13th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 1998

January 24-31, 1998
Marilleva, Trento, Italy

RT-237

Dual chamber pacing with optimized AV delay in congestive heart failure patients: 6th month results of a randomized study

S. Mangiameli, D. Castelli, G. Doria, P. Lo Giudice, G. Chiaranda and ISSC Group.
Divisione di Cardiologia, Ospedale Garibaldi, Catania, Italy

The ISSC study

The Italian Study on Stimulation in Cardiomyopathy (ISSC) provided the enrolment of a large number of patients affected by chronic heart failure due to coronary artery disease, idiopathic dilated cardiomyopathy or hypertensive cardiomyopathy with a left ventricular ejection fraction < 25% and a mitral regurgitation time > 50% of the R-R interval, who were followed for 2 years^10,11.

The randomization created 2 groups of patients: subjects with optimal pharmacological therapy and patients with the same therapy associated with sequential pacing with shortened optimized AV interval. The optimized AV interval was defined as the specific programmed AV delay which resulted in the minimal mitral regurgitation time that did not reduce the cardiac output during paced ventricular rhythm. We associated to the paced group enrolled for the ISSC, a group of paced patients with the same clinical and hemodynamic enrolment characteristics but not randomized, reaching a total of 26 subjects, and then evaluated the clinical and hemodynamic outcome in 4 subsets: patients with an echocardiographic pattern of altered relaxation represented by an E/A ratio < 1 at echo-doppler curve (Group 1) versus subjects with restrictive pattern represented by an E/A ratio > 2 (Group 2); patients with a PR interval „ 200 ms (Group 3) versus patients with a PR interval < 200 ms (Group 4).

Twenty-one patients of Groups 1 (11 patients) and 2 (10 patients) reached the 1-month follow-up and 12 (7 patients of group 1) reached the 6-month follow-up, while groups 3 (11 patients) and 4 (9 patients) were analyzed only at the 6-month follow-up; the subjects with an E/A ratio between 1 and 2 were not considered. In table I it appears that in Group 1 the arterial blood pressure deteriorated significantly while NYHA functional Class, energy and activity scores are equally and significantly improved at the 1-month follow-up. The echocardiographic parameters, except left atrium diameter, diastolic left ventricular diameter and cardiac output, were significantly improved.

In Group 2 (Tab. I) none of the clinical and echocardiographic data improved significantly.

In table II (6-month follow-up) it appears that in Group 1 the arterial blood pressure deteriorated too, but not significantly, and that the NYHA functional Class and the activity score improved too, but not significantly; the outcome of the other echocardiographic data was like the first month of follow-up.

No significant improvement in the clinical and echocardiographic parameters was found in Group 2 at the 6-month follow-up (Tab. II).

As illustrated in table III, we did not find any significant improvement in the Group 3 patients (PR > 200 ms) except for the systolic left ventricular diameter and the mitral regurgitation time. The Group 4 patients showed a significant improvement in all the data except the arterial blood pressure, the NYHA functional Class and the diastolic left ventricular diameter (Tab. III).

TABLE I - Clinical and hemodynamic outcome for Groups 1 and 2
at 1 month follow-up

ABP = arterial blood pressure; NYHA = New York Heart Association functional Class; LAD = left atrial diameter; LVSD = left ventricular systolic diameter; LVDD = left ventricular diastolic diameter; FS = fractional shortening; EF = ejection fraction; CO = cardiac output; MRT = mitral regurgitation time; LVFT = left ventricular filling time; ES = energy score; AS = activity score.

TABLE II - Clinical and hemodynamic outcome for Groups 1 and 2
at 6-month follow-up

ABP = arterial blood pressure; NYHA = New York Heart Association functional Class; LAD = left atrial diameter; LVSD = left ventricular systolic diameter; LVDD = left ventricular diastolic diameter; FS = fractional shortening; EF = ejection fraction; CO = cardiac output; MRT = mitral regurgitation time; LVFT = left ventricular filling time; ES = energy score; AS = activity score.

TABLE III - Clinical and hemodynamic outcome for Groups 3 and 4
at 6-month follow-up

ABP = arterial blood pressure; NYHA = New York Heart Association functional Class; LAD = left atrial diameter; LVSD = left ventricular systolic diameter; LVDD = left ventricular diastolic diameter; FS = fractional shortening; EF = ejection fraction; CO = cardiac output; MRT = mitral regurgitation time; LVFT = left ventricular filling time; ES = energy score; AS = activity score.