Prevalence of Pathogenic Gene Mutations and Prognosis Do Not Differ in Isolated Left Ventricular Dysfunction Compared With Dilated Cardiomyopathy.

BACKGROUND: Genetic evaluation is recommended in patients with unexplained dilated cardiomyopathy (DCM), but its diagnostic yield and prognostic relevance in unexplained isolated left ventricular dysfunction (LVdys) is unknown. METHODS AND RESULTS: A total of 127 LVdys and 262 DCM patients underwent genetic screening. Long-term outcome consisted of a combined end point of life-threatening arrhythmia, heart transplantation, and death. At baseline, LVdys patients were younger and had less frequently New York Heart Association class ≥3 when compared with DCM (55±13 versus 58±12; P=0.019 and 21% versus 36%; P=0.003, respectively). The prevalence of familial disease and pathogenic mutations was similar in LVdys and DCM (45% versus 40%; P=0.37 and 19% versus 17%; P=0.61, respectively). After a follow-up of 56 (31-82) months, outcome did not differ in LVdys compared with DCM patients (hazard ratio, 0.83; 95% confidence interval, 0.47-1.45; P=0.51). Overall, outcome was less favorable in patients with a genetic mutation or familial disease when compared with those without (hazard ratio, 2.7; 95% confidence interval, 1.07-7.7; P=0.048 and hazard ratio, 2.2; 95% confidence interval, 1.2-4.2; P=0.013, respectively). Thus, the diagnostic yield of genetic testing in LVdys and DCM is similarly high. The presence of a gene mutation or familial predisposition results in an equally worse prognosis. CONCLUSIONS: Genetic evaluation is advised in LVdys patients and should not merely be restricted to DCM.

The value of the 12-lead ECG for evaluation and optimization of cardiac resynchronization therapy in daily clinical practice.

Based on existing literature and some new data we propose a simple three-step strategy using the standard 12-lead ECG for patient selection and optimal delivery of cardiac resynchronization therapy (CRT). (1) Complete LBBB with regard to the indication for CRT can probably best be identified by a QRS duration of ≥ 130 ms for women and ≥ 120 ms for men with the presence of mid-QRS notch-/slurring in ≥ 2 contiguous leads of V1, V2, V5, V6, I and aVL. (2) Left ventricular (LV) free wall pacing should result in a positive QRS complex in lead V1, with estimation of the exact LV lead position in the circumferential and apico-basal direction using lead aVF and the precordial leads, respectively. Wide and fractionated LV-paced QRS complexes may indicate pacing in scar tissue. (3) Atrioventricular and interventricular stimulation intervals may be optimized by adjusting them until precordial leads show fusion patterns between left and right ventricular activation wavefronts in the QRS complex.