Evaluation Of Cardiac Mechanical Dyssynchrony In Patients With Congestive Heart Failure By Tissue Doppler Imaging

Objective To determine the prevalence of interventricular and intraventricular mechanical dyssynchrony in patients with congestive heart failure (CHF), to assess whether or not mechanical dyssynchrony is related to QRS duration or to the other factors, to evaluate the relationship between interventricular and intraventricular dyssynchrony,and to optimize selection criteria of patients for receiving CRT in order to improve response of CRT.Methods Eighty-one patients with CHF who met the Framingham criteria were included in this study,as well as 26 healthy adults recruited as control group.Patients with CHF were divided into 2 groups:systolic heart failure(SHF,n=39)and diastolic heart failure(DHF,n=41)(1 CHF patient was not grouped).Standard echocardiography and color-tissue Doppler imaging (C-TDI) were performed.Using IVMD>33 ms by conventional Doppler echocardiography,and TsO-diff>47ms,or TsP-diff>95ms by C-TDI were defined as interventricular dyssynchrony.Using TsO-longest delay >70ms,or TsO-SD >31ms,or TsP-longest delay >121ms,or TsP-SD >47ms by C-TDI were defined as intraventricular systolic dyssynchrony.Using TeO-longest delay >102ms,or TeO-SD>39ms,or TeP-longest delay >75ms,or TeP-SD>26ms by C-TDI were defined as intraventricular diastolic dyssynchrony. Echocardiographic variables, prevalence of interventricular and intraventricular mechanical dyssynchrony in patients with CHF including with SHF and DHF were compared with the control group.Relationships of QRS duration and other factors to echocardiographic parameters were analyzed. Results1 Assessment of interventricular dyssynchrony(1)Using conventional Doppler echocardiography: IVMD was longer in HF group than in control group(25.7±16.3ms vs 12.8±8.8ms, p<0.0001). Significant positive correlation was found between IVMD and QRS duration (r=0.44,p<0.0001). The prevalence of interventricular dyssynchrony in HF patients with QRS duration≥120 ms was higher than with QRS duration <120ms (66.7% vs 20.9%, p<0.05).A considerable percentage of patients with QRS duration <120ms also showed interventricular dyssynchrony (20.9%).The prevalence of interventricular dyssynchrony in HF patients was significantly higher than in control group (33.3% vs 3.8%, p<0.01). The SHF group had comparable interventricular dyssynchrony than the DHF group (34.8% vs 29.0%, p=NS).(2)Using C-TDI:①Assessment of interventricular systolic dyssynchrony: The prevalence of interventricular systolic dyssynchrony in HF patients was significantly higher than in control group(31.5% vs 4.3%, p<0.05). The SHF group had comparable interventricular systolic dyssynchrony than the DHF group (34.8% vs 29.0%, p=NS). A positive correlation was found between TsO-diff and QRS duration (r=0.37, p<0.01).②A ssessment of interventricular diastolic dyssynchrony: TeO-diff,TeP-diff were longer in HF group than in control group (TeO-diff:62.4±59.0ms vs 25.4±23.8ms, p<0.01;TeP-diff:66.9±58.1ms vs 36.9±33.8ms, p<0.05, respectively). Positive correlations were found between TeO-diff, TeP-diff and QRS duration (r=0.36, p<0.01, for all).③There was poor agreement between standard echocardiography and C-TDI for diagnosing interventricular dyssynchrony(Kappa<0.4).2 Assessment of left intraventricular dyssynchrony(1) All echocardiographic variables of intraventricular systolic and diastolic dyssynchrony except TsO-longest delay were significantly longer in HF group than in control group. (2) The SHF group had similar normal synchrony, isolated systolic dyssynchrony, isolated diastolic dyssynchrony, combined systolic dyssynchrony and diastolic dyssynchrony with the DHF group (mostly p=NS).(3)No significant relations were found between QRS duration and intraventricular dyssynchrony variables in SHF and DHF group. All echocardiographic variables of intraventricular systolic and diastolic dyssynchrony except TsO-longest delay were significantly longer in HF patients with QRS duration≥120 ms than with QRS duration <120 ms. (4) The relations between intraventricular systolic dyssynchrony variables: Positive relations were found between TsO-longest delay and TsO-SD, between TsP-longest delay and TsP-SD, between TsO-longest delay and TsP-longest delay, and between TsO-SD and TsP-SD, respectively. The relations between intraventricular diastolic dyssynchrony variables: Positive relations were found between TeO-longest delay and TeO-SD,between TeP-longest delay and TeP-SD,between TeO-longest delay and TeP-longest delay,between TeO-SD and TeP-SD, respectively.3 The relationships between interventricular and intraventricular dyssynchrony variables: No significant relations were found between IVMD and TsO-longest delay, between IVMD and TsP-longest delay, between IVMD and TsP-SD, respectively. Weak relations were found between IVMD and TsO-longest delay, between TsO-diff and TsO-longest delay, between TsO-diff and TsO-SD, respectively. No significant relations were found between TsP-diff and TsP-longest delay, between TsP-diff and TsP-SD, between TeO-diff or TeP-diff and interventricular diastolic dyssynchrony variables, respectively.Conclusions1 The prevalence of interventricular and intraventricular mechanical dyssynchrony in HF patients were significantly higher than in control group by conventional Doppler echocardiography and C-TDI.2 No significant relations were found between the prevalence of interventricular systolic dyssynchrony and the cause of heart disease, NYHA class, and HF type, respectively. There were significant relations between IVMD and QRS duration, between TsO-diff and QRS duration, respectively.The prevalence of interventricular mechanical dyssynchrony expressed by IVMD in HF patients with QRS≥120ms was significantly high. But a considerable percentage of patients with normal QRS duration also showed interventricular dyssynchrony.3 There is a poor agreement between standard echocardiography and C-TDI for diagnosing dyssynchrony. But it is not sure which one may be better.4 No significant relations were found between the prevalence of intraventricular systolic dyssynchrony and QRS duration regardless of SHF or DHF. It remains to be confirmed whether or not intraventricular diastolic dyssynchrony is related to left ventricle mass index (LVMI).5 Positive relations were found between intraventricular systolic dyssynchrony variables,between intraventricular diastolic dyssynchrony variables,respectively.It is suggested that either TsO or TsP may be selected , either TsO- longest delay or TsO-SD may be used while evaluating intraventricular systolic dyssynchrony. Either TeO or TeP may be selected , either TeO- longest delay or TeO-SD may be used while evaluating intraventricular diastolic dyssynchrony.6 Both standard echocardiography and TDI are necessary to describe the entire spectrum of intraventricular and interventricular dyssynchrony while evaluating mechanical dyssynchrony since no significant relations or only weak relations were found between variables of interventricular and intraventricular dyssynchrony.