the left anterior descending artery. At one year, all improvements in both groups were similar. After surgical myectomy, more patients were on medications (p < 0.05) and there was a higher incidence of mild aortic regurgitation (p < 0.05). After NSRT, the incidence of pacemaker implantation for complete heart block was higher (22% vs. 2% in surgery; p = 0.02). However, seven of the nine pacemakers in the NSRT group were implanted before a modified ethanol injection technique and the use of contrast echocardiography. CONCLUSIONS: Nonsurgical septal reduction therapy resulted in a significantly higher incidence of complete heart block, but the risk was reduced with contrast echocardiography and slow ethanol injection. Surgical myectomy resulted in a significantly higher incidence of mild aortic regurgitation. Nonsurgical septal reduction therapy, guided by contrast echocardiography, is an effective procedure for treating patients with HOCM. The hemodynamic and functional improvements at one year are similar to those of surgical myectomy.

Echocardiographic assessment of diastolic function.

Abnormal diastolic function is increasingly appreciated as a major contributor to cardiac morbidity and mortality. Accurate noninvasive assessment of the presence and severity of diastolic impairment is crucial to the broad application and understanding of this common condition. Echocardiographic parameters have become the backbone of this noninvasive assessment. Active investigation into both old and new Doppler variables will provide the framework that can lead to a more uniform assessment and reporting that will be essential as we prepare to confront clinically the next frontier in cardiac pathophysiology. This review discusses the clinical impact of recent echocardiographic contributions to the field of diastology.

Clinical utility of Doppler echocardiography and tissue Doppler imaging in the estimation of left ventricular filling pressures: A comparative simultaneous Doppler-catheterization study.

BACKGROUND: Noninvasive assessment of diastolic filling by Doppler echocardiography provides important information about left ventricular (LV) status in selected subsets of patients. This study was designed to assess whether mitral annular velocities as assessed by tissue Doppler imaging are associated with invasive measures of diastolic LV performance and whether additional information is gained over traditional Doppler variables. METHODS AND RESULTS: One hundred consecutive patients referred for cardiac catheterization underwent simultaneous Doppler interrogation. Invasive measurements of LV pressures were obtained with micromanometer-tipped catheters, and the mean LV diastolic pressure (M-LVDP) was used as a surrogate for mean left atrial pressure. Doppler signals from the mitral inflow, pulmonary venous inflow, and TDI of the mitral annulus were obtained. Isolated parameters of transmitral flow correlated with M-LVDP only when ejection fraction <50%. The ratio of mitral velocity to early diastolic velocity of the mitral annulus (E/E') showed a better correlation with M-LVDP than did other Doppler variables for all levels of systolic function. E/E' <8 accurately predicted normal M-LVDP, and E/E' >15 identified increased M-LVDP. Wide variability was present in those with E/E' of 8 to 15. A subset of those patients with E/E' 8 to 15 could be further defined by use of other Doppler data. CONCLUSIONS: The combination of tissue Doppler imaging of the mitral annulus and mitral inflow velocity curves provides better estimates of LV filling pressures than other methods (pulmonary vein, preload reduction). However, accurate prediction of filling pressures for an individual patient requires a stepwise approach incorporating all available data.

Assessment of right atrial pressure with 2-dimensional and Doppler echocardiography: a simultaneous catheterization and echocardiographic study.

OBJECTIVE: To derive a clinically useful, noninvasive determination of right atrial pressure. Noninvasive assessment of right ventricular systolic pressure from Doppler-derived tricuspid regurgitant velocity requires an accurate assumption of right atrial pressure. PATIENTS AND METHODS: Seventy-one patients were studied in the cardiac catheterization laboratory, comparing right atrial pressure (measured at mid systole) with simultaneous 2-dimensional echocardiographic measurement of inferior vena cava diameter and Doppler recordings of hepatic vein systolic, diastolic, and atrial reversal velocities. The initial 28 patients were used to derive a clinical algorithm to predict right atrial pressure, which was tested in the subsequent 43 patients. RESULTS: Inferior vena cava dimension correlated directly with right atrial pressure (r2=0.74; P<.001). The systolic filling fraction of the hepatic vein velocity curves correlated poorly with right atrial pressure. However, the correlation between the hepatic vein Doppler sum of systolic forward flow velocity and atrial reversal velocity and right atrial pressure was inverse (r2=0.32; P=.002). With a combination of variables from both inferior vena cava diameter and hepatic vein velocity curves, patients can be divided into those with normal right atrial pressure, mildly increased right atrial pressure, and severely increased right atrial pressure. CONCLUSION: The combined information from inferior vena cava diameter and hepatic vein velocity curves can be used to assess right atrial pressure.

Comparison of long-term results of percutaneous mitral balloon valvotomy with closed transventricular mitral commissurotomy at a single North American Institution.

Long-term (>3 years) follow-up data were obtained from 102 consecutive patients undergoing percutaneous mitral balloon valvotomy (PMBV). Data were collected prospectively by review of the medical record, mailed questionnaire, and/or telephone. Data on patients with closed mitral commissurotomy (CMC) at our institution have been previously reported and serve as the comparison group. Follow-up data was 98% complete at a mean of 57 months for PMBV patients. Compared with patients undergoing CMC, these patients were older (54+/-14 vs 43.6+/-10 years, p <0.001) and more likely to have undergone previous mitral valve surgery (17% vs 4%, p <0.001). The observed 5-year survival in the PMBV group was no different from that observed in the CMC group (83% vs 90%, p = NS) or from that predicted by the model developed from the CMC patients. Commissural calcium was associated with death and death or repeat mitral valve procedure in the multivariate analysis. Long-term survival free from repeat procedures was equivalent when patients with commissural calcium were excluded. Thus, PMBV offers long-term survival and freedom from subsequent mitral valve procedures similar to CMC.

Dynamic left ventricular outflow tract obstruction in acute coronary syndromes: an important cause of new systolic murmur and cardiogenic shock.

Dynamic left ventricular outflow tract (LVOT) obstruction has traditionally been associated with hypertrophic obstructive cardiomyopathy. Recently, acute dynamic LVOT obstruction has been described as a complication of myocardial infarction (MI). Herein the cases of 3 patients are described, all of whom presented with a systolic murmur and electrocardiographic evidence of MI. All 3 patients developed cardiogenic shock and were subsequently found by echocardiography to manifest an acute dynamic LVOT obstruction. Cardiogenic shock persisted until therapy was directed toward decreasing the degree of the dynamic LVOT obstruction. The treatment of acute coronary syndromes in the presence of a dynamic LVOT obstruction differs from the traditional treatment of acute coronary syndromes and includes the use of beta-blockers and alpha1-agonists, as well as the avoidance of therapies that aggravate the magnitude of the LVOT obstructive gradient, including nitrates, inotropic agents, and afterload reduction. The development of a systolic murmur in the setting of acute MI complicated by cardiogenic shock with only a small elevation in creatine kinase suggests the presence of a dynamic LVOT obstruction, as well as the classical mechanical complications of MI, namely, ventricular septal rupture and papillary muscle rupture. The presence of a dynamic LVOT obstruction is reliably detected by transthoracic echocardiography or by transesophageal echocardiography if transthoracic image quality is suboptimal.

Comparison of dual-chamber pacing versus septal myectomy for the treatment of patients with hypertrophic obstructive cardiomyopathy: a comparison of objective hemodynamic and exercise end points.

OBJECTIVES: The purpose of this study was to compare the treatment effects of septal myectomy with dual-chamber pacing in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: The optimal treatment for symptomatic patients with drug-refractory HOCM is unknown. Both dual-chamber pacing and surgical myectomy may result in subjective symptom improvement. However, no direct comparisons with objective end points have been reported. METHODS: Thirty-nine patients with symptomatic HOCM were analyzed in this concurrent cohort study. Twenty patients underwent surgical myectomy, and 19 received dual-chamber pacemakers based on patient preference. These patients had prospective baseline and follow-up evaluations including physician assessment, echocardiography and standardized metabolic treadmill exercise testing. RESULTS: Baseline symptom status, left ventricular outflow tract gradients, exercise times and maximal oxygen consumption peak were similar between the two groups. Left ventricular outflow gradient was reduced from 76+/-57 to 9+/-17 mm Hg (p = 0.0001) after myectomy, and from 77+/-61 to 55+/-39 mm Hg (p = 0.07) after pacing (p = 0.02 for comparison with myectomy). Ninety percent of myectomy patients experienced symptomatic improvement as compared with 47% in the pacing group. Exercise duration increased significantly from 6.6+/-2.8 to 8.7+/-3.0 min (p = 0.0003) after myectomy compared with a change from 6.4+/-2.1 to 7.0+/-2.2 min (p = NS) in the pacing group. Maximal oxygen consumption increased from 19.4+/-6.4 to 22.2+/-6.5 ml/kg/min after myectomy (p = 0.004), whereas the pacing group did not experience any significant change (19.6+/-6.5 vs. 20.1+/-6.5 ml/kg/min, p = NS). CONCLUSIONS: Surgical myectomy and dual-chamber pacing improve subjective measures of functional status in patients with symptomatic HOCM. In this nonrandomized study, myectomy offered greater reduction in left ventricular outflow tract gradients and larger improvements in objective measures of patient symptoms and functional status when compared with dual-chamber pacing.

Summary of the Mayo Clinic experience with direct left ventricular puncture.

Hemodynamic assessment of patients with prosthetic valves can be challenging. Noninvasive techniques may be limited by interference from the prosthetic material, whereas access to the left ventricle for direct pressure measurements often is not possible using common methods. The technique of direct, percutaneous left ventricular puncture has been proven to be a safe method that often provides needed data to help manage difficult clinical situations. We report our 8-yr experience with this technique for assessment of patients with valvular prostheses. Direct left ventricular puncture is a safe technique in patients with prior cardiac surgery and provided significant diagnostic information in the set of patients with multiple valvular prostheses.

Predictive power of the relative lymphocyte concentration in patients with advanced heart failure.

BACKGROUND: The physiological stress suffered by patients with heart failure results in an increased production of cortisol and a shift in the leukocyte differential toward a decreased percentage of lymphocytes (%L). The purpose of this study was to determine the prognostic significance of a low %L in advanced heart failure. METHODS AND RESULTS: Patients evaluated in our cardiac transplantation clinic between April 1988 and July 1995 were retrospectively reviewed (n=263). Fifty-two patients were excluded because they had recent trauma, infection, surgery, myocardial infarction, corticosteroid use, or history of malignancy. In the remaining 211 patients, we used Cox proportional hazards analysis to examine the association between survival and transplant-free survival with baseline variables. Univariate analysis showed a significant association between time to death and %L (P=.004), New York Heart Association (NYHA) class (P=.002), and maximal oxygen uptake (P=.05). Univariate analysis of the end point of survival free from transplantation yielded similar results. One- and 4-year survival rates for patients with a low %L (<20.3%) were 78% and 34% compared with 90% and 73% for those with a normal %L. Multivariate analysis showed NYHA class (P<.008) and %L (P<.01) were independent predictors of survival and survival free from cardiac transplantation. CONCLUSIONS: The relative lymphocyte concentration is an inexpensive, readily available, simple prognostic marker in patients with symptomatic heart failure who do not have recent trauma, infection, surgery, myocardial infarction, corticosteroid use, or history of malignancy. It could be incorporated into clinical models to predict patient outcome and to aid in the selection of patients for cardiac transplantation.

Usefulness of the lymphocyte concentration as a prognostic marker in coronary artery disease.

The prognostic utility of the relative lymphocyte concentration was tested in a population-based study of chronic coronary artery disease. This inexpensive, readily available test was found to be significantly related to survival (p = 0.03) in 211 patients followed for a mean of 45 months.