Sven A. Tulner

Hemodynamic Effects of Long-Term Cardiac Resynchronization Therapy Analysis by Pressure-Volume Loops

Background— Acute hemodynamic effects of cardiac resynchronization therapy (CRT) were reported previously, but detailed invasive studies showing hemodynamic consequences of long-term CRT are not available. Methods and Results— We studied 22 patients scheduled for implantation of a CRT device based on conventional criteria (New York Heart Association class III or IV, left ventricular [LV] ejection fraction <35%, left bundle-branch block, and QRS duration >120 ms). During diagnostic catheterization before CRT, we acquired pressure-volume loops using conductance catheters during atrial pacing at 80, 100, 120, and 140 bpm. Studies were repeated during biventricular pacing at the same heart rates after 6 months of CRT. Our data show a significant clinical benefit of CRT (New York Heart Association class change from 3.1±0.5 to 2.1±0.8; quality-of-life score change from 44±12 to 31±16; and 6-minute hall-walk distance increased from 260±149 to 396±129 m; all P<0.001), improved LV ejection fraction (from 29±10% to 40±13%, P<0.01), decreased end-diastolic pressure (from 18±8 to 13±6 mm Hg, P<0.05), and reverse remodeling (end-diastolic volume decreased from 257±67 to 205±54 mL, P<0.01). Previously reported acute improvements in LV function remained present at 6 months: dP/dtmax increased 18%, −dP/dtmin increased 13%, and stroke work increased 34% (all P<0.01). Effects of increased heart rate were improved toward more physiological responses for LV ejection fraction, cardiac output, and dP/dtmax. Moreover, our study showed improved ventricular-arterial coupling (69% increase, P<0.01) and improved mechanical efficiency (44% increase, P<0.01). Conclusions— Hemodynamic improvements with CRT, previously shown in acute invasive studies, are maintained chronically. In addition, ventricular-arterial coupling, mechanical efficiency, and chronotropic responses are improved after 6 months of CRT. These findings may help to explain the improved functional status and exercise tolerance in patients treated with CRT.

Clinical and Functional Effects of Restrictive Mitral Annuloplasty at Midterm Follow-Up in Heart Failure Patients

BACKGROUND Restrictive mitral annuloplasty (RMA) is increasingly applied to treat functional mitral regurgitation in heart failure patients. Previous studies indicated beneficial clinical effects with low recurrence rates. However, the underlying pathophysiology is complex and outcome in terms of left ventricular function is not well known. We investigated chronic effects of RMA on ventricular function in relation to clinical outcome. METHODS Heart failure patients (n = 11) with severe mitral regurgitation scheduled for RMA were analyzed at baseline (presurgery) and midterm follow-up by invasive pressure-volume loops, using conductance catheters. Clinical performance was evaluated by New York Heart Association class, quality-of-life-score, and 6-minute hall-walk-test. RESULTS All patients were alive without recurrence of mitral regurgitation at follow-up (9.4 ± 4.1 months). Clinical parameters improved significantly (all p < 0.05). Global cardiac function, assessed by cardiac output, stroke volume, and stroke work did not change after RMA. Reverse remodeling was demonstrated by decreased end-systolic and end-diastolic volumes (16% and 11%, both p < 0.001). Systolic function improved, evidenced by increased ejection fraction (0.32 ± 0.05 to 0.36 ± 0.07, p = 0.001) and leftward shift of the end-systolic pressure-volume relation (ESV(100): 116 ± 43 to 74 ± 26 mL, p < 0.001). Diastolic function, however, demonstrated impairment by increased tau (69 ± 13 to 80 ± 14 ms, p < 0.001) and stiffness constant (0.022 ± 0.022 to 0.031 ± 0.028 mL(-1), p = 0.001). CONCLUSIONS Restrictive mitral annuloplasty significantly improved clinical status without recurrence of mitral regurgitation at midterm follow-up in patients with heart failure. Hemodynamic analyses demonstrated significant reverse remodeling with unchanged global function and improved systolic function, but some signs of diastolic impairment. Overall, RMA appears an appropriate therapy for patients with dilated cardiomyopathy and functional mitral regurgitation.

Haemodynamics and left ventricular function in heart failure patients: Comparison of awake versus intra-operative conditions

Heart failure patients are increasingly subjected to surgery. Left ventricular (LV) function is generally assessed in awake patients, but intra‐operative LV function is not well studied.

Response to Letter Regarding Article, “Hemodynamic Effects of Long-Term Cardiac Resynchronization Therapy: Analysis by Pressure-Volume Loops”

BACKGROUND Acute hemodynamic effects of cardiac resynchronization therapy (CRT) were reported previously, but detailed invasive studies showing hemodynamic consequences of long-term CRT are not available. METHODS AND RESULTS We studied 22 patients scheduled for implantation of a CRT device based on conventional criteria (New York Heart Association class III or IV, left ventricular [LV] ejection fraction <35%, left bundle-branch block, and QRS duration >120 ms). During diagnostic catheterization before CRT, we acquired pressure-volume loops using conductance catheters during atrial pacing at 80, 100, 120, and 140 bpm. Studies were repeated during biventricular pacing at the same heart rates after 6 months of CRT. Our data show a significant clinical benefit of CRT (New York Heart Association class change from 3.1+/-0.5 to 2.1+/-0.8; quality-of-life score change from 44+/-12 to 31+/-16; and 6-minute hall-walk distance increased from 260+/-149 to 396+/-129 m; all P<0.001), improved LV ejection fraction (from 29+/-10% to 40+/-13%, P<0.01), decreased end-diastolic pressure (from 18+/-8 to 13+/-6 mm Hg, P<0.05), and reverse remodeling (end-diastolic volume decreased from 257+/-67 to 205+/-54 mL, P<0.01). Previously reported acute improvements in LV function remained present at 6 months: dP/dtmax increased 18%, -dP/dtmin increased 13%, and stroke work increased 34% (all P<0.01). Effects of increased heart rate were improved toward more physiological responses for LV ejection fraction, cardiac output, and dP/dtmax. Moreover, our study showed improved ventricular-arterial coupling (69% increase, P<0.01) and improved mechanical efficiency (44% increase, P<0.01). CONCLUSIONS Hemodynamic improvements with CRT, previously shown in acute invasive studies, are maintained chronically. In addition, ventricular-arterial coupling, mechanical efficiency, and chronotropic responses are improved after 6 months of CRT. These findings may help to explain the improved functional status and exercise tolerance in patients treated with CRT.

738 Quantification of mechanical dyssynchrony and non-uniform left ventricular mechanical function by conductance catheter in heart failure patients

from rats fed a diet containing alcohol, rates of protein synthesis were assessed in vivo. The global rate of protein synthesis was reduced by 30% (P<0.05) in hearts from animals consuming alcohol compared with pair-fed controls. We conclude that defects in protein metabolism in animals consuming a diet containing alcohol may contribute to reduced LV function through changes in the mass of the ventricle. (Suppored by NIH grant NIAAA12814)