Disopyramide in hypertrophic cardiomyopathy. I. Hemodynamic assessment after intravenous administration

Disopyramide improves the balance between myocardial oxygen supply and demand in patients with hypertrophic obstructive cardiomyopathy

We evaluated the effects of disopyramide in terms of the balance between myocardial oxygen supply and demand in patients with hypertrophic obstructive cardiomyopathy (HOCM). The myocardial oxygen supply was evaluated by measuring coronary flow velocity and the myocardial oxygen demand was assessed by the pressure-volume area (PVA). The time velocity integral of coronary flow did not change significantly (20 +/- 6 to 21 +/- 8 cm), but the peak left ventricular pressure and left ventricular external work decreased significantly (206 +/- 44 to 157 +/- 37 mmHg, P < 0.001; 1.09 +/- 0.33 to 0.80 +/- 0.23 J/beat, P < 0.001) after disopyramide administration. From theoretical analysis using these data, we concluded that disopyramide improves the myocardial oxygen supply-demand balance in patients with HOCM.

Hypertrophic cardiomyopathy. Clinical spectrum and treatment

HCM is a heterogeneous disease genotypically, phenotypically, pathophysiologically, clinically, and therapeutically. In decisions on the management of these patients, it is important to recognize this heterogeneity and to direct therapy at the predominant abnormalities.

Salutary effect of disopyramide on left ventricular diastolic function in hypertrophic obstructive cardiomyopathy

OBJECTIVES

The purpose of this study was to estimate the effect of disopyramide on left ventricular diastolic function in patients with hypertrophic obstructive cardiomyopathy.

BACKGROUND

Although disopyramide has been reported to lessen clinical symptoms in patients with hypertrophic obstructive cardiomyopathy, few data exist regarding its effect on diastolic function in these patients.

METHODS

Thirteen patients with hypertrophic cardiomyopathy (six with and seven without left ventricular outflow obstruction) were examined. Before and after intravenous disopyramide, hemodynamic and angiographic studies were performed.

RESULTS

In patients with outflow obstruction, pressure gradient at the outflow tract decreased from a mean +/- SD of 100 +/- 45 to 26 +/- 33 mm Hg (p < 0.01). Although systolic function was similarly impaired in both groups, the time constant of left ventricular pressure decay (tau) shortened from 56 +/- 10 to 44 +/- 8 ms (p < 0.01) and the constant of left ventricular chamber stiffness (kc) decreased from 0.049 +/- 0.017 to 0.038 +/- 0.014 m2/ml (p < 0.01) only in patients with outflow obstruction. Shortening in tau correlated best with decrease in left ventricular systolic pressure (r = 0.84, p < 0.01). In contrast, tau was prolonged from 52 +/- 10 to 64 +/- 11 ms (p < 0.01) and kc was unchanged in patients without outflow obstruction.

CONCLUSIONS

The primary effects of disopyramide on the hypertrophied left ventricle were negative inotropic and negative lusitropic. However, left ventricular diastolic properties in patients with outflow obstruction were improved with a decrease in outflow pressure gradient. Relief of clinical symptoms in hypertrophic obstructive cardiomyopathy with disopyramide might be due in part to improvement of diastolic function, which appears secondary to the reduction in ventricular afterload.

Acute dose-response effects of intravenous disopyramide in hypertrophic obstructive cardiomyopathy

To evaluate the acute hemodynamic effects of intravenous disopyramide in hypertrophic obstructive cardiomyopathy (HOCM), 25 patients (12 men, 13 women) with an average age of 40 years (range 18 to 70 years) were evaluated while undergoing cardiac catheterization-angiography. Biplane left ventricular angiography was performed with standard intracardiac-systemic hemodynamics, including resting and provoked (after ventricular premature beat) left ventricular outflow tract gradients, by using simultaneous LV and aortic pressures as disopyramide was being administered (total dose 100 mg, bolus 10 mg every 3 minutes). Average baseline thermodilution cardiac output equalled 4.5 +/- 1.2 L/min, with all 25 subjects demonstrating systolic anterior motion of the mitral apparatus (mild, 3 [12%]; moderate, 8 [32%]; severe, 14 [64%]). Although heart rate originally slowed during disopyramide administration, average heart rate increased during the final stages (before, 78 +/- 15 vs after, 82 +/- 13 beats/min; p < 0.05). Systemic aortic pressures increased during intravenous disopyramide (before, 107 +/- 21/71 +/- 19 mm Hg vs after, 120 +/- 28/81 +/- 13 mm Hg; p < 0.05), with a decline in LV end-diastolic pressure (before, 19 +/- 7 vs after, 16 +/- 6 mm Hg; p < 0.01). Maximum LV systolic pressures decreased (before, 193 +/- 32 vs after, 146 +/- 29 mm Hg; p < 0.01), with a substantial reduction in resting LV outflow tract gradients (before, 86 +/- 34 vs after, 27 +/- 20 mm Hg; p < 0.001) in conjunction with less inducible obstruction (before, 124 +/- 33 vs after, 64 +/- 33 mm Hg; p < 0.001). Only minor electrocardiographic changes were seen during disopyramide infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Unilateral pulmonary oedema in a patient with hypertrophic cardiomyopathy and severe narrowing of the left pulmonary artery

A patient with hypertrophic cardiomyopathy developed unilateral right sided pulmonary oedema. Pulmonary angiography showed a proximal severe narrowing of the left pulmonary artery.

Disopyramide in hypertrophic cardiomyopathy. II. Noninvasive assessment after oral administration

The effects of oral disopyramide 150 mg 4 times a day were compared with propranolol 40 mg 4 times a day and placebo in 10 patients with hypertrophic cardiomyopathy and resting obstruction (7 patients) or latent obstruction (3 patients), in a randomized double-blind crossover design; each drug was given for a period of 4 days. As determined from echocardiographic evaluation of systolic anterior motion of the mitral valve, the subaortic pressure gradient was decreased from 61 +/- 20 mm Hg with placebo to 5 +/- 15 mm Hg with disopyramide (p less than 0.01), and 30 +/- 30 mm Hg with propranolol (p less than 0.01). Disopyramide was more effective than propranolol (p less than 0.01). Disopyramide and propranolol both shortened left ventricular ejection time from 352 +/- 51 ms with placebo to 314 +/- 26 and 322 +/- 41 ms, respectively (p less than 0.01). Preejection period was lengthened from 93 +/- 35 ms with placebo to 119 +/- 25 ms with disopyramide, but was unchanged by propranolol at 98 +/- 23 ms. Disopyramide increased exercise duration versus placebo (10.4 +/- 2 vs 9.6 +/- 2 minutes, respectively (p less than 0.05), whereas propranolol produced no significant change (8.8 +/- 2 minutes).