Feasibility, safety, and mid-term efficacy of cardiac resynchronization therapy in patients with severe heart failure and ventricular conduction delay: Chulalongkorn experience.

BACKGROUND: Heart failure is a major and growing public health problem in developed and developing countries. Despite major advances in medical therapy, morbidity and mortality remain high. Cardiac resynchronization therapy (CRT) has been proposed as an adjunctive therapy in patients with drug-refractory heart failure and ventricular conduction delay. Short and long-term studies have demonstrated the clinical benefits of CRT. OBJECTIVE: The present study was designed to assess the feasibility, safety, and mid-term efficacy of CRT in patients with severe heart failure and ventricular conduction delay in the institute. MATERIAL AND METHOD: Ten patients with severe heart failure in New York Heart Association (NYHA) functional class III or IV with left ventricular ejection fraction (LVEF) < 35%, QRS duration >120 ms with left bundle branch block morphology received CRT At baseline, and 6 months after implantation, the following parameters were evaluated: NYHA class, QRS duration, LVEF N-terminal pro-brain natriuretic peptide (NT-pro BNP) level, 6-minute walking distance, SF-36 quality-of-life (QOL) score, and number of heart failure visit. RESULTS: All clinical parameters improved significantly at 6 months. NYHA class decreased from 3.5 +/- 0.5 to 2.4 +/- 0.7 (p < 0.01). QRS duration decreased from 145 +/- 22 ms to 126 + 6 ms (p < 0.01). LVEF increasedfrom 21 +/- 6% to 31 +/- 12% (p < 0.01). NT-pro BNP level decreased from 2503 +/- 1953 pg/ml to 767 +/- 342 pg/ml (p < 0.01). The 6-minute walking distance increased from 153 +/- 122 m to 278 +/- 128 m (p < 0.01). QOL score improved from 66 +/- 14 to 98 +/- 25 (p < 0. 01). The number of heart failure visits was reduced from 3.8 +/- 3.7 per year to 0.5 +/- 0.8 visit per year (p < 0.01). Seventy percent of patients were free of heart failure visit for one year after implantation. One patient had sudden cardiac death eleven months after implantation. There was no procedure-related mortality. One patient had left ventricular lead dislodgement 3 months after implantation. CONCLUSION: In the present study, CRT was safe and effective in improving heart failure symptom, functional status, LV function, and quality of life. CRT also reduced heart failure hospitalization in the presented severe heart failure and ventricular conduction delay patients.

Linkage analyses and SCN5A mutations screening in five sudden unexplained death syndrome (Lai-tai) families.

Sudden Unexplained Death Syndrome (SUDS) (or in Thai Lai-tai) share the same ECG pattern as Brugada Syndrome: RSR' and ST segment elevation in V1 to V3. Brugada Syndrome is a genetic disorder with the inheritance pattern of autosomal dominant (using the ECG pattern and unexplained sudden death as phenotype) and the cardiac sodium channel gene (SCN5A) mutations caused this syndrome. To determine whether SUDS was associated with the same mutations as Brugada Syndrome, the authors performed a linkage studies on 5 SUDS families with the Brugada Syndrome ECG pattern and found one family could not be excluded from linkage to SCN5A. However, the direct sequencing in 8 reported mutations on exon 5, 12, 17, 18 and 28 in this family failed to demonstrate the mutations. It was concluded that SUDS mutations maybe a novel mutation different from previously reported mutations, further genetic studies in SCN5A and other candidate genes might elucidate the molecular basis of SUDS.