<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><FONT class="Apple-style-span" face="Arial">Dr. Leonid Makarov from Russia asks</FONT><DIV><FONT class="Apple-style-span" face="Arial"><BR class="khtml-block-placeholder"></FONT></DIV><DIV><DIV><DIV><DIV class="MsoNormal"><FONT class="Apple-style-span" face="Arial">- If there was a need to perform ECG screening in the healthy population to detect patients in high risk of noncoronary arrhythmogenic sudden death, which and how many electrocardiographic signs would you use for this purpose?</FONT><DIV><DIV><P class="MsoNormal"><FONT class="Apple-style-span" face="Arial">Dr. Wojciech Zareba from U.S.A. answers</FONT></P><P class="MsoNormal"><FONT class="Apple-style-span" face="Arial">- Identification of the SCD risk in general population is of major interest and there is no single test that could be considered as a gold standard due to a complexity of mechanisms leading to SCD. ECG screening is an attractive and easily obtained option. In particular, a standard 12-lead ECG could be considered useful. Evaluating step-by-step prognostic information coming from an ECG, one has to focus first on:
</FONT></P><P class="MsoNormal"><FONT class="Apple-style-span" face="Arial">1. Rhythm – presence of non-sinus rhythm in otherwise healthy population is rather infrequent, nevertheless, in cohorts of elderly healthy it is likely to find at least few percent of subjects with undiagnosed atrial fibrillation. Atrial fibrillation is first risk factor which is associated with an increased (at least 2-fold) risk of cardiac death and increased risk of SCD.
</FONT></P><P class="MsoNormal"><FONT class="Apple-style-span" face="Arial">2. Rate of heart rate – tendency to resting tachycardia, especially >80bpm usually indicates additional underlying medical problem and should also be considered as a risk factor. The association between elevated resting heart rate and mortality is observed in postinfarction patients and patients with heart failure, but data on healthy subjects are less convincing. Increased heart rate should prompt physicians to investigate further the reason for this finding.
</FONT></P><P class="MsoNormal"><FONT class="Apple-style-span" face="Arial">3. QRS – conduction abnormalities, namely left bundle branch block, are associated with increased risk of cardiac events and SCD in healthy cohorts with hazard ratios >2.0. Data on RBBB do not show significant association with mortality. QRS prolongation is associated with increased risk of death and SCD in healthy cohorts. LVH is of lesser prognostic importance assuming that QRS duration is analyzed.
</FONT></P><P class="MsoNormal"><FONT class="Apple-style-span" face="Arial">4. QT-T wave – repolarization parameters are considered as an important marker of increased risk in healthy subjects. Elevated QTc (>0.44 sec) in healthy cohort, especially in elderly subjects, was reported to be associated with significantly increased risk of cardiac death and SCD. Abnormal T wave morphology (usually inverted or flat T wave or abnormal T wave axis) also serves as a sign of increased risk for cardiac death and SCD in cohorts of healthy subjects. </FONT></P><P class="MsoNormal"><FONT class="Apple-style-span" face="Arial">Therefore patients with atrial fibrillation and those in sinus rhythm with wide QRS complex (LBBB) or patients with abnormal repolarization (either prolonged QTc or abnormal T wave morphology) are at increased risk of cardiac death and SCD. Such subjects identified in the screening process require further attention to elucidate causes of the abnormalities and to consider preventive/therapeutic measures. </FONT></P><P class="MsoNormal"><FONT class="Apple-style-span" face="Arial">It is worth adding that exercise ECG testing with analysis of heart rhythm recovery (difference between heart rate at peak exercise and heart rate at 1-minute recovery) seems to be useful in identifying high-risk healthy individuals. The heart rate recovery <12bpm was reported as indicator of SCD in healthy cohorts.</FONT></P><DIV class="MsoNormal"><FONT class="Apple-style-span" face="Arial">Electrocardiology has a limited option in identifying patients with a vulnerable plaque, and ischemic incidents are the major causes of SCD. Therefore, the above screening should be combined with additional measures reflecting an increased risk of atherosclerotic changes including lipid profile and some inflammatory markers (sedimentation rate, CRP, etc…) while we are awaiting novel more specific markers of plaque vulnerability.</FONT></DIV></DIV></DIV></DIV></DIV></DIV><FONT class="Apple-style-span" face="Arial"><BR></FONT><DIV><DIV><FONT class="Apple-style-span" face="Arial">--</FONT></DIV><DIV><FONT class="Apple-style-span" face="Arial">Dr. Sergio Dubner</FONT></DIV><DIV><FONT class="Apple-style-span" face="Arial">President of Scientific Committee</FONT></DIV><DIV><FONT class="Apple-style-span" face="Arial"><BR></FONT></DIV><DIV><FONT class="Apple-style-span" face="Arial">Dr. Edgardo Schapachnik</FONT></DIV><DIV><FONT class="Apple-style-span" face="Arial">President of Steering Committee</FONT></DIV><DIV><FONT class="Apple-style-span" face="Arial"><BR class="khtml-block-placeholder"></FONT></DIV><DIV><FONT class="Apple-style-span" face="Arial"><BR class="khtml-block-placeholder"></FONT></DIV><FONT class="Apple-style-span" face="Arial"><BR class="Apple-interchange-newline"></FONT></DIV><FONT class="Apple-style-span" face="Arial" size="3"><SPAN class="Apple-style-span" style="font-size: 13px;"><BR></SPAN></FONT></DIV></BODY></HTML>